CN110774521A

CN110774521A - Multiple-forming vertical injection molding machine

Info

Publication number: CN110774521A
Application number: CN201911233230.1A
Authority: CN
Inventors: 吴邦文
Original assignee: Dongguan Jiaxing Chang Machinery Industry Co Ltd
Current assignee: Dongguan Jiaxing Chang Machinery Industry Co Ltd
Priority date: 2019-12-05
Filing date: 2019-12-05
Publication date: 2020-02-11

Abstract

The invention provides a multi-forming vertical injection molding machine which comprises a machine base, a mounting bracket, a material rack, a rotating mechanism and an injection molding mechanism, wherein at least two injection molding stations are sequentially arranged on the machine base along the outer side of the rotating mechanism, the material rack is mounted on the rotating mechanism, so that the material rack is driven by the rotating mechanism to be switched between the injection molding stations, the injection molding stations are respectively provided with the injection molding mechanism, the mounting bracket penetrates through the middle part of the rotating mechanism and is arranged on the machine base, the injection molding mechanism comprises an injection molding head, an upper die and a lower die, the lower die is mounted on the machine base, and the injection molding head and the upper die are. The invention can realize multiple injection molding, the space around the machine base is not occupied, the injection molding of the formed part with longer tail is convenient, barrier-free rotation is realized, continuous cycle operation can be realized, the production efficiency is high, the operation is stable, the installation and disassembly are convenient, and the maintenance cost is low.

Description

Multiple-forming vertical injection molding machine

Technical Field

The invention relates to the technical field of injection molding machines, in particular to a vertical injection molding machine capable of molding for multiple times.

Background

An injection molding machine, also known as an injection molding machine or an injection molding machine, is a main molding device for manufacturing thermoplastic plastics or thermosetting plastics into plastic products of various shapes by using a plastic molding mold, and is divided into a vertical type, a horizontal type and a full-electric type. Traditional vertical injection molding machine mainly adopts the stand of many vertical settings to install one set of mechanism of moulding plastics around the frame, sets up the upper die base in the mechanism of moulding plastics, and the die holder is fixed on the carousel of frame, and the product only needs once to mould plastics and can be moulded, and at the rotatory in-process of carousel, stand all around causes the hindrance to the longer formed part of afterbody, is not convenient for mould plastics the longer formed part of afterbody.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides the multiple-forming vertical injection molding machine which can realize multiple-forming, the space around the machine base is not occupied, the injection molding of the formed part with a longer tail is convenient, barrier-free rotation is realized, continuous cycle operation can be realized, the production efficiency is high, the operation is stable, the installation and disassembly are convenient, and the maintenance cost is low.

In order to achieve the purpose, the invention adopts the following technical scheme:

the utility model provides a vertical injection molding machine of multiple forming, includes frame, installing support, work or material rest, rotary mechanism and the mechanism of moulding plastics, be equipped with two at least stations of moulding plastics that set gradually along rotary mechanism's the outside on the frame, the work or material rest is installed on rotary mechanism for the work or material rest is driven by rotary mechanism and is switched between the station of moulding plastics, the station department of moulding plastics all is equipped with the mechanism of moulding plastics, the middle part that the installing support passed rotary mechanism sets up on the frame, the mechanism of moulding plastics is including moulding plastics the head, going up mould and lower mould, the lower mould is installed on the frame, the head of moulding plastics passes through.

As a preferable scheme, the mounting bracket comprises a first C-shaped bracket and a second C-shaped bracket, the first C-shaped bracket and the second C-shaped bracket both comprise two C-shaped support plates and a bracket connecting plate connected between the two C-shaped support plates, and the rotating mechanism is sleeved outside the C-shaped support plates.

As a preferable scheme, the first C-shaped support and the second C-shaped support are integrally connected, the injection molding mechanism is installed at the upper ends of the first C-shaped support and the second C-shaped support, and the lower ends of the first C-shaped support and the second C-shaped support are connected with the base.

As a preferred scheme, be equipped with on the mechanism of moulding plastics and be used for controlling two compound die hydro-cylinders of going up mould towards the motion of lower mould direction and be used for controlling the hydro-cylinder of moulding plastics of the overhead up-and-down motion of moulding plastics, the compound die hydro-cylinder is installed in the C shape backup pad, be formed with first logical groove between two C shape backup pads of first C shape support and between two C shape backup pads of second C shape support, the head of moulding plastics that the mechanism of moulding plastics passes first logical groove and stretches out downwards, compound die hydro-cylinder swing joint is equipped with the mould mounting panel that is used for installing the mould, be equipped with the head through-hole of moulding plastics that supplies the head of moulding.

As a preferred scheme, the rotating mechanism comprises a supporting plate and a rotating frame arranged on the supporting plate, wherein the rotating frame is provided with insections, the supporting plate is provided with a motor, and a transmission gear on the motor is meshed and connected with the insections on the rotating frame.

As a preferred scheme, be equipped with a plurality of gaskets that distribute along the swivel mount on the layer board, the upper surface of gasket and the lower surface frictional contact of swivel mount, be equipped with the stopper that is used for preventing the swivel mount from rocking from top to bottom and be used for fixing a position the location bearing of swivel mount position on the layer board, the axis of location bearing is parallel with the axis of swivel mount.

As a preferred scheme, the swivel mount is the swivel, the swivel includes two sections at least circular arc racks that can dismantle the connection, connect through the connecting block between the circular arc rack, be equipped with the first groove of stepping down that corresponds with the connecting block on the circular arc rack, the connecting block is installed in the first groove of stepping down.

As a preferred scheme, be equipped with the elevating system who is used for controlling the layer board activity from top to bottom on the frame, elevating system includes linking arm and the drive assembly of drive linking arm up-and-down motion, the one end and the layer board of linking arm are connected, and the other end is connected with drive assembly, be equipped with the guide bar of vertical setting on the frame, be equipped with the sliding sleeve that corresponds with the guide bar on the linking arm, the upper end of guide bar is passed the sliding sleeve and is upwards stretched out.

As a preferred scheme, the supporting plate comprises at least two splicing plates which are detachably connected, the splicing plates are connected through a connecting arm, a second yielding groove corresponding to the connecting arm is formed in each splicing plate, and the connecting arm is installed in the second yielding groove.

As an optimal scheme, the work or material rest is equipped with at least one, the work or material rest includes connecting portion and charging portion, connecting portion are connected with the swivel mount, the charging portion is kept away from the swivel mount and is radially outwards stretched out, be equipped with the locating lever in the charging portion, it all is equipped with the constant head tank that corresponds with the locating lever to go up mould and lower mould, the below of lower mould is equipped with the ejection mechanism who is used for jack-up work or material rest, ejection mechanism includes thimble board and the ejection cylinder of control thimble board up-and-down motion, be equipped with the thimble that is used for jack-up work or material rest on the thimble board, be equipped with the thimble through-.

Compared with the prior art, the invention has obvious advantages and beneficial effects, particularly,

1. the injection molding mechanism is sequentially used for injection molding products, multiple times of injection molding can be realized, the injection molding mechanism is arranged on the base through the mounting support, the space around the base is not occupied, the injection molding of a formed part with a long tail is facilitated, and barrier-free rotation is realized.

2. Through setting up the swivel mount, set up three evenly distributed's work or material rest on the swivel mount, every rotatory a week of work or material rest realizes the continuous cycle operation of product material loading, moulding plastics and unloading, and production efficiency is high.

3. The lifting mechanism is arranged on the base, so that the rotating mechanism and the material rack can descend to be in place with the lower die in a fitting mode, the ejection mechanism is arranged below the lower die, and when the material rack ascends, the lifting mechanism and the ejection mechanism synchronously work to enable the rotating mechanism and the material rack to move upwards simultaneously, and the phenomenon that the material rack is blocked due to nonuniform stress is avoided.

4. Through set up a plurality of stoppers at the inboard periphery of conversion, avoid the swivel mount to rock from top to bottom at the pivoted in-process, set up a plurality of location bearings that are used for fixing a position the swivel mount position at the outside periphery of swivel mount, location bearing's axis is parallel with the axis of swivel mount, improves the rotational stability of swivel mount for the injection molding machine operation is stable.

5. Through setting up swivel mount and the layer board of dismantling the connection, the installation is disassembled conveniently, and the maintenance cost is low.

To more clearly illustrate the structural features and technical means of the present invention and the specific objects and functions attained thereby, the present invention will be described in further detail with reference to the accompanying drawings and specific embodiments:

drawings

FIG. 1 is a schematic view of an assembly structure of an embodiment of the present invention;

FIG. 2 is a top view of an embodiment of the present invention;

FIG. 3 is an exploded view of an embodiment of the present invention;

FIG. 4 is a schematic view of the mounting bracket and rotating mechanism assembly of the embodiment of the present invention;

FIG. 5 is a schematic view of a mounting bracket configuration of an embodiment of the present invention;

FIG. 6 is a schematic view of the assembly of the rotating mechanism and the lifting mechanism according to the embodiment of the present invention;

FIG. 7 is an exploded view of the rotating mechanism and the lifting mechanism according to the embodiment of the present invention;

FIG. 8 is an enlarged partial schematic view of portion A of FIG. 7;

FIG. 9 is a cross-sectional view of a lift mechanism of an embodiment of the present invention;

FIG. 10 is an enlarged partial schematic view of portion B of FIG. 9;

FIG. 11 is another perspective cross-sectional view of the elevator mechanism according to an embodiment of the invention;

fig. 12 is a partially enlarged schematic view of portion C of fig. 11;

FIG. 13 is an exploded view of a rotary mechanism according to an embodiment of the present invention;

FIG. 14 is an enlarged partial schematic view of portion D of FIG. 13;

fig. 15 is a partially enlarged schematic view of a portion E in fig. 13.

The attached drawings indicate the following:

10-a machine base; 20-an injection molding mechanism; 21-a hopper;

22-an injection molding head; 23-upper mould; 24-lower die;

241-positioning grooves; 25-mold closing oil cylinder; 26-a mould mounting plate;

261-injection head through hole; 27-injection molding oil cylinder; 30-mounting a bracket;

31-a first C-shaped bracket; 32-a second C-shaped bracket; a 33-C shaped support plate;

34-a bracket connection plate; 35-a first through slot; 36-a second through slot;

37-mouth; 40-a rotating mechanism; 41-a supporting plate;

411-splice plate; 412-a second yielding slot; 42-a rotating frame;

421-arc rack; 423-connecting block; 424-first yielding slot;

43-arc guard plate; 44-annular guard plate; 45-motor;

451-drive gear; 46-a limiting block; 461-limiting plate;

47-a gasket; 48-positioning the bearing; 49-positioning gear;

50-a linker arm; 501-sliding sleeves; 51-a lift cylinder;

52-cylinder mounting seat; 53-a guide bar; 54-ejection oil cylinder;

55-ejector plate; 551-ejector pin; 60-a material rack;

61-a connecting portion; 62-a charging part; 621-positioning rod;

622-opening.

Detailed Description

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the positions or elements referred to must have specific orientations, be constructed and operated in specific orientations, and thus, are not to be construed as limiting the present invention.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood as appropriate by those of ordinary skill in the art.

As shown in fig. 1-15, a multi-molding vertical injection molding machine comprises a machine base 10, a mounting bracket 30, a material rack 60, a rotating mechanism 40 and an injection molding mechanism 20, the machine base 10 is provided with at least two injection molding stations which are sequentially arranged along the outer side of the rotating mechanism 40, the material rack 60 is arranged on the rotating mechanism 40, so that the material rack 60 is driven by the rotating mechanism 40 to switch between injection molding stations, the injection molding stations are provided with injection molding mechanisms 20, the mounting bracket 30 is arranged on the machine base 10 through the middle part of the rotating mechanism 40, the injection molding mechanism 20 comprises an injection molding head 22, an upper mold 23 and a lower mold 24, the lower mold 24 is installed on the machine base 10, the injection head 22 and the upper die 23 are disposed above the lower die 24 by a mounting bracket 30, the injection molding mechanism 20 further comprises a hopper 21, and the injection molding head 22 is communicated with the injection molding head 22 through a feeding channel.

In this embodiment, the mounting bracket 30 includes a first C-shaped bracket 31 and a second C-shaped bracket 32, the first C-shaped bracket 31 and the second C-shaped bracket 32 each include two C-shaped support plates 33 and a support connecting plate 34 connected between the two C-shaped support plates 33, the rotating mechanism 40 is sleeved outside the C-shaped support plates 33, the first C-shaped bracket 31 and the second C-shaped bracket 32 are integrally connected, an included angle between the C-shaped support plates 33 of the first C-shaped bracket 31 and the second C-shaped bracket 32 is 120 degrees, the injection molding mechanism 20 is installed at the upper ends of the first C-shaped bracket 31 and the second C-shaped bracket 32, the lower ends of the first C-shaped bracket 31 and the second C-shaped bracket 32 are connected with the machine base 10, the injection molding mechanism 20 is provided with two mold clamping cylinders 25 for controlling the upper mold 23 to move toward the lower mold 24 direction and an injection cylinder 27 for controlling the injection head 22 to move up and down, the mold closing oil cylinder 25 is mounted on the C-shaped supporting plates 33, first through grooves 35 are formed between the two C-shaped supporting plates 33 of the first C-shaped support 31 and between the two C-shaped supporting plates 33 of the second C-shaped support 32, the injection head 22 of the injection molding mechanism 20 extends downwards through the first through groove 35, a movable joint of the mold closing oil cylinder 25 is provided with a mold mounting plate 26 for mounting the upper mold 23, and an injection head through hole 261 for the injection head 22 to pass through is formed in the mold mounting plate 26.

The rotating mechanism 40 comprises a supporting plate 41 and a rotating frame 42 arranged on the supporting plate 41, wherein the inner side wall of the rotating frame 42 is provided with insections, the supporting plate 41 is provided with a motor 45, a transmission gear 451 on the motor 45 is meshed with the insections on the rotating frame 42, the supporting plate 41 is provided with a plurality of positioning gears 49, the positioning gears 49 are meshed with the insections on the rotating frame 42, the supporting plate 41 is provided with a plurality of gaskets 47 distributed along the rotating frame 42, the upper surface of each gasket 47 is in frictional contact with the lower surface of the rotating frame 42, the supporting plate 41 is provided with a limiting block 46 for preventing the rotating frame 42 from shaking up and down and a positioning bearing 48 for positioning the position of the rotating frame 42, the positioning bearing 48 is abutted against the outer side wall of the rotating frame 42, the axis of the positioning bearing 48 is parallel to the axis of the rotating frame 42, and an arc-shaped guard plate 43 is, the arc-shaped guard plate 43 is fixedly connected with the supporting plate 41, a plurality of limiting blocks 46 are arranged, the limiting blocks 46 are annularly distributed on the inner side of the rotating frame 42, the limiting blocks 46 are arranged in an L shape, each limiting block 46 is provided with a limiting plate 461 extending outwards, the limiting plates 461 are blocked above the rotating frame 42, and an annular guard plate 44 is arranged above the rotating frame 42; the annular backplate 44 is connected with the stopper 46 through the bolt, the swivel mount 42 is the swivel, the swivel includes two sections circular arc racks 421 that can dismantle the connection, two sections connect through connecting block 423 between the circular arc rack 421, be equipped with the first groove 424 of stepping down that corresponds with connecting block 423 on the circular arc rack 421, connecting block 423 passes through the bolt and installs in first groove 424 of stepping down.

It should be noted that, in this embodiment, the positioning bearing 48 may be replaced by a roller or other structure having the same positioning effect, the positioning bearing 48 may also be disposed on the rotating frame 42, a surrounding plate is disposed outside the rotating frame 42, and the surrounding plate is in pressing contact with the positioning bearing 48.

Be equipped with the elevating system who is used for controlling layer board 41 activity from top to bottom on frame 10, elevating system includes the drive assembly of linking arm 50 and the up-and-down motion of drive linking arm 50, drive assembly includes lift cylinder 51 and is used for installing lift cylinder 51's hydro-cylinder mount pad 52, the one end of linking arm 50 is connected with layer board 41, and the other end is connected with hydro-cylinder mount pad 52, the middle part of installing support 30 has the second through groove 36 of vertical setting, lift cylinder 51 and hydro-cylinder mount pad 52 all are located second through groove 36, be equipped with the oral area 37 that supplies linking arm 50 to stretch out on the installing support 30, oral area 37 and second through groove 36 intercommunication, lift cylinder 51's movable joint stretches out downwards and frame 10 fixed connection, be equipped with the guide bar 53 of vertical setting on the frame 10, be equipped with the sliding sleeve 501 that corresponds with guide bar 53 on the linking arm 50, the upper end of guide bar 53 passes sliding sleeve 501 and upwards stretches out, connecting arm 50 is equipped with three, layer board 41 is including the three splice plate 411 of dismantling the connection, and is three connect through connecting arm 50 between the splice plate 411, be equipped with the second groove 412 of stepping down that corresponds with connecting arm 50 on the splice plate 411, connecting arm 50 passes through the bolt and installs in second groove 412 of stepping down.

The three material racks 60 are uniformly arranged on the rotating frame 42, each material rack 60 comprises a connecting part 61 and a material loading part 62, each connecting part 61 is connected with the rotating frame 42, each material loading part 62 is far away from the rotating frame 42 and extends outwards in the radial direction, an opening 622 for exposing a part of a product to be injection-molded is arranged on each material loading part 62, a positioning rod 621 is arranged on each material loading part 62, each upper die 23 and each lower die 24 are provided with positioning grooves 241 corresponding to the positioning rods 621, an ejection mechanism for ejecting the material racks 60 is arranged below each lower die 24, each ejection mechanism comprises an ejector plate 55 and an ejection oil cylinder 54 for controlling the ejector plate 55 to move up and down, an ejector 551 for ejecting the material racks 60 is arranged on each ejector plate 55, an ejector through hole for the ejector 551 to extend upwards is arranged in each positioning groove 241 on each lower die 24, and when the lifting oil cylinders 51 control the rotating frame 42 to drive the material racks 60 to move upwards, the ejection oil cylinder 54 and the lifting oil cylinder 51 work synchronously, the ejection oil cylinder 54 drives the ejector plate 55 to drive the ejector pin 551 to move upwards, so that the upper end of the ejector pin 551 abuts against the positioning rod 621, and the phenomenon that the material rack 60 is clamped due to uneven stress is avoided.

It should be noted that in the present embodiment, the lift cylinder 51 and the ejection cylinder 54 may be replaced by other mechanisms having a lifting function, and are not limited to the lift cylinder 51 and the ejection cylinder 54.

The working principle of the invention is as follows: an operator puts a product to be injection-molded on a material rack 60, a motor 45 drives a rotating rack 42 to rotate for 120 degrees, the material rack 60 moves to a lower die 24 of an injection-molding station, a lifting oil cylinder 51 is condensed to enable a connecting arm 50 to drive a supporting plate 41, the rotating rack 42 and the material rack 60 to move downwards, the lifting oil cylinder 51 stops when a positioning rod 621 on the material rack 60 enters a positioning groove 241 on the lower die 24, a mold closing oil cylinder 25 is opened to push a mold mounting plate 26 downwards, an upper die 23 and the lower die 24 are closed, an injection oil cylinder 27 controls an injection head 22 to move downwards to perform injection molding operation, the product is subjected to first injection molding, the upper die 23 moves back to an initial position, the lifting oil cylinder 51 is opened, meanwhile, an ejector oil cylinder 54 controls an ejector plate 55 to move upwards, an ejector 551 ejects the material rack 60, the supporting plate 41, the rotating rack 42 and the material rack 60 move upwards synchronously, the motor 45, and repeating the steps, performing injection molding on the product for the second time, driving the material rack 60 to continue rotating by the motor 45 again to return to the feeding station, and taking down the molded product by an operator to finish injection molding operation.

In view of the above, it is desirable to provide,

The above description is only for the preferred embodiment of the present invention and is not intended to limit the present invention, so that any modifications, equivalents, improvements, etc. made to the above embodiment according to the present invention are within the scope of the present invention.

Claims

1. The utility model provides a vertical injection molding machine of multiple forming, its characterized in that, includes frame, installing support, work or material rest, rotary mechanism and the mechanism of moulding plastics, be equipped with two at least stations of moulding plastics that set gradually along rotary mechanism's the outside on the frame, the work or material rest is installed on rotary mechanism for the work or material rest is driven by rotary mechanism and is switched between the station of moulding plastics, the station department of moulding plastics all is equipped with the mechanism of moulding plastics, the middle part that the installing support passed rotary mechanism sets up on the frame, the mechanism of moulding plastics is including moulding plastics the head, going up mould and lower mould, the lower mould is installed on the frame, the head of moulding plastics passes.

2. The vertical multiple-shot molding machine of claim 1, wherein said mounting bracket comprises a first C-shaped bracket and a second C-shaped bracket, said first C-shaped bracket and said second C-shaped bracket each comprising two C-shaped support plates and a bracket connecting plate connected between said two C-shaped support plates, said rotating mechanism being sleeved outside said C-shaped support plates.

3. The vertical multiple-shot molding machine according to claim 2, wherein the first and second C-shaped supports are integrally connected, the injection mechanism is mounted at upper ends of the first and second C-shaped supports, and lower ends of the first and second C-shaped supports are connected to the base.

4. The vertical multiple-forming injection molding machine according to claim 3, wherein the injection mechanism is provided with two mold closing cylinders for controlling the upper mold to move in the direction of the lower mold and an injection cylinder for controlling the injection head to move up and down, the mold closing cylinders are mounted on the C-shaped support plates, first through grooves are formed between the two C-shaped support plates of the first C-shaped support and between the two C-shaped support plates of the second C-shaped support, the injection head of the injection mechanism extends downwards through the first through grooves, the movable joint of the mold closing cylinders is provided with a mold mounting plate for mounting the upper mold, and the mold mounting plate is provided with injection head through holes for the injection head to pass through.

5. The vertical injection molding machine of claim 1, wherein the rotating mechanism comprises a support plate and a rotating frame arranged on the support plate, the rotating frame is provided with insections, the support plate is provided with a motor, and a transmission gear on the motor is meshed with the insections on the rotating frame.

6. The vertical injection molding machine of claim 5, wherein the support plate is provided with a plurality of spacers distributed along the rotating frame, the upper surfaces of the spacers are in frictional contact with the lower surface of the rotating frame, the support plate is provided with a limiting block for preventing the rotating frame from shaking up and down and a positioning bearing for positioning the position of the rotating frame, and the axis of the positioning bearing is parallel to the axis of the rotating frame.

7. The vertical injection molding machine of claim 6, wherein the rotating frame is a rotating ring, the rotating ring comprises at least two sections of circular arc racks detachably connected, the circular arc racks are connected through a connecting block, a first yielding groove corresponding to the connecting block is arranged on each circular arc rack, and the connecting block is installed in the first yielding groove.

8. The vertical injection molding machine of claim 1, wherein the base is provided with a lifting mechanism for controlling the support plate to move up and down, the lifting mechanism comprises a connecting arm and a driving component for driving the connecting arm to move up and down, one end of the connecting arm is connected with the support plate, the other end of the connecting arm is connected with the driving component, the base is provided with a vertically arranged guide rod, the connecting arm is provided with a sliding sleeve corresponding to the guide rod, and the upper end of the guide rod passes through the sliding sleeve and extends upwards.

9. The vertical injection molding machine of claim 8, wherein the supporting plate comprises at least two splicing plates detachably connected, the splicing plates are connected through a connecting arm, a second abdicating groove corresponding to the connecting arm is formed in each splicing plate, and the connecting arm is installed in the second abdicating groove.

10. The vertical injection molding machine for multiple molding according to claim 1, wherein the rack is provided with at least one, the rack comprises a connecting portion and a loading portion, the connecting portion is connected with the rotating frame, the loading portion extends outward in a radial direction away from the rotating frame, a positioning rod is arranged on the loading portion, positioning grooves corresponding to the positioning rod are arranged on both the upper die and the lower die, an ejection mechanism for ejecting the rack is arranged below the lower die, the ejection mechanism comprises an ejector plate and an ejection cylinder for controlling the ejector plate to move up and down, an ejector pin for ejecting the rack is arranged on the ejector plate, and an ejector pin through hole for the ejector pin to extend upward is arranged in the positioning groove on the lower die.