Y axis is making X axis stall...!!

[Swarfing]

Good to hear it's work Steve :-)

by the way the last PP card i bought was from this guy. Had to search quite hard but found him.

http://myworld.ebay.co.uk/fullspeedit

[JAZZCNC]

Great news Steve. . I've known a few case's of failing or poor quality cables giving troubles, thou I still think it's your PP causing the problem. Thats why dropping the microstepping works.
Bet if you dropped the kernel speed to 25K you will be able to micro step higher.? . . . Give it a try and I think you'll find you can get 2000 M/S.!

Edit: The only reason to run higher Kernel speeds is if you can get higher speeds from your motor/screws than the kernel allows and your if PP is upto the job.
Other wise Mach works best or should say most stable at 25K. . . . If your happy to run at around 5mtr/min then I would leave it at 25K for best stabilty.

[Jonathan]

I agree entirely that 10m/min is more than enough and that the difference in machining time between 10m/min and greater is often negligeble. My machine will do at least 15m/min on X and 60m/min on Y, but I leave it at 10-12m/min as it's less likely to go wrong and more time to react should something go wrong. I think the most I've actually cut at is 8m/min.

The reason I tested the Y-axis up to 60m/min was an experiment to verify my modifications to Irving's motor calculation spreadsheet to include pulleys. I was ascertaining how accurate the calculation was by trying different ratios and comparing the limit to the calculated value.

I meant that comment to be just pointing out it is probably possible to get round the vibration problem and the feedrate gain is a bonus.

[JAZZCNC]

I meant that comment to be just pointing out it is probably possible to get round the vibration problem and the feedrate gain is a bonus.

Nah much better to replace the bent screw IMO because after you have gone to all that trouble and expense for what amounts to a very costly and mostly un-usable bonus the screw is still bent.:exclaim:

RE 60M/min Y axis out of interest how much pulley ratio did you have to use and what sort of accelleration did you achieve.? . . . If you don't mind me asking.!

[Jonathan]

Nah much better to replace the bent screw IMO because after you have gone to all that trouble and expense for what amounts to a very costly and mostly un-usable bonus the screw is still bent.:exclaim:

True it is quite costly having already bought the bearings etc for rotating the screw. If the nut is rotating and the screw is tensioned (ideally a lot) then the bend should not matter much. As long as the ballnut is precisely on centre (which admittedly is tricky) then there's no radial force on the screw. If the screw is bent and spinning there is a large cyclical radial force which causes it to vibrate... No doubt there's more to it than that but I bet it would be a lot better.
I'm guessing it's a 25mm screw, what length is it?

RE 60M/min Y axis out of interest how much pulley ratio did you have to use and what sort of accelleration did you achieve.? . . . If you don't mind me asking.!

It was 42:14, but I accidently put 42:12 on the video. See here, post #136:

http://www.mycncuk.com/forums/showth...outer-building...

I can't remember what the acceleration was... think it was 2m/s^2, might have been 3. Either way it only hits 60m/min for about 200mm... except if you smash it into the side :whistling: