To punch free of deformations with the through-punchingmethod, the upper tube wall is cut by the punching die. Afterwards, the slug serves as the punching die’s extension and punches the lower tube wall. Hence, the punching slug becomes a cutting tool. The slug guide in the expansion die and the die holder has to be very tight so the slug can’t loosen. Using expanding mandrels, which are driven separately and have exchangeable dies, the tube can literally be punched free of burrs without further postproduction. PETIG machines allow the manufacturing of tubes up to 8 m length, diameter up to 100 mm and a wall thickness of 0.5 to 10 mm.
The disposal of the punching slugs is easy as well because these fall through the machine table after each punch. Tubes can be turned for further processing without additional work step.
Thanks to the control system, the collet chucks in the feed can be rotated into any tube position. Depending on the tube size, up to four tubes can be processed simultaneously. In order that the quality of the upper and lower perforations is virtually equal, the punch holes with slug guide have to be identical. Possible deviations of up to 0.2 mm of the lower perforation have no effect on the product. Decisive for the punching quality is always the punching tool and this has to, due to occasionally large tube diameters, have long tool guides. Especially when the punching holes are in visible areas, deformations should be avoided.
PETIG’s punching method with the expansion die has been successful for several years and finds application in the production of ladders, pallet racks and shop fittings,
handrails and stairs as well as in factories in the scaffolding, steel and metal construction and enables, compared to single-sided punching, an increase of productivity of up to 35%.
However sophisticated your application may be, at Petig you will find the technical and cost-effective solution.
Tube Today, No. 29 (June 2010)