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

[Jonathan]

Steve has hopefully already reduced the kernel speed as I mentioned it early in this thread (#17). Perhaps not I was not forceful enough.

If it's 800step/rev then on 25kHz with 10mm pitch screw and direct drive the maximum feed is 25000/800*10*60=18750mm/min ... so plenty. Clearly half that with 1600, which it sounds like is still a lot more than your machine will currently do.

The only time I've used more than 25kHz is experimenting ... when I got 1m/s feed on Y-axis that was with a higher kernel speed. I've also monitored the port at 100kHz with oscilloscope and interestingly it seemed fine.

[JAZZCNC]

Steve has hopefully already reduced the kernel speed as I mentioned it early in this thread (#17). Perhaps not I was not forceful enough.

Seem to remember Steve saying he was running 35K thats why mentioned running 25K.! . . . Obviously it's the bent screw thats now Screwing him..:cry:

If it's 800step/rev then on 25kHz with 10mm pitch screw and direct drive the maximum feed is 25000/800*10*60=18750mm/min ... so plenty. Clearly half that with 1600, which it sounds like is still a lot more than your machine will currently do.

Well yes those figures are right in Theory regards what Mach could actually put out in pulse's but in actual practice 1/1 direct drive on 10mm pitch then a realistic usable figure is 8000mm/min 10,000mm/min Max due to running nema 34's which 800rpm is about the norm and 1000rpm would be about max.
Steve was getting close to half this lower figure with bent screws so when every things running straight and true I'm sure he will reach these figures. . . . I'd also wager at higher M/S as well if he was indeed running 35K not 25K.?

[Jonathan]

Seem to remember Steve saying he was running 35K thats why mentioned running 25K.! . . . Obviously it's the bent screw thats now Screwing him..:cry:

He said 45kHz, so even worse.

Well yes those figures are right in Theory regards what Mach could actually put out in pulse's but in actual practice 1/1 direct drive on 10mm pitch then a realistic usable figure is 8000mm/min 10,000mm/min Max due to running nema 34's which 800rpm is about the norm and 1000rpm would be about max.

Yes obviously I was just stating the limit...clearly those motors are not going to get anywhere near that with the current setup.

Tension the screw + rotating ballnut = no whipping ? Since that requires a timing belt could gear it up to go even faster anyway. As this is (I think) an 8x4' machine it would help...

[JAZZCNC]

He said 45kHz, so even worse.

Sorry Jonathan should made it clearer.!..I was refering to a telephone conversasion I had with Steve.

Tension the screw + rotating ballnut = no whipping ? Since that requires a timing belt could gear it up to go even faster anyway. As this is (I think) an 8x4' machine it would help...

Seriously don't get your fasination with speed jonathan.?. . . The ONLY thing it's usefull for is Rapids and seen as 85% + of the time a machine spends is cutting why go to all the trouble of rotating nut, esp on a machine with twin screws .? . . . I see the bennifit of rotating nut to allow long screws but not extra speed and 10mtr/min rapids is good enough for most machines even an 8 x 4.!

Let me ask you this.? What do you CUT above 10mtr/min.?? . . .Not much if anything I bet.! . . Also out of the last job (other than mass drilling, which high rapids can help) you cut how much of the overall job cycle time consisted time wise of rapid moves.? . . bet it was easily less than 10% of total cycle time.?

Thats an awfull lot of extra work and expense incorparating 2 rotating ballnuts into a DIY machine just to gain a few percent saving on cycle times, the Key word being DIY machine where cycle times are usually not an issue. . . .Yes in industry every little bit helps but in DIY it's not worth the expense and trouble just for a few percent.!! . . IF . . normal screw setup can be used.

Said this before .!!. . .It takes a substancial machine with a powerfull spindle using high quality tooling to cut at high feed rates. . . . High rapids are only usefull on very small percentage of jobs other than that they are just used for bragging.!!
Also seen as most DIY builders use modified routers usually of the cheaper quality range or spindles like Kress then high cutting feeds with any reasonable depth are simply not achievable anyway.