Stainless steel is a wonderful material. Shiny, resistant, durable. But it's also expensive, difficult to bend, and easy to scratch. When working pieces that will be used as cladding, home appliances, and furniture, even a small scratch becomes a big problem. How can we cut and bend stainless steel without damage?

1. Slide: Data
10 ways to avoid scratches and
dents when forming stainless
steel

2. Slide: Data
Stainless steel is a wonderful material. Shiny, resistant, durable. But it's also
expensive, difficult to bend, and easy to scratch. When working pieces that
will be used as cladding, home appliances, and furniture, even a small
scratch becomes a big problem. How can we cut and bend stainless steel
without damage?

3. Slide: Data
Shearing is often the first critical point. A
bench equipped with plastic ball
transfers, that let sheet metal to slide
freely, is highly recommended. When the
blank is cut, it has to be pressed against
the bench to hold it in place. This system
has a downside: pressure against balls
leaves dents. Top manufacturers provide
an antiscratch system, with ball transfers
mounted on a pneumatic support, that
lets them disappear below the resting
surface.

4. Slide: Data
Pressure of blank holders must also be
adjustable. Smaller and thinner pieces
require a lower force, else cylinders will
leave marks on the surface. Quality
machines are equipped with a CNC able
to vary the applied force through an
independent hydraulic circuit. Also,
cylinder feet must be capped with anti-
scratch plastic material. Nylon is typically
used because of its low coefficient of
friction. Pistons must also be absolutely
tight to avoid oil or grease leaks that
might stain the sheet.

5. Slide: Data
After shearing, forming comes into play. Most frequent cosmetic damages in this
phase are due to sheet metal scraping against the die edges. To limit this problem,
you have to use special dies, with a bigger edge radius.

6. Slide: Data
Another more expensive solution is to use dies with rollers. Small cylinders are
embedded at the edges of the die opening. These pins can rotate, reducing
friction and scraping. This type of tools must be kept particularly clean, so that
dirt does not block the rollers. Specific protective plastic films can be applied to
the die to limit scratching, but they may also lead to lower accuracy.

7. Slide: Data
Speaking of tools, it's important to choose a
punch/die pair suitable to the sheet metal, its
thickness and the desired angle. High-strength
steels have a bigger bending radius and need
a bigger die opening. Else, it could crack on
the outer edge, damaging both the aspect
and the resistance. Tools must always be olied
to reduce friction, and kept clean from debris,
dust, dirt, rust, chips and other material that
can scratch the surface.

8. Slide: Data
Stainless steel sheets are often large and thin. If they are not properly supported
during metalforming, they curve under their own weight making the so-called
"counterbend" around the die. Sheet followers solve this problem. They are front
supports equipped with ball transfers that, during the bending phase and when
the ram is raised, support the sheet. As well as rotating they also have to shift
because the center of rotation is not fixed.

9. Slide: Data
Top-quality press brakes are
equipped with retractable supports
next to back gauges. In certain cases,
sheet followers can be mounted also
in the inner side of the pressbrake.
These accessories support the sheet
while it's resting against the back
gauges, avoiding deformation.

10. Slide: Data
Gasparini Industries s.r.l.
Via F. Filzi, 33
31036 – Istrana (Treviso – TV)
Italia – Italy
t (+39) 0422 8355
f (+39) 0422 835700
e info@gasparini.it
Codice Fiscale, Partita IVA: IT 04364470262 – REA: TV 343703 gasparini.it
Get info and free quotes on
www.gasparini.it - press brake
and guillotine shears