205:
known to be dangerous and outlawed in many countries unless the pinch point is fully guarded. This is because the braking mechanism depends on a set of raised keys or "dogs" to fall into matching slots to stop the ram. A full revolution clutch can only bring the ram to a stop at the same location - top dead center. Newer presses are often "part revolution" presses equipped with braking systems identical to the brakes on commercial trucks. When air is applied, a band-type brake expands and allows the crankshaft to revolve. When the stopping mechanism is applied the air is bled, causing the clutch to open and the braking system to close, stopping the ram in any part of its rotation. Modern part revolution clutch and brake units are normally combined units that operate in a fail safe mode, a dual air safety valve engages clutch and starts slide motion and brake is applied by springs.
64:
practice. These slots run up to a central hole made in the plate, the hole being large enough to accommodate another bush with a hole, the hole being used for dropping the punched part to the bottom of the press. The top of the tool butted against a vertical sliding ram with a clamping system which accommodates only a particular diameter of a threaded cylindrical member called the "shank" of the tool. The bottom portion of the tool is locked to the bottom bed plate and the top portion of the tool is locked to the sliding ram. Top and bottom portions of the tool are generally guided by suitable pillar and bush assemblies, which gives safety to the punching elements of the tool.
209:
44:
134:
36:
149:) which, when pressed together, form a hole in a workpiece (and may also deform the workpiece in some desired manner). The punches and dies are removable, with the punch being attached to the ram during the punching process. The ram moves up and down in a vertically linear motion, forcing the punch through the material into the die.
204:
Mechanical punch presses fall into two distinct types, depending on the type of clutch or braking system with which they are equipped. Generally, older presses are "full revolution" presses that require a full revolution of the crankshaft for them to come to a stop. Full revolution clutch presses are
222:
allow the ram to be proportionally controlled to within fixed points as commanded. This allows greater control over the stroke of the ram, and increases punching rates as the ram no longer has to complete the traditional full stroke up and down but can operate within a very short window of stroke.
221:
Hydraulic punch presses power the ram with a hydraulic cylinder rather than a flywheel, and are either valve controlled or valve and feedback controlled. Valve controlled machines usually allow a one stroke operation allowing the ram to stroke up and down when commanded. Controlled feedback systems
166:
To start a cycle, the CNC controller commands the drives to move the table along the X and the Y axis to a desired position. Once in position, the control initiates the punching sequence and pushes the ram from top dead center (TDC) to bottom dead center (BDC) through the material plane. (The terms
157:
The main bed of most machines is called the 'X' axis, with the 'Y' axis being at right angles to that and allowed to traverse under CNC control. Dependent on the size of the machine, the beds, and the sheet metal workpiece weight, the motors required to move these axis tables will vary in size and
67:
Generally the tool is placed slightly above the bottom bed plate by providing two parallel blocks accurately ground to the same size. This is a necessary action since many tools, scrap (cut pieces which are a waste) is discharged through the bottom element of the tool, not necessarily in the centre
124:
Punch presses are usually referred to by their tonnage and table size. In a production environment a 30-ton press is mostly the machine used today. The tonnage needed to cut and form the material is well known, so sizing tooling for a specific job is a fairly straightforward task. According to the
234:
press uses twin AC servo drives directly coupled to the drive shaft. This drive system combines the simplicity of the original clutch and brake technology with the speed of a hydraulic ram driven system. This results in high performance, reliability, and lower operating costs. A servo drive press
170:
On its stroke from TDC to BDC, the punch enters the material, pushing it through the die, obtaining the shape determined by the design of the punch and die set. The piece of material (slug) cut from the workpiece is ejected through the die and bolster plate and collected in a scrap container. The
71:
In very heavy presses with higher tonnage, the sliding ram has also a thick plate with T slots for locking the top plate of the tool (called the top bolster). In such cases the threaded cylinder called shank is not attached to the tool. The clamps are either mechanical (manually operated using
63:
C type presses have a bed plate which is used to lock the die bottom bolster. For locking the die, T-bolts are used and so this plate contains T-slots into which T-bolts are slid in. These slots are placed diagonally and with a slot horizontal to the longer side of the plate, is the general
235:
system has no complex hydraulics or oil-cooling chillers, thus reducing maintenance and repair costs. A turret press can be equipped with advanced technology that stores and reuses energy generated during ram deceleration, providing extended electrical power savings.
68:
of the tool. The scrap or the blank (the required portion) come out from the die at different places. These have to be taken out horizontally from between the parallels placed. Otherwise they get accumulated inside the tool itself and cause severe damage to the tool.
174:
The punch press is used for high volume production. Cycle times are often measured in milliseconds. Material yield is measured as a percentage of parts to waste per sheet processed. CAD/CAM programs maximize yield by nesting parts in the layout of the sheet.
75:
Turret type punch press machines have a table or bed with brushes or rollers to allow the sheet metal workpiece to traverse with low friction. Brushes are used where scratches on the workpiece must be minimized, as with
196:. In the 19th century, the flywheels were powered by leather drive belts attached to line shafting, which in turn ran to a steam plant. In the modern workplace, the flywheel is powered by an electric motor.
60:
type has the hydraulic ram at the top foremost part, whereas the portal frame is much akin to a complete circle with the ram being centered within the frame to stop frame deflection or distortion.
188:
Most punch presses today are hydraulically powered. Older machines, however, have mechanically driven rams, meaning the power to the ram is provided by a heavy, constantly rotating
167:
BDC and TDC go back to older presses with pneumatic or hydraulic clutches. On today's machines BDC/TDC do not actually exist but are still used for the bottom and top of a stroke.)
365:
327:
158:
power. Older styles of machines used DC motors; however, with advances in technology, today's machines mostly use AC brushless motors for drives.
358:
683:
146:
142:
351:
320:
296:
208:
379:
313:
43:
673:
105:
Speed or productivity (typically characterized by the speed of strokes with a step movement of 25 and 1 mm)
595:
436:
137:
Quick change tool system (left: die; front: punch, split punch retainer; back: tool body; right: punch guide)
647:
466:
441:
431:
678:
491:
486:
426:
421:
375:
56:
Punch presses are large machines with either a 'C' type frame, or a 'portal' (bridge) type frame. The
688:
476:
25:
622:
617:
552:
446:
395:
292:
47:
Punched hole: best results for cutting surface with above 70% cutting, low clearance necessary
244:
527:
471:
133:
24:
used to cut holes in material. It can be small and manually operated and hold one simple
575:
496:
90:
Mechanism of delivering power to the ram (mechanical, electro-mechanical or hydraulic)
35:
667:
570:
565:
102:
The type of tool shop and its capacity (e.g., store revolving type, capacity 34 tool)
77:
21:
506:
461:
336:
249:
231:
32:
operated, with a multi-station turret and hold a much larger and complex die set.
286:
405:
642:
637:
400:
193:
632:
627:
560:
537:
451:
481:
189:
652:
612:
590:
585:
542:
522:
501:
456:
580:
125:
requirement the tonnage may even go up to 2000 to 2500 ton presses.
532:
207:
132:
42:
347:
309:
305:
171:
return to TDC signals to the control to begin the next cycle.
29:
108:
Speed of movement without shock (speed-load displacement)
83:
The punch press is characterized by parameters such as:
212:
Part revolution clutch system on modern gap frame press
285:
Todd, Robert H.; Allen, Dell K.; Alting, Leo (1994),
551:
515:
414:
388:
93:Size of working area (e.g., 2500 x 1250 mm)
268:
359:
321:
8:
366:
352:
344:
328:
314:
306:
141:A die set consists of a set of punches (
34:
288:Manufacturing Processes Reference Guide
261:
192:. The flywheel drives the ram using a
80:aluminium or high polished materials.
72:spanners) or air operated varieties.
7:
99:Force rating (for example, 20 tons)
14:
226:Servo drive turret punch press
1:
269:Todd, Allen & Alting 1994
111:Maximum weight of workpiece
705:
684:Metalworking cutting tools
96:Single or multiple station
608:
343:
291:, Industrial Press Inc.,
437:Electrohydraulic forming
162:CNC-controlled operation
442:Electromagnetic forming
28:set, or be very large,
427:Casting (metalworking)
213:
200:Mechanical punch press
138:
48:
40:
39:Mechanical punch press
648:Tools and terminology
217:Hydraulic punch press
211:
136:
46:
38:
477:Progressive stamping
120:The type of software
553:Finishing processes
271:, pp. 107–108.
214:
139:
49:
41:
661:
660:
604:
603:
516:Joining processes
447:Explosive forming
415:Forming processes
117:Power consumption
696:
674:Cutting machines
383:
368:
361:
354:
345:
330:
323:
316:
307:
301:
272:
266:
245:Punching machine
704:
703:
699:
698:
697:
695:
694:
693:
664:
663:
662:
657:
600:
547:
511:
472:Press hardening
410:
384:
382:, and finishing
374:
372:
339:
334:
299:
284:
281:
276:
275:
267:
263:
258:
241:
228:
219:
202:
186:
181:
164:
155:
131:
114:Safety features
54:
12:
11:
5:
702:
700:
692:
691:
686:
681:
676:
666:
665:
659:
658:
656:
655:
650:
645:
640:
635:
630:
625:
620:
615:
609:
606:
605:
602:
601:
599:
598:
593:
588:
583:
578:
576:Mass finishing
573:
568:
563:
557:
555:
549:
548:
546:
545:
540:
535:
530:
525:
519:
517:
513:
512:
510:
509:
504:
499:
494:
489:
484:
479:
474:
469:
464:
459:
454:
449:
444:
439:
434:
429:
424:
418:
416:
412:
411:
409:
408:
403:
398:
392:
390:
386:
385:
373:
371:
370:
363:
356:
348:
341:
340:
335:
333:
332:
325:
318:
310:
304:
303:
297:
280:
277:
274:
273:
260:
259:
257:
254:
253:
252:
247:
240:
237:
230:A servo drive
227:
224:
218:
215:
201:
198:
185:
184:Flywheel drive
182:
180:
177:
163:
160:
154:
151:
130:
127:
122:
121:
118:
115:
112:
109:
106:
103:
100:
97:
94:
91:
88:
53:
50:
13:
10:
9:
6:
4:
3:
2:
701:
690:
687:
685:
682:
680:
679:Machine tools
677:
675:
672:
671:
669:
654:
651:
649:
646:
644:
641:
639:
636:
634:
631:
629:
626:
624:
621:
619:
616:
614:
611:
610:
607:
597:
594:
592:
589:
587:
584:
582:
579:
577:
574:
572:
571:Heat treating
569:
567:
564:
562:
559:
558:
556:
554:
550:
544:
541:
539:
536:
534:
531:
529:
526:
524:
521:
520:
518:
514:
508:
505:
503:
500:
498:
495:
493:
490:
488:
485:
483:
480:
478:
475:
473:
470:
468:
465:
463:
460:
458:
455:
453:
450:
448:
445:
443:
440:
438:
435:
433:
430:
428:
425:
423:
420:
419:
417:
413:
407:
404:
402:
399:
397:
394:
393:
391:
387:
381:
377:
369:
364:
362:
357:
355:
350:
349:
346:
342:
338:
331:
326:
324:
319:
317:
312:
311:
308:
300:
298:0-8311-3049-0
294:
290:
289:
283:
282:
278:
270:
265:
262:
255:
251:
248:
246:
243:
242:
238:
236:
233:
225:
223:
216:
210:
206:
199:
197:
195:
191:
183:
178:
176:
172:
168:
161:
159:
152:
150:
148:
144:
135:
128:
126:
119:
116:
113:
110:
107:
104:
101:
98:
95:
92:
89:
86:
85:
84:
81:
79:
73:
69:
65:
61:
59:
51:
45:
37:
33:
31:
27:
23:
22:machine press
20:is a type of
19:
507:Tube bending
462:Hydroforming
337:Metalworking
287:
279:Bibliography
264:
250:Punchcutting
232:turret punch
229:
220:
203:
187:
173:
169:
165:
156:
145:) and dies (
140:
123:
82:
74:
70:
66:
62:
57:
55:
17:
15:
689:Press tools
618:Fabrication
566:Galvanizing
406:Sheet metal
396:Fabrication
380:fabrication
52:Description
18:punch press
668:Categories
638:Metallurgy
581:Patination
401:Piece work
256:References
194:Pitman arm
179:Drive type
87:Frame type
633:Machining
628:Jewellery
596:Polishing
561:Anodizing
538:Soldering
452:Extrusion
643:Smithing
533:Riveting
528:Crimping
497:Spinning
482:Punching
467:Stamping
239:See also
190:flywheel
653:Welding
623:Forming
613:Casting
591:Plating
586:Peening
543:Welding
523:Brazing
502:Swaging
492:Sinking
487:Rolling
457:Forging
432:Drawing
422:Coining
389:General
376:Forming
129:Die set
78:brushed
295:
147:female
293:ISBN
153:Axis
143:male
30:CNC
26:die
670::
378:,
16:A
367:e
360:t
353:v
329:e
322:t
315:v
302:.
58:C
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.