EP3700692A1

EP3700692A1 - Multistage press and method for producing a formed part

Info

Publication number: EP3700692A1
Application number: EP17816709.4A
Authority: EP
Inventors: Justus ERHARD
Original assignee: Nedschroef Herentals NV
Current assignee: Nedschroef Herentals NV
Priority date: 2017-12-12
Filing date: 2017-12-12
Publication date: 2020-09-02
Anticipated expiration: 2037-12-12
Also published as: US11285526B2; KR102463749B1; US20200298301A1; EP3700692B1; JP2021505408A; CN111886086B; KR20200094151A; BR112020011149A2; PL3700692T3; RU2741761C1; ES2903138T3; CN111886086A; CA3084234A1; JP7021367B2; WO2019114929A1

Abstract

The invention relates to a multistage press for the bulk deformation of a piece of wire, comprising a wire feed with associated apparatus for cutting to length, and a transfer device – having grippers – for receiving a piece of wire that has been cut to length and transferring the latter to subsequent forming stages, there being arranged, on that side of the cutting-to-length apparatus (3) opposite from the wire feed (2), means for partially heating a length of wire (81). The invention also relates to a method for producing a formed part with a multistage press of this type.

Description

Multi-stage press and method for producing a formed part

The invention relates to a multi-stage press for massive forming a Drah tabschnitts according to the preamble of claim 1. The invention further relates to a method for producing a Umformteils, in particular a screw, with a multi-stage press according to claim. 7

Multi-stage presses for cold forming of wire are in various designs from, for example, EP 0 215 338 A1 known. A directional wire is fed from the coil into the machine, where a defined Drahtab section is cut to length. The wire section is conveyed via a gripper of a transfer device to a first forming step formed of a die and a punch, where it is positioned in a receptacle of the punch. Subsequently, the wire section is pushed over the punch in the die and deformed. After forming, the formed piece of wire is positioned by means of an ejector pin in a further gripper of the transport device and transported via this in each case to the next forming stage. The stamp of the forming tools arranged one behind the other are arranged regularly on a common horizontal cylinder, so that each advance of this cylinder in each of the forming steps, a deformation of a wire section. About the successively arranged forming stages of the wire section is formed to the finished workpiece. In the last forming stage, the finished part is ejected. Common multi-stage presses have six forming stages.

By means of a multi-stage press of the aforementioned type can be differentiated most diverse cold forming parts such as screws or bolts hersteilen. On the Umformstufen arranged behind each other, a high process speed can be achieved because with each feed of the cylinder six wire sections can be formed vice. However, the deformation is problematic for special materials, such as heat-resistant nickel-based alloys (eg NI 53 / FE19 / CR19 / NB / MO / TI). For the production of screws from this material, it is necessary, the area of the screw head before des- heat up to 1000 ° C. It should be noted that the screw shank must remain cold, otherwise the loss of quality of subsequently introduced into the screw shank thread would result. For the preparation of such special screws blanks are first made of wire sections, in which an end portion under vorhe Riger heating is converted to a screw head. These blanks are then fed piecewise to a multi-stage press to produce the desired screw.

A disadvantage of the previously known production method of such special screws is that this is very expensive. In addition, an individual order setting of screw length or dimension is possible, please include only at great expense, since this first corresponding blanks must be created.

The invention aims to remedy this situation. The invention has the object zugrun de to provide a multi-stage press for massive forming a wire section ready, which also allows the production of special screws of the aforementioned type directly from wire coil. According to the invention this object is achieved by a multi-stage press with the features of claim 1 ge.

With the invention, a multi-stage press for massive forming a wire section is provided, which also allows the production of special screws of the aforementioned type directly from a wire of heat-resistant nickel alloy. Characterized in that on its wire feed opposite Be te the cutting means are arranged for partial heating of a wire section, heating of a defined end Drahtab is section for the subsequent shaping of the screw head allows, after heating the end wire section of the wire to a ge desired length can be cut to length before being transported via the transfer device to the first deformation stage. The fact that the Drahtzu leadership, the forming stages (or drive the punch of the forming stages de cylinder) and the cutting device independently controllable are, a timely deformation of an end heated and then cut to length wire section over all forming stages during simultaneous gene heating of the next end portion allows.

In a further development of the invention, the means for heating a wire section comprise an induction coil, wherein the wire feed for temporary introduction of a wire section is set up in the induction coil. As a result, the setting of a defined temperature of an end Drahtab section is possible. The temperature of the wire section results from the output from the induction coil power and the residence time of the wire section in the induction coil.

In an embodiment of the invention, the wire feed comprises a servo drive for defined forward and backward movement of a wire section. Here by an accurate, needs-based feeding the wire from the coil he allows. The possibility of the defined forward and Rückwärtsbewe movement of the wire, the introduction of the wire end in the induction coil as well as a subsequent return movement of the wire for determining the ablated wire section is possible.

In a further embodiment of the invention, the wire feed can be controlled via a controller connected to it, in which a defined dwell time of a wire section in the induction coil and / or a target temperature can be stored. In this case, means for detecting the temperature of a wire located in the induction coil wire section are preferably arranged, which are connected to the Steue tion, wherein in the control a control is integrated, through which in dependence on the temperature of the wire section, the wire feed is controlled. Alternatively, the empirical determination of residence times to achieve desired temperatures is possible, which are deposited in the controller.

In a further development of the invention, the control with the cutting device is connected and arranged in such a way that, after the end-side partial recovery heating a wire section whose lengthening takes place in a defined length. As a result, the length of the respective screws to be produced is individually adjustable.

The present invention also has the object of providing a method for producing a special screw of the aforementioned type with a Mehrstu fenpresse directly from the coil. According to the invention, this task is solved by a method having the features of claim 7. Characterized in that first a wire is heated end, then a wire section at a defined distance from the heated end abge lengthen and the thus obtained partially heated wire section via a transfer device is successively supplied to several forming stages, is an individual adjustment of the length of the screw produced allows. In this case, the wire is preferably fed coil from a coil via a wire feed induction coil, where it is heated to the end to a defined temperature.

In a further development of the invention, the wire is fed via a servo drive in the induction coil, wherein the wire according to the desired Län ge of the end-side area to be heated in the induction coil is reindeer ren and after reaching the desired temperature or for this purpose he required residence time again from the Induction coil is moved out, after which a wire section of desired length is cut to length. As a result, an accurate process management for the production of screws of different lengths is made possible by a coil.

In an embodiment of the invention, the measurement of the temperature of the endsei term range of the wire via a non-contact temperature sensor, in particular a pyrometer or via an infrared measuring device. This further improves the accuracy of the process control. Alternatively, the required residence time to achieve the desired temperature within the induction coil can also be determined empirically and stored in a connected to the servo drive control. That way is also conceivable creation of a database with appropriate target temperatures to ordered residence time in the manner of an expert system.

Other developments and refinements of the invention are specified in the remaining subclaims. An embodiment of the invention is illustrated in the drawings and will be described in detail below. Show it:

Figure 1 is a partial schematic representation of a multi-stage press with an orderly induction coil for end wire heating;

Figure 2 is a schematic representation of the arrangement of Drahtzufüh tion, cutting device and induction coil for producing egg nes end heated wire section within the Mehrstu fenpresse of Figure 1 in the operating states: a) feed of the wire from the coil;

b) heating of the end wire section in the

Induction coil;

c) return movement of the wire with adjustment of the desired length and th

d) cutting the wire section in the desired length with acquisition by the transfer device.

The horizontal multi-stage press 1 chosen as an exemplary embodiment is a multistage press in a horizontal design, as used for the production of screws and similar small parts. The construction of such horizontal multi-stage presses is well known to the person skilled in the art and described for example in EP 0 215 338 A1. The forming tools are arranged next to each other. A cross-transfer device brings the workpieces from forming stage to forming stage. Usually, these presses work with a transverse transport carriage, which has a number of transfer grippers corresponding to the number of forming steps, which projects between the stamping tools and the dies. A detailed description of such a horizontal multi-stage press is therefore omitted here. The following Description focuses on the essential components of the multi-stage press according to the invention.

FIG. 1 shows a detail of a multi-stage press 1 according to the invention. It is the die block 1 1 with individual forming stages 12 ersicht Lich, between which transfer gripper 71 of the cross transfer device 7 are angeord net. Before the first forming stage 12, a wire feed is arranged, which is formed in the embodiment as a servo drive 2. The Drahtzufüh tion 2 takes one of a - unwound coil - unwound wire 8. Before the wire feed 2 a separately controllable wire cutter 3 for cutting the wire 8 is arranged. Viewed from the wire feeder 2 behind the wire cutter 3, the transfer gripper 71 of the transfer device 7 are positio ned, which are adapted to cut a cut from the wire cutter 3 Drahtab 81. In turn, behind the transfer grippers 71 a Induktion coil 4 is arranged, which is positioned so that a wire of the wire 2 received wire via the servo drive 21 in the induction coil 4 is inserted. The wire feeder 2, the wire cutter 3 and the induction coil 4 are connected to a control and regulating device 6, which in turn is connected to a arranged on the induction coil 4 pyrometer 5 for measuring the temperature of an introduced into the induction coil 4 wire tendabschnitts 82. In addition, the control and Regelein device 6 is also connected to the cross transfer device 7 for controlling the transfer gripper 71. The control and regulating device 6 is part of - not shown - overall machine control, via which also the Ansteue tion of - not shown - the individual forming die bearing Stem pelblocks done.

In Figure 2, the process for producing a high temperature resistant screw by forming a wire of a nickel-based alloy skiz graced. A wire 8 is fed from the coil (not shown) via the wire feed 2 through the wire cutters to the induction coil 4 until an end-side wire end section 82 of defined length protrudes into the induction coil 4. The length of the wire end section 82 to be heated and the Desired temperature is this purpose behind in the control and regulating device 6 sets, which also controls the servo drive 21 of the wire feed 2 (Figure 2a). After that, the servo drive 21 is stopped, so that the wire end portion 82 dwells in the induction coil 4. The temperature of the wire end section 82 is continuously measured via the pyrometer 5. The measured values are reported to the control and regulating device 6, which compares them with the stored setpoint temperature of the wire end section 82 (FIG. 2b).

After reaching the stored target temperature of the wire end portion 82 of the servo drive 21 of the wire feed 2 via the control and Regeleinrich lines 6 is driven in the opposite direction, so that the wire 8 is withdrawn through the wire feed 2 until the wire cutter located behind the wire section 71st which has reached in the control and regulating device 6 behind laid length (Figure 2c). Now, the wire cutter 3 is operated via the control and regulating device 6, whereby the wire section 81 is cut to length in the hinterleg th length. The thus cut wire section 81 is received by the gripper 71 of the transfer device 7 and transferred to the first forming stage 12 of the die block 1 1 of the multi-stage press 1. At the same time he follows a new feed of the wire 8 in the direction of the induction coil 4, until in turn the wire end portion 82 projects in the desired length in the Indukti onsspule 4. During the heating of this next Drahtendab section 82, the further deformation of the wire section 81 via the white direct forming stages 12. The further deformation of the inserted into the first forming stage 12, end heated wire section 81 via the forming stages 12 of the multi-stage press are known in the art, and require no further explanation at this point.

At this point, it should be noted that the drive of the - not shown - stamp block, which receives the individual forming die mechanically ent coupled from the servo drive of the wire feed 2 and also from the drive to the cross transfer device 7 is. It should also be mentioned that he inventive multi-stage press can be used both for conventional production of formed parts by means of continuous cold forming process. Here- to the wire 8 is advanced immediately so far that a wire section 81 of the desired length is arranged behind the wire cutter 3, after which this wire section 81 is cut to length.

Claims

claims

1. Multi-stage press for massive forming a wire section, encompass send a wire feeder with arranged cutting device and ei ne gripper having transfer device for receiving a abge long wire section and its transfer to subsequent order form stages, characterized in that on their wire feeder

(2) opposite side of the cutting device (3) means for partiel len heating a wire portion (81) are arranged, wherein the wire feed (2), the forming stages (12) and the cutting device

(3) are independently controllable.

2. Multi-stage press according to claim 1, characterized in that the means for partially heating a wire section (81) comprise a Indukti onsspule (4), wherein the wire feed (2) for temporary insertion of a wire section (81) in the induction coil (4) is directed.

3. Multi-stage press according to claim 2, characterized in that the wire feed (2) comprises a servo drive (21) for the defined forward and backward movement of a wire section.

4. Multi-stage press according to claim 2 or 3, characterized in that the wire feed (2) via an associated with this Steue tion (6) is controllable, in which a defined residence time of a wire tendabschnitts (82) in the induction coil and / or a target temperature can be stored.

5. Multi-stage press according to claim 4, characterized in that with tel for detecting the temperature of a in the induction coil (4) befind union wire end portion (82) are arranged, which are connected to the controller (6), wherein in the controller (6). integrated a regulation is, by the function of the temperature of the Drahtendab section (82), the wire feed (2) is controllable.

6. Multi-stage press according to claim 4 or 5, characterized in that the controller (6) with the Ablängvorrichtung (3) is connected and arranged such that after the end-side partial Erwär tion of a wire section (81) whose lengthening takes place in a defined length.

7. A process for producing a formed part, in particular a

Screw, with a multi-stage press, wherein first a wire (8) is heated end, then a wire section (81) at a defined distance from the heated Drahtendabschnitt (82) abge lengthen and thus obtained partially heated wire section (81) via a transfer device (7) one after the other several forming stages (12) is supplied.

8. The method according to claim 7, characterized in that the wire (8) from a coil via a wire feed (2) an induction coil (4) is supplied, where it is heated at the end of a wire end portion (82) to ei ne defined temperature.

9. The method according to claim 8, characterized in that the wire (8) via a servo drive (21) of the induction coil (4) is fed, wherein the wire (8) corresponding to the desired length of the wire to be heated end portion (82) in the Induction coil (4) is moved into it and is moved out of the induction coil (4) after reaching the desired temperature or the residence time required for this purpose, after which a wire section (82) of desired length is cut to length.

10. The method according to claim 9, characterized in that the Tempe temperature of the wire end portion (82) via a non-contact temperature Tempe sensor, in particular a pyrometer (5).

1 1. A method according to claim 9, characterized in that the erforder Liche residence time to achieve the desired temperature within the induction coil (4) is determined empirically and in a with the servo drive (21) connected control (6) is deposited.