strange motor problem

[sp00k1e]

I machined some aluminium for the first time on my homebrew system lastnight and came across a strange problem. I was just jogging the machine to flatten the end, moving in the x axis i noticed that as the tool just touched the ali the y axis started to move, I dont think it is mechanical, so therefore it must be electrical noise, does anyone know where I should start looking, none of my leads are screened, but earthing the job didnt remove the problem. I am using Mach2 and Hans Wedermier's (?) control circuit.
I havnt noticed this happening with wood or plastic.

Paul

[Urgundiz]

well, if earthing the job does not solve the problem, maybe some kind of 'feedback' is going from Z to Y trough the material, are you able to guess a electric path between those elements? the problem repeats if you do a trial test with a non conductive (fake) tool?

hope it helps
/U

[sp00k1e]

I think I have narrowed the problem down. I changed the parallel cable, that didnt make a difference. Then I started changing the speed of the router, this changed the speed of the spurious movements on the y axis, moving the router cable around the machine altered which motor was turning, lifting the cable upwards caused all the motors to move. It looks like the router is generating a lot of emi when cutting the metal for some reason.
Therefore my next question - what would be the best cheapest method of checking and removing the problem?
Maybe this is why B&Q were selling these units of cheaply.

[Al_The_Man]

Paul, It sounds like you have a ground current loop, there may be slight ground leakage on your spindle that finds a path through the material if it is conductive. I would ensure that you have a good ground conductor from all your servo's and the spindle and make sure all these grounds and shields are connected to a common point and also your incoming earth ground should be connected to this point.
If you are operating from a PC, make sure the case of the supply is also connected to this point.
If you have any auxilliary dc supplies, I would make sure the DC common is grounded, unless the control instructions specify otherwise.
Al

[sp00k1e]

I will try tomorrow to ground and shield everything, unfortunately the router is double insulated and therefore cannot be grounded.
Paul