MISSING STEPS IN X,Y,Z AXIS

[richbat]

My Shark is in an unheated garage (I do have a gas heater but it takes time to warm up the shop). I have been using the Shark on a regular basis for the past several months with no problems. Since the weather has turned cold I have noticed occasions where I get some significant errors in the x,y or z axis while carving. Can the temperature play a part in this? If so , how do I compensate? If not the temperature what other things should I look for in order to prevent these errors?

Thanks

[jeb2cav]

Hi - I've been thinking about your post, and suspect that at a certain temperature, the rods the gantry rides on are going to be affected by cold temperatures. I don't have a lot of direct experience with this type of machine and cold weather, but I doubt the designers intended it to perform within certain temperature tolerances. Certainly below freezing or less would cause some movement of the rods the gantry rides on for example.

Another possible source is your waste table - or table worksurface - again a result of the cold/frozen conditions. Warming back to 50 or so I would think would address most of the "metal" issues. If your table surface is wood of some sort, even after thawing out, you may need to take steps to level it off.

I lost heat to my shop this week. It did get well below freezing and I did take a few token measurements - the table was "off" in several areas from my last check.

It could also be less an issue of expansion due to the cold and more an issue of poor lubrication/frozen dust particles in the spirals and along the travel rods. This would cause some "sticking" in movement and thus bad x,y,z outcomes. Again, no extensive direct experience, just some educated speculation.

[Tim Owens]

Question,

I assume you dont have a pro plus (black shark). One of the things that could be the problem is that there are connectors in the controller that might be having issues due to extreem cold. Are you keeping your computer outside as well?
I would plug in the unit and let the controller box warm up for a few mins or put a heater in the area so it will warm up.

Thanks

Tim

[Consultingwoodworker]

I use my Pro in a pretty cold shop as well, and I've not had problems yet. That being said, the linear guide rods and bearings use grease to keep themselves moving smoothly. All greases (unless specifically designed for extreme cold) will thicken and stiffen at very cold temps. The same is true of the drive screws.

You might want to try a radient heater aimed toward the machine. Let the machine warm up a bit before using. Try running the same program and see if there is an improvement.

Ralph

[FERGUSOPTICAL]

Hello, I think I may be having similar troubles. I have some code that ran fine a few weeks ago, and now that the weather is colder is has problems in all directions (xyz) Did anyone confirm if the cold weather was the cause of the missing steps? My shop is also in my garage and its cold in there right now.

Thanks.

[rungemach]

If you have machines that have the 1/4 " dia stepper motor shaft extending out of the back of the motor,
you can mount lightweight knobs on the shaft ends to allow you to easily turn the steppers by hand when the power is off.

This lets you fine position the axis, and also check to see how difficult it is to turn the motor when cold. ( or check for binding etc)

I used these knobs and they work very well and are available just about everywhere.
http://www.radioshack.com/product/index ... =107598756

If your machine needs some warm up time, you can try some air cuts to loosen it up, then check to see if that helped.

How cold are you guys talking about. below freezing? I am formerly from the upper midwest so I know how cold a garage can get. Yikes...

Bob

[FERGUSOPTICAL]

Hello, I am in the Chicago Suburbs and it was below freezing all weekend - only a little warmer in the shop. I am going to try and heat up the garage to see if that helps.

The machine jogs fine - or at least it seems to. Its also cuts fine when it gets to the first cut path. Its seems to have trouble on the rapid movement sections and starts to loose its place and gets worse every time it tries to move quickly.

[jeb2cav]

What are you using to lubricate the rails and the lead screws? I use a teflon/silicon spray and don't seem to have a problem in this regard in the cold or heat? Maybe it just needs lubricated and is more noticeable in the cold.

[FERGUSOPTICAL]

Right now, I haven't added any lubrication to the system. I will try some silicone spray.

[FERGUSOPTICAL]

I managed to get everything working tonight. I heated up my garage with a propane heater, I lubricated all moving parts with some silicone spray, and finally managed to get some parts to run properly. It took a while, and I was about to give up and blame something else on the problem... Once it was working I ran the same file 5-6 times and it worked every time. I am guessing it took a while to get the parts in the control box warm enough - as the cooling fan kept pulling cold air into the box.

Tim, what parts need to be warmed up? Maybe I can save some energy by only heating the control box? It really wasn't that cold in the shop today - around 40 degrees.