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General Mach Discussion / Re: Accuracy or repeatability of homeing switches, something to worry about?
« on: November 08, 2008, 06:59:18 PM »
It will depend on the type of switches you use I suppose. On my Bridgeport I have optical switches and I have confirmed they are accurate by doing 100 homing moves and confirming the actual position by using a glass scale and DRO, out of the 100 moves one or two (cant remember exactly as it was at least 4 yrs ago) were out but the amount was only 0.005mm, the rest all had the DRO reading zeros.
I have heard prox switches also can achieve good accuracy but I have no experience with them so cant comment further.
On my lathe I use switches but they are just to trigger my servo drives to look for the index pulse on my encoder and the mill I am retrofitting at the moment will be homed in exactly the same manner as well.
For your other part of the question, yes Mach will remember where it last was if you have persistent DRO option chosen. However it can not confirm that it is in that same position as it is open loop.
Hood
I have heard prox switches also can achieve good accuracy but I have no experience with them so cant comment further.
On my lathe I use switches but they are just to trigger my servo drives to look for the index pulse on my encoder and the mill I am retrofitting at the moment will be homed in exactly the same manner as well.
For your other part of the question, yes Mach will remember where it last was if you have persistent DRO option chosen. However it can not confirm that it is in that same position as it is open loop.
Hood