[unalpha]

Well for the past year I've been dealing with a 5x10 router made in china and sold by a US based company. I thought by doing so I would get support from company. Not so I took delivery of machine and that was it. I had problems with power supply blowing up. I called got one sent and it too was DOA. So I got one on my own. Machine ran but then the xml file was garbage. So I tuned only to fine out I had to go thru machine to tighten up every nut and bolt because it was all loose. Now I'm tuned and can't seem to get machine to make any quality parts. X and Y are rack and pinion and z axis is ball screw. From what I see my z axis repeats perfectly. Its only the racks. I've done everything I can imagine but to this day a simple profiled circle is an issue. I'm .015 to .045 of when measuring the diameter. Manufacture states +-.002. Can anyone help shed some light? Or are rack and pinion setups not able to hold or repeat.

Thank you,

[Pierke]

Maybe you can in your program that is whit your machine compensate the backslash, measure this and compensate!
What program are you using to run your maschine?
Pierke

[unalpha]

Mach 3 is the software. And I have tried using the backlash compensation on the software. My y axis is where I believe my problems are. I had a very hard time setting the pinions. This was due to the pinions are pressed into a bearing holder that has an eccentric adjustment. If I tighten pinion up against the rack the machine locks up. So I have to leave the pinion slightly lower than the rack. You compound it by two pinion adjustment on either side. So I'm thinking that the machine design was just garbage. I'm thinking the pinion should have some type of spring tension.

[victorofga]

compared with machines that has ballscrew, rack n pinion always behind.. i cant say values, but a very popular us brand says 0.15 mm for their products that has rack n pinion....
thats likely 0.005 inches..

you seeing rigth it must be springloaded even a ground rack and paired pinion has very minor backlash..
i guessing you choosed the machine by its speed.. yes they are.. but this is the price for
precision or speed..

the simplest solution as others said, the backlash setting in the program,,, in mach3 you can set very well..

other solution selling machine and getting one with ballscrews.. you going to get likely 0.001 inches backlash.. just like your Z has now..