Bending pre-painted sheet metal parts or parts that are made of
aluminum, stainless steel, brass, copper and other materials that are
not going to be painted is likely to cause die marks. And the odds are
good that customers will not accept them. Die marking is an age-old
problem that historically had fairly limited solutions, and even those
often compromised press brake productivity.
The part on the left
was formed with a standard die and a No-Mar Cloth, while the part on the
right was formed with a standard die and no polyurethane sheeting or
No-Mar Cloth.Early solutions
An early solution to
alleviate this problem was to use die holders made from steel or
aluminum that utilized a polyurethane pad, which served as the die. This
method normally worked well – and still does – in eliminating die
marks, but it comes with several inherent problems. They include the
deterioration of the polyurethane pad during use, which creates the need
for frequent angle adjustments. In addition, the pad tends to collect
grit or debris that might find its way onto the sheet metal. As the
residue becomes embedded in the pad, it causes die marking.
Read the whole article that is published in the 'Fabshop Magazine Direct'.