DE102016123496A1 - Tool for casting and / or forming a molded part, casting device, press and method for compensating a thermal load of a molded part - Google Patents

Abstract

The invention relates to tools for casting and / or forming a molded part, which has a first tool part and a second tool part, wherein in the case of closing the tool, the first tool part and the second tool part form a shape, and arranged a tempering in a tempering distance to the mold is that which increases by tempering a mold-forming material in the first tool part and / or in the second tool part, a temperature in the mold and / or the molding, lowered or kept constant, so that a thermal stress in the molding during casting and / or Reshaping is compensated. Furthermore, the invention relates to a casting device for casting a molded part, a press for casting and / or forming a molded part and a method for compensating a thermal load of a molded part during casting and / or forming.

Description

The invention relates to a tool for casting and / or forming a molded part, which has a first tool part and a second tool part, wherein in the case of closing the tool, the first tool part and the second tool part form a shape. Furthermore, the invention relates to a casting device for casting a molded part, a press for casting and / or forming a molded part and a method for compensating a thermal load of a molded part during casting and / or forming.

In methods of hot forming, for example, casting and / or pressing a material above its recrystallization temperature, the forming tool and / or the mold undergo temperature changes during the process.

By different heat flows within the forming device, for example due to the installation of the tool on the press ram or on the press table top, and by different heat inputs during hot forming, for example when the workpiece to be formed asymmetries and / or different material thicknesses, temperature differences arise within a tool, between opposing areas of Tool parts and / or in the mold and on the workpiece to be formed.

These temperature differences can lead to the situation where the optimum temperature is not present locally during hot forming. Consequently, there is a risk that the workpiece will be deformed in certain areas at too high or too low a temperature. The disadvantage here is that the material, for example, does not assume the desired structural change.

Unwanted temperature differences within a tool and / or a mold and / or the workpiece and a hot forming at the non-optimal local temperature lead to increased wear of the tool and / or the mold and / or to an undesirable microstructure arrangement of the workpiece. In addition, temperature differences between two opposing tool parts, such as a top and bottom tool, lead to a displacement of the contact surfaces and thus also the sealing surfaces between the two tool parts.

In particular, during casting, this shift can lead to the unwanted escape of liquid, hot melt from the tool.

The object of the invention is to improve the state of the art.

The object is achieved by a tool for casting and / or forming a molded part, which has a first tool part and a second tool part, wherein in the case of closing the tool, the first tool part and the second tool part form a shape, and a tempering in a tempering distance is arranged to form, which increases by tempering a mold-forming material in the first tool part and / or in the second tool part, a temperature in the mold and / or the molding, lowered or kept constant, so that a thermal stress in the molding during casting and / or reshaping is compensated.

Thus, a temperature in the thermally loaded form and / or the thermally loaded molded part is kept constant by targeted by tempering a tool, deliberately lowered or increased specifically. Consequently, excessive thermal stress on the tool, displacement of contact surfaces, touching of the tool parts and thus tool breakage are prevented.

Above all, the optimum temperature for hot forming is or will be set in the mold and / or in the molded part. Consequently, a high-quality component is manufactured.

It is particularly advantageous that the locally present temperature in the mold and / or in the molded part is adapted to the contour and / or wall thickness of the molded part and to the locally required casting pressure and / or the required pressing force. Thus, too high or too low thermal loads are avoided in the molding during casting and / or pressing.

An essential idea of the invention is based on the fact that, in the case of an at least two-part tool, the mold-surrounding material of at least one of the two tool parts is tempered by means of a tempering device, so that an optimum temperature is present in the mold and / or the molded part during hot forming. Thus, thermal stresses on the molded part can be compensated, for example, due to the filled hot melt during casting in the mold and / or due to a non-optimum hot working temperature in combination with the mechanical stress due to the pressing force.

Of course, even when the tool is still open, the mold-forming material of the mold half of the first and / or the second tool part can be precooled or preheated and only then the tool is closed and the casting and / or forming can be started.

Thus, locally the temperature of a part of the tool, a part of the mold or a part of the workpiece / molded part can be acted upon.

The following concept is explained:

A "tool" is in particular an object with which a machining of a workpiece and / or a casting for the production of a molded part takes place, wherein the tool is guided by a human and / or a machine. A tool is in particular a molding tool. The tool is used in particular in a forming manufacturing process such as preforming, forming and / or casting. The tool is used in particular in a machine tool, a casting device and / or a press. The tool consists in particular of at least two tool parts, for example a lower and / or an upper tool, or of more than two tool parts, wherein in the case of closing the tool, these several tool parts form the shape. The tool may have an inner contour, which is impressed as an outer contour of a workpiece or a molded part.

"Casting" is in particular a manufacturing process in which a solid material of a specific shape is formed from a liquid material (melt) after solidification. For casting, in particular, a tool is used as a permanent mold. Casting includes in particular die casting, die casting and / or continuous casting.

"Forming" is in particular a production method in which a workpiece made of metal and / or metal alloy is deliberately plastically brought into another shape. In particular, a workpiece is transferred by forming into a molded part. When forming can be deep drawing and / or pressing. The forming is in particular a hot forging and / or a hot forming, wherein in the latter the workpiece is heated to a temperature, for example above the recrystallization temperature of its material before forming.

A "molding" is in particular a made of a workpiece or a cast item. The finished molded part can serve as a component of a technical complex, such as a machine and / or an apparatus. The molded part is created in particular plastically due to a change in shape through targeted casting and / or forming. Thus, a molded part in particular almost finished shapes or geometries.

A "mold" is understood to mean, in particular, a cavity of the tool, the inner contour of which is impressed as an outer contour on a workpiece, and / or in which the cavity of the mold is filled with melt to produce the molded part. A mold is also referred to in particular as a "mold cavity".

A "tempering device" is in particular a device for tempering a mold-surrounding material. Thus, by means of the tempering the temperature of the mold-forming material and a temperature in the mold and / or the molded part can be adjusted and / or regulated. By means of the tempering device, the temperature in the mold and / or the molded part is in particular increased, lowered or kept constant.

A "tempering distance" is in particular a distance in which the tempering device is arranged to form. Within the Temperierentfernung takes place in particular a tempering of the formumgebenden material.

By "tempering" is meant, in particular, the temperature adaptation of the shape-changing material by increasing, decreasing and / or keeping the temperature constant.

By "mold-surrounding material" is meant in particular the material of a tool part which is arranged on one side of the mold. The mold-surrounding material is present in particular on and / or in the vicinity of the shape of the tool part.

In particular, a "temperature" is a physical quantity that characterizes the thermodynamic equilibrium. In particular, two bodies which are in direct contact with each other have different temperatures, so heat flows from the warmer body to the colder. The temperature is given in units of Kelvin (K) or Celsius (° C).

A "thermal load" is understood in particular to mean that the molded part is not poured and / or reshaped at an optimum temperature. In particular, the thermal stress occurs in a limited area of the molded part, wherein the molded part can have different areas with different thermal loads. A thermal load may be too low or too high a temperature. A thermal load in particular also includes a heat load due to a too high and / or unmatched pressing force.

In a further embodiment, the tool has a second tempering device, a third tempering device, a fourth tempering device and / or a further tempering device.

Thus, in each of the opposing tool parts each have their own tempering be arranged.

In addition, a plurality of tempering devices can be arranged in one tool part, so that, in particular in the case of large-area and / or complex shaped parts, a plurality of different local temperatures are set in accordance with the respective thermal loads of the molded part.

As a result, different heat flows and / or heat inputs into the tool, into the mold and / or the molded part can be locally compensated for very finely tuned by a plurality of tempering devices in a tool part. Thus, for example, heating and cooling tempering can alternate in a tool part.

A second, third, fourth and / or further tempering device corresponds in its embodiment and function of the above-defined tempering.

In order to optimally adapt the tempering device to the geometry and / or the position of the tool parts and / or the mold, the tempering device or the tempering devices is or are an inductive tempering device and / or a conductive tempering device.

In addition, the speed of the heat flow from the mold-forming material to the mold and / or the molded part can also be influenced by the choice of the type of tempering device.

An "inductive tempering device" is, in particular, an induction coil through which low and / or medium-frequency alternating current flows, thereby generating a magnetic alternating field. The alternating magnetic field induces eddy currents, in particular in the mold-surrounding material of a tool part, as a result of which the mold-surrounding material and / or the tool part is or will be heated. In this case, it is particularly advantageous that the heat arises directly in the mold-forming material and / or the tool part itself and does not have to be transferred to the mold-forming material by heat conduction. For the inductive heating of the mold-forming material, in particular a further gap and / or a distance between the induction coil and / or the mold-surrounding material is to be maintained within the tool part.

A "conductive temperature control device" is in particular a tempering device in which heating of the mold-surrounding material and / or of the tool part takes place due to a heat flow in the mold-surrounding material and / or the tool part as a result of a temperature difference. In the case of a conductive tempering device, the heat flow can occur, for example, due to water cooling or heating and / or direct conduction of direct or alternating current through the material surrounding the mold.

In order to be able to determine the temperature in the mold and / or the molded part, the first tool part and / or the second mold part has or have at least one temperature sensor.

Thus, an undesirable thermal stress on the molding can be detected early on the temperature.

A "temperature sensor" is in particular a technical component which detects a temperature of its environment qualitatively or quantitatively. The detected temperature as a qualitative or quantitative measured variable is converted in particular by the temperature sensor into a processible electrical measurement signal. It is particularly advantageous if the temperature sensor is a passive sensor with regard to the use of energy, so that it does not need any auxiliary electrical energy for generating an electrical measuring signal. In particular, a temperature sensor may be a Surface Acoustic Wave (SAW) sensor with a wide temperature range of -50 ° C to over 400 ° C.

In a further embodiment, the tool is assigned a control and / or regulating device, so that the temperature in the mold and / or in the molded part can be set as a function of a measured value of the temperature sensor.

Thus, the temperature of the mold and / or the molded part can be detected and adapted during the forming and / or casting process in real time. Above all, the temperature and / or the thermal load can be controlled and / or regulated according to the requirements of the molded part to be manufactured and / or the various phases of the casting and / or forming process.

A "control and / or regulating device" is a device for controlling and / or regulating a variable and / or a parameter. In the case of control by the control device, in particular one size or several variables influence as input variables a different size than the output variable. The control device influences in particular specifically the temperature in the mold and / or the molded part. In the case of "rules" by the control device, in particular a controlled variable is continuously recorded and compared with another variable (reference variable) and influenced for matching to the reference variable. By the control device, for example, the temperature of the mold and / or the molding is adjusted to a predetermined target temperature.

In order to achieve an optimum temperature distribution over the shape and / or along the contour of the molded part, the first tool part and / or the second tool part has different tempering zones as a function of a local thermal loading of the molded part.

It is particularly advantageous if corresponding tempering zones are arranged in opposite tool parts. As a result, opposing cooling and / or heating zones in opposing tool parts with the same temperature zone and thus very low temperature difference, in particular between ± 5 ° C, preferably between ± 3 ° C can be realized. Consequently, the mold and / or the molding is or are brought on both sides over the tool parts to an identical or very similar temperature. Thus, a local thermal stress is compensated completely circumferentially around the mold and / or the molded part.

In a further aspect of the invention, the object is achieved by a casting device for casting a molded part with a previously described tool.

As a result, locally different melt temperatures during casting are compensated by the thermal compensation in the mold and / or the molded part by means of the tempering device and ensures optimum casting

In addition, the melt flow in the mold can be influenced in a targeted manner by the tempering device or the tempering devices. For example, can be improved by a local heating by means of a tempering of the melt flow within the mold or reduced by cooling the melt flow and / or slowed down.

A "casting device" is in particular a device for casting a molded part. A casting device has, in particular, a melt container, a melt feed, a casting mold and / or a mold-forming tool.

In a further embodiment of the casting apparatus, the first tool part and the second tool part are aligned horizontally and / or vertically by means of a tool holder.

In the conventional prior art vertical alignment of the tool parts during casting, the filling of the vertical mold is promoted by gravity.

It is particularly advantageous that, in the case of a horizontal alignment of the tool parts and thus of the casting mold, in addition the melt flow and / or the melt distribution within the mold can be optimized by the tempering device or the tempering devices.

A "tool holder" is a component which receives and / or holds the tool and / or the tool parts during machining. The tool holder in particular allows a quick change of the tool and provides an interface between the tool and drive.

In an additional aspect of the invention, the object is achieved by a press for casting and / or forming a molded part, wherein the press has a drive for applying a pressing force and / or a tool holder for receiving a tool, with a previously described tool and / or a casting device described above.

Consequently, an optimal hot forming of a workpiece into a molded part and / or casting of a molded part in the press can take place. In addition, the thermal stress of a molded part, which is first cast and then compacted by pressing, can be optimally adapted over all production phases.

Above all, a press is provided which, due to the optimum temperatures during production, enables a qualitatively very high-quality and / or homogeneous manufactured molded part.

In particular, defects in the structure of the molded part are thereby avoided.

A "press" is in particular a forming machine with rectilinear relative movement of the tool. In particular, manufacturing processes such as prototyping, casting, forming, deep-drawing, joining, coating, cutting, cutting and / or changes of material properties are carried out in a press. In particular, a press is a bound, energy or force press.

• - Schließen des Werkzeuges und Ausbilden einer Form zwischen dem ersten Werkzeugteil und dem zweiten Werkzeugteil,
• - Gießen des Formteils aus einer Schmelze und/oder Umformen eines zuvor eingebrachten Werkstücks zu dem Formteil,
• - Temperieren des formumgebenden Materials in dem ersten Werkzeugteil und/oder in dem zweiten Werkzeugteil mittels der Temperiereinrichtung und Erhöhen, Erniedrigen oder Konstanthalten der Temperatur in der Form und/oder in dem Formteil, sodass die thermische Belastung in dem Formteil während des Gießens und/oder des Umformens kompensiert wird.

In a further aspect of the invention, the object is achieved by a method for compensating a thermal load of a molded part during casting and / or forming by means of a previously described tool and / or a previously described casting device and / or a previously described press, with the following steps:

• Closing the tool and forming a mold between the first tool part and the second tool part,
• Casting the molding from a melt and / or forming a previously introduced workpiece to the molding,
• Tempering the mold-surrounding material in the first tool part and / or in the second tool part by means of the tempering device and increasing, decreasing or keeping constant the temperature in the mold and / or in the mold part, so that the thermal load in the mold part during casting and / or of the forming is compensated.

Thus, a method is provided in which the thermal load of a molding during casting and / or forming is kept low or fully compensated. Thus, the method allows the production of a very high quality molded part without defects due to thermal stresses.

• - Schließen des Werkzeuges und Ausbilden einer Form zwischen dem ersten Werkzeugteil und dem zweiten Werkzeugteil,
• - Gießen des Formteils aus einer Schmelze und/oder Umformen eines zuvor eingebrachten Werkstücks zu dem Formteil,
• - Temperieren des formumgebenden Materials in dem ersten Werkzeugteil und/oder in dem zweiten Werkzeugteil mittels der Temperiereinrichtung oder der Temperiereinrichtungen und Erhöhen, Erniedrigen oder Konstanthalten der Temperatur in der Form und/oder in dem Formteil, und
• - insbesondere Kompensieren der thermischen Belastung in dem Formteil während des Gießens und/oder Umformens, sodass ein homogen gefertigtes Formteil vorliegt.

In an additional aspect of the invention, the object is achieved by a method for casting and / or forming a molded part by means of a previously described tool and / or a previously described casting device and / or a previously described press, comprising the following steps:

• Closing the tool and forming a mold between the first tool part and the second tool part,
• Casting the molding from a melt and / or forming a previously introduced workpiece to the molding,
• - Temperieren the mold-forming material in the first tool part and / or in the second tool part by means of the tempering or the tempering and increasing, lowering or keeping constant the temperature in the mold and / or in the molding, and
• - In particular compensating the thermal stress in the molded part during casting and / or forming, so that a homogeneously manufactured molded part is present.

Thus, a method for casting and / or forming is provided in which an optimal casting and / or forming is made possible by thermal compensation of the load of the molding and / or the melt flow. Consequently, a very homogeneous molded part is produced.

In a further aspect of the invention, the object is achieved by a molded part, wherein the molded part is manufactured according to a method described above.

Consequently, a finished molded article having a very homogeneous structure in the required microstructure without gas pockets or other defects is provided.

• 1 eine schematische Schnittdarstellung einer Presse mit Druckgießvorrichtung und Werkzeug mit Induktionsspulen und Wasserkühlung, und
• 2 eine schematische Darstellung von fünf Temperierzonen verteilt über eine Werkzeugkontur und eine Formteilkontur.

Furthermore, the invention will be explained in more detail with reference to embodiments. Show it

• 1 a schematic sectional view of a press with die casting and tool with induction coils and water cooling, and
• 2 a schematic representation of five tempering zones distributed over a tool contour and a molding contour.

A press 101 has a die casting device 103 and a tool 105 on. The tool 105 consists of an upper mold half 107 and a lower mold half 109 , which are aligned horizontally. Furthermore, the press points 101 a drive 115 , a pestle 117 and a tool holder 111 on. On the tool holder 111 is the upper tool half 107 attached. The lower half of the mold 109 is at a press table 119 arranged.

With the tool closed 105 form the upper mold half 107 and the lower half of the mold 109 the mold cavity 113 out.

In the middle of the mold cavity 113 show the upper half of the mold 107 and the lower half of the mold 109 surrounding the mold cavity 113 one water cooling each 127 and a temperature sensor 133 on. Surrounding the both sides outer edges of the mold cavity 113 show the upper half of the mold 107 and the lower half of the mold 109 one induction coil each 125 on. The lower half of the mold 107 also has a temperature sensor on both sides 133 on.

The following operations are done with the press 101 , the die casting device 103 and the tool 105 realized:

In the lower mold cavity 113 the lower mold half is filled by means of a casting robot, not shown, hot melt of a light metal. The tool 105 is closed and the upper half of the mold 107 and the lower half of the mold 109 form the mold cavity 13. through the water cooling 127 In each case, a mold-surrounding material in the middle of the upper mold half 107 and the lower half of the mold 109 cooled to a predetermined temperature by a control device, not shown. This results in a heat flow from the hot melt within the mold cavity 113 to the cooler mold-surrounding material of the upper mold half 107 and the lower mold half 109 , By means of temperature sensors 133 is on both sides in each case a temperature in the form 113 determined and the control device, not shown, a control signal to the water cooling 127 sent to the mold-forming material of the upper mold half 107 and the lower half of the mold 109 continue to cool until a set temperature is reached.

At the same time at the two outer edges of the mold cavity 113 the mold cavity 113 and the melt contained therein by means of the respectively oppositely arranged induction coils 125 the upper tool half 107 and the lower tool half 109 heated, so that the melt passes with an optimum flow rate in these marginal areas with low material thickness of the molded part to be manufactured and thereby premature solidification of the melt is prevented there. The temperature of the melt in these edge regions is determined by means of the temperature sensors arranged on both sides 133 in the upper half of the mold 107 determined and adjusted by means of the control device, not shown. Thus, opposing temperature zones are in the two-sided outer edge regions of the mold cavity 113 with a temperature difference of ± 1 ° C between the mold-forming material of the upper mold half 107 and the lower half of the mold 109 in front.

While the melt in the mold cavity 113 solidified, by means of the drive 115 and the pestle 117 a pressing force on the upper mold half 107 and the lower half of the mold 109 applied for recompression of the cast molding. Due to the pressing force and thus the action of the upper mold half 107 and the lower half of the mold 109 the temperature rises above all in the middle region of the mold cavity 113 so that the centrally located temperature sensors 133 the upper half of the mold 107 and the lower half of the mold 109 detect an increase in temperature above the setpoint temperature.

As a result, the mold-surrounding material becomes the upper mold half 107 and the lower half of the mold 109 and thus the finished molded part due to the rules by means of the control device, not shown, and a stronger cooling by the water cooling 127 cooled to the set temperature and then kept constant, so that the thermal load is compensated by the application of the pressing force.

After completion of the recompression, the tool 105 is opened and the upper mold half 107 over the pestle 117 and the drive 115 moved upwards. Subsequently, the finished molded part by means of a not shown ejector in the press table 119 ejected.

Thus, a press with compensation of the thermal load of the molded part is provided, which allows a thermally adapted casting and recompression and thus a very high quality finished molded part.

In one alternative, a press has a tool for hot forming with a tool contour 201 on. About the tool contour 201 and a molding contour 203 in the form of a steel beam are five tempering zones 205 . 207 . 209 , 211 and 213. The tempering zones 205 . 207 . 209 , 211 and 213 are each opposite in the lower tool and upper tool executed. The molding contour 203 points in the five tempering zones 205 . 207 . 209 . 211 and 213 each have a different wall thickness. By temperature sensors, not shown, in each case a temperature in the respective temperature control zone 205 . 207 . 209 . 211 and 213 the lower and upper tool measured and by means of a control device, not shown, different target temperatures due to the different wall thicknesses in the five temperature zones 205 . 207 . 209 . 211 and 213 set. At the same time a temperature difference of ± 2 ° C between the respective tempering zone 205, 207, 209, 211 and 213 of the lower tool and the upper tool is maintained. Due to the different set temperatures, the entire contour of the molding is affected 203 achieved a uniform cooling rate and thus structural transformation.

Thus, the tempering zones 205 . 207 . 209 211 and 213 optimally both to the tool contour 201 as well as to the molding contour 203 adapted so that the different local thermal loads of the molding are optimally compensated during the hot forming.

LIST OF REFERENCE NUMBERS

101

Press

103

die casting

105

Tool

107

upper mold half

109

lower mold half

111

toolholder

113

mold cavity

115

drive

117

tappet

119

press table

125

induction coil

127

water cooling

133

temperature sensor

201

tool contour

203

Molding contour

205

first tempering zone

207

second tempering zone

209

third temperature zone

211

fourth tempering zone

213

fifth temperature zone

Claims (12)

Tool (105) for casting and / or forming a molded part, which has a first tool part (107) and a second tool part (109), wherein in the case of closing the tool, the first tool part and the second tool part form a mold (113), characterized in that a tempering device (125, 127) is arranged in a tempering distance to the mold, which increases a temperature in the mold and / or the molded part by tempering a mold-surrounding material in the first tool part and / or in the second tool part or holds constant, so that a thermal load in the molded part during casting and / or forming is compensated. Tool after Claim 1 , characterized in that the tool has a second tempering device, a third tempering device, a fourth tempering device and / or a further tempering device. Tool according to one of the preceding claims, characterized in that the tempering device or the temperature control devices is or are an inductive temperature control device (125) and / or a conductive temperature control device (127). Tool according to one of the preceding claims, characterized in that the first tool part and / or the second tool part has at least one temperature sensor (133) or have. Tool after Claim 4 , characterized in that the tool is associated with a control and / or regulating device, so that the temperature in the mold and / or in the molded part in dependence of a measured value of the temperature sensor is adjustable. Tool according to one of the preceding claims, characterized in that the first tool part and / or the second tool part has different tempering zones (205, 207, 209, 211, 213) in response to a local thermal stress of the molded part. Casting apparatus (103) for molding a molded part, characterized by a tool according to one of Claims 1 to 6 , Casting device after Claim 7 , characterized in that the first tool part and the second tool part by means of a tool holder (111) are aligned horizontally or vertically. Press (101) for casting and / or forming a molded part, wherein the press has a drive (115) for applying a pressing force and / or a tool holder (111) for receiving a tool, characterized by a tool according to one of Claims 1 to 6 and / or a casting device according to Claim 7 or 8th , Method for compensating a thermal load of a molded part during casting and / or forming by means of a tool according to one of Claims 1 to 6 and / or a casting device according to one of Claims 7 or 8th and / or a press Claim 9 characterized by the following steps: closing the tool and forming a mold between the first tool part and the second tool part, Casting the molding from a melt and / or forming a previously introduced workpiece to the molding, tempering the molding material in the first tool part and / or in the second tool part by means of the tempering device and increasing, decreasing or maintaining the temperature in the mold and / or in the molding so that the thermal stress in the molding is compensated during casting and / or forming. Method for casting and / or forming a molded part by means of a tool according to one of Claims 1 to 6 and / or a casting device according to one of Claims 7 or 8th and / or a press Claim 9 characterized by the following steps: closing the tool and forming a mold between the first tool part and the second tool part, casting the molding from a melt and / or reshaping a previously introduced workpiece to the molding, tempering the mold-surrounding material in the first mold Tool part and / or in the second tool part by means of the tempering device or the tempering devices and increasing, decreasing or keeping constant the temperature in the mold and / or in the molded part, and - in particular compensating the thermal load in the molded part during the casting and / or forming, so that a homogeneously manufactured molded part is present. Molded part, characterized in that the component according to a method Claim 11 is made.

Images