PROCESS AND APPARATUS FOR MANUFACTURING A CUTTING TOOL BY PRESSING

TECHNICAL FIELD

The present invention relates to a process for manufacturing a cutting tool, a precursor cutting tool, a blank, and/or a cutting tool insert, to cutting tools, precursors, blanks and inserts obtained by the process and to an apparatus for conducting the process.

BACKGROUND ART AND PROBLEMS SOLVED BY THE INVENTION

Cutting tools such as end mills are typically manufactured by feeding a granulated material, such as a metal and/or carbide powder, into an extruder for pressing and extruding rods, hydrogen de-waxing, sintering, cutting, centerless grinding, flute grinding and coating. Different steps may be conducted by different manufacturers. The step-of dewaxing is typically conducted in a hydrogen furnace, and sintering in an HIP (hot isostatic pressing) furnace. In some cases, the flutes are subjected to honing before cleaning and coating.

The cutting edges or flutes of the cutting tool are formed in the step of grinding the rod so as to obtain desired shape of flutes.

Only few manufacturers have the equipment for producing so-called blanks, which are extruded carbide rods that are already cut to correct length and centerless ground to correct the diameter. Small and mid-sized companies may buy the blanks, conduct the grinding process and coating. This may be conducted by way of a flute grinding machine, which will grind the flutes so as to obtain a specific geometry.

The above way of producing in particular round cutting tools suffers from several disadvantages and limitations. The step of grinding the flutes into the extruded rod or blank results in high amounts of waste material, since a lot of material is cut away from the extruded rod when cutting the flutes or other cutting edges of the cutting tool. In other words, a lot of the starting material is lost due to grinding the flutes into the cutting tool. While it is possible to filter and re-use scrap carbide, it would be advantageous to reduce the amount of the waste material during grinding,

In addition, the flute grinding process is typically a slow process conducted on a relatively expensive grinding machine. So there is a high capital investment for grinding the flutes and the process is costly. In would be advantageous to reduce the costs related to the grinding step.

The energy expenditure of the whole process from extruding up to the production of the final product is very high. It is an objective of the invention to reduce energy costs related to the production of cutting tools.

It is an objective of the present invention to reduce the time, cost and energy expenditure of the manufacturing process by reducing the time of grinding the flutes and loss of material due to grinding.

It is an objective of the invention to produce blanks, which have already the desired length and diameter, and have the flutes already finished or which have pre-flutes or nearly finished flutes already present, such that only a final grinding is necessary to obtain a desired geometry of the finished product. As becomes clear from the above, there is a need for such nearly-finished tools by the small and midsized companies, that do not produce blanks by themselves.

In the prior art, it has been proposed to produce cutting tools by some type of mold-pressing process. For example, US 2010/0090362 discloses an apparatus using a bag made from an elastic material, the bag comprising the mold of a cutting tool. After filling the bag with a powder, it is transferred to a pressure sleeve, which is branched to an isostatic press using high pressure liquid. The pressure liquid applies a generally uniform compressive load to the outer surface of the elastic mold, pressurizing thereby the powder inside the bag. This process seems to comprise several steps, some of which have to be conducted manually, such as fixing top and bottom caps to the bag, transferring the bag to a filling sleeve, transferring the bag to a pressurizing sleeve, for example. Second, US 2010/0090362 does not disclose how cutting tools containing helicoidal or threaded flutes can be obtained using this process.

FR 2 078 131 discloses an apparatus for pressing helical or threaded pinions from metal powders. The apparatus uses two opposed punches containing helicoidal outlines, fitting the helicoidal shape of a mold comprising an inner thread. After filling the mold with a metal powder, the pinion is pressed by rotating the punches while they approach from the top and bottom end into the mold, thereby pressing the pinion obtaining a thread. While this process may be suitable to obtain a pinion characterized by an overall helicoidal outer thread, the process is not suitable for cutting tools. In particular, this document does not disclose how to obtain a cutting tool such as an end mill, the latter requiring a non-helical, frequently cylindrical shank, which is used to hold and locate the cutting tool in the tool holder.

JP H08 260006A concerns a method for manufacturing a drill by displacing a first rotating punch in a mold cavity comprising a shank part and a groove part of the drill. The method proposes to spray a film forming agent onto the pressed preform during extraction, in order to prevent the preform to collapse during extraction from the mold cavity.

US 2016/0229082 discloses a press for making a cutting tool green body using a dye having helical protrusions and two electrical punches simultaneously rotating in order to press the green body. This document addresses the problem of providing two rotating helical punches for the press. In accordance with this disclosure, it is not possible to produce an end mill comprising a shank and a helical region by pressing.

US 2012/0003443 discloses a split case dye for producing a cutting insert. This document does not disclose how to produce an end mill or a drill and teaches separating dye parts in a direction that is non-parallel to the pressing axis to release the part.

The present invention addresses the problems depicted above.

SUMMARY OF THE INVENTION

Remarkably, the present inventors have provided a process for producing cutting tools by pressing, for example by mold-pressing.

In an aspect, the invention provides a process for manufacturing a cutting tool, a blank tool and/or a precursor cutting tool, the process comprising the steps of: providing a mold, wherein said mold, comprises first and second openings; filling an appropriate powder or granulate into said mold; exerting a pressure on said powder, thereby obtaining a pressed cutting tool, a blank tool and/or a precursor cutting tool.

In an aspect, the process comprises providing first and second mold units, joining the mold units to provide a continuous mold of the tool to be produced, filling a powder or granulate into the mold, and pressing the powder or granulate in the mold so as to provide a pressed cutting tool.

In an aspect, the invention provides a process for manufacturing a cutting tool, a blank tool and/or a precursor cutting tool, the process comprising the steps of: providing a first mold unit and a second mold unit, wherein said first mold unit comprises a first mold part or area defining at least part of shank of the tool to be manufactured, wherein said second mold unit comprises a second mold part or area comprising ridges designed to define flutes of the tool to be manufactured, and wherein each of said first and second mold units, respectively, comprises a first opening; forming a mold with said first and second mold units by bringing a first opening of said first mold unit in contact with a first opening of said second mold unit; filling a powdered composition comprising a carbide, ceramic, metal, nitride or cermet powder, or a powder comprising a mixture comprising one, two or more of the aforementioned, into said first and said second mold units; exerting a pressure on said powdered composition, thereby obtaining a pressed cutting tool, a blank tool and/or a precursor cutting tool.

In an aspect, the invention provides an apparatus for conducting the method of the invention. Preferably, the apparatus of the invention is for manufacturing a cutting tool, a blank tool and/or a precursor cutting tool.

In an aspect, the apparatus of the invention comprises a first mold unit comprising a first mold part of the tool to be manufactured; a second mold unit comprising a second mold part of the tool to be manufactured; at least one pressure device arranged for being inserted through an opening of said first and/or second mold units and pressing a powder retained in said mold.

In an aspect, the invention provides an apparatus for manufacturing a cutting tool, a blank tool and/or a precursor cutting tool, the apparatus comprising: a first mold unit comprising a section comprising a first mold part or area defining at least part of a shank of the tool to be manufactured; a second mold unit comprising a second mold part comprising ridges designed to define flutes of the tool to be manufactured; at least one pressure device arranged for being inserted through an opening of said first and/or second mold units and for moving coaxially with an axis of a mold formed by joined mold units, for pressing a powder retained in said mold.

Further aspects and preferred embodiments of the invention are defined herein below and in the appended claims.

Further features and advantages of the invention will become apparent to the skilled person from the description of the preferred embodiments given below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an apparatus according to an embodiment of the present invention.

FIG. 2 A shows various exemplary components of an apparatus according to an embodiment of the present invention.

FIG. 2 B shows an exemplary cutting tool obtainable by the process of the present invention.

FIGS. 3 A and 3 B show an empty and a powder-filled, respectively, filling funnel of the apparatus of FIG. 1.

FIGS. 4A and 4B show longitudinal sections of mold units and a punch of FIG. 2 as arranged at an early stage of the process of an embodiment of the invention.

FIG. 5 is an enlarged view of the mold units of FIG. 4B, filled with a powder.

FIGS. 6 A, 6B and 6C illustrate the pressing of a cutting tool in accordance with an embodiment of the invention.

FIGS. 7 and 8 illustrate the removal of a pressed tool from a mold following the pressing of a cutting tool in accordance with an embodiment of the invention.

FIG. 9 illustrates the ejection of a pressed cutting tool in accordance with an embodiment of the present invention.

FIGS. 10 A and 10 B illustrate the method and apparatus according to a second embodiment of the invention, where a different punch is used for exerting pressure on the powder in the mold.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention relates to a process for manufacturing a cutting tool and to an apparatus or machine for conducting the process.

The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the scope of the invention, its application or uses.

For the purpose of the present specification, the term “comprising” and its various grammatical forms are intended to mean “includes, amongst others”. It is not intended to mean “consists only of”.

FIG. 1 shows an apparatus 100 according to an embodiment of the invention. The apparatus comprises a support, mount or framework 60, on which the mold units 4, 5, and the pressing punches 12, 13 are supported. The apparatus 100 comprises a displacement and positioning arrangement 90, which is configured to displaceably support one or more parts of the apparatus with respect to the framework 60. In an embodiment, one or more selected from the first mold unit 4, the second mold unit 5 and a filling recipient 40 is displaceably positioned by the positioning arrangement 90. In the embodiment shown, the first or lower mold unit 4 is preferably arranged so as to be able to move along an axis of movement of said punches, shown vertically in the figures, and optionally also to move horizontally. In order to render certain parts of the apparatus displaceable, the positioning arrangement 90 may comprise guiding structures or rails 91, 92, 93, on which a particular part or element is displaceably arranged.

In the embodiment shown, the positioning arrangement 90 comprises a first rail or guiding arrangement 94, comprising first rails 91. The first guiding arrangement 94 allows the displacement of a mold unit, here the first mold part 4, along a first axis, which here is the vertical axis 27 (see FIG. 2A).

In the embodiment shown, the positioning arrangement 90 comprises a second rail or guiding arrangement 95, comprising second rails or guiding structures 92, which allow displacement of a mold unit, here the second mold unit 5, to be displaced along a second axis, here a horizontal axis that is perpendicular with respect to the first axis 27.

In the embodiment shown, the positioning arrangement 90 comprises a third rail or guiding arrangement 96, comprising third rails or guiding structures 93, which allow displacement of a powder filling recipient or funnel 40, preferably along a third axis. The filling recipient is preferably arranged so as to be displaceable along a horizontal axis, for example perpendicular with respect to said first and/or second axis.

For the present specification, the terms “first”, “second” and “third” are not necessarily used to imply an order or importance, but are used to distinguish structural elements, some of which may be optional. For example, any one, two or all three of said first, second and third guiding arrangements 94-96 may be absent. The above referenced second guiding arrangement 95 may well be a first and/or only guiding arrangement, for example. It is preferred that at least one mold unit and/or the filling recipient 40 is displaceably arranged.

It is further noted that the guiding arrangements shown are configured to allow displacement along straight, linear axis. In other embodiments, the invention encompasses guiding arrangements allowing displacement of one or more mold units 4, 5 and other structural parts, such as the filling recipient 40, along non-linear axis.

The first and second pressing punches 12, 13 are preferably displaceably arranged on the apparatus 60. The pressing punches are preferably configured so as to be movable along a common axis 27 (FIG. 2A). Preferably, the pressing punches 12, 13 are coaxially arranged and are coaxially movable along a common axis during the process of the invention.

The apparatus 100 of the invention preferably comprises first and second punch holders or fixers 81, 82, in which said pressing punches are fixed. The apparatus preferably comprises pressure generators (not shown), allowing said punches 12, 13 to move while exerting pressure, and or to displace against a certain counter pressure. Preferably, the pressure and counter pressure exerted by said punches 12, 13 can be adjusted.

The apparatus of the invention preferably comprises a data processing unit (not shown), such as a computer, for controlling and conducting the process of the invention. The data processing unit may be used to configure the process steps, to control the timing, speed and sequence of movements of structural parts of the apparatus and the amount of pressure exerted, for example, as well as the activity of the powder compacting entity, such as an ultrasound generator, for example.

In the embodiment shown, the structural parts of the apparatus are arranged so as to have an overall vertical operation mode. The punches 12, 13 are coaxial along a vertical axis, and the mold parts 4, 5 are vertically superposed, one vertically above the other. The vertical arrangement may provide some advantages, for example allowing filling of the molds by gravity and facilitating adjustment and alignment of structural components, such as the mold units and the punches. However, the invention is not meant to be limited to such an overall vertical arrangement. Parts, such as the punches and the molds, may as well be aligned on another axis, for example with respect to a horizontal axis or even a skewed axis, without departing from the concept of the present invention. Preferably, the molds and punches are configured to be positioned coaxially.

The apparatus of the invention preferably comprises propelling means for actively propelling the movement of certain movable components, such as motors, actuators, which may include electric motors or actuators, pneumatic and hydraulic actuators and the like, for example.

FIGS. 2A and 2B show components of an apparatus for conducting the process of the invention as well as an exemplary cutting tool 20 that can be manufactured by way of the process of the invention.

For the purpose of the present specification, the term “cutting tool” is used to refer to any one or all selected from a cutting tool, a blank tool, a cutting tool blank and/or a precursor cutting tool, for example. For example, the “cutting tool” may be a cutting tool blank. As indicated in the introduction, a cutting tool ready for commercialization may be subjected to various steps such as hydrogen de-waxing, sintering, cutting, centerless grinding, flute grinding, honing, cleaning and coating. These known steps are not described in detail in the present specification, but are also encompassed as optional further or complementary process steps of the invention. For the purpose of the present specification, a “cutting tool” is the product obtained by the process disclosed in this specification, optionally further processed so as to be ready for commercialization.

In an embodiment, the cutting tool is selected from an insert and a solid round tool. Solid round tools encompass solid end mills, reamers, drills and thread mills.

In a preferred embodiment, the cutting tool 20 is a milling cutter, preferably an end mill. Preferably, the cutting tool is longitudinal, that is longer than large. It has preferably a longitudinal axis 23.

In a preferred embodiment, said cutting tool, blank tool and/or a precursor cutting tool 20 is a solid round tool, blank solid round tool and/or precursor solid round tool, preferably an end mill, blank end mill or precursor end mill, more preferably a solid end mill, solid blank end mill or solid precursor end mill.

The cutting tool 20 shown in FIG. 2B has an overall essentially rod-like form. Due to its longitudinal, rod-like form, the cutting tool 20 has two extremities, corresponding to the bottom and top ends of the tool 20 as shown in FIG. 2B. Furthermore, the cutting tool preferably comprises two parts or sections, in particular two rod sections 1, 2, which cover at least the first and second extremities of the cutting tool. The first rod section 1 preferably encompasses at least a first extremity of the cutting tool. The first rod section 1 preferably defines or comprises the shank of the cutting tool. The two extremities are preferably present at two opposed sides of the cutting tool. When the cutting tool is used, it is preferably placed in a cutting tool holder at the shank 1 and caused to rotate.

The second rod section 2 preferably encompasses at least a second extremity of the cutting tool. The second rod section preferably comprises flutes and/or flanks 10. The flutes and/or flanks preferably determine geometry of the cutting part of the tool and therefore generally contribute to defining at least part of the cutting properties of the cutting tool. The flutes 10 at the second rod section 2 allow the cutting of an appropriate material by the rotating cutting tool 20.

In a preferred embodiment, said flutes are helicoidal flutes, for example helical flutes.

Furthermore, the cutting tool may comprise additional surface structures as are generally used for cutting tools. Such additional structures may be integrated into the helical-flute section 2, for example on the surface of the helical flute section 2.

The cutting tool preferably comprises and/or consists essentially of a hard material, such as metal, ceramic and/or carbide. In a preferred embodiment, the cutting tool comprises or essentially consists of tungsten carbide. For example, the cutting tool comprises at least 50 wt. %, preferably at least 70 wt. % and more preferably at least 90 wt. % of one selected from the group consisting of metal, cermet, ceramic, nitride or carbide, preferably tungsten carbide.

Some components of the apparatus 100 of the invention are arbitrarily arranged for illustration in FIG. 2A. The apparatus comprises in particular a first mold unit 4 and a second mold unit 5, which mold units are both shown in longitudinal cross section in FIG. 2A.

The mold units 4, 5 are the components that preferably comprise mold parts or areas 14, 15, that is, the parts that contain the shape as a negative or template 14, 15 for the cutting tool 20 to be produced.

As can be seen in FIG. 2A, the first mold unit 4 may be provided in the form of a single piece 4 comprising a longitudinal bore 24. So as to form first and second openings 6, 8 in the mold unit 4. As will be apparent in more detail from the description blow, the mold part or section 14 of said bore 24 comprises the negative or mold area 14 of a part of the cutting tool to be produced. Preferably, the first mold area 14 provides the negative of the shank section 2 of the cutting tool 20 to be produced. The bore 24 is preferably a cylindrical bore having a straight axis 27.

In an embodiment, the duct 24 and the area 14 have the shape of a straight hollow cylinder of a constant cross section along the axis 27 of the duct. The first and second openings 6, 8 are provided at the first and second ends or extremities of the duct 24.

At and close to the first opening 6, the duct 24 defines a first mold area 14. At the second opening 8, the duct forms a punch access opening for the first punch 12. At this opening, the bore 24 preferably has the purpose of guiding the first punch 12 during a pressing operation.

In a preferred embodiment, the mold area 14 and/or the entire bore 24 comprises smooth, regular and/or non-structured surfaces. Preferably, the mold area 14 is substantially free of structures and/or bulging structures emerging from the inner surface defining the mold area 14 and/or the inner lining of the duct 24. Preferably, the duct 24 is free of an inner thread and/or ridges. Preferably, the mold area 14 lacks helicoidal ridges. The presence of ridges would imply that the shape and/or contour of the cross section of the mold area or cavity 14 changes, due to the presence of ridges along the longitudinal axis 27. The smooth surface and absence of bulging structures is preferred for facilitating access of the first pressing punch and for allowing removal of the first mold 4 by a translational movement along axis 27, as described elsewhere in this specification. The above does not exclude the possibility that the duct 24 comprises zones of different diameter. For example, the diameter at the area 14 may be different, for example smaller or larger, than the diameter of duct 24 at the punch access opening 8.

Preferably, the cross section of the bore 24 is a circle having a constant radius along axis 27, such that the bore 24 in the first mold 4 has a hollow cylindrical form. Preferably, the bore 24 is tubular. The invention does not exclude that the duct 24 has another cross-section, such as a polygonal (e.g. rectangular, hexagonal, etc.). The cavity 24 formed by the first mold 4 may thus have the form of a prism, for example.

It is noted that the expressions duct, bore, cavity, and molds are used with reference to the empty space tagged with reference numerals 24, 25 and 26. The different terms are used to emphasize different functions and/or geometrical particularities of the space in question. For example, the terms duct and/or bore may be used to indicate the continuous nature of the empty space across the exemplary mold units 4 and 5, the term cavity generally expresses the fact that a defined empty space is provided and the term mold expresses, generally, that at least part of the empty space provides a mold or negative for the cutting tool to be prepared.

The apparatus of the invention preferably comprises a second mold unit 5. In the embodiment shown, the second mold unit 5 is a mold component assembly. The second mold unit 5 preferably comprises an insert 50, which is fixed or housed in a mold fixing piece 43. The insert 50 preferably comprises the negative or mold area 15 of a part of the cutting tool to be produced. Preferably, the second mold area 15 provides the negative of the flute section 2 of the cutting tool 20 to be produced.

The insert 50 comprises a longitudinal duct 28 the walls of which define the mold area 15 of part of the cutting tool to be produced. In this regard, the surface lining or forming the duct 28 comprises preferably ridges 3 designed to define flutes 10 of the cutting tool to be manufactured.

In a preferred embodiment, said ridges 3 in the mold area 15 are helicoidal, preferably helical ridges, thereby providing the negative or mold for helicoidal flutes 10 on the cutting tool.

The ridges 3 in the second mold area 15 may be compared to, may resemble or may be disposed along the lines of a straight inner thread, providing the female part to the straight outer thread in the second section 2 of the cutting tool 20 to be pressed in accordance with an embodiment. While the expressions inner and outer threads may be employed in this specification, these terms are not used to exclude the generally more complex shapes of the flutes of cutting tools, which need not be symmetrical, and which contribute to defining the cutting geometry and/or cutting properties of the cutting tool 20.

In an embodiment, the ridges 3 comprise and/or provide a straight inner thread, provided in the longitudinal duct 28 of the second mold unit, and in particular in the longitudinal duct 28 of the insert 50.

The insert 50 may fixed in a housing 26 which may be in the form of a bore provided in said holding piece 43, said bore 26 being preferably such that as to allow the longitudinal mold are 15 be positioned coaxially with respect to the mold area 14 of the first mold unit 4. The insert 50 may be fixed rigidly but removably with respect to the holding piece 43 by way of a screw (not shown) extending in a bore 29 provided in said piece 43, said bore 29 preferably comprises an internal threading.

One advantage of providing the second mold part 15 in the form of an insert 50 of the mold unit 5 is that it allows to use the same holding piece 43 for producing cutting tools having different flutes 10. An operator can simply replace a particular insert 50 by another one, the mold area of which 15 defining a different pattern of flutes 10. Furthermore, assuming that the mold area 15 suffers from abrasion during the process of the invention, it can be replaced rapidly and with little cost by a new one.

It is noted that the housing 26 may be provided in the form of a cylindrical bore, but may also be on the form of a hollow, uniform prism, for example having a polygonal cross-section. A non-circular housing, matching a corresponding, non-circular outer lateral surface of the insert 50, may assist in preventing rotation of the insert 50 during the process of the invention.

In the embodiment shown, the piece 43 that holds the mold insert 50 comprises a further or second insert 36, comprising a longitudinal bore or duct 25. The pieces 50 and 36 are preferably coaxially fixed in said piece 43, in particular in a longitudinal hole or bore 26 provided in said piece 43. More specifically, the inserts 50 and 36 are fixed with respect to said piece 43 such that the bore 25 in piece 36 is coaxial and aligned with the longitudinal mold area 15 in the insert 50. Preferably, insert 36 is also removably fixed to the mold fixing piece 43. In this manner, it is possible to change and replace insert 36 if necessary.

It is noted that it would be possible to provide a mold component assembly 5 comprising only one insert 50, such that the duct 25 is directly provided in piece 43 and not provided by a separate insert 36. Furthermore, the entire assembly 5 may be provided in the form of a single piece.

Preferably, the second mold unit 5 comprises a continuous duct 25, 28, which comprises a second opening or punch access region 9 as well as the duct 28 in insert 50. The punch access opening 9 of the duct 25 and the duct 28 at the second mold area 15 are preferably coaxial, so as to form one single, preferably straight duct 25, 28.

The insert 50 is preferably housed in such a manner that duct 28 of the insert 50 is coaxial with the duct 25 of the piece 36 and forms one continuous duct 25, 28 with the latter. The second opening 16 of the insert 50 is thus formed by a terminal opening of the duct 28 of the insert 50. The first opening 7 of insert 50 preferably provides and coincides with the first opening 7 of the second mold unit 5.

For the purpose of the present invention, the separate mold units 4 one the one side and 5 on the other hand, both these units containing their own mold areas 14, 15, respectively, may independently, be provided in the form of a single piece or as an assembly, such as assembly 43, 50, 36 in the case of the second mold unit 5.

In another embodiment in accordance with the aspect where only one mold or one mold assembly is used instead of two separate mold units 4, 5, the mold assembly may also be in the form of a single piece or in the form of an assembly comprising several pieces that are rigidly connected, but may be disassembled, for example.

A unit or assembly comprising one of the two mold parts may thus be referred to as a “mold assembly”, independently from the number of separate pieces use to constitute the arrangement. Together, these first and second mold units 4, 5 can be positioned, provided or oriented one with respect to the other so as to form a complete mold for the cutting tool 20. The mold units 4, 5 may also be considered as partial molds.

Accordingly, a mold unit is preferably considered to be one of two or possibly more elements comprising part of a mold of a cutting tool to be produced. Such mold unit may be provided as a single piece, as said first mold unit 4, or may be formed of several pieces, such as mold unit 5. In the embodiment shown, each mold unit comprises an end-to-end duct, such that each mold unit has at least two openings. An opening of the first mold unit is preferably configured to be joined with an opening of the second mold unit, so as to form a continuous mold 14, 15. Preferably, one or both of the two other openings are preferably used for inserting pressing punches and/or, more generally, for exerting pressure on a powder provided in the continuous mold.

In other embodiments, not shown in the figures, the invention encompasses the use of three or more partial molds 4, 5 or partial mold units to be joined to forming an entire mold of a cutting tool. For example, the invention encompasses three, four, five or more mold parts that can be joined to form a continuous mold for a cutting tool to be produced by pressing.

It is noted that at least one of the two mold units 4, 5 is preferably provided to be displaceable with respect to the other one of the two mold units, such that the two mold units 4, 5 can be joined to form a mold and/or can be separated from each other, allowing for removal of the cutting tool 20 produced in the mold.

The openings 8, 9 provided in the mold units are preferably such as to allow pressing punches 12, 13 to access bores and/or channels 24, 25 provided in the first and second mold units. The bores and/or channels 24, 25, 28 preferably allow the pressing punches 12, 13 to enter the respective bores and/or channels 24, 25, 28 so as to exert a pressure on a powder 30 contained in said bores and/or channels, as will be described elsewhere in more detail.

In FIG. 2A, the first and second pressing punches 12 and 13 are also shown. The first pressing punch 12 comprises a preferably cylindrical punching rod 31, an optional collar 33 and a shank 32. The shank 32 and collar 33 are designed for connecting the pressing punch 12 to a press appropriate to produce a linear pressing movement along an axis, preferably a vertical axis, in order to press the cutting tool as described elsewhere in this specification. For example, an electrically driven press may be used for exerting pressure. As can be seen in FIG. 1, the collar 33 lies upon and abuts on the first punch holder 81, the shank 32 being releasably fixed in said first punch holder, like in a boring socket.

The second pressing punch 13 also comprises a shank 37 and an optional collar 38, for facilitating releasable but rigid fixing to the second punch holder 82 (FIG. 1). The punching rod 39 of the second pressing punch 13 differs from the one of the first pressing punch 12, due to the role of the second pressing punch 13 in relation to the second mold unit 5 comprising the ridges 3. The punching rod 39 comprises a thinned region or stem 41 having a smaller diameter compared to the diameter of the punching rod 31 or the upper part of the punching rod 39. The stem 41 connects the head 22 of the second pressing punch with the larger region of the longitudinal rod 39. The purpose of the thin stem 41 of rod 39 is to allow the head 22 to penetrate into the mold area 15 when pressing and/or ejecting a pressed cutting tool, as will described elsewhere in this specification. The head 22, stem 41, longitudinal rod 39 and the shank 37 of the ejection rod 21 are preferably coaxial.

The head 22 of the second pressing punch preferably comprises cutouts or an straight, outer thread allowing it to move by a linear rotational movement through the helicoidal ridges 3 in the second mold unit 5. Accordingly, either at least head 22 or, as in the embodiment shown, the entire pressing punch 13, is preferably configured to be able to rotate when moving along its axis.

The dimensions of the rods 31, 39, stem 41 and the cutouts in the head 22 are provided in order to enable the punching rods to enter to the respective mold units 4, 5 and/or pieces 43 in a matching, measured manner. The bores and channels 14, 24, 25, 15 are preferably just sufficiently large to let the rods enter without causing any undue friction and abrasion, but without leaving too much space so as to occupy the respective bores and channels in a maximized, optimal manner.

It is also noted that the collars 33, 38 provided on the pressing punches are optional and are preferably provided for facilitating precise positioning of the pressing punches 12, 13 in their respective punch holders 81, 82.

FIGS. 3A and 3B show a powder filling recipient or funnel 40, which is preferably displaceably arranged with respect to the apparatus 100 of the invention. In FIG. 3A, the funnel 30 is empty, but placed in a guiding structure or housing 42. In FIG. 3 B, the funnel is shown when filled with a powder 30. The funnel 40 can be filled with the powder at a particular position on the apparatus and, after filling, can be displaced so as to release the powder at a desired position for filling the molds. The displacement of the funnel 40 and of other movable components of the apparatus, such as the molds 4, 5 is preferably driven actively, for example with a motor or by a pneumatic or hydraulic actuator, and guided by guiding structures 93 (FIG. 1).

In an embodiment, the process of the invention comprises the step of forming a mold by joining and/or releasably connecting two separate mold units 4, 5 or partial mold parts 14, 15.

In an embodiment, the process of the invention comprises the step of forming a mold 14, 15 with said first and second mold units 4, 5 by bringing a first opening 6 of said first mold unit 4 in contact with a first opening 7 of said second mold unit 5.

FIGS. 4A and 4B show a configuration where the first mold unit 4 is brought in contact and is aligned with the second mold unit 5. In particular, the first opening 6 of the first mold unit 4 is brought in contact with the first opening 7 of second mold unit 5. In the embodiment shown, the first opening 7 of the second mold unit 5 is the free opening of the insert 50. In this configuration, the ducts 24, 25 and 28 in the first and second mold units are aligned to form one single, straight duct having a single axis 27.

In an embodiment, said first and second mold units are joined by moving at least one of the mold units so as to bring it in contact with the respective other mold unit. For example, the moving mold unit is moved along a common axis, for example a vertical axis. The configuration as shown in FIGS. 4A and 4B may be achieved, for example, by keeping the second mold 5 at a fixed position and moving the first mold unit 4 in a linear movement upwards (along axis 27) until its engagement with the second mold unit 5.

A precise alignment of the opening 7 provided at the bottom of the second mold unit 5 with the opening 6 of the first mold unit 4 is facilitated by the complementary tubular forms of the tubular end regions 34 and 35, respectively, of the first and second mold units 4, 5, at their respective first openings 6, 7. In the embodiment shown, the tubular collar 34 of the first mold unit 4 fits into the tubular collar 35 provided by the second mold unit 5 at the opening 7. In the embodiment shown, the collar 35 at the second mold unit 5 is provided by the mold holder piece 43, in particular by the opening of the cavity 26 in which insert 50 is provided (FIG. 2A). Of course, the invention encompasses the inverse arrangement, in which the collar 35 provided at the second mold unit 5 fits into a collar provided at the first mold unit 4. Furthermore, the invention may provide other and/or additional means for stabilizing or guiding the alignment of the mold units on an axis and/or for connecting the mold units in a reversible, releasable manner.

In an embodiment, the extremities of the first and second mold molds 4 and 5 at their openings 6 and 7, have geometrical complementary, matching forms allowing a connection that stabilizes the two molds 4, 5 on a common axis. In other words, the matching forms prevent displacement of one of the mold relative to the other one along an axis that is perpendicular to the common axis 27.

In an embodiment, said first mold unit 4 is in communication with a punch access opening 8, the method comprising the step of closing said punch access opening 8 by positioning a pressing punch 12 at or in said punch access opening 8 before filling said first and said second mold units 4, 5 with said powder. In the embodiment shown, said punch access opening 8 corresponds to the second or bottom opening of said mold unit 4, provided by the duct 24 in said mold unit 4.

It is also noted that in FIGS. 4A and 4B, the first punch 12 is also aligned on the common axis 27, such that the ducts 24 and 25 of first and second mold units 4, 5 and the punching rod 31 of the first punch 12 are coaxial. It is noted that the free end of the punching rod 31 is in contact with the second opening 8 of first mold unit 4. In particular, the punching rod 31 slightly penetrates through opening 8 into duct 24. In this configuration, the first opening 8 is closed or capped by punch 12. The invention encompasses that the first punching rod 31 may advance further into duct 24 of the first mold unit 4 than shown in the figures, so as to substantially close the second opening 8. It is also noted that said closure of opening 8 by punch 12 need not necessarily be airtight, but has the purpose of preventing the powder 30 from leaking when the molds are filled. The play allowed for between rod 31 and opening 8 and duct 24 may depend to some extent by the granularity of the powder used for pressing tool 20.

As can be seen, by bringing the first and second mold units 4, 5 in a coaxial alignment as described, a continuous, complete and/or “overall” mold 14, 15 is formed by the first mold area 14 of the first mold 4 and the second mold area 15 provided by the second mold 5. If an insert 50 is used as in the embodiment shown, the duct 28 in the insert (or part thereof) preferably provides the second mold area 15. In this case, the duct 28 of the insert is preferably also aligned and/or coaxial with the ducts 24 and 25.

As can be understood from FIGS. 4A and 4B, when the two molds 4, 5 are in a contact at their respective first openings 6, 7, and when the second (or bottom) opening 8 is capped, the ducts 24, 25 form a cavity comprising a single opening, in particular the top opening 9, which in the embodiment shown is the second and/or punch access opening of second mold 5.

In an embodiment, the method of the invention comprises the step of filling a powder 30 into said first and said second mold units 4, 5. In particular, the molds can be filled by a powder through opening 9.

The powder 30 may be a commercially available powder that is used conventionally for producing cutting tools by extrusion, for example. In an embodiment, the powder is selected from a powder comprising a carbide, ceramic, metal, nitride or cermet powder, or a powder comprising a mixture comprising one, two or more of the aforementioned. Examples of nitride powders are boron nitride, titanium nitride, silicon nitride and chromium nitride powders, for example. Preferably, a carbide powder, most preferably a tungsten carbide powder is used or contained in the powder 30.

Preferably, the powder is a powdered composition comprising a carbide and one or more metals, for example a cermet powder and/or a cemented carbide powder.

In a preferred embodiment, said powder 30 is a powdered composition further comprising one or more organic components. Preferably, said one or more organic components provide 0.5 to 10 wt. % of said powdered composition, preferably 1 to 5 wt % of said powdered composition.

In a preferred embodiment, said one or more organic components provide 1.4 to 3 wt % of said powdered composition, preferably 1.5 to 2.5 wt %.

The organic components preferably have binding properties, allowing the inorganic powder components to stick together after pressing. Such organic components are thus generally known as binders. The binders allow the pressed tool comprising the pressed inorganic powders to keep the pressed shape and prevent the tool to break apart during extraction from the molds.

In a preferred embodiment, the powder is a powdered composition comprising said inorganic components (carbide, metals, cermet, etc, as mentioned elsewhere) and one or more organic binders.

Organic components, in particular binders may be selected from waxes and PEG (polyethylene glycol), for example. Typically, the powder (or powdered composition) to be pressed comprises one selected from waxes and PEG. Possibly, other organic polymers may be used as binders. Preferably, said organic components essentially consist of said binders.

In a preferred embodiment, the above percentages of organic components apply to one or several selected from waxes, PEG, and other organic polymers. Other organic polymers may be selected from cellulose and derivatives thereof, such as alkyl cellulose and nitrocellulose. Ethyl alcohol and/or ammonium stearate are not considered binders for the purpose of this specification and the powder is preferably free of ethyl alcohol and/or ammonium stearate.

In a preferred embodiment, said one or more organic components comprise and/or essentially consist of one selected from waxes and PEG. Preferably, said powder is a powdered composition comprising at least 30 wt % of waxes and/or PEG, preferably at least 50 wt %, more preferably at least 75 wt %, and most preferably at least 90 wt % of waxes and/or PEG.

Interestingly, in accordance with the present invention, powders comprising a comparatively low portion of organic components may be used. Typically, for producing rods by extrusion as described herein above, about 15 wt. % waxes are contained in the powder. In this case, due to the high amount of waxes, a separate de-waxing step needs to be conducted before sintering. Typically, de-waxing is conducted in a particular furnace (the de-waxing or H2 furnace). De-waxing in such furnaces is generally conducted at temperature below 500° C., for example at 200° C. Sintering is generally conducted at temperatures above 1000° C., for example at about 1400° C.

In the case of the present invention, a low amount of organic binders is contained in the powder. This has the advantage that a separate de-waxing step can be omitted. The pressed tool or precursor tool can directly be sintered and separate de-waxing is not necessary.

In an embodiment, the process of the invention comprises sintering the pressed cutting tool, blank tool and/or precursor cutting tool without conducting a separate de-waxing step before sintering.

FIG. 4B shows the funnel 40 filled with a powder 30 and having been displaced to be positioned directly above opening 9 of the second mold unit 5.

As described above with respect to FIG. 1, the funnel 40 may, for example, be guided on a horizontal rail 93 from a lateral filling station to get to the position shown in FIG. 4B, where the powder is released. In a preferred embodiment, the mold formed by molds 4, 5 are filled by way of gravity, gravity being the force used for filling the continuous mold comprising mold units 4 and 5.

FIG. 5 shows the mold units 4 and 5 filled with powder 30, which has been released from the movable recipient 40, preferably by way of gravity. In FIG. 5, the recipient 40 has already been removed, for example by a displacement back to the filling station, before the subsequent process step, so as to give access to the punch access opening 9 of the second mold unit 5.

Although not shown, the apparatus of the invention preferably comprises a sound generator, preferably an ultrasound generator or another powder compacting entity, such as a vibrating entity. In an embodiment, the method of the invention comprises the step of exposing said powder to sound waves, preferably to ultrasound during filling said powder and/or while exerting said pressure on the powder. Accordingly, the powder 30 is preferably already exposed to (ultra) sound waves during the step of filling the molds 4, 5 between FIG. 4B and FIG. 5. In an embodiment, the ultrasound generator is preferably in physical contact with the mold units 4, 5, such that sound waves penetrate through the mold units 4, 5, and get to the powder 30 during filling. A sound or ultrasound generator is preferably arranged so as to efficiently transmit the appropriate sound waves to the powder in the interior of the mold units 4, 5. For example, the sound or ultrasound generator (or other compacting entity) is in direct contact with the mold or mold elements.

Without wishing to be bound by theory, it is supposed that the sound waves, in particular ultrasound, favours compaction of the powder in the molds 4, 5, 50.

During filling of the mold units 4, 5 with powder 30, the first pressing punch 12 stays preferably substantially still and/or does not move away from the opening 8, such that the free end of the rod 31 of the pressing punch keeps closing the second opening 8 of the first mold unit 4.

In an embodiment, the method of the invention comprises the step of exerting a pressure on said powder 30, thereby obtaining a pressed cutting tool, a blank tool and/or a precursor cutting tool 20. Preferably, said pressure is exerted by one or both of said first and second pressing punches 12, 13.

FIGS. 6A, 6B and 6C but in particular the transition between FIGS. 6B and 6C illustrate the pressing of the cutting tool 20 by the movement of one or both of the pressing punches 12, 13 along common axis 27, so as to result in approaching of the punches and pressing of the powder inside the mold.

In FIG. 6A, the second pressing punch 13 has been aligned with the first punch 12 so as to be coaxial with the latter, and also with the ducts 24 and 25 of the mold units 4, 5. In FIG. 6B, the second pressing punch has been inserted into the duct 25, just down to the filling level of the powder 30 in the ducts 24, 25. In FIG. 6B, the movement of the second punch 13 is stopped just where the head 22 of the punch gets in contact with the powder. The first punch 12 has not been moved, and therefore still functions so as to close the lower opening (or the second opening 8) of the first mold unit 4. During the movement of the second punch 13, and in general in the position shown in FIG. 6B, the powder 30 has not yet been exposed to pressure.

In an embodiment, during said step of exerting a pressure on said powder, a pressing punch is moved, preferably said pressing punch moves in a punch access opening of the respective mold unit.

In an embodiment, said first mold unit 4 comprises a punch access opening 8 and wherein during said step of exerting a pressure on said powder, a pressing punch 12 is moved in said punch access opening 8 of said first mold unit 4. As can be seen from FIG. 6B, said first punch 12 preferably moves in a duct 24 of the first mold 4.

In an embodiment, said second mold unit 5 comprises a punch access opening 9, or second opening 9, and wherein during said step of exerting a pressure on said powder, a pressing punch 13 is moved in said punch access opening 9 of said second mold unit 5. As can be seen from FIG. 6B, said second punch 13 preferably moves in a duct 25 and/or 28 of the second mold 5.

In an embodiment, a first pressing punch 12 and/or a second pressing punch 13 move(s) along a common, preferably vertical axis 27 during said step of exerting a pressure on said powder 30.

In an embodiment, the process of the invention comprises the steps of: providing a first pressing punch 12 and/or a second pressing punch 13; providing a first punch access opening 8 in communication with said first mold unit 4 and/or a second punch access opening 9 in communication with said second mold unit 5, wherein during said step of exerting a pressure on said powder, said first pressing punch 12 is moved through said first punch access opening 7 so as to exert pression on said powder and/or said second pressing punch 13 is moved through said second punch access opening 9 so as to exert pressure on said powder.

In an embodiment, during said step of exerting pressure on said powder 30, said first and said second pressing punches 12, 13 are arranged coaxially on a common axis 27 and said first or said second punch 12, 13, or both, move along said common axis 23, 27, in a converging direction, thereby exerting pressure on said powder.

In accordance with the embodiment shown in the figures, the first pressing punch 12 is a lower or bottom-up pressing punch 12, moving in an upward direction during said step of exerting a pressure on said powder 30, and/or wherein a second pressing punch 13 is an upper or top-down pressing punch 13, moving in a downward direction during said step of exerting a pressure on said powder 30.

Starting from the position shown in FIG. 6B, one or both of the first and second punch 12, 13 can now be moved along axis 27 to further penetrate into the ducts 24 and 25 of molds 4 and 5, thereby exerting pressure on the powder present in the continuous mold 14, 15. Preferably, in the process of the invention, one or both of the first and second punch 12, 13 are moved translationally along their common axis 27 so as to approach each other and pressurizing the powder 30. It is noted that the outer dimension of the punching rods 31, 39 are such that they fit the dimension of the ducts 24, 25. The first punching rod 31 thus penetrates (further) through the second opening 8 of the first mold unit 4 and/or the second punching rod 39 penetrates (further) through the second opening 9 of the second mold unit 5. Preferably, the first and/or second punches 12, 13 move along the common axis in a linear, translational movement. The first punch 12 preferably conducts a non-rotational movement while exerting pressure on the powder 30. In the embodiment shown, the first pressing punch 12 moves in a bottom up direction.

As becomes apparent, when only one punch moves so as to compress the powder, the respective other punch is preferably fixed at a particular position, preferably fixed at a vertical position, so as to support the counter pressure transmitted from the moving punch via the pressure exerted on the powder.

FIG. 6C illustrates the stage where both punches 12 and 13 have approached and exerted pressure on to powder 30. Accordingly, the first pressing punch has been raised along axis 27 and the second punch has been lowered along that axis, so as to compact the powder 30.

In an embodiment of the process of the invention, said first and second pressing punches 12, 13 exert pressure on said powder by sequential advancing movement of said punches with respect to said mold units 4, 5. Accordingly, one of the two punches moves first, followed by the movement of the other punch so as to further compress the powder. There may be just two successive alternate movements of the first and second punches, or a sequence of successive, alternate movements.

In an embodiment, the first, bottom punch starts pressing the powder by moving upwards. Preferably, the pressing punch 12 preferably moves until a predetermined counter pressure or force has been reached. After the first punch has finished its stroke, the second punch 13 exerts pressure by moving downwards along the common axis 27.

In an embodiment, the process comprises the step of providing a pressing punch 13 comprising a head 22 comprising complementary forms, such as cutouts or an outer thread, allowing said pressing to move by a linear rotational movement through said mold part 15 comprising helicoidal ridges 3. The form of the head 22 is thus preferably complementary to the structure 3 (FIG. 2A) of the inner surface on the mold part 15 designed to define flutes 10 of the tool 20 to be manufactured.

In an embodiment, the process of the invention comprises the step of rotating a pressing punch 13 while exerting a pressure on said powder, preferably rotating and linearly moving said pressing punch 13 while exerting said pressure.

In an embodiment, during the step of exerting pressure on said powder 30, a head 22 of a pressing punch 13 advances into the second mold part 15 comprising ridges 3, wherein said head 22 and/or pressing punch 13 rotates around an axis 23, 27 while advancing into said second mold part 15.

During the step of exerting pressure, the second punch 13 (or only head 22 thereof) preferably rotates. In this manner, the second punch, in particular head 22 of the second punch, moves along part 15 comprising ridges 3 of the mold unit. This is possible because of the design of the head 22, which preferably comprises forms, for example cut-outs, matching the helicoidal ridges 3 and thus allowing to move the head in the duct 28 while rotating, while being close to the inner wall of the duct 28, so as to effectively exert the pressure on the powder.

In order to allow punch 13 to advance through section 15, only head 22 needs to rotate. It would in principle be possible that rod 39 and/or stem 41 do not rotate during this step. This may be achieved, for example, by rotatably connecting head 22 to the second punch 13. for example, head 22 may be rotatably connected to rod 39 or to stem 41. Alternatively, the entire punch 13 may be caused or allowed to rotate.

It is also worthwhile noting in this context that the rotational movement by the second punch 13 (or of head 22 thereof) may be an active or passive rotational movement. For example, the punch 13 or only head 22 may be caused to rotate, preferably in a determined manner, by a motor or other adequate propelling device. Alternatively, the punch or head 22 may be configured to be enabled to rotate passively, for example being housed in a bearing or ball bearing, which allows the punch 13 and/or head 22 to rotate passively while it advances in the section 15 comprising the helical ridges 3. The forces exerted by the helical ridges will then cause the head 22 to rotate as it advances in duct 28.

The second punch 13 preferably moves along axis 27 until a predetermined counter pressure or force is reached.

The apparatus of the invention preferably comprises one or more force sensors, suitable to determine the force exerted by one or both of the pressing punches at a particular moment.

Preferably, the data processing entity is configured so as to exert pressure until a pressure or force threshold value is reached.

In another embodiment, the data processing entity is configured so as to conduct a movement of a predetermined distance and/or a predetermined speed during the step of exerting pressure.

In another embodiment, the data processing entity is configured so as to conduct a movement of a predetermined maximum speed and up to a particular force during the step of exerting pressure.

In an embodiment, the data processing entity is configured to apply an algorithm when moving a pressing punch during the step of exerting pressure, wherein the algorithm may use one, several or all of the parameters selected from the group consisting of: (1) force determined by data processing entity and/or by a force sensor (2) speed of the movement of the punch, and (3) distance that the punch has run.

Preferably, the apparatus and/or data processing entity of the invention is apt to be configured by an operator or technician, and allows the latter to enter one or more selected from a predetermined force, speed, and/or distance that a pressing punch exerts during the step of exerting pressure.

In some embodiments, the top-down punch moves first, and the bottom up moves up in a subsequent step of exerting pressure. Alternatively, the bottom-up punch moves first, followed by movement of the top-down pressing punch. In other embodiments, the first and second punches move and exert pressure simultaneously.

In a preferred embodiment, the non-rotational pressing punch, here the first punch 12, conducts the first pressing movement, followed by a pressing movement of the rotational punch 13.

In other embodiments of sequential steps of exerting pressure, a rotational punch moves first, and a non-rotational punch exerts pressure thereafter.

In an embodiment, the rotational punch 13 rotates only during part of the step of exerting pressure. As can be seen in FIGS. 5 and 6A, the top filling level of powder 30 coincides with the top end 16 of the section 28 of the mold unit 4, which comprises the helical ridges. Accordingly, the second punch has to rotate in order to be able to enter the section 28 while exerting pressure and compacting powder 30. The invention also envisages that the ducts 24, 25 are filled up to a filling level that is higher, above the top end 16 of duct 28/insert 50.

When exerting pressure without entering into the duct 28, the punch 13 may or may not rotate.

In yet other embodiments, none of the pressing punches is rotational. In such another embodiment (FIGS. 10A and 10B), both pressing punches may have a straight, cylindrical punching rod 31.

In yet another embodiment, one of the two punches, such as the lower punch 12 or the upper punch 13, is actually not exerting pressure positively while moving, but just stays at a fixed position and operates as an abutment, supporting and withstanding the pressure exerted by the other of the two punches on powder 30, while the powder is compacted. In this case, the non-moving punch may actually be a simple blocking structure and not necessarily a movable pressing punch.

During the step of exerting pressure on the powder 30, the compacting unit, such as the ultrasound generator, is preferably activated, so as to continue to act upon the powder while it is under pressure from one or two pressing punches. In case of sequential movement of two separate pressing punches, the compacting unit is preferably activated during both movements of the pressing punches. In another embodiment, the compacting unit is only activated during one or some but not all of the movements of the pressing punches during the step of exerting pressure. Preferably, the compacting unit is activated during at least part of the step of exerting pressure on the powder.

After completion of the step of applying pressure on the powder, the pressed cutting tool is contained in the mold units 4, 5 (FIG. 6C). The process of the invention preferably comprises the step of removing the pressed cutting tool from one or both of the mold units.

Care is preferably taken in order not to break or otherwise damage the pressed cutting tool 20 when removing it from the mold.

In an embodiment, the removal of the tool 20 from the molds is accomplished in two or more separate process steps.

In a first step, the pressure from the first or bottom punch 12 is released first. Preferably, the punch 12 stays in contact with lower end of the pressed tool 20 as shown in FIG. 6C.

In an embodiment, the first or bottom mold 4 is removed first. In an embodiment, the process comprises the step of linearly moving the first mold unit 4 along said axis 23, 27 away from said pressed tool 20 so as to conduct a relative movement with respect to said pressed tool 20 and/or said pressing punch 12. This process step is preferably illustrated by the transition from FIG. 6C to FIG. 7. The mold unit 4 has been moved in a downward direction and is no longer visible in FIG. 7. It is noted in this regard that the length of the punching rod 31 is preferably longer than its length as apparent from the figures, such that the entire mold unit 4 can preferably be moved along axis 27 until the shank part 1 (FIG. 2B) of the tool 20 is completely released from the mold 4. During the linear movement of removing the mold 4, the first punch 12 preferably stays in contact with the bottom end of the shank, as shown in FIG. 7.

Preferably, the mold part 4 defining the shank of the cutting tool is removed first. In the embodiments shown, this is the first or bottom mold 4. Since the invention is not limited to a particular orientation of the molds during the process of the invention, the mold unit that is removed first may as well be the top mold unit 4, or a laterally positioned mold unit.

In an embodiment, the process of the invention comprises the step of removing a first pressing punch 12 away from said pressed tool 20 preferably after the removal of the first mold unit 4 with from said tool 20. After the first mold 4 has been removed, as shown in FIG. 7, the first pressing punch 12 is also removed, preferably vial a translational movement along axis 27, in a direction opposite to the direction of exerting pressure. Preferably, the first punch or bottom punch 12 is lowered.

The complete removal of the pressed tool 20 from the second mold 5 is illustrated in FIGS. 8 and 9. In an embodiment, the process of the invention comprises the step of removing said pressed tool 20 from said second mold 5 by linearly moving a pressing punch 13 through said second mold unit 5, preferably while said pressing punch 13 conducts a linear and a rotational movement (possibly only head 22 rotates). In other words, the data processing entity causes punch 13 to further advance into the duct 28 of mold unit 5 comprising the helical ridges. As described above, punch 13 or at least head 22 has to rotate in order to be able to advance in duct 28, since duct 28 does not contain a constant cylindrical cross section but contains structures defining helical flutes of tool 20. The second punch 13 preferably crosses the entire duct 28, until it reaches the first opening 7 of the second mold unit 5, as shown in FIG. 9. At this position, the cutting tool 20 has been completely ejected from the second mold part and will drop. It can be collected manually or by an appropriate collecting device.

FIGS. 10 A and 10 B show another embodiment of the method and apparatus of the invention. In accordance with this embodiment, the second pressing punch 13′ differs from the second pressing punch 13 shown in the preceding figures in that the second pressing punch is not adapted for entering the duct 28 of the second mold unit 5, where the second mold area 15 is provided. The second pressing punch 13′ preferably lacks a head 22 comprising cut-outs or similar forms complementary to the second mold area 15. The second punch 13′ also preferably lacks a rod 39 having a thinner cross section, as provided on the punch 13 shown in the previous figures. Therefore, the second pressing punch 13′ of this embodiment may not be configured to rotate, or may not rotate during the step of exerting pressure. For example, the second pressing punch may be configured to exert pressure on the powder 30 in a similar manner as the first pressing punch and may have the same overall configuration.

The cutting tool 20 may be prepared exactly as described above, with the exception that the second pressing punch 13′ does not advance into the duct 28 of the second mold unit. The punch 13′ preferably stops the linear movement at the opening 16 of the insert 50, or before reaching the opening 16.

For ejecting the pressed tool 20 obtained according to the second embodiment, it will be necessary to withdraw the second pressing punch 13′ from the second mold unit 5 and to use an ejection punch 13 as shown in the previous figures. Accordingly, the punch 13 as shown in these figures is preferably still used for ejecting the pressed tool 20, but preferably this punch 13 is not used for exerting pressure, in accordance with the alternative embodiment illustrated in FIGS. 10A and 10B.

A further difference of this second embodiment can be seen when comparing FIGS. 5 and 6A on the one hand with FIG. 10A on the other hand. In FIG. 10A, the powder is filled above the level 16 of the duct 28 which is the duct characterizing the presence of the second mold area 15. In FIGS. 5 and 5A, the powder 30 is filled preferably not substantially higher than said opening 16. Accordingly, in the first embodiment, pressure may be exerted as from about the opening 16 or lower (or from above), whereas in the second embodiment pressure is exerted already above the opening 16.

Once the tool 20 is ejected, the cutting tool, a blank tool and/or a precursor cutting tool is preferably obtained. The tool may be commercialized as it is, or may be subjected to further steps for further processing and/refining. In an embodiment, the process of the invention comprises one or more further steps selected from the group consisting of (1) hydrogen de-waxing, (2) sintering, (3) cutting, (4) centerless grinding, (5) flute grinding, (6) honing, (7) coating, and/or (8) cleaning, for example. Of course, the invention does not exclude other or further steps of finalizing a cutting tool that is ready for use.

From the present specification, it is apparent that the term “pressing” is preferably used in the context of pressing a material 30 provided in a mold or several mold units. The term “pressing” is thus preferably not intended to refer to production of blanks by extrusion, for example extrusion through a nozzle. “Pressing” in accordance with the present invention may be referred to as mold-pressing, or mold-based pressing.

With reference to the figures, an example of exerting pressure by way of one or two co-axial pressing rods has been discussed in detail. The invention also encompasses the possibility of exerting pressure to the powder in the mold from lateral and/or in a non-axial manner. For example, in an embodiment, a mold entity may comprise a lateral opening in which a pressing structure is provided, such that the powder may be pressed from the pressing structure pressing the powder in a non-axial direction. For example, such non-axial or lateral pressure may be used to form openings or flat lateral surfaces or concavities in the cutting tool. Such openings, flat surfaces or cavities may thus be provided laterally with respect to the axis of the cutting tool and may result in the reduction of the number of symmetry axis of the tool, and/or may result in cutting tools that are not axially symmetric. The invention also envisages the use of interlacing or nested mold parts, which may be displaced so as to pressure a powder contained in a lumen formed by interlacing, interleaving and/or nested mold parts.

Furthermore, the figures illustrate the invention comprising two mold units that are joined to form a continuous mold. In another embodiment, a single mold unit comprising the mold is encompassed. In other words, the mold of the tool may be contained entirely in a single piece, or in several pieces that are rigidly connected. Preferably, such a mold still comprises at least two openings, such as to allow one or two co-axial pressing rods enter the mold and allow ejection of the cutting tool after pressing. In case of a single mold unit, the mold unit may or may not comprise a first mold area defining at least part of shank, and a second mold area comprising ridges designed to define flutes of the tool to be manufactured. The single mold unit may define only helical ridges or may define only a rod lacking helical flutes, for example a substantially cylindrical rod. When using a single mold unit, the process may generally be conducted in accordance with the steps as described in this specification, with the exception of steps where the one or both of the two part-mold units are displaced one with respect to the other.

In accordance with the embodiment described above, the invention also provides an apparatus comprising only one mold assembly, for example a single mold assembly or a single mold unit.

Several publications and patent documents are cited in the foregoing specification in order to more fully describe the state of the art to which this invention pertains. The disclosure of each of these citations is incorporated by reference herein.

While certain of the preferred embodiments of the present invention have been described and specifically exemplified above, it is not intended that the invention be limited to such embodiments. Various modifications may be made thereto without departing from the scope and spirit of the present invention, as set forth in the following claims.

PROCESS AND APPARATUS FOR MANUFACTURING A CUTTING TOOL BY PRESSING

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