[Grandad]

Have managed to get my router table cutting. It took me three hours with mach 3 manual in one hand and a couple of aspirin in the other, it is extremely accurate and the feed rate is fine, but OH Dear!! the rapid is slower than molasses in january . My leadscrewss are 1/2" x 10tpi but my config is in metric. My settings in motor tuning dialogue are steps per 78.74,
velocity is 200 and acceleration 100 I have altered the velocity and acc. many times but these settings are the fastest without the motor missing steps and stalling. My motor and driver/PU setup is the Stepperworld FET3 combo 176 0z motors. Am I expecting too much from this combo or can it do better, thanks in advance for your help and advice...Rod

[spalm]

Doesn’t the Stepperworld controller use microstepping? I looked at their web site and they talk about it in a document, but I can’t find it in the specs. Anyway, you need to multiply your steps of 78.74 times the microstepping amount of 4 or 8 or 16, whichever the board is set to.

Another thing I noticed is your velocity is set to 200 mm per minute. This is pretty slow. Crank that up to about 1000 (40 ipm) for starters.

And maybe you have a mechanical bind somewhere. Can you turn the motors by hand without power applied?

Steve

[ger21]

You don't say what voltage your running at, but higher voltages will give you higher speeds. The velocity setting IS your rapid speed, in case you weren't aware of that.

[Grandad]

Hi Gerry,

Unfortunately the drive does not support microstepping ( when I bought them I didn't know what microstepping was) the input voltage to the drive is 5v so I presume the motor voltage is the same,or am I wrong. I have just tried to put the velocity setting up but anything over 300 and the motor stalls. All the axis are free, I can turn the leadscrew with two fingers quite easily (with power off). Would you recommend that I change the drive or is there any thin else I can try, thank you very much for your help. Rod

[joecnc2006]

I would run a min of 24v into your motors (mine is 33.6vdc), and the driver will be set according to motor specs.

But if you are using 1/2-10tpi, and motors are 200step per revolution, right there is 2,000 for full step.

mine are set at 8,000 for 1/4 micro. and i have 80 vel. and 15 accel. (mach-3) and cut constant at 80ipm. works for me.

if i increase the accel. higher the motors will stall trying to accel that quickly, i think they say set the vel. until motor stals then back down 15-20% but others can verify that.

Joe

[Grandad]

I've just had a look around the power supply and drive, this is a standard PC power supply, it gives outputs of 5 & 12v, but the instructions re the fet3 drive only give a 3v or 5v connection to the board, if you use the 5v option you have to connect 50 watt power resistors on the centre tap connections to the motors and these little devils get plenty hot, I suspect that if I input any more than 5v I will have a toaster on my hands. What do you think, a new drive and power supply perhaps??...Rod

[Madclicker]

You have just found the big drawback of non-chopped drives. I was thinking of going with something like this until the knowledgable people here steered me in the right direction. Here's a link to the dialog in my blog:

Chopped vs. Non-chopped drives


BTW, my new geckos should be here today! :cheers:

[Grandad]

well I guess i'll be needing a new drive or drives, one last question i have nema 24 / 8 wire motors, will I have to change these if I go for microstepping drive Rod

[Grandad]

guess i'll have to look for the whole package again, my motors are unipolar and I don't think you can microstep with them, or can you? Rod

[Madclicker]

I think you mean nema 23. Unless I'm wrong you can run 8 wire motors in all modes: bipolar (series and parallel) and unipolar. Many have said that bipolar parallel is the best way. I have 1 8 wire motor and will experiment when I get running.

The only unipolar motors that can't be run bipolar is the 5 wire ones. The 6 wire ones can be run bipolar series.

[Madclicker]

Oh, and microstepping is a function of the drive not the motor.

[Grandad]

Steve, thanks for info, you've cheered me up a lot. I only have to upgrade the drive and possibly the power supply. Can you tell you what drive you would recommend for, yes you were right, Nema 23. I'm attaching a picture of my router so you can see what i'm playing with...Rod

[ger21]

Either the Xylotex or the HobbyCNC should work fine for you. What are the current and voltage ratings for your motors?

[Grandad]

Looking at the documentation supplied with motors we have 8 wire universal stepping motor 2.76v and 3.0 amps per phase.....Rod

[ger21]

Does it say how they are rated? Bipolar parallel, series or unipolar?

[joecnc2006]

if it is 8 wire it should be able to be wired in all three situations, however unipolar will loose 1/4 or the motors ratings from what i understand.

[Grandad]

I can't see any info as to how they are rated, I think I will contact stepperworld for this. They are very specific as to how these motors are wired, it does not leave much room for experimenting. Each motor has its centre taps commoned and connected to the drive via a 50w power resistor. As you suggest Gerry , i will order a new drive from probably Xylotec and see what that will do. I am amazed at the accuracy of the machine, it will repeat right on the button and hold tolerance to within a thou, and this is a wooden machine. I don't know how long this accuracy will last but i'm enjoying it while I can, many thanks, this is a fantastic forum...Rod

[Madclicker]

If you don't get the info from SW post the model info and I'll see if I can find the data sheets. Was pretty lucky with the three different motors I'm using.

[Grandad]

Thanks Steve, i'll post the info tomorrow as all the documentation is at work,,,Rod