Shopbot with Plasma Cutter

[olwinangus@msn.com]

How many people here have the plasma cutter? Have you had any trouble out of it? What are your likes and dis-likes about the machine. Last question I promise how does the outside edges of the material come out after plasma(smooth, rough)? Thanks Dana

[arkadin]

Hi, here are some info for you.
I have been using a plasma cutter on a custom PR (9000 x 2200 mm) since 1999.
We have cut so far more than 600 sheets of steel and built around 20 fishing boats ranging from 13 to 30 metres.
We are located in Italy.
We deeply modified the control box, adding new circuits, allowing the plasma to start without interfering with the Pr movements.
The plasma machine should be earthed separately from the Control box otherwise the Control box could lose steps at every plasma start. We also changed the wiring completely since it is not shielded to any european standard and too rigid to follow many and many carriage movements. The routing also was changed, we use hinged belts (I do not know the exact english name but they look as the same as in tanks), they are much more reliable and allow for big movements along any axis.
Thicknesses vary from 3 to 35 mm without problems, the only thing that matters is the power of the Plasma machine.
cutting speed could be quite high, but you must experiment. We cut many nested parts joined by bridges in a single large file, being aware that the sheet heathens up a lot and therefore the subsequent passage near an already cut area could encounter a raised surface due to expansion. Our operator anticipates this raising tha plasma tip before arriving there.
The edges of a plasma cut are never square due to the conical shape of the jet, this does not really matters for thickess up to 12 mm.
They are also a little jagged but this is really unimportant since edge preparation is an easy task.
We cut without offset because the gap left ( 4-6 mm) is just what we need to allow for proper welding.
Be aware of the gasses that come out from the cut, they are really dangerous, organise a suitable vacuum to clear them; one solution is to enclose the underside of the table into a steel box, watertight, leave some water on the bottom to take care of the flame and clear the rest with an industrial vacuum cleaner.
We enclosed the whole table into a box that resembles a car body painter's shop, with large windows and a big vacuum cleaner on top.
A remote control is mandatory, both for the plasma and the PR.
We have not tried the sensor for automatic height yet.
Any more questions?