Settings on Driver Modules for Alpha

[ron_moorehead]

I was doing some maintenance on the ShopBot and was looking at the Alpha diver modules in the control box and was looking at the Current and V.Fil settings on the modules, and was wondering what setting most of the new PRS alpha are set at from ShopBot and was wondering if some one with a newer machine could look at the Current and V.fil setting on their modules and let me know if mine are set right or not.

My Current setting is F and my V.Fil is set at 8.

I found a manual for the modules here at explains the settings.

Thanks.

http://www.orientalmotor.com/products/pdfs/opmanuals/HM-6159-17E.pdf?__utma=130825808.1503807395.1340821435.134 0821435.1340827653.2&__utmb=130825808.0.10.1340827666&__utmc=130825808&__utmx=-&__utmz=130825808.1340821435.1.1.utmcsr=google|utmc cn=(organic)|utmcmd=organic|utmctr=(not%20provided )&__utmv=-&__utmk=98322527

[Brady Watson]

Those settings are fine. Current is set all the way up to F (dial is in Hex - 16 positions) and you don't want to mess with that. The Velocity Filter should be anywhere from 6 to 8 on the dial. Late PRTAlphas with 7.2s and early PRS Alphas were set to 8, I believe the newer ones are set to 6. The VFil deals more with mid band resonance inherent of all stepper motors. Go ahead and turn the VFil down to 0 or 2 on the Xs or the Y and then move the tool around with the keyboard. Notice how it sounds. Now turn it back to 6 or 8 & listen again. If you have an Alpha with AS911 motors, go ahead and adjust your VFil to 6 or 8. It will take a lot of resonance out of the tool for you without affecting performance.

You should adjust with the power off to be safe.

-B

[ron_moorehead]

Thanks Brady,

Question I have is the Bot sounds fine moving forward and backwards and side to side. But if I move it in a diagonal route she sound terrible, sound like a load hum. I get great cuts going in straight lines and my curves and circles look fine, but on some of my diagonal straight cut I looking like I am getting a lot of chatter in the cut. I just replaced my pinion gears and know they are tight and made sure everything was aligned and riding on the rails, like I said most my cuts are great just some chatter in the diagonal cuts. Any help would be great.

Thanks.

[Brady Watson]

Ron,
Does the degradation of cut quality happen at certain speeds, or all speeds? What's your communication speed percentage? (Run SpeedTest.exe)

Have you called SB to inquire about this? I know at one point they spent some time fixing this issue...and at one time I knew the remedy(!)...although I cannot think of what it is at the moment.

-B

[ron_moorehead]

Thanks for the reply.

Almost all my cutting is done around 1.6, I checked the file I last noticed it on and the move speed is set for 1.66. My communication speed is at 81 % . My computer is running windows XP and I have stripped it down to the basics per black viper.

I will give shopbot a call on Friday.

Thanks.

[jerry_stanek]

Try bumping the speed up a little I found mine would make a lot of noise at low speeds

[Brady Watson]

Try bumping the speed up a little I found mine would make a lot of noise at low speeds

X2 - Mid-band resonance...No way around it at certain speeds with steppers. The Alphas are way better than most, but that resonance can get transferred to the cut at certain speeds.

Of course...the parts being cut also influence the 'jaggies' on diagonals. I did a bear of a job in Birch ply with Formica laminate on both sides and there was thin webbing (around 5/8" wide) on the part that would vibrate unless you nailed the speed, chipload and depth of cut to what the part wanted...Some parts are real killers in that regard.

-B

[richards]

ALL stepper motors have "resonance". Another word for "resonance" is excessive vibration at low speed. It's inherent in the design of stepper motors.

In the process control world, I could quickly ramp past the portion of the curve where resonance occurred, but in CNC work, sometimes an axis has to move slowly - hench, resonance.

EXPERIMENT.

There is no perfect setting for all cuts and all occasions. Learn what works best for your machine and then change the settings as required.