might be the wrong sub section for this, but here goes..
I have been asked to look into getting an old (60's vintage) oxy/acetylene profile cutter machine going again. This is a fairly large table machine, built by BOC (british oxygen company) in the late 60's. For automation it uses a "magic eye" control head, (called BOC autoscan MK2). The idea of this was to follow a chalk line or profile drawn on a seperate sheet of material, and cut the exact same profile in the steel. The machine was effectively made useless when someone removed the circuit board for controlling the magic eye.
And so I was asked to have a look at it and try and get it going again.
The control/cutting head is a weird design. There is an approx 100 mm / 4 inch diameter roller tube which spans the width of the table, and turning this moves one axis up and down the table. The control/cutting head has a small motor driven toothed wheel which sits on top of the roller tube, and the toothed wheel can also turn around on top of the roller tube. By doing this it can move both axes, by rolling the tube and by dragging the head across the roller tube. So if the wheel is perpendicular to the roller tube, it will only move the X axis, and if it is parallel to the roller tube it will only move the Y axis. A 45 degree angle would move both axes the same distance.
I know this is hard to visualise, so I can take photo's of the head if necessary.
Getting the electronics of the head going again is out of the question, due to the age (think germanium transistors) of the gear. So I thought rather than making this old system work again, it might be better to turn it into a proper CNC machine, using something like EMC for PC control. But i can see a difficulty in controlling the axes, since its not a straightforward drive arrangement.
Overall accuracy of the machine probably needs to be maybe +- 5mm, since its an oxy cutter it would not be too accurate anyway.
If i keep the original drive arrangement, I will probably need to design a motor controller, maybe using a PIC. Or i could chuck it and use proper leadscrews and motors. And use proper feedback.
Would ye have any opinions on this project ?.
Any advice or help would be appreciated..