DE19850616B4 - Method and device for the automatic separation of the front and rear ends of material rods processed in forming presses - Google Patents

Abstract

Method for the automatic separation of the front (3) and rear (4) ends of material bars (2) of finite length (L0) processed in forming presses (1), which initially move continuously on a straight transport path and then move against a stop (5 ) are fed to a shear knife (6), in the area of which at least the front (3) and rear (4) ends of each material rod (2) are separated, characterized by the following process steps: a) Determination of the distance (a) in the direction of the longitudinal axis the material bar (2) between the shear plane of the shearing knife (6) and the stop (5); b) monitoring the entry of the rear end (4) of the material rod (2) into a measuring area (7) which is arranged at a distance (E) in front of the shear plane of the shear blade (6) in the transport direction; c) When the rear end (4) of the material rod (2) enters the measuring area (7): Determination of the exact position (f) of the rear end (4) of the rod (2); d) Calculating the ...

Description

The invention relates to a method for the automatic separation of the front and rear ends of processed in forming press rods of finite length, which are initially moved on the rectilinear transport path continuously and then fed by intermittent feed against a stop a shearing blade, in the area at least the front and the rear end of each material bar is eliminated.

Furthermore, the invention relates to a device for carrying out the method.

Automatic horizontal presses, which transform bar stock into workpieces up to several 100 pieces per minute without cutting, are continuously fed with bars, which are heated frequently before forming. Immediately prior to forming, the bars are divided into sections of equal length by means of a shearing blade, which must correspond to relatively narrow volume tolerances. To ensure the required volume of each section, the starting and ending parts of the bars are eliminated.

The procedure in a known method is as follows, wherein the 3 and 4 referring to this solution: a forming press 1 become material bars 2 fed from a bar magazine, from the bars 2 become sections 16 needed with a given length a. It is practically not that a rod 2 can be divided into sections of length a without residue; rather, there is always a back end 4 the pole 2 that is to be eliminated. Since the subsequent rod is flush with the previous one, there falls a front end piece 3 at. The bars 2 be using pick rollers 15 promoted, against a pole stop 5 transported and then with the cleaver 6 sections 16 separated.

The two photocells 13 and 14 are at a known distance F in the feed direction before the mechanically driven feed rollers 15 arranged. The retracted rod 2 Intermittent with each stroke of the press to the catch length, the length a of a voluminous, from the shear blade 6 section to be cleared 16 corresponds to, against the bar stop 5 emotional. The rod following from the rod magazine or a heater is initially tracked at a constant speed. As a result, a gap between the two rods, which corresponds to at least one intake or section length a, is briefly created during a feed stroke of the press. Passes the end of the retracted rod 2 the first photocell 13 , the light circuit triggers the counting of the subsequent feed strokes in the machine computer. Passed the end of the retracted rod - as is in 4 you can see - the second light barrier 14 , the calculator determines the number of indents between the light barriers.

Before the end of the retracted rod reaches the feed rollers, the upper, in the feed direction first feed roller is raised, and the subsequent rod closes at high speed with increased Aufholengeschwindigkeit on the end of the front rod, so that the intake gap is closed. Thereafter, the upper feed roller is lowered again. Both bars are drawn in without any intake gap.

After light switching of the second light barrier 14 With each additional feeder, the machine computer counts down the previously calculated number of remainders to the shearing blade and sends a pulse to the machine control if the section, which now consists of two bar end pieces, rests against the bar stop. During the shearing process in the following press cycle, this transitional section is eliminated.

With the aid of the light barrier distance F, the computer must calculate the number of indents over the remaining distance E up to the shearing blade in order to be able to exit the transition section at the right time.

This prior art method has a number of disadvantages: only under almost ideal operating conditions, the method works sufficiently reliable. Slippage between the feed rollers 15 and the bar to be transported 2 falsifies the measurement result, so that can not be predicted with sufficient certainty that rod end pieces are separated and eliminated at the right moment. Profiled feed rollers to reduce slippage often can not be used because profiled rollers can leave unwanted pressure marks on the heated bars, for example, which reduces the surface quality of the forgings.

Added to the uncertainties of the photoelectric sensor. Of crucial importance here is the exact alignment of the infrared transmitter and the reflector to each other and the rectangular orientation of the light beam to the rod. A clear weakness of the light / dark monitoring is the high risk of failure with closely spaced rods: The gap suddenly opened for a short time behind the retracted rod and the subsequent rod is quickly closed again by the continuously lagging rod. This is often the response of the Infrared sensors overwhelmed, added to the rapid pollution of the reflectors by the scale of the heated rods.

From the JP 55150914 A A method is already known with which an automatic separation of the rear ends of processed material bars can take place. The bars are here driven against a stop in the area of a Schermessers and determined the position of the rod end. Since due to the measured position of the rear end of the rod a purely calculatory determination of the number of remaining, abzuscherenden workpieces is made, there is a risk of production of waste, if due to the performed measurement and calculation, a actually useful workpiece due to tolerances no longer produced properly can be.

The invention is therefore based on the object to further develop the previously known method such that the disadvantages mentioned are eliminated. It is therefore intended to provide a method for the automatic separation of the end pieces of the material rods, which is not affected by slippage or overstroke of the drive rollers. The gap between two consecutive bars should also be reliably detected in the case of small bars. Furthermore, the problem of contamination and thus the failure of the light barriers to be resolved. The method according to the invention and the associated device should make it possible to reliably determine the end piece region of two successive rods under harsh production conditions and to ensure a high quality of the compacts by excreting them.

• a) Bestimmen des Abstandes (a) in Richtung der Längsachse der Materialstange (2) zwischen der Scherebene des Schermessers (6) und dem Anschlag (5);
• b) Überwachen des Eintritts des hinteren Endes (4) der Materialstange (2) in einen Messbereich (7), der in Transportrichtung vor der Scherebene des Schermessers (6) in einem Abstand (E) angeordnet ist;
• c) Bei Eintritt des hinteren Endes (4) der Materialstange (2) in den Messbereich (7): Bestimmen der genauen Lage (f) des hinteren Endes (4) der Stange (2);
• d) Berechnen der verbleibenden Länge (L) der Materialstange (2) aus der Beziehung: L = f + E + a
• e) Berechnen der Anzahl (n) der für die verbleibende Länge (L) der Materialstange (2) erfolgenden Einzugshübe durch die Beziehung: n = Ganzzahl (L/a)
• f) Durchführen der Anzahl (n) Einzugshübe;
• g) Ausscheiden des Stangenreststücks (4), das nach Durchführung der Anzahl (n) Einzugshübe verbleibt, zusammen mit dem nachfolgenden vorderen Ende (3) der nachfolgenden Stange (2) in an sich bekannter Weise,

wobei der Berechnung der Anzahl (n) der für die verbleibende Länge (L) der Materialstange (2) erfolgenden Einzugshübe gemäß Schritt e) eine Sicherheitsgrenze berücksichtigt wird, die mindestens ein Viertel des Abstandes (a) beträgt.The solution of this problem by the invention is characterized by the following process steps:

• a) Determining the distance (a) in the direction of the longitudinal axis of the material bar ( 2 ) between the shear plane of the shearing blade ( 6 ) and the attack ( 5 );
• b) monitoring the entry of the rear end ( 4 ) of the material bar ( 2 ) into a measuring range ( 7 ), which in the transport direction in front of the shear plane of the shear knife ( 6 ) is arranged at a distance (E);
• c) When the rear end ( 4 ) of the material bar ( 2 ) into the measuring range ( 7 ): Determining the exact position (f) of the rear end ( 4 ) of the rod ( 2 );
• d) calculating the remaining length (L) of the material bar ( 2 ) from the relationship: L = f + E + a
• e) calculating the number (n) of the remaining length (L) of the material bar ( 2 ) take-up strokes through the relationship: n = integer (L / a)
• f) performing the number (n) of feed strokes;
• g) separation of the rod remainder piece ( 4 ) remaining after the number of (n) feed strokes has been made, together with the following leading end ( 3 ) of the following rod ( 2 ) in a manner known per se,

wherein the calculation of the number (n) of the remaining length (L) of the material bar ( 2 ) take-up strokes according to step e) a safety limit is taken into account, which is at least a quarter of the distance (a).

The proposed method differs significantly from the previously known method that a dimensional measurement (length measurement, see step c)) takes place on the rod, while in the prior art is only provided that the rod length is estimated over the path between two light barriers and that Increasing the reliability of the proposed method is further provided that a safety limit is taken into account.

According to a first development it is provided that the determination of the exact position (f) of the rear end ( 4 ) of the rod ( 2 ) according to method step c) with the rod stationary ( 2 ) he follows.

• – Es ist eine präzise Messung der Stangenlänge möglich und damit eine genaue Definition jenes Abscherbereichs, in dem sich die Stangenreststücke befinden; diese können damit sicher und zuverlässig ausgeschieden werden, so dass es zu keinen Fehlpressungen kommt.
• – Schlupf- bzw. Überhub der Einzugsrollen (15) spielen bei dem erfindungsgemäßen Verfahren keine Rolle und gefährden nicht die Bestimmung des auszuscheidenden Abschnitts.
• – Auch kleine Stangenlücken können sicher erkannt werden.
• – Der Verlauf eines Stangenendes kann exakt verfolgt werden.
• – Das Bewegungsverhalten des Stangeneinzugs spielt bei der Bestimmung des auszuscheidenden Abschnitts keine Rolle.

The proposed method achieves the desired benefits:

• - It is possible to precisely measure the length of the rod and thus provide a precise definition of the shear area in which the rod remnants are located; These can be safely and reliably eliminated so that there are no false pressures.
• - Slip or overstroke of the feed rollers ( 15 ) play no role in the method according to the invention and do not jeopardize the determination of the portion to be eliminated.
• - Even small bar gaps can be reliably detected.
• - The course of a rod end can be tracked exactly.
• - The movement behavior of the rod feeder plays no role in the determination of the auszuschcheidenden section.

• – eine geradlinige Transportbahn,
• – Mittel (15) zum kontinuierlichen und intermittierenden Bewegen der Materialstange (2),
• – einen Anschlag (5),
• – ein Schermesser (6) und
• – Mittel zum Ausscheiden von Stangenendstücken (3, 4).

The device according to the invention for automatic separation has:

• - a straight-line transport path,
• - Medium ( 15 ) for continuously and intermittently moving the material bar ( 2 )
• - a stop ( 5 )
• - a cutter ( 6 ) and
• - means for separating rod end pieces ( 3 . 4 ).

• – Mittel (8) zur Bestimmung des Abstandes (a) in Richtung der Längsachse der Materialstange (2) zwischen der Scherebene des Schermessers (6) und dem Anschlag (5);
• – Mittel (9) zur Bestimmung der genauen Lage (f) des hinteren Endes (4) der Stange (2) in einem Messbereich (7);
• – Mittel (10) zur Berechnung der verbleibenden Länge (L) der Materialstange (2) und der Anzahl (n) der für die verbleibende Länge (L) der Materialstange (2) erfolgenden Einzugshübe,

wobei das Mittel (8) zur Bestimmung des Abstandes (a) zwischen der Scherebene des Schermessers (6) und dem Anschlag (5) ein inkrementaler Wegaufnehmer (11) ist und wobei das Mittel (9) zur Bestimmung der genauen Lage (f) des hinteren Endes (4) der Stange (2) ein Laserscanner (12) ist, der aus einer Laserdiode (Sender) und telezentrischer Optik (Empfänger) besteht.According to the invention, the device is characterized by

• - Medium ( 8th ) for determining the distance (a) in the direction of the longitudinal axis of the material bar ( 2 ) between the shear plane of the shearing blade ( 6 ) and the attack ( 5 );
• - Medium ( 9 ) for determining the exact position (f) of the rear end ( 4 ) of the rod ( 2 ) in a measuring range ( 7 );
• - Medium ( 10 ) for calculating the remaining length (L) of the material bar ( 2 ) and the number (n) of the remaining length (L) of the material bar ( 2 ) take-up strokes,

where the means ( 8th ) for determining the distance (a) between the shear plane of the shearing blade ( 6 ) and the attack ( 5 ) an incremental transducer ( 11 ) and where the means ( 9 ) for determining the exact position (f) of the rear end ( 4 ) of the rod ( 2 ) a laser scanner ( 12 ), which consists of a laser diode (transmitter) and telecentric optics (receiver).

In the drawing, an embodiment of the device according to the invention is shown.

1 schematically shows a forming press, in which the inventive method is practiced in

2 is also a schematic view of the forming press shown, in which case the required device elements are shown,

3 and 4 represent the solution according to the prior art.

The schematic representation in 1 shows a forming press 1 into which a material bar 2 is retracted. A second material bar 2 follows from the left eager - not shown - rod magazine or a heater after. From the material bar 2 are sections 16 Shear with a length a, this is a shearing blade 6 provided and a bar stop 5 , The pole 2 is by means of transport rollers 15 against the attack 5 pushed; in this position separates the shearing blade 6 a section 16 from.

A material bar 2 can not usually be left without a remnant in a variety sections 16 split up with the desired length a; Rather, a rear tail remains 4 with a length b ₄ Since the bar (from left) 2 to the end of the bar already in the feeder 2 applies, is also from the subsequent rod a front end piece 3 to be sheared off; this one has a length b ₃ .

For a safe and reliable separation of the two remaining pieces 3 and 4 Existing section is the exact knowledge of the remaining length L of the material bar 2 necessary. The more precisely this can be determined, the safer the separation process works. In 2 it can be seen how the method according to the invention works according to this embodiment.

To carry out the method, first the determination of the distance a between the shear plane of the shearing blade 6 and the stop 5 perform. This is an incremental transducer 11 provided with the value a can be determined with sufficient accuracy. The incremental transducer 11 measures the relative horizontal displacement of the bar stop. After calibration with an adjustment piece, the distance a between the shear plane and the stop can be determined from the position measurement of the stop 5 be derived at any time.

Furthermore, a laser scanner 12 intended. This is located at distance E from the shear plane of the Schermessers 6 away. The laser scanner 12 is capable of measuring a width F of a measuring range 7 to monitor and a rod end in the measuring range 7 to measure. The laser diode (transmitter) shown in the upper part of the picture transmits laser light to the telecentric optics (receiver), which is shown in the lower part of the picture. If the end of the retracted rod is within a range of one stroke 7 , the length f, ie the position of the rear end 4 the pole 2 in the measuring range 7 , the "drop shadow" measured at the scanning head.

From the known distance E of the laser measuring window to the shear plane, from the measured value f and from the measured at the bar stop section length a, the retracted length L of the retracted rod 2 calculated according to the relationship L = f + E + a

The knowledge of this length L and the length of the section 16 (a) allows the calculation and determination of the separation process according to the following procedure: The number n of the remaining length L of the material bar 2 subsequent intake bumps is calculated, after which the transition section (with the front end 3 and the back end 4 the respective pole 2 ) at the bar stop 5 will be located. This number results as n = integer (L / a)

In this way it is possible to pinpoint exactly when the two end pieces 3 and 4 in the shear area, so that they can be reliably eliminated.

In practice it is of great importance that the elimination is ensured with reasonable certainty. Therefore, a "safety margin" is usually added, ie a tolerance that is taken into account in the elimination of the end pieces. This can be done as follows:
The length b _{4 of} the tail 4 the retracted rod results from b ₄ = L - n × a.

To assess the seam in the transition section, a position coefficient lambda is formed. This results too Lambda = b ₄ / a

If the position coefficient lambda exceeds or falls below an upper or lower safety limit S, it can be decided that an additional section should be eliminated after or before the transition section. The safety value S specifies how far away the transition from the front or rear end of the transition section may be relative, without the need for the discharge of an additional section. Because the smallest inaccuracies during assembly or operation can not be ruled out with certainty, it is recommended to set a safety limit S of z. B. 0.25, d. H. a quarter of the distance a.

By applying the following criteria, it is determined again how many feed strokes m should start the rejection process and how many sections z are affected:

The number m of pull-in strokes until retirement is now counted down gradually from the next move-in. If m = 0 is reached, the departure of z sections begins.

LIST OF REFERENCE NUMBERS

1

forming press

2

material rods

3

front end of the rod 2

4

rear end of the rod 2

5

attack

6

razor

7

Measuring range

8th

Means for determining the distance a between the shear plane of the doctor blade 6 and the stop 5

9

Means for determining the exact position f of the rear end 4 the pole 2 in the measuring range 7

10

Computer means for calculating the remaining length L of the material bar 2 and the number n of the remaining length L of the material bar 2 take-up strokes

11

incremental transducer

12

laser scanner

13

photocell 1

14

photocell 2

15

feed rollers

16

section

L ₀

Length of the material bar 2

L

remaining length of the material bar 2

a

Distance in the direction of the longitudinal axis of the material bar 2 between the shear plane of the shearknife 6 and the stop 5

e

Distance between the measuring range 7 and the shear plane of the shearknife 6

f

Position of the rear end 4 the pole 2 in the measuring range 7

n

Number of for the remaining length L of the material bar 2 take-up strokes

b ₃ , b ₄

Lengths of the ends (end pieces) 3 and 4

F

Measuring width of the measuring range 7 or the laser scanner 12

Claims (3)

Method for automatic separation of the front ( 3 ) and rear ( 4 ) Ends of in forming presses ( 1 ) processed material bars ( 2 ) of finite length (L0), which initially moves continuously on a straight-line transport path and then by intermittent feed against a stop (L0). 5 ) a shearing blade ( 6 ), in whose area at least the front ( 3 ) and the rear ( 4 ) End of each material bar ( 2 ), characterized by the following process steps: a) Determining the distance (a) in the direction of the longitudinal axis of the material bar ( 2 ) between the shear plane of the shearing blade ( 6 ) and the attack ( 5 ); b) monitoring the entry of the rear end ( 4 ) of the material bar ( 2 ) into a measuring range ( 7 ), which in the transport direction in front of the shear plane of the shear knife ( 6 ) is arranged at a distance (E); c) When the rear end ( 4 ) of the material bar ( 2 ) into the measuring range ( 7 ): Determining the exact position (f) of the rear end ( 4 ) of the rod ( 2 ); d) calculating the remaining length (L) of the material bar ( 2 ) from the relationship: L = f + E + a e) calculating the number (n) of the remaining length (L) of the material bar ( 2 ) take-up strokes through the relationship: n = integer (L / a) f) performing the number (n) of feed strokes; g) separation of the rod remainder piece ( 4 ) remaining after the number of (n) feed strokes has been made, together with the following leading end ( 3 ) of the following rod ( 2 ) in a manner known per se, wherein in the calculation of the number (n) of the remaining length (L) of the material bar ( 2 ) take-up strokes according to step e) a safety limit is taken into account, which is at least a quarter of the distance (a). Method according to claim 1, characterized in that the determination of the exact position (f) of the rear end ( 4 ) of the rod ( 2 ) according to step c) of claim 1 when the rod is stationary ( 2 ) he follows. Device for automatic separation of the front ( 3 ) and rear ( 4 ) Ends of in forming presses ( 1 ) processed material bars ( 2 ) of finite length (L ₀ ), in particular for carrying out the method according to one of claims 1 or 2, comprising: - a straight-line transport path, - means ( 15 ) for continuously and intermittently moving the material bar ( 2 ), - a stop ( 5 ), - a shearing blade ( 6 ) and - means for separating rod end pieces ( 3 . 4 ), characterized by - means ( 8th ) for determining the distance (a) in the direction of the longitudinal axis of the material bar ( 2 ) between the shear plane of the shearing blade ( 6 ) and the attack ( 5 ); - Medium ( 9 ) for determining the exact position (f) of the rear end ( 4 ) of the rod ( 2 ) in a measuring range ( 7 ); - Medium ( 10 ) for calculating the remaining length (L) of the material bar ( 2 ) and the number (n) of the remaining length (L) of the material bar ( 2 ), whereby the means ( 8th ) for determining the distance (a) between the shear plane of the shearing blade ( 6 ) and the attack ( 5 ) an incremental transducer ( 11 ) and where the means ( 9 ) for determining the exact position (f) of the rear end ( 4 ) of the rod ( 2 ) a laser scanner ( 12 ), which consists of a laser diode (transmitter) and telecentric optics (receiver).

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