Messages

101

General Mach Discussion / Re: Z Axis Problem Need Help Badly

« on: August 21, 2007, 10:16:46 PM »

How can i fix this problem now that we know it is from the ball screw pitch being different than acme lead screw. Right now the reduction rate is 1.65:1 do i need to reduce it even more say 2:1 or 3:1. Thank you everyone that has been helping me with this problem

102

General Mach Discussion / Re: Z Axis Problem Need Help Badly

« on: August 21, 2007, 07:07:02 PM »

The motor wiring and output is the same as it has alway been as i never touched these areas just the screw and pulleys. The Screw leads on the old setup is ".1" and the screw lead on the ball screw is ".2"

103

General Mach Discussion / Re: Z Axis Problem Need Help Badly

« on: August 21, 2007, 04:46:19 PM »

Yes i used the same Motor Sanyo Denki 720oz in 6A stepper i see on the Tormach Website that they use 640 oz in motors direct drive and they have plenty of torque i just can't figure out why i have such little torque with a good sized motor

104

General Mach Discussion / Re: Z Axis Problem Need Help Badly

« on: August 21, 2007, 02:56:09 PM »

My setup before was i had the same gears going to the fine feed the motor had 20 tooth the fine Z feed had 33 tooth 1.65:1 reduction ratio. I was able to drive down into metal under 20 IPM until the cows came home with that setup but my overall goal is to convert everything to ball screw better tolerances.My powersupply is 60VDC. So i started with the Z axis i made a ballscrew setup like the one similar to Jeff Davis at http://homecnc.info i used the same gears 20 tooth on the motor and 33 tooth on the screw 1.65:1 gear reduction which is the same gears as on my x and y axis. Now when i drive the Z axis down it will cut into the metal but it will only go in a few thousandths before stalling and chattering. I will try to get some pictures when i get home from work. The only thing i can think is that there is enough resistance coming from the original return spring in the Z axis to stop the motor when diving into metal i will have to check this when i get home

105

General Mach Discussion / Re: Z Axis Problem Need Help Badly

« on: August 21, 2007, 02:05:22 PM »

I can't believe that no one has any answers to this problem

106

General Mach Discussion / Re: Z Axis Problem Need Help Badly

« on: August 21, 2007, 07:21:10 AM »

My Drives are Gecko G202 and i have the current set for the motor which is 6A the resistor that it calls for is 285K ohms but they don't make a 285K ohms resistor so i used the next closest which is 270K ohms

107

General Mach Discussion / Z Axis Problem Need Help Badly

« on: August 20, 2007, 06:04:47 PM »

I am having a problem with my Z axiz stalling. I just converted it to ball screw from the manual feed cnc. I didn't have any problems with the old setup as far as the axiz diving into metal without stalling but since the conversion i can't seem to get it to feed into the metal without stalling

My motor is a Sanyo Denki 720oz in motor 12-300VDC 6.0A with a 20 tooth gear on the motor and a 33 tooth gear on the ballscrew i have the steps per set at 16500 which is giving me the correct accuracy i just lost all sorts of torque what can i do to get this back

108

General Mach Discussion / Re: Manual Motor tuning

« on: August 20, 2007, 03:22:19 PM »

Anybody find out what that step/dir pulse (0-5) Thing is all about i have the same HF mill 33686 as you and am having problems with accuracy

109

General Mach Discussion / Re: Help with Motor tuning

« on: August 20, 2007, 12:37:41 PM »

Thanks for the help guys i will give that a try when i get home tonight and post my findings

110

General Mach Discussion / Help with Motor tuning

« on: August 20, 2007, 09:17:06 AM »

I need some help getting my machine to cut parts accurately. I set my machine up the way i think that it should cut parts accurately by the manual but my parts are off by about .012 could some one please help me get this fixed as i am pretty new to this and am about to rip out my hair.

Machine specs:
I have a harbor Freight Big Green Round column Mill part number 33686
i Beliece the lead screw is 10 teeth per inch. I am using 1.65:1 Gear reduction

the stepper motors are 200 pulse i have Gecko G202 which i 10 Microstep drives

i believe it would be 200 * 10 = 2000

then i take my gear reduction
2000 * 1.65 = 3300