CN209920482U - Molding machine and operating device for molding machine - Google Patents

Abstract

The utility model relates to a forming machine, the forming machine includes at least one measuring device, at least one measuring device is used for measuring the distance of two selected points of forming machine, at least one measuring device has at least one piezoresistive micro-mechanical sensor. This achieves a high measurement sensitivity and a good mechanical or thermal load bearing environment. Furthermore, the invention relates to an operating device for a molding machine, comprising at least one measuring device for measuring the distance of two selected points of the operating device, the at least one measuring device having at least one piezoresistive micromechanical sensor.

Description

Molding machine and operating device for molding machine

Technical Field

The utility model relates to a make-up machine, in addition the utility model discloses still relate to an operating means for make-up machine.

Background

It is known to detect mechanical stress in one selected member or displacement of two selected members of a molding machine by means of a measuring device having strain gauges. EP2239125B1 discloses a corresponding molding machine.

A drawback of such a forming machine lies in the fact that: strain gauges are only limitedly suitable for use in environments subject to mechanical or thermal loads. Over time, the strain gauge may experience thermal drift, which results in distorted measurement results. Furthermore, the measurement accuracy achievable with strain gauges is hardly any longer satisfactory for modern control methods in molding machines.

It is often problematic that the LSB ("least significant bit") is too large: when only one sensor is used to measure both a small load range and a large load range, the resolution of the strain gauge is often insufficient.

SUMMERY OF THE UTILITY MODEL

The object of the present invention is to provide a molding machine and an operating device for a molding machine, in which the described problems are avoided.

The object is achieved by a molding machine or an operating device for a molding machine according to the invention. The molding machine or the operating device for a molding machine comprises at least one measuring device for measuring the distance of two selected points of the molding machine or the operating device, wherein the at least one measuring device has at least one piezoresistive micromechanical sensor.

Piezoresistive micromechanical sensors usable according to the present invention are sometimes referred to simply as MEMS sensors (MEMS-micro electro mechanical systems). Piezoresistive micromechanical sensors have a sensitivity 100 times that of strain gauges and can be used in environments subject to mechanical or thermal loads. There is no thermal drift and thus the desired long-term stability of the calibration of the measuring device is ensured. The piezoresistive micromechanical sensor provides a signal with excellent linearity. Therefore, the utility model discloses a technological effect lies in at least: the measurement accuracy is increased and the environmental resistance to mechanical or thermal loads is improved.

Piezoresistive micromechanical sensors usable according to the present invention are for example disclosed by the following prior art:

-WO 2010/139034 A2；

a lateral displacement MEMS sensor, v.stavrov et al, twenty-four european sensor conference, 9.5 to 8 days 2010, austria linz;

-sub-nanometer resolution static measurements with MEMS displacement sensors, twenty-fifth european sensor conference, 9/month 4 to 7/year 2011, greece-athens;

contact mode MEMS position sensor with piezoresistive detection, v.todorov et al, the twenty-eighth european sensor conference 2014; and

improving the performance of MEMS piezoresistive pressure sensors using germanium nanowires, s.maflin shary et al, second international conference on nanomaterials and technology (CNT 2014).

In order to measure the change in length, a piezoresistive micromechanical sensor is available which is connected to two selected points between which the distance is measured or between which the change in distance is measured. The two selected points, which measure the distance or change in distance between them, may be provided on the same component or on different components.

For further processing, the measurement signals of the piezoresistive micromechanical sensors or physical quantities derived from these signals can be used directly.

By means of the measuring device, mechanical stresses or thermal deformations in the components of the molding or operating device can be measured or movements of the components of the molding or operating device can be measured. The movement of the molding machine or of the operating device component is also understood to mean, in particular, its displacement.

In particular, it is preferably provided that the piezoresistive micromechanical sensor is connected to the molding machine or the operating device via a measuring body. The measuring body is used to increase the accuracy of the measurement of the distance between selected points by means of piezoresistive micromechanical sensors, in the following manner: the change in distance between the selected points is transmitted to a member of the measuring body that moves relatively in the measuring direction and the piezoresistive micromechanical sensor measures the movement of a movable member of the measuring body. By suitable design of the measuring body (for example by means of the below-described guide for the movable component), a movement in a direction deviating from the measuring direction can be prevented, so that the piezoresistive micromechanical sensor measures a movement only in the measuring direction. But multi-axis piezoresistive micromechanical sensors may also be used. This enables multi-dimensional measurements.

The measuring body can be constructed, for example, as follows:

at least one first component which is fixed relative to one of the setpoint points and at least one second component which is movable relative to the first component and is fixed relative to the other setpoint point are provided, the movement of the at least one first component relative to the at least one second component (in the measuring direction) being measurable by the piezoresistive micromechanical sensor and being able to be provided therefrom as a measuring signal. For this purpose, the piezoresistive micromechanical sensor is connected (e.g. glued) to the first and second component in a suitable manner.

In order to minimize or even exclude influences from directions deviating from the measuring direction, it can be provided that the measuring body has a guide for the at least one first component and/or the at least one second component, which guide at least substantially only allows a movement of the first and/or second component in the measuring direction.

The guide means may here be by means of a flexible hinge

Is connected to the at least one first component and/or the at least one second component. Preferably, each flexible hinge has two hinge parts, which may be configured, for example, in the form of two material weakenings or reductions along the flexible hinge.

The guiding means may be configured as a frame at least partially enclosing the at least one first member and/or the at least one second member. Other designs are also contemplated. For example, the first and/or second member may be movably arranged along the rail.

It can be provided that the measuring body is embodied mirror-symmetrically with respect to an axis of symmetry extending transversely to the measuring direction.

The displacement behavior of the measuring body in respect of different temperatures and the desired compensation of the displacements caused by these temperatures can be taken into account by selecting materials with suitable thermal expansion properties. For example invar can maximize the temperature-induced displacement of two selected points into the measurement, while a more suitable material will minimize, ideally compensate for, the temperature-induced displacement component. Thus, a material more suitable for the measuring body is the same material as the material carrying the two selected spots or a material having the same or similar thermal properties as the material carrying the two selected spots. If the two selected points are provided on different materials, the material of the measuring body is matched to one of the two materials carrying the two selected points, or a suitable compromise is found for the material of the measuring body in respect of the thermal properties of the material with the two selected points. More suitable materials can be determined, for example, by experimentation.

Preferably, the measuring body comprises at least one first component which is fixed relative to one of the selected points and comprises at least one second component which is movable relative to the first component and which is fixed relative to the other of the selected points, a movement, preferably a displacement, of the at least one first component relative to the at least one second component in a measuring direction being measurable by the piezoresistive micromechanical sensor and being providable by the piezoresistive micromechanical sensor as a measuring signal.

Preferably, the measuring body has a guide for the at least one first component and/or the at least one second component.

Preferably, the guide means is connected to the at least one first member and/or the at least one second member by a flexible hinge.

Preferably, the guide is configured as a frame at least partially enclosing the at least one first component and/or the at least one second component.

Preferably, the measuring body is configured mirror-symmetrically with respect to an axis of symmetry extending orthogonally to the measuring direction.

Preferably, the signal of the at least one temperature sensor can be supplied to a microcontroller to compensate for a thermally induced displacement of the measuring body.

Preferably, the microcontroller is integrated in the at least one measuring device, preferably on the measuring body.

Preferably, it can be provided that the measuring body is designed as a thermally symmetrical measuring body.

In addition to the piezoresistive micromechanical sensors, at least one temperature sensor may also be provided. The measured temperature can be used, for example, to compensate for temperature-induced displacements of the measuring body. The measurement evaluation and conversion can take place directly in the at least one measuring device (for example in a microcontroller integrated in the measuring device, preferably the measuring body). If a plurality of measuring devices with temperature sensors are provided, then the measurement data (displacement, temperature) of the different temperature sensors can be carried out in a measurement value converter of one of the measuring devices.

In order to ensure a spatially stable, rigid fixation of the measuring body at the measuring point at two selected points of the molding machine or the handling device, one or more of the following measures can be provided:

-providing means for increasing the friction, such as a membrane between the measuring point and the measuring body;

-using a defined three-point support: sharpening, cutting and the like;

-avoiding bending transmission;

-avoiding sliding friction that may cause hysteresis;

when fixing the measuring device by gluing, the adhesive should be chosen such that the viscoplastic effect of the partly elastic adhesive does not occur.

In particular, it is preferably provided that the piezoresistive micromechanical sensor is fastened to the measuring body with an adjustable prestress. This is because piezoresistive micromechanical sensors in the unloaded state can hardly or not at all withstand compression. By selecting the prestress, the piezoresistive micromechanical sensor can be mounted on the measuring body in a zero position which is different from the unloaded state and thus provides a measuring signal in and against the measuring direction during operation from the zero position.

There are many possibilities with regard to the arrangement of the measuring device on or in the molding machine or the handling device:

for example, it can be provided that the measuring device is part of an injection unit of the molding machine, preferably a cartridge, and that the measuring device is configured to determine the injection force of the injection unit from a measurement signal provided by the piezoresistive micromechanical sensor.

The cartridges are often also referred to as plasticating cartridges, injection cartridges, etc.

Additionally or alternatively, it can be provided that the measuring device is part of a mold clamping unit of the molding machine and that the measuring device is configured to determine a mold clamping force of the mold clamping unit from a measurement signal provided by the piezoresistive micromechanical sensor.

In addition or alternatively, it can be provided that a measuring device is provided on the movable arm of the actuating device and that the measuring device is configured to determine the acceleration of the arm from a measurement signal provided by the piezoresistive micromechanical sensor. In addition or alternatively, the force acting on the operating device (for example the weight of an object arranged on the operating device, preferably to be transported, or the contact force of the operating device) can also be determined by a measuring device arranged on the movable arm of the operating device.

Other application possibilities in the molding machine include, for example:

-positioning at least one measuring device on the mould for measuring the mould breathing;

-at least one measuring device is arranged on the pressing device for the plasticizing cylinder of the molding machine for measuring the pressing force and/or the hot runner decompression;

-arranging at least one measuring device on at least one link of the mould clamping unit of the moulding machine for measuring link elongation and/or mould clamping force distribution;

-an elongation of the cylinder in the pad region in the radial and/or axial direction for measuring the instantaneous internal pressure of the plastic material in the plasticizing cylinder of the molding machine;

the molding machine is preferably designed as an injection molding machine, particularly preferably as a plastic injection molding machine.

Drawings

The details of the invention are explained below with reference to the drawings. The attached drawings are as follows:

figure 1 shows a schematic view of a molding machine according to the present invention;

figure 2 shows a schematic view of an operating device for a moulding machine according to the invention;

fig. 3a, 3b show a schematic representation of a measuring body of a piezoresistive micromechanical sensor in a top view and in a cross-section;

fig. 4a, 4b show in top view and in cross section an alternative design schematic of a measuring body of a piezoresistive micromechanical sensor;

fig. 5 shows a schematic view of an adjustment device;

fig. 6 shows a schematic illustration of the measuring body shown in fig. 3a, 3b with a piezoresistive micromechanical sensor.

Detailed Description

Fig. 1 and 2 show a molding machine 1 according to the invention and an operating device 2 for a molding machine 1 according to the invention, in which a plurality of possible positions of a measuring device 3 are shown.

The details are as follows with reference to fig. 1:

the measuring means 3 at the first position 3.1 are arranged for measuring the injection force,

the measuring device 3 at the second position 3.2 is provided for measuring the instantaneous internal pressure of the plastic material in the plasticizing cylinder of the molding machine,

the measuring device 3 at the third position 3.3 is arranged for measuring the connecting rod elongation and/or the clamping force distribution,

the measuring device 3 at the fourth position 3.4 is arranged for measuring the clamping force,

the measuring device 3 at the fifth location 3.5 is provided for measuring the pressing force and/or the hot runner decompression, and

the measuring device 3 at the sixth position 3.6 is arranged for measuring the mould breathing.

Fig. 3a shows a measuring body 5 of a non-piezoresistive micromechanical sensor 4. The measuring body 5 is of mirror-symmetrical design about an axis of symmetry S and has a first component 51 and a second component 52 which are guided in the measuring direction M by a guide 53 in the form of a frame which surrounds the two components 51, 52.

In this example, the first member 51 is fixedly arranged with respect to the selected point a through the hole 55 and the second member 52 is fixedly arranged with respect to the other selected point B through the hole 56.

The piezoresistive micromechanical sensor 4 yet to be mounted measures the movement of the two edges 57, 58 (i.e. the size of the gap 59 formed by the edges 57, 58, which here is, for example, 1 mm) and outputs it as a measurement signal.

The guide 53 is connected to the first component 51 by four flexible joints 54 and to the second component 52 by four flexible joints 54. These flexible hinges have two material weakenings along their extension in a direction orthogonal to the measuring direction M, thereby creating two hinge portions, respectively, preventing the first and second members 51, 52 from moving in a direction different from the measuring direction M.

Figure 3b shows a cross-section along the line a-a shown in figure 3 a.

An alternative design of the measuring body 5 is shown in fig. 4 a. No mirror-symmetrical design is given here. Fig. 4B shows a cross-section along the line B-B shown in fig. 4 a.

Fig. 5 shows a possible design of an adjusting device 6 for a piezoresistive micromechanical sensor 4.

The adjusting device serves to fix the piezoresistive micromechanical sensor 4 to the measuring body 5 with an adjustable prestress. By selecting the prestress, the piezoresistive micromechanical sensor 4 can be mounted on the measuring body 5 in a zero position which differs from the unloaded state and thus provides a measuring signal in or against the measuring direction M during operation.

The measuring body 5, for example as shown in fig. 3a, b, can be fixed by means of its second member 52 through the hole 56 in the hole 61 or 62 (depending on the size of the hole 56). The first member 51 can then be positioned and secured in the elongated hole 63 through the hole 55 as desired. The size of the gap 59 is varied according to the positioning of the hole 55 in the elongated hole 63. The piezoresistive micromechanical sensor 4 is then connected (e.g. glued) to the first member 51 and the second member 52 in the region of the gap 59. The measuring body 5 together with the piezoresistive micromechanical sensor 4 can now be removed from the adjustment device 6 and be ready for use (see fig. 6).

List of reference numerals

1, a forming machine is used for forming,

2, operating the device to make the device,

3a measuring device is arranged on the base plate,

3.1 measuring a first position of the device,

3.2 measuring the second position of the device,

3.3 measuring a third position of the device,

3.4 measuring the fourth position of the device,

3.5 measuring a fifth position of the device,

3.6 measuring the sixth position of the device,

4a piezoresistive micro-mechanical sensor of the type comprising a piezoelectric layer,

5 measuring the volume of the object to be measured,

51 a first member of the measuring body,

52 the second component of the measuring body,

53 a guide for the measuring body,

54 the flexible hinge of the measuring body,

55 the holes in the first member are such that,

56 the aperture in the second member is such that,

57 the edge of the first member or members,

58 the edge of the second member is then,

59 the gap between the first member edge and the second member edge,

6 adjustment device for piezoresistive micromechanical sensors,

the hole is 61, and the hole,

the holes are 62 holes, and the holes,

the shape of the long hole is 63,

A. b, selecting a fixed point, wherein the fixed point is selected,

m measures the direction of the beam of light,

s axis of symmetry.

Claims (37)

1. Moulding machine comprising at least one measuring device (3) for measuring the distance of two selected points (A, B) of the moulding machine (1), characterized in that the at least one measuring device (3) has at least one piezoresistive micromechanical sensor (4).

2. Moulding machine according to claim 1, characterized in that the piezoresistive micromechanical sensor (4) is connected to the moulding machine (1) by a measuring body (5).

3. Moulding machine according to claim 2, characterized in that the measuring body (5) comprises at least one first member (51) fixed with respect to one of the selected points (A, B) and comprises at least one second member (52) movable with respect to the first member and fixed with respect to the other selected point of the selected points (A, B), the movement of the at least one first member (51) with respect to the at least one second member (52) in the measuring direction (M) being measurable by the piezoresistive micromechanical sensor (4) and being providable by the piezoresistive micromechanical sensor as a measuring signal.

4. The molding machine according to claim 3, characterized in that the measuring body (5) has a guide device (53) for the at least one first member (51) and/or the at least one second member (52).

5. Moulding machine according to claim 4, characterized in that said guide means (53) are connected to said at least one first member (51) and/or to said at least one second member (52) by means of a flexible hinge (54).

6. Moulding machine according to claim 4 or 5, characterized in that the guiding means (53) are configured as a frame at least partially enclosing the at least one first member (51) and/or the at least one second member (52).

7. Moulding machine according to one of claims 3 to 5, characterized in that the measuring body (5) is constructed mirror-symmetrically with respect to an axis of symmetry (S) extending orthogonally to the measuring direction (M).

8. Moulding machine according to one of claims 2 to 5, characterized in that the measuring body (5) is configured as a thermally symmetrical measuring body.

9. Moulding machine according to one of claims 2 to 5, characterized in that at least one temperature sensor is provided in addition to the piezoresistive micromechanical sensor (4).

10. Moulding machine according to claim 9, characterized in that the signal of the at least one temperature sensor can be supplied to a microcontroller to compensate for thermally induced displacements of the measuring body (5).

11. Moulding machine according to claim 10, characterized in that said microcontroller is integrated in said at least one measuring device (3).

12. Moulding machine according to one of claims 2 to 5, characterized in that the piezoresistive micromechanical sensor (4) is fixed to the measuring body (5) with an adjustable prestress.

13. Moulding machine according to one of claims 3 to 5, characterized in that the measuring device (3) is part of an injection unit of the moulding machine (1) and that the measuring device (3) is configured for determining the injection force of the injection unit from the measurement signal provided by the piezoresistive micromechanical sensor (4).

14. Moulding machine according to one of claims 3 to 5, characterized in that the measuring device (3) is part of a clamping unit of the moulding machine (1) and that the measuring device (3) is configured for determining the clamping force of the clamping unit from the measurement signal provided by the piezoresistive micromechanical sensor (4).

15. The molding machine of one of claims 1 to 5, wherein the molding machine is configured as an injection molding machine.

16. Moulding machine according to claim 2, characterized in that the measuring body (5) comprises at least one first member (51) fixed with respect to one of the selected points (A, B) and comprises at least one second member (52) displaceable with respect to the first member and fixed with respect to the other selected point of the selected points (A, B), the displacement of the at least one first member (51) with respect to the at least one second member (52) in the measuring direction (M) being measurable by the piezoresistive micromechanical sensor (4) and being providable by the piezoresistive micromechanical sensor as a measuring signal.

17. Moulding machine according to claim 9, characterized in that said at least one temperature sensor is provided in said at least one measuring device (3).

18. Moulding machine according to claim 9, characterized in that said at least one temperature sensor is arranged on the measuring body (5).

19. Moulding machine according to claim 10, characterized in that the microcontroller is integrated on the measuring body (5).

20. The molding machine of claim 13, wherein the injection unit is configured as a barrel of the molding machine.

21. The molding machine of claim 15 wherein said molding machine is configured as a plastic injection molding machine.

22. Operating device for a moulding machine, said operating device (2) comprising at least one measuring device (3) for measuring the distance of two selected points (A, B) of the operating device, characterized in that said at least one measuring device (3) has at least one piezoresistive micromechanical sensor (4).

23. Operating device for a moulding machine according to claim 22, characterized in that the piezoresistive micromechanical sensor (4) is connected to the operating device (2) by a measuring body (5).

24. Operating device for a moulding machine according to claim 23, characterized in that the measuring body (5) comprises at least one first member (51) fixed with respect to one of the selected points (A, B) and comprises at least one second member (52) movable with respect to the first member and fixed with respect to the other selected point of the selected points (A, B), the movement of the at least one first member (51) with respect to the at least one second member (52) in the measuring direction (M) being measurable by the piezoresistive micromechanical sensor (4) and being providable by the piezoresistive micromechanical sensor as a measuring signal.

25. Operating device for a moulding machine according to claim 24, characterized in that the measuring body (5) has a guide device (53) for the at least one first member (51) and/or the at least one second member (52).

26. Operating device for a moulding machine according to claim 25, characterized in that said guide means (53) are connected to said at least one first member (51) and/or to said at least one second member (52) by means of a flexible hinge (54).

27. Operating device for a moulding machine according to claim 25 or 26, characterized in that the guide means (53) are configured as a frame which at least partially surrounds the at least one first member (51) and/or the at least one second member (52).

28. Operating device for a moulding machine according to one of claims 24 to 26, characterized in that the measuring body (5) is configured mirror-symmetrically with respect to an axis of symmetry (S) extending orthogonally to the measuring direction (M).

29. Operating device for a moulding machine according to one of claims 23 to 26, characterized in that the measuring body (5) is configured as a thermally symmetrical measuring body.

30. Operating device for a moulding machine according to one of claims 23 to 26, characterized in that at least one temperature sensor is provided in addition to the piezoresistive micromechanical sensor (4).

31. Operating device for a moulding machine according to claim 30, characterized in that the signal of the at least one temperature sensor can be supplied to a microcontroller to compensate for thermally induced displacements of the measuring body (5).

32. Operating device for a moulding machine according to claim 31, characterized in that said microcontroller is integrated in said at least one measuring device (3).

33. Operating device for a moulding machine according to one of claims 23 to 26, characterized in that the piezoresistive micromechanical sensor (4) is fixed to the measuring body (5) with an adjustable prestress.

34. Operating device for a moulding machine according to one of claims 24 to 26, characterized in that the measuring device (3) is arranged on a movable arm of the operating device (2) and in that the measuring device (3) is configured to determine the acceleration of the movable arm from a measuring signal provided by the piezoresistive micromechanical sensor (4).

35. Operating device for a moulding machine according to claim 23, characterized in that said measuring body (5) comprises at least one first member (51) fixed with respect to one of said selected points (A, B) and comprises at least one second member (52) displaceable with respect to the first member and fixed with respect to the other of said selected points (A, B), the displacement of said at least one first member (51) with respect to said at least one second member (52) along the measuring direction (M) being measurable by means of the piezoresistive micromechanical sensor (4) and being providable by the piezoresistive micromechanical sensor as a measuring signal.

36. Operating device for a moulding machine according to claim 30, characterized in that said at least one temperature sensor is provided in said at least one measuring device (3).

37. Operating device for a moulding machine according to claim 30, characterised in that said at least one temperature sensor is provided on the measuring body (5).

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