US3072279A

US3072279A - Riveting machine

Info

Publication number: US3072279A
Application number: US838872A
Authority: US
Inventors: Gerald S Ikelheimer
Original assignee: Individual
Current assignee: Individual
Priority date: 1959-09-09
Filing date: 1959-09-09
Publication date: 1963-01-08
Anticipated expiration: 1980-01-08

Description

Jan. 8, 1963 G. s. IKELHEIMER 3,072,279

RIVETING MACHINE Filed Sept. 9, 1959 2 Sheets$heet 2 INVENTOR 66/ 0 [d 5. Ike! hell/Her BY All/rm, Lida y, Dame/5 5 Marci ATTORNEYfi United States Patent has! 3,l72,279 RIVJETKNG MACHINE Gerald S. llreiheirner, 95 Lexington Ave, Apt. III, New York, NE. Filed Sept. 9, 1959, Ser- No. 838,872 26 Claims. (Cl. 218-1) This invention relates to riveting machines and more particularly to machines of the type wherein automatically fed rivets are utilized in the manner of punches, to pierce the work-pieces which are to be joined together, thereby obviating the need for a separate punch and die and also a separate piercing operation.

An object of the invention is to provide a novel and improved combination die and heading tool or structure, in a riveting machine of the above type.

A further object of the invention is to provide .an improved combiuation die means and heading structure, wherein the die is made to have advancing and retracting movements, to enable the work pieces to be pierced by the rivets and to facilitate the rapid and effective heading over the rivets.

A further object of the invention is to provide .an improved combination die and heading tool as above said forth, which is characterized by a novel slug-discharge means adapted to use fluid under pressure, by which the slug which is removed from the work pieces during the piercing of the same, may be readily disposed of prior to the heading of the rivets.

Yet another object of the invention is to provide an improved retractable combination die and heading tool, wherein novel and simplified means are provided for effecting the retracting and advancing movement of the tool, and for correlating the same with the advancing and retracting movements of the rivet-heading punch.

A feature of the invention resides in tne provision of novel mechanical locking means for maintaining a combination die and heading tool in an advanced position during the work piercing and supporting operation.

Another feature of the invention resides in provision of novel and simplified fluid-actuated means for controlling the advancing and retracting movements aforesaid, and also like movements of the rivet heading punch, all in conjunction with a novel mechanical inter-lock means.

A further object of the invention is to provide an improvide and simplified advancable and retractable combination die and heading tool in accordance with the fore going, wherein there is provided a simplified mechanical interlock and novel alternately operable means for maintaining the inter-lock in operative condition.

Other objects of the invention are to provide effective mechanical locking and control means in conjunction with a retractable and advanceable combination die andheading tool, which means are extremely simple in construction, relatively small and compact, reliable in operation and capable of being economically fabricated and produced.

Other features and advantages will hereinafter appear. In the drawings accompanying this specification, similar characters of reference have been used to designate like components.

FIG. 1 is a vertical axial sectional view through a combination die and heading tool as provided by the invention, mounted in a riveting machine, portions of which latter are shown in elevation.

FIG. 2 is the front elevational view of the structures depicted in FIG. 1.

FIG. 3 is a top plan view of the combination die and heading tool shown in FiGS. l and 2.

FIG. 4 is a fragmentary vertical axial sectional view similar to that shown in FIG. 1, but illustrating the re tracted position of the die.

FIG. 5 is a view like FlG. 4- hut showing the die and 3,d72,279 Patented Jan. 8, 1953 rivet heading punch in their advanced positions, heading over a rivet, which has pierced the work pieces.

FIG. 6 is an axial sectional view of a combination die and heading tool illustrating a modification of the invention, wherein the movements of the die and punch are under the control of pressurized fluid.

Referring first to FIGS. 1 through 5, the bed of the riveting machine is indicated by the numeral 10 said machine having a power driven connecting rod 11 coupled to a bell crank 12 which is in turn joined by means of a pivoted link 14 to a driving fitting 15 which is vertically slidable Within a bushing 17 threaded into a bed 16.

The riveting machine further has a rivet feed device indicated generally by the numeral 19, including a vertical tubular rivet guide 21 in which there is disposed a rivet driver 23.

As will be understood, the rivets, which are adapted to constitute punching devices for piercing the work pieces and cutting out slugs therefrom are deposited in the vertical tubular guide 21 with their heads uppermost, and are brought downward into engagement with, and forced through the work piece sheets 24 by the driver 23.

Carried by the machine bed 10 is a stationary sleeve 26 said sleeve at its lower end abutting the upper end of the bushing 17 and being accurately located thereby. As seen in FIGS. 1, 4, and 5, the stationary sleeve 26 may constitute a rest for the work pieces 24-.

In accordance with the present invention, in conjunction with the stationary sleeve 26, the rivet feeding means 19 and the driver 23 there is provided a novel combination die means and heading tool, which enables the rivets, indicated at 28, to be forced into and through the work pieces 24 in the manner of punches, and to effect a head ing over of the rivets for the purpose of securing together the work pieces 24. This combination die means and heading tool as shown in FIGS. 1-5 comprises an inner sleeve 30 (also hereinafter referred to as a material supporting sleeve) which is vertically movable within the outer stationary sleeve 26 between advanced and retracted positions. In FIGS. 1 and 5, the material supporting sleeve 30 is shown advanced whereas in FIG. 4 it is shown as being retracted.

The material supporting sleeve 30 at its upper end has an opening or bore which is commensurate with the diameter of the rivets which are to be utilized. The said upper end of the sleeve 30 is constituted to function as a die member whereby, when engaged with the under surface of the work pieces 24, it will enable the rivets to puncture holes through the work pieces and to be disposed therein, in the manner indicated in FIGS. 1, 4 and 5. In FIG. 1 two slugs 32 are shown .as having been punched from the work pieces 24 by the: rivet 28 while the work pieces are being supported by the outer stationary sleeve 26 and the inner material supporting sleeve 39.

As seen in FIGS. 2 and 3, opposite side portions of the stationary sleeve 26 are removed to provide

slots

26x and 26y respectively at two places on the outside of the material support sleeve 30, whereby certain oppositely disposed areas of the sleeve 30 are uncovered and exposed.

In accordance with the present invention, see FIGS. 2 and 3, the material supporting sleeve 30 is arranged to enable the struck-out slugs 3 to be readily ejected or discharged from the sleeve, by the use of pressurized fluid, such as compressed air or the like. In accomplishing this, the sleeve 30 is provided with a relatively large side opening 34 and has a second and smaller side opening 36 disposed at a higher level than the larger opening 34. The larger opening 34 is elongate and in the nature of a slot, as seen in FIG. 1. The outer stationary sleeve 26 has an opening 38 connected with an injection air tube 39. A suitable source of air is supplied through a usual valving '2 ea means. When the material supporting sleeve is in its advanced position as shown in FIGS. 1 and 5, the openings 36 and 33 are in registration with each other, and under such conditions a periodic blast of compressed air through the tube 39 will eject the slugs 32 from sleeve 30, through the large opening 34. It will be understood that the blast of air is periodically efiected, by timed action of the control valve in the line supplying the tube 39.

By the present invention, a novel and simplified locking means or inter-lock is provided between the inner material supporting sleeve 30 which constitutes the die, and the outer stationary sleeve 26. In effecting such interlock, and also for the purpose of supporting the material supporting sleeve 30, there is provided a plunger or carrier sleeve 42 having a lower portion 42a of an enlarged diameter which slidably bears in an enlarged bore of the outer stationary sleeve 26. The upper extremity of the plunger 42 is internally threaded, and receives the lower threaded end of the material supporting sleeve 30 whereby these two sleeves are joined together to move as a unit.

Within the stationary sleeve 26 there is provided a helical compression retracting spring 44 engaging an internal annular shoulder in the stationary sleeve 26 and an annular shoulder provided by the enlarged portion 42a of the plunger sleeve 42. Thus, the plunger sleeve 42 and also the material supporting sleeve 30 are biased downward by the spring 44, as viewed in the drawings.

To effect a releasable inter-lock between the outer stationary sleeve 26 on the one hand and the inner

movable sleeves

30 and 42 on the other hand there are provided in accordance with the invention, locking members. These are in the, form of balls 47 which are carried in recesses 48 in the lower portion 42a of the plunger 42. The balls 47 may be received, in part, in opening provided in the outer stationary sleeve 26. The said openings 50 are registered with the recesses 48 carrying the balls, as clearly shown in FIGS. 1 and 5, to maintain the locking balls 47 in the positions wherein portions of them will occupy the openings 50 in the outer stationary sleeve 26. A novel control means is also provided which is associated with a heading punch 52 slidably mounted within the plunger 42 and material supporting sleeve 30. The lower extremity of said means is affixed to the driving fitting 16. The heading punch 52 has a portion 52a of enlarged diameter which is adapted to engage the locking balls 47 and maintain the same in spread-apart relation, as shown in FIG. 1. When the balls 47 are so held, the plunger 42 and the material supporting sleeve 30 will be securely locked to the outer stationary sleeve 26 and the upper end surfaces of the

sleeves

26 and 30 will be flush with each other. For such condition, the material supporting sleeve 30 may function truly as a die in conjunction with the work pieces 24, whereupon driving force supplied to the rivet 28 will enable the latter to constitute a punch, so as to pierce the work pieces 24 and punch out the slugs 32 therefrom. Prior to such punching, the rivet 28 will be sitting on top of the work pieces 24 with the driver 23 in a raised position (not shown). Descent of the driver 23 then effects piercing of the work pieces 24 by the punch.

In accordance with the invention, the heading of the rivet 28 which has thus acted as a punch and has passed through the work pieces 24 is accomplished by the heading punch 52 in response to advancing or raising movement of the punch, as imparted to it by a clockwise turning movement of the bell crank 12 and a left-to-right movement of the connecting rod 11. The raising movement of the heading punch 52 is illustrated in FIG. 4. As shown, the enlargement 52a of the punch has left the locking balls 47. Under the action of the retracting spring 44, the locking balls 47 will be cammed inward and forced out of the openings 50 in the outer stationary sleeve 26. The plunger 42 and the material supporting sleeve 30 will be thus forced downward by the spring 44 after such releas- 4 ing movement of the balls 47, and the plunger and sleeve will be halted by engagement between the bottom surface of the plunger 42 and a stop ring 54. The stop ring 18 disposed in the interior of the stationary sleeve 26 and adjacent the bottom edge thereof.

After the aforesaid punching through of the work pieces 24 by the rivet 28 (see FIG. 1) and prior to the retracting movement of the material supporting sleeve 30 and the advance of the heading punch 52, the blanked out slugs 32 will be ejected by a blast of air through the tube 35 as already hereinabove described.

Referring now to FIGS. 4 and 5, the rivet 28 and the associated mechanism is illustrated following the punching and during the heading procedure. In FIG. 4, the heading punch 52 is ascending, whereas the material supporting sleeve 30 is in its retracted position with the slugs 32 already ejected or discharged. Further upward movement of the punch 52 from the position shown in FIG. 4, will cause the tapered nose or upper extremity of the punch to engage the correspondingly tapered bore of the material supporting sleeve 30. Upon such engagement occurring, the continued upward movement of the punch 52 will cause the material supporting sleeve 30 and the plunger 42 to be carried along with the punch, and as the punch and die sleeve engage the lower extremity of the rivet shank, the rivet will be headed and spread apart, as clearly illustrated in FIG. 5. The final movement of the plunger 42, die sleeve 30 and heading punch 52 will take place after the retraction of the backing punch 23 has commenced, and will cause the Work pieces 24 to be raised slightly above the top surface of the stationary sleeve 26, by an amount equal to the thickness of the headed portion of the rivet.

Further, in accordance with the present invention, means are provided for now locking the raised material supporting sleeve 30 and plunger 42 in the position of FIG. 5, this means being associated with the heading punch 52 and comprising a locking collar 57 which is slidably carried by the punch 52, together witha collar actuating spring 58 in the form of a helical compression coil, said spring being also carried by the punch 52. Referring to FIGS. 4 and 5, upon a continuation of the raising movement of the punch 52, and as the latter carries with it the plunger 42 and the material supporting sleeve 30, the ball-carrying recesses 48 in the plunger will again be brought into registration with the openings 50 in the outer stationary sleeve 26, as in FIG. 5, thereby enabling the locking balls 47 to again partially enter the openings 50. The halls are forced into these locking positions by a camming action, by means of the locking colar 57 which is spring-urged upward by the compression spring 58, and the positions of these parts are shown in FIG. 5 wherein the plunger 42 is again locked to the outer stationary sleeve 26.

Upon the heading of the rivet being completed, the heading punch 52 is withdrawn to the starting position shown in FIG. 1. During this action and movement of the punch 52, the control collar 57 will remain in engagement with the locking balls 47 until the collar is finally forcibly displaced by the en argement 52a on the punch 52. Thus. the interlock which has been established between the plunger 42 and the outer stationary sleeve 26 will be maintained at all times during the descent of the plun er, whereby the material supporting sleeve 30 will be held in its raised or advanced position in readiness for the next riveting operation. From the positions shown in FIG. 5 the parts are returned to the starting positions of FIG. 1, and during such return the plunger 42 and the material supporting sleeve 30 have been retained in their raised positions, securely locked to the outer stationary sleeve 26.

The connecting rod 11, bell crank 12 and the connecting rod 14 may be considered as a power means for effecting actuation of the heading punch 52.

In connection with the above action it will be noted that the collar-actuating spring 58 at its lower end engages the driving fitting 16, and that the size of the spring is then determined by the distance between the fitting 16 and the enlargement 52a on the punch 52, less the length of the locking collar 57 and the space between the latter and enlargement as shown in FIG. 1.

It will be noted that in the above construction relatively few parts are employed, said parts being of simple structure and being easily economically fabricated. Moreover, an effective support is given to the work pieces for carrying out a punching operation utilizing the rivets, thereafter the punched-out slugs are disposed of and the die element is retracted and then advanced with the heading punch to effectively head over the rivet and join together the work-pieces. After the heading operation, the die sleeve is retained in its advanced position in readiness for the next riveting operation.

Another embodiment of the invention is illustrated in FIG. 6. In this embodiment there is shown a material supporting sleeve 300 carried by a plunger 420, said sleeve and plunger being shifted to retracted positions after being unlocked from an outer stationary sleeve 260, by means of pressurized fluid introduced through a tube 70 and acting against a shoulder 42011 on the plunger 420. The plunger thus constitutes a piston, whereas the outer stationary sleeve 260 constitutes a cylinder therefor. Suitable O-rings are carried by the plunger 420, as shown, to provide for sealing engagement with the outer sleeve 2649.

Advance of the plunger 420 and the material supporting sleeve 3% is effected by a helical compression spring '72 engaged with the plunger 420 and with a stationary nozzle member 74 carried within the sleeve 2-60 against a retainer ring 75 thereof.

Retraction of the heading punch 520 is effected by a helical compression spring 81 engaging the enlarged portion 520a of the punch and an internal annular shoulder within the plunger 420, as shown. The advancing move ent of the heading punch 520 is effected by fluid under pressure which is introduced through a tube 77 into the nozzle part 74, said fluid acting against the lower end surface of the punch 520, this bottom surface being on an enlarged lower portion of the punch which carries an O-ring and functions as a piston. The nozzle member 74 also has an O-ring for sealing purposes, and the plunger 42th constitutes a cylinder for the lower enlarged portion of the heading punch 520, as will be understood.

Aligned vent openings 79 and 89 are provided in the outer sleeve 2m and the machine bed 10, to provide for freedom of movement of the plunger 4-20.

The locking balls 47 are under the control of the enlarged portion 520a of the heading punch 520, as in the previous embodiment of the invention. When the punch 520 is advanced, the balls 47 will be released, unlocking the plunger 42% from the outer sleeve 260 and permitting the plunger and the die sleeve 3% to be shifted downward or retracted against the action of the spring 72 by air introduced into the tube 70.

it will be understood that the piston and cylinder constituted by the plunger 42!} and the stationary sleeve 260 respectively may be considered as a power means.

By alternately applying compressed air to the tubes 76, '77 the movements of the punch 52% and the plunger 420 carrying the die sleeve may be controlled in a manner described above in connection with FIGS. 1-5. More specifically the operation of the modified embodiment as illustrated in FIG. 6 is as follows. Applying an air pressure to lines '77 will cause the punch 520 to move upwardly. Upward movement of punch 520 thus displaces the enlarged portion 526a thereof permitting the locking balls 47 to be cammed inwardly so as to release the plunger 42% from the stationary sleeve 260. The camming of the locking balls 47 to release plunger 424) is effected by applying air pressure on shoulder portions 42% through line 70 to force the plunger downwardly against the action of spring 81. As the tapered nose of the punch 520 engages the corresponding tapered bore portion of the material supporting sleeve 3%, pressure to line 70 is cut off and the continued movement of punch 520 will carry with it sleeve 3%. As the punch 520 and the sleeve 3% engage the lower extremity of the rivet as described with reference to FIGS. 1 to 5, the rivet will be headed and spread apart.

While the invention has been described in some detail, it will be understood that variations and modifications may be made Without departing from the spirit thereof or the scope of the appended claims.

I claim:

1. In a riveting machine, in combination, a workpiece supporting sleeve member mounted for axial movements in reverse directions, said member having an end portion constituted as a die for engagement with workpieces to support the same for piercing by rivets, and being provided with a bore commensurate in size with a rivet shank whereby the rivet may act as a punch to pierce the workpieces; a driving member disposed adjacent the die-constituting end of the sleeve member, said driving member being enga geable with a rivet for the purpose of effecting said piercing of the workpieces; said driving member being adapted to be advanced toward said rivet whereby relative advancing movement between said members cause an intervening rivet to punch through workpieces disposed between the members; means for effecting retracting movement of said sleeve member relative to said driving member; a rivet heading punch extending through the sleeve member; and means for effecting relative advancing movement between the driving member on the one hand and the rivet-heading punch and sleeve member on the other hand, to head over the rivet after it has pierced the workpieces.

2. The invention as defined in claim 1, in which the means for effecting reiative advancing movement between the said members comprises a plunger connected with one of said members, and comprises a power means engaged with the said plunger for driving the same.

3. The invention as defined in claim 1, in which means for effecting relative retracting movement between the members comprises a plunger connected with one member.

4. The invention as defined in claim 1 in which said last named means include cooperating engageable and disengageable abutting portions formed on said rivet heading punch and said sleeve member, said abutting portions being rendered engageable to effect concurrent movement of the punch and sleeve member when the punch is being driven toward said driving member.

5. In a riveting machine, a movable work-supporting sleeve shiftable between advanced and retracted positions and having an end portion constituted as a die for engagement with workpieces to support the same for piercing by rivets, said sleeve being provided with a bore commensurate in size with a rivet shank whereby the rivet may act as a punch to pierce the workpieces, said sleeve further having a small hole and a second and larger hole in its side walls at the said end portion; and a stationary compressed air orifice disposed adjacent the said end portion of the sleeve, said orifice being directed at the small hole of said side wall when the sleeve is in its advanced position so as to effect an injection of air into the bore of the sleeve and to effect an ejection through the large hole of the sleeve side wall, of slugs deposited in the sleeve bore. when the workpieces are pierced.

6. The invention as defined in claim 5, in which there is an outer sleeve surrounding and movably carrying the work-supporting sleeve, and in which the said outer sleeve has a side opening comprising the said orifice and having means for connection to a source of air under pressure, said side opening being registrable with the said small hole of the work-supporting sleeve to introduce air thereto.

7. in a riveting machine, in combination, a work-supporting die sleeve mounted for axial movements in reverse directions; a rivet heading punch disposed within said sleeve and arranged to be longitudinally movable therein; releasable locking means for locking the sleeve in a given operative position, said means including a movable part comprising a locking member extending into the said sleeve; means on said punch engageable with the locking member to block the same and maintain the said locking means operative; and a collar movably carried by the punch Within the sleeve and engageable alternatively with the said member to similarly block the same for holding the locking means operative during retracting movement of the punch and prior to blocking of the locking member by said means on the punch, the said sleeve being displaced and shifted out of such blocking engagement by said means during retracting movement of the punch.

8. The invention as defined in claim 7, in which the means on said punch which is engageable with the locking member comprises a projection extending laterally from the punch, said projection having a camming surface which initially engages the locking member.

9. In a riveting machine, in combination, a workpiece supporting sleeve mounted for movement between advanced and retracted positions, said sleeve having an end portion constituted as a die for engagement with workpieces to support the same for piercing by rivets and being provided with a bore commensurate in size with a rivet shank whereby the rivet may act as a punch to pierce the work pieces, releasable means for locking the sleeve in its advanced position, a heading punch movable in said sleeve for heading rivets which have pierced the workpiece, means on said punch for rendering said releasable locking means inoperative in response to the initial advance of said punch to enable the sleeve to be retracted after such initial movement of said punch, means for effecting retraction of said unlocked sleeve, and means for returning the sleeve to advanced position with continued movement of said punch.

10. The invention as defined in claim 9, in which there is a holder disposed around and carrying he said sleeve, and in which the means for locking the sleeve comprises loc.:ing members adapted to be engaged between the sleeve and the said holder.

11. The invention as defined in claim 10, in which the locking members comprise balls, and in which the sleeve has recesses in which the balls are carried and in which they are movable.

12. The invention as defined in claim 10, in which the holder compirses an outer stationary sleeve surrounding and carrying the said workpiece supporting sleeve, said outer stationary sleeve having abutting shoulders constituting a portion of the said releasable locking means for the sleeve.

13. The invention as defined in claim 9, in which the means effecting retraction of the sleeve comprises a helical compression spring which becomes operative when the locking means is rendered inoperative.

14. The invention as defined in claim 9, in which the locking means includes a projection on the heading punch, and includes locking members engageable with the said projection to effect locking of the sleeve.

15. The invention as defined in claim 9, in which the locking means for the sleeve includes locking members movably carried by the sleeve, and in which there is means movably carried by the punch and engageable with the said locking members, for effecting a locking of the sleeve in its advanced position after it has been returned thereto by continued advance of the punch.

16. The invention as defined in claim 15, in which the means movably carried by the punch comprises a locking collar longitudinally movable thereon, and in which there is a helical compression spring carried by said punch and engageable with the said collar, to bias the latter in a direction tending to engage it with the said blocking members.

17. The invention as defined in claim 9, in which the means for effecting retraction of the sleeve includes a piston and cylinder structure, having means for connection to a source of fluid under pressure.

18. The invention as defined in claim 9, in which there is means for efiFectin'g advance of the punch comprising a piston and cylinder structure having means for connection to a source of fluid under pressure.

19. The invention as defined in claim 9, in which the means for returning the sleeve to its advanced position comprises a helical compression spring engaged with the said sleeve, and in which the means for effecting retraction of the sleeve comprises a piston and cylinder structure adapted to oppose the action of the said spring.

20. The invention as defined in claim 9, in which there is means for effecting a retraction of the punch, comprising a helical compression spring, and in which there is means for etiecting an advance of the punch, comprising a piston and cylinder structure adapted to oppose the action of the said spring.

References Cited in the file of this patent UNITED STATES PATENTS

Claims

1. IN A RIVETING MACHINE, IN COMBINATION, A WORKPIECE SUPPORTING SLEEVE MEMBER MOUNTED FOR AXIAL MOVEMENTS IN REVERSE DIRECTIONS, SAID MEMBER HAVING AN END PORTION CONSTITUTED AS A DIE FOR ENGAGEMENT WITH WORKPIECES TO SUPPORT THE SAME FOR PIERCING BY RIVETS, AND BEING PROVIDED WITH A BORE COMMENSURATE IN SIZE WITH A RIVET SHANK WHEREBY THE RIVET MAY ACT AS A PUNCH TO PIERCE THE WORKPIECES; A DRIVING MEMBER DISPOSED ADJACENT THE DIE-CONSTITUTING END OF THE SLEEVE MEMBER, SAID DRIVING MEMBER BEING ENGAGEABLE WITH A RIVET FOR THE PURPOSE OF EFFECTING SAID PIERCING OF THE WORKPIECES; SAID DRIVING MEMBER BEING ADAPTED TO BE ADVANCED TOWARD SAID RIVET WHEREBY RELATIVE ADVANCING MOVEMENT BETWEEN SAID MEMBERS CAUSE AN INTERVENING RIVET TO PUNCH THROUGH WORKPIECES DISPOSED BETWEEN THE MEMBERS; MEANS FOR EFFECTING RETRACTING MOVEMENT OF SAID SLEEVE MEMBER RELATIVE TO SAID DRIVING MEMBER; A RIVET HEADING PUNCH EXTENDING THROUGH THE SLEEVE MEMBER; AND MEANS FOR EFFECTING RELATIVE ADVANCING MOVEMENT BETWEEN THE DRIVING MEMBER ON THE ONE HAND AND THE RIVET-HEADING PUNCH AND SLEEVE MEMBER ON THE OTHER HAND, TO HEAD OVER THE RIVET AFTER IT HAS PIERCED THE WORKPIECES.