Machining copper is fairly easy but
there are some pitfalls to watch out for:
Copper work-hardens. Which
means that the more you push the material about the harder it becomes.
Therefore sharp cutters with the correct geometry are
to use sharp cutters will lead to poor surface finish,
large burrs and
incorrect finished sizes. We recommend the use of solid carbide cutters
wherever possible. The extra initial cost is easily recouped by the
extra life span achieved over HSS cutters.
Most copper bar and plate has
a 'skin' which is under tension.
Which means that when cut the electrode has a tendency to bend. How
much distortion that occurs will depend on the size and shape of the
copper blank and how much material is removed. Care needs to
taken in the machining strategy employed and with the method of holding
the electrode to overcome this problem.
Small ribs and features can
easily bend and break off if the wrong machining strategy
is used. We have developed methods of machining even the tiniest of
features without problems.
finishing strategies can leave dwell, and machining marks on the
surface of the copper that are difficult to polish out. Ideally you
want the CNC machine to get the best finish possible to cut dressing
and polishing down to a minimum.
choice of cutter sizes and strategies
when picking out corners can lead to cutters pulling-in to the
workpiece and gouging. This can lead to extensive polishing, re-cutting
the electrode or even having to scrap the electrode and start again.
huge experience in producing programs to machine copper electrodes
we can avoid all these pitfalls and you can be confident
first class results every time.
more forgiving to machine than copper but there is still a couple of
points to watch out for:
Graphite is abrasive so watch out
for cutter wear. Excessively
worn cutters can lead to chipped edges and poor surface finish. Carbide
cutters are essential for all but the smallest amount of machining. If
you are machining large quantities of graphite then diamond coated
cutters may be a worthwhile investment.
Small features can be difficult
to machine and prone to breaking off.
Here at Alphatech, through many years of experience we have developed
methods that will enable you to machine most small features without
Graphite does have some definite
advantages over copper:
as well as weight and cost, generally much longer cutters can be used
successfully with graphite, especially with high speed machines also
stress distortion is not a problem.
We know a great deal about
machining graphite from years of experience - We can help
you take advantage of the time saving benefits of rapid graphite