Patent Application
20170341115
None.
The technology relates generally to machine tools, and more particularly to the removal of swarf or unwanted shavings or particles created during the operation of the machine tools.
A machine tool is a machine for shaping or machining metal or other rigid materials, usually by cutting, boring, grinding, shearing, or other forms of shaping the material. A machine tool uses a tool to perform the cutting or shaping of the rigid material and the material being shaped is called a workpiece. There are a wide variety of machine tools but they all contain a way to hold the workpiece and the cutting tool. Many machine tools include one or more live tools. These are tools, typically cutting tools, perform the cutting or shaping of the workpiece. The machine tool moves the cutting tool or cutting tool and the workpiece both move, in a controlled process, performing the cutting or shaping of the workpiece, and during that cutting and shaping create discarded scraps from the workpiece are called swarf.
Many modern machine tools use computer numeric controlled (CNC) machining to increase the productivity and accuracy of manufacturing processes. A vertical machining center (VMC) is an example of a CNC machine tool. A typical VMC includes motors that move the machine bed holding the workpiece in the x-y plane and moves the spindle along the z-axis, all under the control of the machine control unit operating a computer program. The control unit controls movement of the active parts of the machine according to the instructions in this computer program creating very detailed, precise, and accurate cutting and shaping operations at high speeds. Other examples of CNC machine tools using live tooling include horizontal machining centers, various CNC router designs, turning tools with multi-axes live tooling, like horizontal and vertical lathes, screw machines, and turret lathes.
Advances in CNC and machine tool technologies have dramatically changed machining. For example, variable frequency drives have created faster and more powerful spindles. The spindle is a motor assembly that causes the rotation of the cutting tool. In a typical modern CNC machine tool, the cutting tool is held in a tool holder and the tool holder is attached to a rotating portion of the spindle. Spindle speeds have increased from 4,000 or 5,000 rpm to speeds up to or over 40,000 rpm. But these increased speeds have also created the problem of higher swarf loads (i.e., as noted, the excess chips, turnings, filings, or shavings created during the shaping of the workpiece).
All machine tools, from basic, operator driven machine tools to computer operated CNC machines, during the drilling or cutting process, create swarf. But especially with the higher speeds of the CNC machines, a critical design feature of a CNC machine is the removal of swarf during the machine's operation. Otherwise, swarf can get trapped between the cutting edge of the tooling and the workpiece. This can degrade the surface finish of the workpiece and shorten the tool life.
Some technologies have been developed to remove swarf from the cutting area during machining operations: like blowing away swarf with compressed air, flooding the workpiece with liquid coolants, or through-spindle coolant systems. But these methods require additional plumbing, pumps, filters, and other parts, and significant modifications to the machine tool. Additionally, it is difficult to point the nozzles of these systems in the right direction to consistently evacuate swarf; especially in pocket milling applications. All current swarf removal technologies suffer from one or more of these disadvantages, and as CNC milling machines reach higher and higher machining speeds, swarf loads increase, making current swarf removal methods increasingly expensive to build and integrate into the machine tool, and difficult to maintain.
Therefore, there is a need for a method or apparatus for improved swarf removal from a workpiece during the operation of any machine tool, especially in high-speed CNC machines.
The present invention provides an apparatus and method for removing swarf from a workpiece during the operation of a machine tool on a workpiece. In a preferred embodiment, a set of slanted vanes attached to a rotating part of the machine tool, directed at the workpiece, and during the operation of the machine tool the vanes connected to the rotating part blow swarf out and away from the workpiece. The method for removing swarf from a workpiece during the operation of the machine tool consists of choosing a rotating part of the machine tool directed at the workpiece, mounting a set of slanted vanes onto that rotating part, and during machine operation the rotation of the chosen rotating part with the attached slanted vanes creates an airflow on the workpiece sufficient to keep the workpiece free of swarf.
One embodiment of the invention has an inner hub attached to the rotating part of the machine tool and the slanted vanes attach to this inner hub and extend outwardly from it. Aspects of the present swarf removal invention reside in various constructions and arrangements and parts and uses of the disclosed embodiments. In embodiments of the vanes, they are composed of a wide variety of metallic or non-metallic materials, and the only requirement of the chosen material is whether it gives the vanes the required stability during high speed rotation so they don't significantly bend while creating the required air force on the workpiece. Among the many different possibilities contemplated, the swarf removal invention also connects the slanted vanes to an outer shroud surrounding the machine tool swarf removal apparatus, and this arrangement also gives the slanted vanes the required stability during high speed rotation to create the required air force on the workpiece, during the operation of the machine tool.
Another embodiment of the machine tool swarf removal apparatus is designing the apparatus as a one-piece component, such as a molded part. Still another embodiment is to cut grooves into the inner hub, fit O-rings into these grooves, and thus provide one way to firmly and securely attach the machine tool swarf removal apparatus to the rotating part of the machine tool. Other embodiments include inserting, gluing, or molding an elastomer insert into the inner hub instead of using O-rings; this would also increase the adhesion between the rotating machine tool part and the apparatus. Another embodiment of the invention is having the rotating part be the tool holder. Still another embodiment is designing the slanted vanes as part of the tool holder and thus reduce eliminate the need to maximize the adhesion between the tool holder and a separate apparatus. A further embodiment is choosing the endmill as the rotating part, and yet another embodiment choosing the rotating portion of the spindle as the rotating part.
Another embodiment attaches the slanted vanes to rigid inner hub. The inner bore of this inner hub is lined with an elastomer insert, providing increased adhesion between the rigid inner hub and the rotating part of the machine tool.
Among the many possibilities contemplated in the design and use of the machine tool swarf removal apparatus is having it operate in low-pressure coolant system, directing the vanes at the cutting area, and thus diverting coolant to that cutting area.
In further embodiments of the invention the vanes attach to an inner hub, and this inner hub forms an interference fit between the inner bore of the hub and the outer diameter of the rotating tool part. Also, another refinement of the invention is connecting the inner hub to the machine's tool holder.
Various other objects, features, aspects, and advantages of the present invention will become more apparent from the following detailed description of embodiments of the invention, along with the accompanying drawings. However, the drawings are illustrative only and numerous other embodiments are described below. Additionally, the scope of the invention, illustrated and described herein, is only limited by the scope of the appended claims.
Various embodiments of the invention are disclosed in the following detailed description and accompanying drawings.
The following is a detailed description of exemplary embodiments to illustrate the principles of the invention. The embodiments are provided to illustrate aspects of the invention, but the invention is not limited to any one embodiment. The scope of the invention encompasses numerous alternatives, modifications and equivalents; it is limited only by the claims. The details set forth in this description give a thorough understanding of the invention and for the purpose of clarity, the technical details of machine tools, known by one of ordinary skill in this technical field, are not described in detail so that the invention is not unnecessarily obscured.
The disclosed embodiments of the machine tool swarf removal apparatus operates in all types of machine tools with live tooling or rotating cutting tools. Additionally, the disclosed embodiments of the swarf removal apparatus can be easily shaped and fitted to operate in CNC milling machines, CNC vertical machining centers, CNC routers, and CNC machine lathes. Additionally, the disclosed embodiments of the swarf removal apparatus work equally well in enclosed or open CNC machines. The embodiments of the machine tool swarf removal apparatus will work when attached to any spinning parts of a machine tool, when that spinning part is directed at the workpiece, and provides enough air pressure on the workpiece to clear keep it of the unwanted swarf during the operation of the machine.
Additionally, in one embodiment of the swarf removal apparatus 17 the slanted vanes 20 connect to a rigid inner hub 22, and the inner bore of this inner hub 22 is lined with an elastomer insert, providing increased adhesion between the rigid inner hub 22 and the rotating part of the machine tool. In another embodiment, the inner hub 22 is composed of an elastomer material and gives the inner hub 22 itself, without any inserts, the necessary tight connection between the swarf removal apparatus 17 and the rotating tool part.
Although, the outer edges of the slanted vanes 20 connect to outer shroud 18, other embodiments could do without this outer shroud 18. For example, one embodiment could use smaller slanted vanes 20 spinning at a high enough speed to clear the workpiece 7 of swarfs with no need for the outer shroud 18. The key design feature of the slanted vane device 17 is the slanted vanes 20 providing adequate air force on the workpiece 7 during machine tool operation to clear unwanted swarf out of and away from the workpiece 7 during machine tool operation.
The swarf removal apparatus 17 has many variations enabling it to connect it to any machine tool, and any rotating part directed at the workpiece 7, as long as the position and speed of the swarf removal apparatus 17, when directed at the workpiece, provides the required force of air flow to keep workpiece 7 of unwanted swarf during the machine tool's operation.
Also, the swarf removal apparatus 17, could be designed as a one piece injection molded component, with the inner hub 22, the slanted vanes 20, and outer shroud 18 forming a single part, or it could be created with an assembly of parts. The swarf removal apparatus 17 could be made from zytel (nylon 66) or any other nylon resin, plastic, any natural or synthetic polymer having elastic properties like elastomer, e.g., rubber, or injection molded plastic, or any suitable metal, or nonmetallic materials, as long as slanted vanes 20 have enough stability to provide the necessary air pressure to keep the workpiece 7 clear of swarf, during machine operation.
When the swarf removal apparatus 17 is designed with elastomer, and sized to fit on a machine part like the tool holder 4, it allows a novel way to install the swarf removal apparatus 17 on the correct sized tool holder, with the elastomer connecting to the tool holder 4 with the required friction to keep the swarf removal apparatus 17 securely in place during spindle 4 ramp up, operation, and shut down. Once installed and while the spindle 4 rotates the slanted vanes 20 provide the required force of air directed at the workpiece 7, and keeps workpiece 7 clear of swarf.
Using the swarf removal apparatus 17 to blow swarf out of and away from a workpiece 7 is novel and innovative. There's no need to change the existing programming when used in a CNC system because the swarf removal apparatus 17 does not interfere with any existing cutting operations or machine devices. Additionally, as noted, another embodiment of swarf removal apparatus 17 would be incorporating the slanted vanes 20 into a tool holder design, becoming part of the tool holder.
Other embodiments include the swarf removal apparatus 17 created as a single elastomer sleeve mounted or overmolded (combining two different molds into one part) into the bore of the shroud 18. The slanted vane device 17 would also allow designs that mount to the endmill, with an endmill having enough length to hold the slanted vane device 17.
Additionally, the swarf removal apparatus 17 could attach to any other suitable moving machine part, moving over the workpiece 7, with an elastomer, or other type of O-ring, installed in grooves cut into the inner hub 22, as seen in
As noted, CNC vertical machining centers include vertical and horizontal machining centers, as well as other orientations, and other machine types like routing machines, and all of these machine types are suitable for different embodiments of the disclosed swarf removal apparatus 17. Additionally, embodiments of the swarf removal apparatus 17 could operate in lower pressure coolant systems and enhance these systems by diverting the coolant to the cutting area for far less cost than upgrades to the coolant system. The only modifications to the novel swarf removal apparatus 17 would be refitting and re-sizing the slanted vane device 17 to fit a rotating part of the coolant system directed at workpiece 7.
As noted, the disclosed embodiments are illustrative, not restrictive. While specific configurations of the swarf removal apparatus 17 have been described, the present invention can be applied to a wide variety of machine tools, providing many alternative ways of implementing the invention.
