In Reply to: Re: multicavity die making posted by SenthilMani.S.S on 06/10/03 at 8:06 AM:
When u say, it is a blanking die with multi holes, the construction of the die
should be very rough & tough.
When the burr formation takes place, it means that the cutting edges of the
either punch or die button is worn out. which means, the load required to blank
this holes will automatically increase. With the increase in load on one punch
(ie. one hole) there is a unequal load that is acting on the whole die. which
means, your die construction is not suitable for this unequal load conditions.
probable measures to get rid of this problem:
1] establish a statical data of, after how many parts does ur tool wear out.
accordingly resharpen the tool. check for the wear & tear in some intervals,
2] if space permits, make sturdy die design to carry this unequal loads.
3] you can provide shear angle to the cutting edge (on punch) to have gradual
load than an instanteneous load.
4] maintian the cutting gaps on punch and die properly. generally for steels 8
to 10% of the sheet thk is the clearance (cutting gap) followed widly.
5] check for the alignment on pillar & bush assly.
6] if there are 4 holes to be blanked, u can have 2 holes blanked first with say
6mm punch entry and the other 2 holes blanked with 4mm punch entry.
The above measures are given without knowing the actual die construction, blank
thickness, press tonnage etc. In general, the above are the measures.