Anyone ever involved in the use or maintenance a plasma trace cutting Machine?
I am trying to remember just how exactly the reading head worked.?
The machine had a table along side and attached to the plasma cutting torch table.
The side table had a reading head that would read a specific B&W shop drawing print placed below it and follow the line, taking the plasma torch with it. Hence producing an actual metal part at the same time.
IOW the plasma would produce a part as outlined on the shop print DWG.
IIRC the head had a light it shone down on to the print in order to pick up the line , and an oscillating mirror in the head would pick up the outline of the print and steer the positioning servo's to track the print image exactly.
Similar to the many examples of line following vehicles out there, but very accurate and also capable of reading the fine detail of a shop print.
I assume now it has been replaced with DNC S/W.

 

plasma xerox?

never seen one. my guess is that it was simply using same line scan sensor as found in document scanners. mirror is angled and with sensor and light source forms a head (or they could be stationary, simplifies wiring). the head is rotated by small motor so sensor could pick lines in any direction. an encoder would provide rotation angle value to correlate line scans with head angle.

 

What I recall from reading a service manual is a lot of cautions about keeping all of the optical string "perfectly clean" to avoid it being at all out of focus because of diffusion of the light beam. That had to have been in 1967 or 1968. There were also warnings about tube aging, and line voltage issues.But I never got to actually service the machine.

 

I am working on a line trace mechanism that will follow a CAD printed part DWG, The idea is similar to the line following toy cars, but the line has to be of typical CAD origin and much narrower than the toy car version..
The same principle, and Picmicro based logic.

 

I am working on a line trace mechanism that will follow a CAD printed part DWG, The idea is similar to the line following toy cars, but the line has to be of typical CAD origin and much narrower than the toy car version..
The same principle, and Picmicro based logic.

Really, that seems more like 1950's technology. CNC is much better, more accurate and faster, based on the descriptions. What I would do at the last two jobs is produce a sketch with the dimensions stated accurately and give it to the machinist. That worked quite well, and if there were any "issues" I would be asked about the details. Mechanically tracing out a drawing was never an option. It seems it would depend very much on the linework and line quality.

 

I have designed and built quite a few CNC machines over the years, but this is a unique application ,a one-off, that mimics the older trace cutting machines that ran a plasma or gas torch quite well by tracing a machine drawing.