My x3 is so close, yet so far.

[bryanrabb]

I can't figure out my steppers. I have 425 oz on the x&y and 600+ on the Z. My question is if my settings are incorrect in Mach, would it cause poor operation with regards to torque? I am in 1/8th step mode, and I can put a finger on the table and stop it with little effort. Could the xylotex board be bad? I am adding ballscrews as soon as they come in, but I need it working ASAP. Would changing the step mode give me more torque? Someone please give me some advice.

Thanks.

[askman]

1/8 is terrible for torque with any kind of speed. go with 1/2 or full step on that motor and run it aobut 20IPM. frankly with acme, you won't get high speed.

[project5k]

i agree with askman, also check your jibs and locks, make sure that thier set up correctly and not causing excess bind.

[Ron111]

You might also verify that the current is setup correctly for bipolar operation whether you are using bipolar series or bipolar par.

[bryanrabb]

First, i think i fried my xylotex board. It still lights up, but now the motors don't lock when I turn it on. I was screwing with the vrefs and now i get nothing. How do i verify the setup as to bi or unipolar? The motors with 8 wires can be wired 3 ways. I have them wired the way xylotex told me to. They worked before, now they don't.

[Oldmanandhistoy]

Hi,

Information about stepper motor wiring http://www.wimb.net/index.php?s=motion&page=52

As for the Xylotex board it’s unusual to get all 3 axes die on you; start by double checking your wiring. If that all seems ok then go back to the Xylotex instruction and set ever thing up again from the start.

As for the poor performance of the stepper motors; what are their amps and volts ratings and how are they wired? Also what are the ratings of your power supply?

For instance if your 600 oz in stepper motor is rated 2.5Amps and its wired bipolar parallel then you will only be getting 300 oz in at best. Also you are probably running the stepper well under its max volts rating so torque will drop off very quickly as you increase speed. Sounds like the Xylotex is a poor match for the steppers motors.

John

[cyclestart]

Originally Posted by Oldmanandhistoy Sounds like the Xylotex is a poor match for the steppers motors.

Could be. Xylotex doesn't offer 600oz-in motors, maybe for good reason. If you read between the lines at the companies homepage, even the 425's are offered with some reservations. However, I'm using 425's with 5 tpi ballscrews and it's working OK. These motors were purchased direct from Xylotex.

I don't know enough about electronics to help with the no-lockup situation. The builder answers questions at his yahoo group. He has also been good about answering questions the few times I've emailed him. Just a thought to help get this resolved quicker.

[S_J_H]

Ok guys how about some real world figures,

I have been using a Xylotex 4 axis drive and motors for about a year now on my x3.
I have the 425oz motors on all 4 axis. I have the Vrefs all set at 3.5volts.
I run every motor in 1/8 step. I power the drive with 28volts.

.2 pitch ballscrews on the table X & Y axis.
I can easily run 100IPM rapids however for best reliablity from lost steps I have my rapids at 60IPM.
I cannot stop the table from moving and it has enough torque to EASILY snap a 3/8" endmill.

.1 pitch Acme on the Z-axis. I run it at 20IPM.
Steve

[bryanrabb]

I think I was fighting 2 issues. The xyotex drive was never working properly to begin with, and i did not have ballscrews.

I am going with the CNC fusion ballscrews, and G201 geckos.

[pzzamakr1980]

If you would like a recommendation on your drivers. Go with the new 203v geckos. They are much more resilient to screwups and the benefits over the 201 are easily worth more than the 45 bucks they cost extra. Also, with the low torque it could also be something simple like you have a current resistor that is not correct. Recalculate your resistor setting and make sure you have it right.