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General Mach Discussion / Re: Bridgeport Knee Mill Conversion?
« on: July 13, 2016, 08:34:50 PM »
Hi - My first post - so this might not be the right place - for which I apologise in advance, so here goes I use an Elliot knee mill daily for work and have slowly converted it to CNC - ball screws one day when mill not used - then X under Mach3 then Y and then the quill - so I could continue to use the mill partially manually and learn Mach 3 etc as I went along - this has worked really well as I don't really want the mill for fast / production type CNC work but for cutting complex curves and similar that manual milling with rotary tables and dividing heads had just become a real pain. For a bit of history / reasoning behind this I am a self employed engineer who grew up on punch cards, Unix, VB etc and restore vintage cars / manufacture parts so CNC is really a time saving and helpful step forwards for me I simply write the G code into Mach as I go to produce some fantastic parts - leave the machine running and go and make something else on the lathe's whilst I wait for it to complete ! Mach is great for retro fitting a mill and has been done very simply with Nema 34 steppers.
I am now developing a fourth axis for complex cam follower profiles and the like which I have made on a small mill in the past which I had also converted for 4 axis CNC - so yes by all means retrofit a knee mill but a bed would have been more rigid - the Elliot is much more rigid than a Bridge which gives me great cutting with hard steels and a superb surface finish.
Now a problem has crept in - if I leave the mill standing but all powered up under Mach then the X, Y, X and 4th axis often start counting on their own ! into the millions but none of the axis are moving until I quit Mach then restart, home everything to zero the millions stored and start again - this is now becoming a real pain as I develop the G code as " going along " if it happens at that point all is lost ! Please help me - someone must know what causes this ?
I am now developing a fourth axis for complex cam follower profiles and the like which I have made on a small mill in the past which I had also converted for 4 axis CNC - so yes by all means retrofit a knee mill but a bed would have been more rigid - the Elliot is much more rigid than a Bridge which gives me great cutting with hard steels and a superb surface finish.
Now a problem has crept in - if I leave the mill standing but all powered up under Mach then the X, Y, X and 4th axis often start counting on their own ! into the millions but none of the axis are moving until I quit Mach then restart, home everything to zero the millions stored and start again - this is now becoming a real pain as I develop the G code as " going along " if it happens at that point all is lost ! Please help me - someone must know what causes this ?