KR101975699B1 - Mold closing unit for a molding machine - Google Patents

Abstract

The mold closing unit 1 for a molding machine comprises a machine frame 2, a movable mold mounting plate 3 movable with respect to the machine frame 2, a stationary mold mounting plate 4, a movable mold mounting plate 3 And a determination device (6) for determining a degree of parallelism of the mold mounting plates (3, 4) with respect to each other, the determination device (6) comprising at least one measurement unit And the measuring unit 7 comprises a molding tool 8 mounted between the closing mechanism 5 and the movable mold mounting plate 3 and / or one of the mold mounting plates 3 and 4 and two Is disposed between one of the mold mounting plates 3, 4.

Description

[0001] The present invention relates to a mold closing unit for a molding machine,

The present invention relates to a machine frame, a movable mold mounting plate movable with respect to the machine frame, a stationary mold mounting plate, a closing mechanism for moving the movable mold mounting plate, and a decision device for determining the parallelism of the mold mounting plates with respect to each other. A mold closing unit for a molding machine, in particular an injection molding machine, wherein the determining device comprises at least one measuring unit.

The mold half of the molding tool, which is essentially mounted on the mold mounting plate, is kept as parallel as possible during injection of the melt for the quality of products (e.g., injection molded parts) produced in the molding machine, The distribution of the closing force is the same. As a result, the at least one cavity formed in the molding tool also maintains the desired shape and position so that the injected melt will accurately shape the cavity during curing. In particular, for high precision products such as, for example, optical lenses, this is of great relevance.

In general, it is already known to measure the degree of parallelism of mold halves or mold mounting plates with respect to each other. Starting with this measurement, in order to reach the desired parallelism again, corresponding precautionary measures can be taken if nonparallelism occurs.

For example, EP 0 712 710 B1 discloses an injection molding machine in which pressure transducers are mounted on a mold half. The pressure transducers are each placed in the mold separation line in contact with the other mold half of the contact. However, it is also possible to use a distance measuring device attached to both platens. The parallel position can be checked via this means or can be automatically adjusted by controlled adjustment of the compensating cylinder with the pressure medium.

In addition, the AT 008 829 U1 has a distance measuring device (specifically, an ultrasonic measuring device) disposed at each of the four corner points of the mold mounting plate and the distance between the two mold mounting plates can be accurately measured with this measuring device And the like. There is also a platen parallelism control in which, in the case of a determined difference between the measured signals, the control valve is adjusted in such a way that the eccentric back pressure caused by the forming tool is compensated by the different oil discharge from the four cylinder chambers. By doing so, the parallelism of the two mold mounting plates is ensured during the opening stroke.

In a similar manner, AT 007 859 U1 discloses a method for monitoring the closing force of an injection-molded tool. Wherein the distances from each other at at least one point of the pressure or end faces that actuate the end faces are determined by at least one sensor.

DE 10 2007 043 855 C5 shows intentional tilting of the mold mounting plate. Also here, the distance between the mold tool halves is measured and monitored at various locations. In particular, the distance measuring device is provided on the four corner areas of the forming tool at the dividing line of the forming tool to form four moving paths. An appropriate off-set may then be predetermined for the movement path. As a result, one half of the molding tool takes a slightly inclined position.

It is also known from DE 10 201 05 012 216 A1 that a distance measuring sensor is arranged on a tie bar of a molding machine. During the injection stamping process, the position value detected by the distance measuring sensor is corrected by the force value also detected by the existing force sensor, taking into account the determined table of strain values. The result is a very accurate understanding of the actual parallelism of the stamping gap on the injection stamping tool (or in the case of non-parallel directions of the mold tool halves relative to one another) without relying on additional sensors.

It is an object of the present invention to provide an alternative or improved mold closure unit as compared to the prior art. In particular, meaningful and as precise detection as possible of nonparallelism and / or closing force distribution should be possible.

This is solved by a mold closure unit having the features of claim 1. According to the present invention, a structure is provided in which a measuring unit is disposed between a mold tool mounted on one of the mold mounting plates and one of two mold mounting plates, between the closing mechanism and the movable mold mounting plate. This allows the determination of the force distribution on the mold mounting plate and the tilted position of the injection-molded part or the forming tool can be ascertained. Thus, a more direct determination of the degree of non-parallelism is possible, since the measurement is performed relatively close to at least one cavity of the forming tool.

According to a preferred embodiment, in the second modification, a structure is provided in which at least one measuring unit is disposed between a molding tool and a stationary mold mounting plate.

For example, the structure in which the measuring unit connects one of the closing mechanism and the movable mold mounting plate and / or the molding tool with the mold mounting plate is preferably provided to prevent the influence or distortion of the determination result by the friction or damping element / RTI > Particularly preferably, only the measuring unit connects one of the drive unit and the movable mold mounting plate and / or the molding tool and the mold mounting plates. Thus, during application of the closing force, the total force flux travels over at least one measurement unit.

It is generally possible for the tie bar to extend through the mold mounting plate. Thus, in the case of such a molding machine, it relates to a vertical or horizontal tie-bar machine. Alternatively, a structure may be provided in which the end plate is connected to the stationary mold mounting plate via a traction plate. Thus, in the case of such a forming machine, it is associated with a vertical gantry machine or a gantry press.

The present invention relates to a machine frame formed in a substantially C-shape, on the other hand having two limbs; A removable mold mounting plate movable relative to the machine frame; A stationary mold mounting plate supported on the rim of the machine frame; And a closing mechanism supported on the other rim of the machine frame and for moving the movable mold mounting plate, without a tie bar.

Such a mold closure unit is illustratively known from AT 514 247 B1. This document shows a mold closing unit without a tie bar, wherein an apparatus for adjusting or adjusting plate parallelism is provided. Specifically, it is performed by a tempered actuator formed from a heatable metal bar.

An object of this aspect of the invention is to provide an improved mold-closing unit without a tie bar. In particular, accuracy will improve.

This is solved by a tie-bar-free mold closing unit having the features of claim 4. According to the present invention, a determination apparatus for determining the parallelism of the mold mounting plates to each other is provided.

In a mold closing unit without such a tie bar, the stationary mold mounting plate is supported on the cross beam of the machine frame by means of a supporting element, preferably comprising a pressure rod, in the lower region and in the upper region on the two side portions of the machine frame A supported structure is preferably provided.

In order to determine the parallelism, a structure in which the crystal device includes at least two measuring units is preferably provided. In order to make the determination or measurement possible as precisely as possible, a structure in which one of the measuring units is disposed on one of the side portions of the machine frame or between one of the side portions and the stationary mold mounting plate is preferably provided .

In order to achieve more accurate determination or measurement, it is preferred that the crystal arrangement comprises at least three measuring units and one of the measuring units is arranged on each side part, either each or each of the two side parts, and the stationary mold mounting plate Is provided. Also particularly preferred is a structure in which one of the measuring units is disposed on a support element or between a support element and a stationary mold mounting plate.

In the case of the arrangement of the measuring unit between the side part and the stationary mold mounting plate, a structure is preferably provided in which the side part is connected to the mold mounting plate only through the measuring unit. Further, in the case of the arrangement of the measuring unit between the supporting element and the stationary mold mounting plate, a structure is preferably provided in which the supporting element is connected to the stationary mold mounting plate only through the measuring unit.

Especially for the mold closing unit without tie bars, because of the closure force, especially as a compensation for the spacing of the different mold mounting plates, the " intelligent frame " or joint between the mold mounting plate and the frame Bending joint) is used. In order to prevent or reduce gapping, the compensating component may also detect or process the measured value (for example, by strain gauges). Preferably, the compensating component is formed separately from the determining device for determining the degree of parallelism of the mold mounting plate. However, it will not be excluded that the measured value determined for compensation is additionally used in the decision device for determining the parallelism. Another example for non-parallelism caused by the closing force is the uneven force action of the pressure pad in the case of two platen mold closing units. Because of the (pure) closure force, possible nonparallel compensation is not an object of the present invention, because it already occurs prior to injection; The present invention relates to a nonparallelism caused by (additional) yarn output.

Preferred embodiments that apply to both aspects of the present invention are cited below. Thus, a structure may preferably be provided in which at least one measuring unit includes a measuring body and at least one measuring sensor attached to the measuring body. The measuring body may be formed as a measuring membrane, a load cell, a pressure bolt or a bending element. The measurement sensor may be formed, for example, as a strain gauge or a piezoelectric sensor.

In this connection, a structure in which several measuring sensors are arranged on the measuring body about the longitudinal axis of the molding machine can preferably be provided. For good detection of a nonuniform closed force distribution, this is advantageous when the measuring sensors are arranged at a constant distance from one another. In particular, this is additionally advantageous when the measuring sensors are arranged at the same distance relative to the longitudinal axis of the molding machine.

As such, any kind of measurement or calculation can be performed with at least one measurement unit. However, preferably a structure is provided in which force measurement, tension measurement and / or distance measurement is performed by at least one measurement unit.

Also preferably, the determination device comprises an evaluation unit, wherein a value measured by the at least one measurement unit can be signaled to the evaluation unit and the value transmitted is evaluated by the evaluation unit, Lt; / RTI > This evaluation unit may be, for example, part of an open or closed loop control unit of the entire molding machine. Also, in the case of different values, a warning signal can be emitted by the crystal device, a parallelism deviation value can be emitted and / or a correction device, preferably a thermal length changing element or piezoelectric actuator, A structure for causing a calibration movement can be preferably provided. If the compensating device is formed as one or several piezoelectric actuators, then this actuator simultaneously forms a measuring unit at the same time. With the thermal length variation element, for example, the side portion or the tie bar can be heated or cooled. The length changing element may also be formed as a heatable, preferably metal, bar as described in AT 514 247 B1.

Finally, the molding machine having the mold closing unit according to the present invention is also protected.

Hereinafter, other details and advantages of the present invention will be more fully described with reference to the embodiments shown in the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a side view of a machine without a tie bar having a measuring membrane between a closing mechanism and a movable mold mounting plate,
Figure 2 is a front view of a gantry machine having a measuring membrane between a stationary mold mounting plate and a forming tool,
Figure 3 shows a plan view of the measuring membrane of Figure 2,
Figure 4 is a front view of a gantry machine having a measurement membrane between a closing mechanism and a movable mold mounting plate,
Figure 5 shows a top view of the measuring membrane of Figure 4,
Figure 6 is a front view of a gantry machine having a measuring unit in the form of a pressure bolt between a stationary mold mounting plate and a forming tool,
Figure 7 shows a plan view of the mold half with the pressure bolts of Figure 6,
Fig. 8 shows a perspective view of a mold closing unit without a tie bar,
Figure 9 shows a side view of a mold-closing unit without a tie bar with a measuring unit and a support element on the side part,
Figure 10 shows a side view of a mold-closing unit without a tie bar with a measuring unit between the side part or the supporting element and the stationary mold mounting plate,
Figure 11 shows a side view of a strain gauge attached within the radius of the side portion and on the pressure bolt of the support element,
Figure 12 shows a side view of a tie-bar-free mold closing unit with a measuring membrane between the closing mechanism and the movable mold mounting plate.

In Fig. 1, a mold closing unit 1 of a molding machine is shown in a side view. A mold closing unit 1 of a so-called three-platen machine with a terminal plate 20, a movable mold mounting plate 3 and a stationary mold mounting plate 4 is shown (machine frame 2) Are not shown. All plates are preferably through four tie bars (9). The mold closing unit 1 includes a closing mechanism 5 in the form of a toggle lever mechanism driven by a driving device 19 (motor). The movable mold mounting plate 3 is linearly movable along the longitudinal axis L of the molding machine with respect to the end plate 20 and the stationary mold mounting plate 4 by means of a closing mechanism 5. The measuring unit 7 is arranged between the closing mechanism 5 and the movable mold mounting plate 3. In particular, the closing force transmission from the closing mechanism 5 onto the movable mold mounting plate 3 is carried out only through the measuring unit 7. In this case, the measuring unit 7 is formed as a measuring membrane, wherein only one measuring body 15 of the measuring unit 7 can be seen in Fig.

Fig. 2 shows a mold closing unit 1 in the form of a so-called vertical gantry machine. Here, the stationary mold mounting plate 4 is formed as an underframe 26 and is connected to the end plate 20 via a traction plate 21. The closing mechanism 5 shown schematically is acting between the end plate 20 and the movable mold mounting plate 3. The mold halves 22 of the forming tool 8 are attached to the movable mold mounting plate 3. The cavity K of the forming tool 8 is formed by the mold half 22 and the mold half 23 in the closed state of the molding tool 8. The measuring unit 7 is positioned between the stationary mold mounting plate 3 and the mold half 23. In this case, in addition to the measuring body 15, a measuring sensor 16 is also shown. The measuring sensor 16 is arranged on a relatively small and therefore deformable measuring bridge 24 of the measuring body 15. The measurement bridge 24 is the first element to be deformed when the closing force is applied. This measuring unit 7 is formed as a measuring membrane.

Fig. 3 shows a plan view to the measuring unit 7 shown in Fig. 2 in the form of a side view. It can be seen that the measuring sensors 16 are arranged on the measuring body 15 with a constant distance from each other and with the same distance to the longitudinal axis L of the molding machine.

2, the measuring unit 7 comprises a determination device 6 for determining the degree of parallelism (and non-parallelism) of the mold mounting plates 3 and 4 with respect to each other with the evaluation unit 17 ). The individual values measured by the measurement sensor 16 are transmitted to the evaluation unit 17 in the form of an appropriate signal S. The evaluation unit 17 compares the values of the individual measurement sensors 16. Since the measuring sensors 16 are all arranged with the same distance relative to the longitudinal axis L of the molding machine, the same value for all of the measuring plates 3 and 4 in relation to each other, (16). However, if there is a deviation, an appropriate warning signal can be emitted by the evaluation unit 17. However, correction of the tilted position of the plate can also be performed, for example, by a correcting device 18 (not shown here). The evaluation unit 17 may be part of the open or closed loop control unit of the entire molding machine. The injection of the plastic melt into the cavity K can be performed by an injection unit (not shown).

Fig. 4 differs from Fig. 2 in that the measuring unit 7 is disposed between the closing mechanism 5 and the movable mold mounting plate 3. Fig. In addition, the parallelism determination and arrangement of the measurement sensor 16 (see FIG. 5) is the same as in FIG.

In Figure 6, the measuring unit 7 is not formed as a measuring membrane - in contrast to Figure 2, but the measuring unit 7 comprises several pressure bolts. This pressure bolt forms the measuring body 15 and connects the molding tool 8 to the stationary mold mounting plate 4. [

7 shows a plan view of the measuring unit 7 to the measuring body 15. Fig. As can be seen in Fig. 7, the individual measuring bodies 15 all have the same distance with respect to the longitudinal axis L of the molding machine. In this case, the longitudinal axis L of the molding machine is the same as the center of the mold half 23 and therefore the center of the mold mounting plates 3 and 4. For example, a measurement sensor 16 (not shown) in the form of a strain gage is placed on an individual pressure bolt.

Fig. 8 shows a mold closing unit 1 without a tie bar in a perspective view. In this case, the machine frame 2 is formed in a C shape. A closing mechanism 5 for moving the movable mold mounting plate 3 is supported on the rim 11 (limb) of the machine frame 2. The stationary mold mounting plate 4 is supported on another rim 10 of the machine frame 2. In the upper region, the stationary mold mounting plate 4 is supported on the two side portions 14 of the rim 10 of the machine frame 2. In the lower region, the stationary mold mounting plate is supported on the cross beam (13). For this reason, the support element 12 is arranged between the stationary mold mounting plate 4 and the cross beam 13. [ The support element 12 includes a pressure rod.

As shown in Fig. 9, the measuring unit 7 is attached to the pressure rod of the support element 12. Fig. In addition, a measurement unit 7 is attached to both side portions 14. In this case, the measuring unit 7 is formed as a load cell. The deformation of the side portion 14 and of the support element can be detected by the measuring unit 7. Since the measuring unit 7 is part of the crystallizing device 6 (not shown), the tilting position of the stationary mold mounting plate 4 can be determined by this measuring unit 7. [ For this purpose, in particular the current measurement value can be compared with the stored value. In the case of a deviation from the correct parallelism of the plate, the correction can be performed by the correction device 18. In this case, the pressure rod of the support element 12 simultaneously forms the compensating device 18. Due to the change in thermal length caused by heating or cooling the pressure rod by means of a suitable tempering device (e.g., a heating tape), the position of the stationary mold mounting plate 4 is influenced until the desired parallelism of the plate is reached again Can receive. This can be done in the form of an adjustment by the evaluation unit 17 (not shown here) of the crystal device 6. [

10, the measuring unit 7 is arranged between the side portion 14 of the rim 10 of the C-shaped machine frame 2 and the stationary mold mounting plate 4. In contrast to Fig. The measuring unit 7 is also disposed between the supporting element 12 and the stationary mold mounting plate 4. [ Thereby, much more precise determination of the parallelism deviation is possible.

According to Fig. 11, the measurement sensors 16, in particular the strain gages, are attached to the curved surfaces of the side portions 14 of the C-shaped machine frame 2, respectively. The measuring sensor 16 is arranged at a distance of about 90 mm from the butting surface of the stationary mold mounting plate 4. [ For monitoring the horizontal parallelism, the tension in the curved surface of the side portion 14 is taken into account at the user side and at the back side. Additionally, at least one measurement sensor 16 (strain gage) is attached laterally (as shown) at approximately the center of the pressure rod of the support element 12. Preferably the two measurement sensors 16 are preferably centrally attached to the pressure rods of the support element 12 on the upper and lower sides. To determine the vertical parallelism, the average tension of the pressure rod (bolt) and the average tension of the side portion 14 are taken into account.

12 shows a variant in which, in the case of a mold closing unit 1 without a tie bar, a measuring unit 7 (in the form of a measuring membrane) is arranged between the closing mechanism 5 and the movable mold mounting plate 3. This measuring unit 7 can be additionally or alternatively provided to the measuring unit 7 shown in Figs.

The present invention has the following advantages:

The force distribution on the mold mounting plate or the tilting position of the injection molded part or the forming tool is determined, although the force is not measured as a whole.

- Very accurate measurement is possible. In particular, if the measurement occurs directly behind the mold mounting plate, there is no friction or damping effect in front of the measuring instrument.

- For applications without mechanical mold overlays (forces exclusively on plastic melts), the distribution of the closing force at the tilted position is detected. Thus, a defective portion can be detected, or it can be adjusted with additional cylinders, actuators (e.g., piezoelectric) or electromechanical drives.

Preferably, the load cell is an actuator at the same time and can also adjust the force distribution immediately.

- Detection of asymmetric forces and non-parallel forming tools during mold closure (other friction in the guide bolt) is possible. This leads to mold protection.

The present invention can be used for vertical and horizontal machines. It has nothing to do with the enclosed system used.

- (for membrane measurements) Depending on whether the inner ring of the membrane or the outer ring of the membrane is mounted on the mold mounting plate, the force distribution can be further pulled outward or towards the center of the plate.

- the measuring membrane can be constructed in such a way that deformation of the movable or stationary mold mounting plate is intentionally permitted (e.g. in the case of a machine without a tie bar) and also each can be measured.

1: mold closing unit
2: Machine frame
3: Removable mold mounting plate
4: Fixed mold mounting plate
5: Closure mechanism
6:
7: Measuring unit
8: Molding tool
9: Taiba
10: rim
11: rim
12: Support element
13: cross-beam
14: side portion
15: Measuring body
16: Measuring sensor
17: Evaluation unit
18: Correction device
19: Driving device
20: end plate
21: traction plate
22: half mold
23: half mold
24: Measurement bridge
26: Lower frame
L: longitudinal axis of the molding machine
K: cavity
S: Signal

Claims (17)

A substantially C-shaped machine frame (2) having two limbs (10, 11); A movable mold mounting plate (3) movable relative to the machine frame (2); A stationary mold mounting plate (4) supported on the rim (10) of the machine frame (2); A closing mechanism (5) for moving the movable mold mounting plate (3) supported on another rim (11) of the machine frame (2); And a determination device (6) for determining the degree of parallelism of the mold mounting plates (3, 4) with respect to each other, characterized in that the determination device (6) comprises at least one measurement unit , Molding machines, tie bar-less mold closing units. 2. A machine according to claim 1, characterized in that the stationary mold mounting plate (4) is mounted on the cross-beam (13) of the machine frame (2) Is supported on two side portions (14) of the tie bar. A mold closing unit according to claim 2, characterized in that the support element (12) comprises a pressure rod. A mold closing unit according to claim 2, characterized in that the determination device (6) comprises at least two measuring units (7). 5. A machine according to claim 4, characterized in that one of the measuring units (7) is mounted on one of the side parts (14) of the machine frame (2) Wherein the tie bar is disposed between the first and second tie bars. 3. Apparatus according to claim 2, characterized in that the crystallizing device (6) comprises at least three measuring units (7), one of the measuring units (7) (14) and the stationary mold mounting plate (4). ≪ Desc / Clms Page number 13 > 5. A device according to claim 4, characterized in that one of the measuring units (7) is arranged on the support element (12) or between the support element (12) and the stationary mold mounting plate (4) No Mold Closure Unit. 2. The apparatus according to claim 1, characterized in that the at least one measuring unit (7) comprises a measuring body (15) and at least one measuring sensor (16) attached to the measuring body No Mold Closure Unit. The mold closing unit according to claim 8, characterized in that the measuring body (15) is in the form of a measuring membrane, a pressure bolt or a bending element. The mold closing unit according to claim 8, wherein the measurement sensor (16) is in the form of a strain gauge or a piezoelectric sensor. The mold closing unit according to claim 8, characterized in that several measuring sensors (16) are arranged on the measuring body (16) around the longitudinal axis (L) of the molding machine. 12. The mold closing unit according to claim 11, wherein the plurality of measurement sensors (16) are disposed at a predetermined distance from each other. 13. The method according to claim 11, wherein the plurality of measurement sensors (16) are located at the same distance on the measuring body (16) about the longitudinal axis (L) Wherein the tie-bar-shaped mold-closing unit is provided with a tie-bar. The mold closing unit according to claim 1, characterized in that force measurement, tension measurement and / or distance measurement is performed by said at least one measurement unit (7). 2. Apparatus according to claim 1, characterized in that the determination device (6) comprises an evaluation unit (17), the values measured by the at least one measurement unit (7) , And the transferred value can be evaluated or compared by the evaluation unit (17). 16. The method of claim 15, wherein if the values are different,
- a warning signal can be emitted from the crystal device 6,
- a parallel deviation value may be emitted, and / or
Characterized in that either the compensating device (18), or one of the thermal length changing element or the piezoelectric actuator, causes a compensating movement of one of the mold mounting plates (3, 4). A molding machine comprising a mold closing unit (1) according to any one of claims 1 to 16.

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