Losing steps - WHAT IS UP?!?

[Sporqster]

I've recently acquired a homemade router table with Xylotex steppers & board and Mach2. I've used it to make some nifty signs, letters, etc from 1/4" ply no problemo.

However, tonight I decided to turn it up a notch and use my 60-day freebie period with MeshCAM to make some of these cool photo carvings I see on here all the time. Trouble is, I keep losing steps on my x-axis after about 30-minutes into a program. I'm running at 10ipm- a rate that it was cutting out signs, cutting all the way through the wood no problem at all- now cutting just 0-0.1" deep with a pointy engraving bit and it's losing steps? What gives?

Maybe the motors are getting hot? They're warm to the touch, but not frightfully so...

[paulC]

Don't know anything about MeshCAM but would put everything back the way it was to try and isolate the problem. That should tell you if its something you have changed or if its due to something going wrong.
Paul

[Sporqster]

That's just it- I haven't changed anything except for running HUGE g-code files 1M+ vs signs that are more on the order of 100K. Seems like it gets "tired" is this reasonable?

[ShayArnett]

Not tired, but your leadnuts could be getting warm and expanding, causing a tighter fit which will stress the motors more and could induce missed steps. It doesn't sound like binding in the ways, or it would do it on any program that ran through the tight spot.

[Death Adder]

Well, all manner of strange things can happen to electronics when they get hot.

You might try this... Cut the engraving in quarters. Cut some, wait a while, cut some more, wait a while, etc. If it works then you might assume that something is getting overheated. At least that will help narrow it down.

[dighsx]

My bet is your Xylotex is overheating. I just had this same problem about a week ago. I'd run a huge job and about 30-40 minutes into it things would get messed up. Sometimes I'd lose steps and a few times my X and Y wouldn't be able to go in one direction. It took a bit to figure out but the fan that blows on the Xylotex board had shifted and wasn't blowing right on them. So what I did is laid the fan right on top of the heat sinks and now everything runs great. In fact I think I can run faster (I have no proof of this but it just feels like I can push things a bit more) Is your Xylotex in a box and what kind of cooling do you have for it?

[randyf1965]

I didn't lose steps on my picsteps but the first 10-15 minute cut I did they got VERY hot... until I put a 12v blower on them to cool... now they stay nice and cool

[Sporqster]

I've got the Xylotex and power supply in a wooden box about the size of a old school Nike shoebox. I've got the fan that came with it sucking air through a 1.5" hole saw cut on one side and blowing out 5 1/2" holes drilled on the other side of the box. You can feel a pretty decent air current coming out of the holes when it's running.

I could believe not enought cooling though... I am asking an awfully little board to move around am awfully big machine...

Come to think of it, I never did check the output voltage on the board - the machine worked when I got it and I assumed it was set properly... but who knows. Low or high voltage maybe causing this?

[paulC]

1.5" is a pretty small hole. You won't get a lot of air moving through that. You also want to ensure the airflow passes over your drives.
Paul

[Sporqster]

OK, as usual, the solution is simple and I should've realized it right away to begin with-

The nuts on either side of the bearings of the axis lead screw had come loose, and when running continuously in the same direction (like meshCAM programs like to do) it started torqing the nut onto the bearing. DOH!

Oh well fixed now. running fine.... except I'm having software issues I think... but that's material for a new topic!

[CurtisU]

Originally Posted by paulC 1.5" is a pretty small hole. You won't get a lot of air moving through that. You also want to ensure the airflow passes over your drives. Paul

Glad you found the problem, Paul's right that sounds like a pretty small hole, depends on the size of your fan. Where electronics are concerned, avoid high temps at all cost.