Tuesday, 19 April 2016

The Lathe still works

So I have finally got everything in place to use my CNC Lathe. To test it I ran it in manual mode. I stuck with the default settings of 80 mm/min, 0.25mm X incremental feed & 0.1mm Z incremental feed. I had a play with the spindle speed just to see what would give the best finish. There didn't seem to be much difference but I was just using a pretty soft piece of some kind of plastic.

This was all I did, the spindle is quite loud so I didn't want to be running this too late. I'm not quite sure what kind of plastic this was but I did get a fair few pieces of what seems to be Delrin that I will be experimenting with once I work out how to hold them as the chuck doesn't open far enough to hold them.

This machine is fairly old and is controlled from a 486 running windows 95. Not the world's oldest machine. But fairly old. The interface is all DOS based so to improve startup time I have disabled the windows GUI entirely and just boot into DOS. The interface, while definitely classic it isn't too hard to use or hard on the eyes, which can be a problem with some of these older user interfaces.

I shot a video of me machining this piece with my phone sitting on top of the safety shield. During the video you can hear the different pitches as I adjust the speed of the motor to see if that would change the finish. Watching the video and also while using the machine there is a lot of backlash evident in the Z axis so I will try to work out what is causing that and hopefully remedy it.

With this now working I should be able to power the spindle for the mill from the accessory port on the control box for the lathe. This will give me a chance to fully test and even start using it to make parts.

I have the manuals for this lathe so I will probably put together a program that will allow me to turn down the Delrin blanks so I can mount the securely in the better chuck. But we'll see about that.