Patent Application
20230111366
The invention relates to what is referred to as a three-plate die casting mold for producing at least one metal die-cast part. The invention also relates to a method for producing at least one metal die-cast part by means of a three-plate die casting mold.
As is known, during die casting, liquid molten metal is pressed at high pressure into the die cavity of a die casting mold (casting die), where it then solidifies. After the molten metal has solidified, the die casting mold is opened to remove the die-cast part (if appropriate, also multiple die-cast parts) from the die. In order to be able to open and close the die casting mold, it has at least two mold parts (mold halves), with at least one of these mold parts being movable relative to the other mold part. The opening and closing is effected using a die casting machine, in which the die casting mold is installed.
A die casting mold usually also has a sprue system, formed by feed channels, distribution points and the like, via which the liquid molten metal enters the die cavity or is fed to the die cavity. The molten metal that has solidified in the sprue system is referred to as sprue, which is separated from the actual die-cast part (shaped part) during removal from the die or after removal from the die and disposed of as waste or else recycled.
The prior art also discloses what are referred to as three-plate die casting molds, in respect of which representative reference is made to the patent document DE 10 2012 107 363 A1. Such a three-plate die casting mold has a third mold part in the form of an intermediate plate, as it were, which is movably arranged between a first, typically stationary mold part and a second, movable mold part. Consequently, there are two mold parting planes, it being possible to remove the die-cast part from the die by way of the first mold parting plane and to remove the sprue from the die by way of the second mold parting plane. When the three-plate die casting mold is being opened, the die-cast part can be pulled away from the sprue by the opening movement of the third mold part (intermediate plate), the die-cast part and the sprue being forcibly parted, or the die-cast part being separated from the sprue.
The object of the present invention is to provide a three-plate die casting mold with improved sprue separation.
The three-plate die casting mold according to the invention (also referred to simply as die casting mold below) for producing at least one metal die-cast part by die casting a molten metal comprises a first, a second and a third mold part, wherein the third mold part (intermediate plate) is arranged between the first and the second mold part. The three-plate die casting mold according to the invention further comprises at least one die cavity (in which the die-cast part to be produced is created) and also a sprue system, through which the molten metal is fed or can be fed to the die cavity, wherein the sprue system has multiple, but at least one, feed channels (which can also be referred to as gates or inflows and/or inflow channels) which are arranged in the third mold part or formed in the third mold part and lead or open into the die cavity. Of course, and therefore at this juncture mentioned only for the sake of completeness, there is a respective mold parting plane between the mold parts, in order to be able to open and close the die casting mold for the purpose of removing the die-cast part created in the die cavity and the sprue created in the sprue system from the die, as is known from the prior art.
According to the invention, what is provided is that the feed channels (of the sprue system) in the third mold part that open into the die cavity, in particular all these feed channels, but at least one of these feed channels, have a respective tapering at their die cavity-side ends, that is to say in the region of the opening into the die cavity, which tapering locally decreases or locally narrows the (respective) channel cross section. These taperings or narrowings make it possible to generate or form predetermined breaking points, in particular annular groove-like or annular notch-like predetermined breaking points, during the die casting operation which allow defined separation of the die-cast part created in the mold cavity from the sprue created in the sprue system or from the sprue webs created in the feed channels when the die casting mold is being opened. That is to say, in other words, that as a result of the taperings, predetermined breaking points, in particular annular groove-like or annular notch-like predetermined breaking points, are created at the transitions between the die-cast part and the sprue during the die casting operation, at which predetermined breaking points the die-cast part, without a parting slide or the like, can be separated, in particular torn away, in a defined way from the sprue or from the sprue webs when the die casting mold is being opened.
The die casting mold according to the invention allows controlled separation of the die-cast part from the sprue at predefined points. Both the die-cast part and the separated sprue therefore have a geometrical state which is always the same, thereby simplifying ejection and/or removal from the die. The outlay on casting finishing for the die-cast part is also reduced. In addition, the mechanical loading of the die casting mold is diminished and as a result the wear on the mold is reduced.
The feed channels in the third mold part that open into the die cavity preferably have a conical, preferentially spherical, form, in particular with cross sections that become smaller in the direction of the die cavity, and in addition to this conical formation each have a tapering at their die cavity-side ends, which tapering locally decreases or locally narrows the channel cross section.
The taperings at the die cavity-side ends of the feed channels in the third mold part that open into the die cavity are preferably each formed by a bead or annular bead or the like around the periphery, preferably around the entire periphery, and in particular having a collar-like shape, which bead(s) are arranged in particular in the opening cross sections and locally narrow the respective feed channel in the opening cross section. As a result, an annular groove-like, in particular annular notch-like, predetermined breaking point can be generated or formed at the respective transition between the die-cast part and the sprue or the sprue web.
The first mold part is preferably formed with pins, in particular with conical or at least semi-conical pins, which, when the die casting mold is closed, project (at the rear side or sprue system-side) into the feed channels that are formed in the third mold part and open into the die cavity. These pins are each formed with an undercut contour or with at least one undercut which, when the die casting mold is being opened, retains or withholds the sprue created in the sprue system or the sprue web created in the respective feed channel and favors the separation of the die-cast part from the sprue as a result. These pins may also be referred to as retaining pins.
It is preferably the case that the pins on the first mold part are in the form not only of retaining pins but also ejectors for the sprue and are coupled in particular to an ejection mechanism or the like for this purpose.
The feed channels in the third mold part that open into the die cavity are preferably aligned perpendicularly or at least substantially perpendicularly to the die cavity, that is to say the feed channels open perpendicularly or at least substantially perpendicularly into the die cavity. This relates in particular to a die cavity for producing a thin-walled and areal die-cast part, in the case of which the feed channels are aligned perpendicularly to the areal extent of the die-cast part to be produced.
The method according to the invention for producing at least one metal die-cast part comprises at least the following steps in the following sequence:
During the opening operation, the die casting mold is preferably opened first in the (second) mold parting plane between the third mold part (intermediate plate) and the first, in particular stationary, mold part (nozzle plate), in which the removal of the sprue from the die also takes place. In this respect, the die-cast part may have been separated from the sprue already at the start of the opening operation, that is to say at the start of the opening movement of the third mold part, which is effected in particular together with the second mold part.
The die-cast part to be produced is preferably a vehicle component, in particular a thin-walled light-metal bodywork component, such as for example a longitudinal member element.
The invention will be described in more detail below with reference to the figures on the basis of a particularly preferred best mode. The features disclosed in the figures and/or the features explained below, also taken in isolation from specific combinations of features, may also be general features of the invention and correspondingly refine the invention.
The three-plate die casting mold 100 shown in
The three-plate die casting mold 100 advantageously allows a lateral feed, substantially perpendicular with respect to an areal extent of the die-cast part to be produced, of the molten metal to the die cavity 140. For this purpose, the sprue system 150 has multiple conical, and as a result nozzle-shaped, feed channels 151 (also referred to as gates) which are arranged in the third mold part 130 or formed in the third mold part 130 and open into the die cavity 140, in particular substantially perpendicularly.
A first mold parting point or mold parting plane T1 is located between the second mold part 120 and the third mold part 130, and a second mold parting point or mold parting plane T2 is located between the third mold part 130 and the first mold part 110. By moving or displacing the second mold part 120 and the third mold part 130, as illustrated by the arrows B1, B2, the die casting mold 100 can be opened at the mold parting planes T1, T2. It is then possible to remove the die-cast part created in the die cavity 140 by the solidified molten metal from the die by way of the first mold parting plane T1, and to remove the sprue created in the sprue system 150 by the solidified molten metal from the die by way of the second mold parting plane T2. When the three-plate die casting mold 100 is being opened, the die-cast part is forcibly separated from the sprue, as will be explained in more detail below.
After the molten metal has solidified, the die casting mold 100 is opened in the second mold parting plane T2, as illustrated in
As a result of the local tapering 153, during the die casting operation an annular groove-like, in particular annular notch-like, predetermined breaking point is generated between the die-cast part 200 and the sprue 300, at which predetermined breaking point a defined separation or tearing away of the die-cast part 200 from the sprue 300 (and specifically directly on the die-cast part 200) takes place already at the start of the opening movement B2 of the third mold part 130, wherein the sprue 300 or the sprue web 310 is retained as a result of a form fit with the undercut contour or with the undercut 165 on the pin 160, thereby favoring separation or tearing away. Only a small, flash-free tear-off point 210 remains on the die-cast part 200.
After the die casting mold 100 has been completely opened, as is shown in
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2020 108 022.0 | Mar 2020 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2021/054309 | 2/22/2021 | WO |
