JPH0260202B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an automatic stack thickness control device in a progressive die device for manufacturing a laminated iron core.

[Conventional technology]

FIG. 1 is a sectional view showing an example of a progressive mold apparatus for manufacturing a laminated core. This mold device has a first station to a fifth station, and a first station to a fifth station.
In the station, as shown in Figure 2, the strip 1 has a skew escape round hole 2 and a pilot hole 3.
A shaft hole 4 and a lotus slot 5 are bored at the second station. At the third station, a cut-and-raised protrusion extraction hole 6 and a cut-and-raised protrusion 7 (see Fig. 3 a, b) leading to the skew escape round hole 2 are formed, and as shown in Fig. 4 a, b. , a hole 6a corresponding to the cut-and-raised protrusion from which the cut-and-raised protrusion 7 has been removed.
are formed every predetermined number of sheets. Due to the structure of the mold, the fourth station is an idle station for maintaining strength, and no processing is performed, and the fifth station performs outline cutting, caulking, and skew processing of the laminated iron core pieces 9 in the die 8.

As schematically shown in FIG. 5, the punch 10 in the third station has a lower cutting edge 10a formed in a shape necessary for forming the cut and raised protrusion 7, and an upper end serving as a base facing into the punch holder 11. It is formed in the cam portion 12. This cam portion 12 is a tapered cam, and a cam 14 is driven forward and backward by a solenoid 13 attached to the punch holder 11.
is in constant contact with. When the vertically moving punch holder 11 descends to the lowest end, the cutting edge 10a of the punch 10 is holding down the stripper 1.
The amount of protrusion from the lower surface of 5 is the cut and raised protrusion 7.
When forming the hole 6, the protrusion 7 is maintained so that the protrusion amount does not exceed the thickness of the strip 1, but when the hole 6a is formed, the protrusion amount is maintained to be more than twice the thickness of the strip 1. (See Figures 6 and 7).

This change in the amount of protrusion is applied to the punch 10 by displacement of the cam 14. The time to increase the protrusion amount of the punch 10 is when the press stroke is performed by the number of laminated core pieces 9 required for one laminated core.

At the fifth station, the punch 16 punches the laminated core piece 9 having the cut and raised projections 7 into the die 8 from the portion indicated by the imaginary line 17 shown in FIG. It can be rotated by the amount corresponding to the amount. Note that detailed explanation thereof will be omitted here.

On the other hand, a cylinder 18 is provided within the die 8 . This cylinder 18 generates receiving pressure when punching and caulking is performed by the punch 16, and each time it is caulked, the cylinder 18 descends by an amount equivalent to the thickness of the laminated core pieces 9. Also, when taking out a product formed by laminating a predetermined number of laminated core pieces 9, is lowered to the extraction position. cylinder 18
When the cylinder 18 is lowered to the removal position, the product on the cylinder 18 is pushed out by another cylinder 19.

The mold device with the above configuration controls the stacking thickness of the product by forming holes 6a (Fig. 4) for non-coupling in the laminated core 9 for each predetermined number of sheets, so the thickness deviation of the strip 1 There is a problem with variations in the stacking thickness of the product. Incidentally, JIS standards allow a tolerance of ±10% for the thickness of electrical steel sheets used for electrical equipment, so the thickness of the laminated core can vary by up to 20%. In addition, since a normal laminated core is formed by stacking 50 to 100 core pieces, the plate thickness is 0.5
50mm by stacking 100 strips using mm strips
When manufacturing thick products, there is a maximum variation of 10 mm, and a product with a plus error would require 10 extra laminated core pieces to be combined in one product. This waste not only causes economic loss, but also has the negative effect of unstable product accuracy and characteristics.

On the other hand, a proximity switch detects the lowering position of the cylinder 18 when the laminated core piece 9 drawn into the die 8 reaches a desired stacking thickness. There is a device that controls the stacking thickness of products by forming holes 6a (Japanese Patent Application No. 59-70542).

Generally, it is difficult to install a proximity switch so as to detect a desired position with high precision, but the above-mentioned device is particularly characterized in that it solves this problem.

That is, the proximity switch is installed so as to detect a position that is above the lowered position of the cylinder 18 when the desired stacking thickness is reached by the installation position error (1 to 2 mm) of the proximity switch, and the proximity switch is turned on. When this happens, a cut signal is output and the punch 10 is
The amount of protrusion is increased to form the non-coupling hole 6a. Note that the station that forms the hole 6a for non-coupling is the third station, and the station that laminates the laminated core pieces is the fifth station, so the hole 6a for non-coupling is formed after outputting the above cut signal. Three laminated core pieces including the laminated core piece for separation are laminated before the laminated core piece for separation is laminated. Therefore, the desired stacking thickness is set to be smaller than the stacking thickness of one product by the thickness of three plates.

Then, we actually measure the laminated thickness of the core laminated as described above, find the difference from the lamination thickness of one normal product, and from next time, we will further laminate the number of laminated core pieces corresponding to this difference. do. That is, the cut signal is output after the press stroke for the above number of sheets after the proximity switch is turned on.

[Problem that the invention seeks to solve]

The above-mentioned conventional device can manage a smaller number of products than a device that manages product stacking thickness only by managing the number of products, and thus can reduce the error in stacking thickness accordingly. However, the proximity switch The number of pieces from when the cut signal is turned on until the cut signal is output, and the number of pieces from when the cut signal is output until the laminated core pieces for separation are stacked (three pieces in the case of the mold device shown in Figure 1). Since the stacking thickness for the total number of sheets is not measured, there is a possibility that a stacking thickness error of ±1 sheet may occur depending on the case.

In addition, when manufacturing products with different stack thicknesses, it is necessary to change the mounting position of the proximity switch and calculate the number of press strokes from when the proximity switch is turned on until the cut signal is output, which can be easily handled. I can't.

The present invention has been made in view of the above-mentioned circumstances, and provides an automatic stacking thickness management device in a progressive die device for manufacturing a laminated core, which can keep errors in the stacking thickness of the laminated core within the thickness of one laminated core piece. The purpose is to provide.

[Means and actions for solving problems]

According to the present invention, a rod is provided that contacts the laminated core piece drawn into the die from below, and the position of this rod is continuously detected by a linear scale, and based on the detection output of the linear scale. detects that the position of the rod has lowered by a predetermined amount related to the laminated thickness of one laminated core, and upon this detection, a cut signal is sent to form a laminated core piece for separation (a hole for uncoupling). I am trying to output .

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 8 shows the fifth station of the mold apparatus according to the present invention, and shows the initial state in which the laminated core piece is not drawn into the die 8.

In the figure, the cylinder 20 is a double-rod cylinder that receives from below the laminated core piece that is pulled out into position 8 by the punch 16, and generates receiving pressure during caulking, as well as performs a lifting motion when taking out the product. .

A rack 21 is disposed on the lower rod of the cylinder 20, and a pinion 22 that meshes with the rack 21 is fixed at a predetermined position of the mold device. Also,
An incremental encoder 23 is provided on the rotation shaft of this pinion 22. Therefore,
By counting the pulse signals output from the incremental encoder 23, the cylinder 20
It is possible to continuously detect the amount of movement in the vertical direction.

Note that the cradle of the cylinder 20 is provided with a proximity switch 24 that detects when a predetermined pressing force is applied.

FIG. 9 is a block diagram showing an embodiment of the automatic stacking thickness management device according to the present invention. In the figure, the phase detection circuit 30 detects the press stroke signal (first
For example, a pulse signal is output to the counter 31 each time the press reaches the top dead center. The counter 31 is reset to 0 in the initial state, counts the pulse signals inputted thereafter, and outputs a signal indicating the counted value to the coincidence detection circuit 32.

A signal indicating a predetermined number of sheets is applied to another input of the coincidence detection circuit 32 from a sheet number setting device 33.
When the two input signals match, the match detection circuit 32 outputs a match signal to the contact 34a of the changeover switch 34. Note that the number of laminated core pieces necessary for the laminated thickness of one product is preset in the number setter 33.

If the movable contact piece 34c of the changeover switch 34 is connected to the contact 34a, the coincidence signal from the coincidence detection circuit 32 is applied to the output circuit 35 via the changeover switch 34. Output circuit 35
receives the coincidence signal and outputs a cut signal for forming a non-coupling hole 6a in the laminated core piece 9. This cut signal energizes the solenoid 13 shown in FIG. 5 to change the amount of protrusion of the punch 10.

In this way, the movable contact piece 34 of the changeover switch 34
When c is connected to contact 34a, control similar to the conventional control method in which the stacking thickness of the laminated core is determined by number management is performed.

On the other hand, the linear scale 40 is composed of the above-mentioned incremental encoder 23 and up/down counter 41. The up-down counter 41 counts the pulse signals input from the incremental encoder 23 and outputs a signal indicating the counted value to the arithmetic circuit 46.

Note that a signal from a delay circuit 43 is applied to the reset input of the up-down counter 41. This delay circuit 43 receives the coincidence signal output from the changeover switch 34, delays it by a time corresponding to three press strokes, and outputs it. In the above three strokes, a match signal (cut signal) is output, a hole 6a for non-coupling is formed in the laminated core piece 9 at the third station, and the laminated core piece is punched and laminated at the fifth station. means the number of strokes,
Therefore, this number of strokes is
If the station positions of the station that forms a and the station that punches out the laminated core piece change, the change will occur accordingly.

Since the up-down counter 41 is reset to 0 by the signal from the delay circuit 43 as described above, the count value of the up-down counter 41 is determined by the laminated core piece in which the non-coupling hole 6a is formed in the die. The cylinder position when stacked is used as a reference, and the amount of elevation and descent of the cylinder 20 from this reference is shown.

The memory 45 stores the actual measured value of the product taken out last time, and the arithmetic circuit 46
A signal representing an actual measurement value from the memory 45 is added to the other input. Note that details of the memory 45 will be described later.

The arithmetic circuit 46 calculates the height of the partially removed product based on the two input signals, and outputs a signal indicating this height to the coincidence detection circuit 42.

That is, Fig. 13a shows the state when laminated core pieces with non-bonding holes 6a formed in the die are stacked, and Fig. 13b shows the state when the cylinder is raised again after the product is taken out. Indicates the condition. As is clear from these figures, the amount e of elevation of the cylinder 20 from the standard is indicated by the count value of the up-down counter 41. Then, the height h of the product that is about to be removed is determined by h=c-e...(1) based on the lifting amount e and the actual measurement value c of the removed product (stored in the memory 45). It is expressed as The arithmetic circuit 46
It performs the calculation of equation (1).

A signal indicating a predetermined stack thickness is applied from a stack thickness setting device 44 to the other input of the coincidence detection circuit 42, and a signal from the proximity switch 24 is applied to its enable terminal EN. The coincidence detection circuit 42 is operable only when the proximity switch 24 is on (FIG. 10b), and if the two input signals match at this time, it outputs a coincidence signal to the contact 34b of the changeover switch 34. Note that the predetermined lamination thickness set in the lamination setting device 44 is a value smaller than the lamination thickness for one product by the lamination thickness for three laminated core pieces. This is because after the cut signal is output as described above, three laminated core pieces including this laminated core piece are further laminated until the laminated core piece in which the non-coupling hole 6a is formed is laminated. This is because that.

Here, in order to simplify the explanation, the coincidence detection circuit 42 outputs a coincidence signal when the value calculated by the arithmetic circuit 46 and the stacking thickness set by the stacking thickness setting device 44 match. However, the stacking thickness setting device 44
There is a predetermined tolerance range for the stacking thickness set by , and when the calculated value of the arithmetic circuit 46 falls within this tolerance range, a coincidence signal is output.

That is, after outputting the cut signal, three laminated core pieces are laminated to complete one product, so the thickness of the laminated core piece is t, and the tolerance is ±.
10%, and the stacking thickness when the cut signal is output is Xmm, the stacking thickness H' of one product is within the range of the following formula, X+2.7t≦H'≦X+3.3t...(2) enter. Here, the conditions for this stacking thickness H' to be within the range of ±t with respect to the desired stacking thickness H are as follows from the above equation (2): H-t≦X+2.7t and X+3.3t≦ H+t...(3) When the above equation (3) is rearranged, H-3.7t≦X≦H-2.3t (4). Therefore, it is sufficient to output a cut signal when X falls within the range of equation (4) above. now,
Assuming H=30mm and t=0.5mm, and substituting these into equation (4), the following equation is obtained: 28.15mm≦X≦28.85mm (5). This sufficiently includes the range of t±10%, and it is possible to output a cut signal during this period. Conversely, the actual stacking thickness is
The stacking thickness can be controlled so that H' falls within the range of ±t.

Note that the plate thickness t of the laminated core piece can be determined as follows based on the output of the linear scale 40 described above.

That is, as shown in FIG. 15, the stacking thicknesses h ₁ , h ₂ , h ₃ for each predetermined number of press strokes are measured with the linear scale 40, and these stacking thicknesses h ₁ , h ₂ , h ₃ are calculated according to the above press strokes. Find the average plate thicknesses ₁ , ₂ , and _3, respectively, by dividing by the number.

Based on these average plate thicknesses ₁ , ₂ , and ₃ and the height in the product from which the average plate thickness was determined, a function (for example, a quadratic function) related to the product height of the average plate thickness is determined (see Figure 16), From this function, the average plate thickness near the desired product height is predicted. The average plate thickness obtained in this manner is defined as the plate thickness t of the laminated core piece.

The memory 45 also stores the calculated value of the arithmetic circuit 46 immediately before the up-down counter 41 is reset by the output signal of the delay circuit 43, that is, the value of the product 1.
The actual measured values of the stack thickness are stored.

Next, the operation of the device of the present invention will be explained.

As shown in FIG. 8, a case will be described in which a laminated core with a lamination thickness of 30 mm (thickness of the strip 1 is 0.5 mm) is manufactured from a state in which the laminated core is not punched in the die 8.

The uppermost position of the cradle of the cylinder 20 is located below the lowermost position of the punch 16 to avoid interference with the punch 16, as shown in FIG. Therefore, when the laminated core piece begins to be removed, the laminated core piece does not rest on the cradle of the cylinder 20, and the piston rod of the cylinder 20 does not descend.

In this case, since the product stacking thickness cannot be controlled by the amount of descent of the piston rod of the cylinder 20, the stacking thickness is managed by controlling the number of stacked products.

That is, in FIG. 9, the counter 31 is set to 0.
The movable contact piece 34c of the changeover switch 34
is connected to contact 34a. In addition, the number setting device 33
Set 60 (=30mm÷0.5mm). and,
When the laminated core pieces are punched out in sequence and 60 laminated core pieces are stacked, the movable contact piece 3 of the changeover switch 34
4c to contact 34b. It goes without saying that the 60th laminated core piece is formed with a hole 6a for non-coupling based on a cut signal generated in association with a coincidence signal from the coincidence detection circuit 32.
In addition, when the laminated core pieces are laminated to a certain thickness,
The laminated core piece at the lowest position comes into contact with the cradle of the cylinder 20, and the cylinder 20 gradually lowers by an amount equivalent to the thickness of the laminated core piece each time an output from the punch 16 is applied during subsequent punching. Figure 11a
1 shows a state in which one product whose stacking thickness is controlled in number is stacked in the die 8.

When the laminated core pieces in which the non-coupling holes 6a are formed are laminated based on the cut signal, the up-down counter 4 of the linear scale 40
The count value of 1 is reset. Then, the laminated core pieces are punched one after another, and the counted value of the counter 41, that is, the laminated thickness actually measured based on the linear scale 40, falls within a predetermined range (number 1) set by the laminated thickness setting device 44.
(See equation (5)), the coincidence detection circuit 42 outputs a coincidence signal via the changeover switch 34, and the output circuit 35 receives this coincidence signal and outputs a cut signal. Thereafter, after three press strokes (after three laminated core pieces have been laminated), the product (Fig. 11b) is completed, and the actual measured values of the product at the time of completion are stored in the memory 45, and the up-down The count value of counter 41 is reset.

Next, the product take-out operation will be explained.

First, the timing of taking out the product will be explained with reference to FIG. 1c. Now, each parameter shown in FIG. 11c is defined as follows.

D: Mold thickness - Punch engagement length H: Height of product that has not been ejected (H ₁ ~ H _N ) h: Height of partially punched product l: Length of product that has come out of the mold N: Completed product that has not been ejected In addition, the maximum thickness of the strip is tmax, the minimum thickness is tmin, the maximum stacking thickness of the product is Hmax, and the minimum stacking thickness is Hmin.

Here, the product is taken out by lowering the cylinder 20 together with the product (Fig. 11 d) and pushing out the product on the receiving stand by another cylinder 19 (Fig. 1) (Fig. 11 d). e). Therefore, the first condition for lowering the cylinder 20 is that one product must definitely come out of the mold, and that the next product will not fall out of the mold even when the cylinder 20 is raised again. , and it is necessary to satisfy the following condition.

H ₂ −11tmax≧l−H ₁ ≧2 (6) Since the cylinder 20 takes 1.5 seconds to take out the press, when the press is operated at 400 spm, the number of press strokes within the unloading time is 10 strokes. In the above equation (6), H ₂ −11tmax
When the cylinder 20 rises again, the next product
This means that H ₂ is present in the mold by the thickness of one plate, and the product H ₂ does not fall. Also, 2 is the product
If the top surface of _H1 protrudes more than 2 mm (this is an example) from the mold, it means that it is completely separated from the mold.

The second condition for lowering the cylinder 20 is that the stacking thickness cannot be measured during the product removal period, so the time to output the cut signal may not come during this period. In other words, the product that is being punched out will not be completed unless it is stacked for, say, 20 strokes or more.

The above 20 strokes are based on the following reasons.

That is, as shown in FIG.
It takes 10 strokes to move up and down, and the cylinder is 20
For safety, a margin of three strokes is allowed from when the cylinder 20 is raised until the cylinder 20 is completely pressed. Furthermore, if there are variations in the output timing of the cut signal as shown in the figure, it is necessary to measure from one stroke before the output of the cut signal. , 3 strokes are required, and in the end, at least 7 strokes are required for measurement. Adding these stroke numbers will result in 10+3+7=20 strokes.

Expressing the above second condition as an equation, Hmin/tmax-h/tmin>20 (7). Note that Hmin/tmax is the minimum number of completed products, and h/tmin is the maximum number of half-finished products.

In the above equation (7), h can be expressed as h=l+D− _N 〓 ^k=1 H _k …(8) from the relationship shown in Figure 11c, and by substituting this into equation (7), ,l
When rearranged, Hmin・tmin/tmax−20tmin−D+ _N 〓 ^k=1 H _k >l (9).

Therefore, it is sufficient to lower the cylinder 20 when l satisfies the above equations (6) and (9). In this embodiment, as shown in FIG. 10d, the cylinder 20 is moved up and down at the 7th stroke after the cut signal (FIG. 6c) is output, and at the 4th stroke after the topmost product is completed. A cylinder start signal is output to start the operation. It goes without saying that l when this cylinder start signal is output satisfies the above-mentioned formulas 6 and 9.

Further, the cylinder 20 starts a downward movement in response to the cylinder start signal as shown in FIG. 10e, stops at the product take-out position shown in FIG. 11d, and after the product has been pushed out, moves upward again. When the cradle of the cylinder 20 abuts the next product and the proximity switch 24 is turned on (see FIG. 10b), its ascent is stopped.

Note that while the cylinder 20 is rising, there is a point in time when the count value of the up-down counter 41 of the linear scale 40 matches the value set by the stacking thickness setting device 44; is turned off and the coincidence detection circuit 42 is rendered inoperative, so that no coincidence signal is output from the coincidence detection circuit 42.

Furthermore, the method of determining the height h of the product that is about to be removed is not limited to the above-mentioned embodiment, and may be performed as follows.

That is, as shown in FIG. 14a, the cylinder 5
The holder 51 of 0 is brought into contact with the lower surface of the mold, and at this time the measured value of the linear scale is set to 0. Note that the pedestal 51 is sufficiently larger than the hole of the die 8.

Here, if the amount of descent of the cylinder measured by the linear scale is e as shown in Fig. 14b, the height h of the product that is about to be removed is calculated by the following formula: h=H'-(A+B)= D+e-(A+B)...(10) D: Expressed as mold thickness - punch engagement length. Note that A and B are the heights of the products that have not been discharged, respectively, and these heights are the heights of the products that are not ejected.
Use the actual measured values stored in .

Furthermore, in this embodiment, the rod position of the cylinder for generating pressure is measured using a linear scale, but in a type of mold device that does not use a cylinder for generating pressure, the rod position of the cylinder that is drawn into the die is A rod may be provided that contacts the laminated core piece and descends together with the laminated core piece, and the position of this rod may be measured using a linear scale.

〔Effect of the invention〕

As explained above, according to the present invention, since the thickness of the laminated core pieces stacked in the die is directly measured using the linear scale, the cut signal for determining the lamination thickness of the laminated core is It is possible to output at an appropriate time so that the lamination thickness error is within the thickness of one laminated core piece. Further, the lamination thickness of the laminated core can be easily changed by simply changing the lamination thickness setting value.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an example of a progressive mold device used in carrying out the present invention, Fig. 2 is a plan view of the strip, Fig. 3a is an enlarged plan view showing the cut and raised protrusion portion, Fig. 3 b is a sectional view taken along the line A-A in FIG. 3a, FIG. 4a is an enlarged plan view showing the hole for non-bonding, FIG. FIG. 6 is an enlarged longitudinal sectional view of the punch mechanism for forming cut and raised protrusions; FIG. 7 is an enlarged longitudinal sectional view of the cut and raised protrusions formed; FIG. FIG. 8 is a partial sectional view of the mold device according to the present invention, FIG. 9 is a block diagram showing an embodiment of the automatic stacking thickness control device according to the present invention, and FIGS. Fig. 11 a to e are diagrams used to explain the operation of the cylinder according to the present invention, and Fig. 12 is a timing chart showing the control mode of the cylinder and the signals of the present invention. Figures 13a, b, and 14a and b are used to explain how to determine the height of a product that is about to be removed, and Figures 15 and 16 are used to illustrate the laminated core FIG. 3 is a diagram used to explain how to determine the thickness of a piece. 1... Strip, 6, 6a... Hole, 7... Cut and raised projection, 8... Die, 9... Laminated iron core piece, 1
0,16...Punch, 12...Cam part, 13...
Solenoid, 14...Cam, 18, 19, 20...
...Cylinder, 21...Rack, 22...Pinion, 23...Incremental encoder, 24
... Proximity switch, 30 ... Phase detection circuit, 31
... Counter, 32, 42 ... Coincidence detection circuit, 3
3... Number of sheets setting device, 34... Changeover switch, 35
...Output circuit, 40...Linear solenoid, 41
...Up-down counter, 43...Delay circuit,
44... Lamination thickness setting device, 45... Memory.

Claims (1)

[Claims] 1. A caulking protrusion having a protrusion amount not exceeding the thickness of the strip is formed on the strip for each press stroke, and the portion where the caulking protrusion is formed is determined by inputting a cut signal. In a progressive die device for manufacturing a laminated core, which has a punching station and a station that draws a laminated core piece from the strip into a die using a punch that is pressed down with each press stroke, the laminated core piece is drawn into the die. a rod that is in contact with the laminated core piece and descends together with the laminated core piece, a linear scale that continuously detects the position of the rod, and a position of the rod that is related to the laminated thickness of one laminated core based on the detection output of the linear scale. 1. An automatic stacking thickness management device for a progressive die apparatus for manufacturing a laminated iron core, comprising: a detection means for detecting that the cut signal has been lowered by a predetermined amount; and a means for outputting the cut signal when the detection means detects the cut signal. 2. The detection means determines whether the caulking protrusion is formed, where n is the number of stations between the two stations, H is the target lamination thickness, and t is the thickness of the strip. A patent claim for detecting that the rod has descended by the predetermined amount expressed by the following equation from the position of the rod when laminated cores having partially punched parts are stacked: (H-n×t)±α; α: a permissible amount range 1
An automatic stacking thickness control device in a progressive molding device for manufacturing a laminated iron core as described in 2. 3. The thickness t of the strip is an average thickness calculated based on a predetermined number of press strokes and the amount of descent of the rod when laminated by this number of press strokes. Automatic stacking thickness control device for progressive mold equipment for manufacturing laminated iron cores. 4 The plate thickness t of the strip is determined by measuring the average plate thickness at multiple locations in one product, and calculating the average plate thickness of the plurality and each height of the product in which these average plate thicknesses were measured. For manufacturing a laminated core according to claim 3, the average plate thickness in the vicinity of a desired product height at which the n laminated core pieces are laminated is predicted based on the above, and the predicted average plate thickness is used. Automatic stack thickness control device for progressive mold equipment.