Accuracy issues

[runninwild400]

OK,,,so my table is now toasty warm so I can't blame the cold any more,,but I seem to be having a slight accuracy issue,,,,for instance if I was cutting out a 8" circle there would be a spot on the circle that would be straight for about 1", and it is right where the y-axis changes direction,,,also if I was cutting out a square frame that was suppose to be even all around the one side will be wider then the other. I also tried cutting a small ring,,2 1/2" OD and 2" ID and there is a definate step in the outside cut in 2 spots where it looks like it just realized hey,,I'm off track,,I better get back on track.
Hope somebody can understand what I'm trying to explain and maybe shed some light on the subject,,,pulling my hair out trying to figure this out and I don't have enough hair to be doin this. If needed I could probably post a picture if somebody wanted to see the steps in the ring I cut out.

[runninwild400]

Well for now I seemed to have fixed the problem,,,,,took the belt and gears off,,checked them out then put them back on,,only difference is I really tightened the belt this time,,tighter then I think it should be but it resolved the problem,,hopefully it doesn't cause another one.

[bakerj99]

i had the same problem but i was the idiot that was so excited about getting up and running i got the 2 x axis motors (a TM3 5x10) out of square and it took me FOREVER to figure this out. lesson learned take time to look at the simplist thing


baker

[reed]

OK,,,so my table is now toasty warm so I can't blame the cold any more,,but I seem to be having a slight accuracy issue,,,,for instance if I was cutting out a 8" circle there would be a spot on the circle that would be straight for about 1", and it is right where the y-axis changes direction,,,also if I was cutting out a square frame that was suppose to be even all around the one side will be wider then the other. I also tried cutting a small ring,,2 1/2" OD and 2" ID and there is a definate step in the outside cut in 2 spots where it looks like it just realized hey,,I'm off track,,I better get back on track.
Hope somebody can understand what I'm trying to explain and maybe shed some light on the subject,,,pulling my hair out trying to figure this out and I don't have enough hair to be doin this. If needed I could probably post a picture if somebody wanted to see the steps in the ring I cut out.

I have the same problem with you,but I don't know whether the same reason.please attached pictures for clear main problem.

reed

[runninwild400]

Sorry for gettng back so late,,,,here's a pic of the problem that the loose belt caused. Hope you have your problem figured out.

[bakerj99]

loose belt or check the set screws on the pulley to be sure the shaft isnt spinning in the bore. yes something else that happened to me while trying to get in a hurry


baker

[ryansuperbee]

I agree with bakerj99. CHECK THE SQUARENESS OF THE GANTRY TO YOUR TABLE!!!!!! I can almost gurantee that this will solve all your problems. Your gantry is probably 3/4 to 1 inch out of square, and this would cause your machine to cut oblong like it is. let me know if this helps or if you need advice on how to do this acurately. I know this is your problem. let me know how it goes.

[millman52]

Sorry for gettng back so late,,,,here's a pic of the problem that the loose belt caused. Hope you have your problem figured out.

Yeah a loose belt = backlash. Same thing will happen with a loose set screw or pinion(s) not being spring loaded into the racks.

For a table to cut as accurate as possible. EVERYTHING & I mean everything must be as wiggle free & as near 0.00 backlash as is possible.

I used self aligning flanged pillow block bearings to support my pinion shafts. I figured on having to run the belts pretty tight. I didn't want the side loading on the pinion shafts to be an issue on bronze bushings. Plus I didn't want to have to try to seal grit out of the bushings either.