I'm looking for a spring loaded cutter to put on a cnc gantry machine. I
could use a pneumatic actuator to apply the correct pressure but I'm looking
for simple. Is 15 psig the correct pressure for most stained glass? Also,
can I use my engraving head to cause the fissures by just cutting too deep?
You're describing what we called in the 70's, an odd shaped glass cutting
machine. My brother designed and used one for years making duplicate lamp
pieces. A stylus followed an engraved pattern in plexi, and the cuttter,
using a pantograph system, scored the glass. I don't remember the PSI we
used, but it worked on a very small compressor. I believe they are still
being old. Google it.
Well for me it is a way to avoid using pneumatics in order to apply a,
mainly constant, pressure (15lbs) in the Z axis. Pneumatics are noisy. I
would have thought a spring loaded cutter would be available for beginners
to apply the right amount of pressure to the mainstream of glass without the
experience to "know" how much pressure to apply.
I think you missed the point of my "WHY".....
What are you trying to accomplish that takes a CNC machine to cut the glass
If you are trying to cut lots of repetitive pieces, the fact that you have
scored them with a machine still hasn't gotten the parts broken out of the
big sheet, which has to be done by hand anyway. Secondly, given the
"grain" of the glass and the color patterns and artistic considerations of
where to put the pattern onto the glass sheet, the idea of mechanically
cutting the glass is counterproductive from where I sit, both from an
artistic and expense point. If you are trying to cut intricate parts, you
probably won't be able to break them out of the glass anyway, unless you
make relief scores on the inside curves. And if you have tight outside
curves, the glass is likely to run off your score...right across another
part the machine has scored. If you are planning on putting small pieces of
glass in the CNC machine and mechanically holding them in place for the
machne to score the glass.....I promise you any competent SG worker can keep
pace with the machine with a lot less waste.
If you are interested in cutting out many multiples of the same part, as in
mass producing lamp shades, you need to be looking at water-jet cutting,
If you are interested in making lots of "square" pieces out of one big sheet
of plate glass....look in the CRLaurence catalog for the automated cutters.
They have machines that will take a stock sheet and make lots of smaller
pieces, minimizing waste.
I thank you for all of the good information. It sounds challenging. I will
grant you that no machine process can duplicate the artistic element
required for professional grade stained glass. I am a machinist, not an
artist. I just want to be able to set my zero and let the machine give me
the same part, over and over again.
I do want to cut multiples of the same part and I want to nest cuts from the
same sheet. I would go with a waterjet but these machines are extremely
Are you saying that there is no algorithm which can be developed to decide
how to cut a sheet of glass depending upon how the part is shaped? That
would be depressing.
I have no idea if such an algorithm exists. But I wouldn't hold my
If you were planning on making "identical" parts from the same sheet, you
could put them side by side, then have the machine make a dividing score
between the rows, and then score another set, side-by-side. I suppose you
could also have the machine do a dividing score between the parts, so that
you could break apart the little rectangles and then weed out the scrap that
surrounds the part.
How big is the table for this machine? You'll likely have to cushion the
table with some carpet between the glass and the table.
The table has a 2' X 3' travel and I imagined having a 1/2" felt table with
a vacuum underneath.
How about just routing the whole thing?
A few years ago I was on the verge of buying an $8,000. Billco but
discovered the Cutters Mate. I can make glass or wood cutting guides
and use that $200. device to do the same work the Billco could.
As to cutting pressure, we teach beginners (and even old timers in
our Cutting Clinics) that the optimum pressure when scoring glass is 5
lbs. A bathroom scale is great for practicing. Just put a piece of
glass on the scale and score it. Watch the weight reading and
practice keeping it to a consistent steady 5 lbs.