Y axis skipping

[wayne]

I'm running a project that is around 30". My bed is 36" deep. After running between 10 - 30 minutes, I hear the worm gear grinding (skipping). Unfortunately it's happened three times and I can't isolate a pattern. I use a dry, spray lube on all my worm gears every day I run the router. I have rebooted and resolved the file. I ran a small project yesterday and today with no problems. Any ideas?

thanks

[gerry]

I don't think a dry lube is all that good for the screws. Most create a buildup if used often. You are basically dirtying up the drive system. I would thoroughly wipe down the screws with DNA (Denatured Alcohol) to clean them, then apply some 3-in-one oil from a rag. I keep a rag stored in a metal can. I add oil to the rag as needed. Each day I wipe the screws and rails down with the rag, then put the rag back in the can.

FWIW get used to the CNC nomenclature. It will allow you to be better understood.

My bed is 36" deep = My CNC has 36" if travel in Y-axis. The bed could be 4' deep, but only 24" of Y travel.

I hear the worm gear grinding (skipping). = That is a ball-screw. A drive system component. The ball-screw is rotated by the stepper motor and provided the means for moving the gantry and spindle along the axes. The ball-screw does not slip, that sound is the stepper motors losing steps. The faster and harder you drive the stepper motors, the less torque they have. Dirty screws and/or lack of lubrication cause the steppers to work much harder.

The owner manual has a pretty good breakdown of terms.

[dadealeus]

I'll second gerry's post, here. I use a light coat of Marvel Mystery Oil every week or so - taking care to clean off any debris I might find when I do.

His notes on pushing max travel speeds can definitely be the cause of the skipping. I think my machine maxes out at about ~300 inches per minute, but if I run it at that rate while milling, I'll definitely get some skipping. The harder the material, the slower I need to go to make sure I don't encounter skips. For example, 150 IPM might be fine for a piece of plywood unless I hit a particularly hard knot in the wood - then it will skip.

For me, lowering the travel speed of the gantry has fixed any issues I've encountered with skipping.

Additionally, if using something like Fusion 360 to generate your toolpaths, I'd recommend throwing in a little smoothing. Fast gantry speeds combined with sharp changes in the path can also causes skips. Sometimes you can get away with keeping the travel speeds fast as long as the path is smoothed out.

[stevem]

I use 3 in 1 oil. Have a small cloth that I soak with oil and just rub it on all the rails and screws. Works fine. You do have to make sure you clean the rails and screws before you put the oil on.

[johnb]

Axiom definitely says that 3 in 1 is the recommended oil, although I will readily admit that Marvel Mystery Oil smells better. Gun enthusiasts will sometimes tell you that, once the volatiles in 3 in 1 evaporate, it leaves a "varnish like" residue, but the Axiom folks tell you to wipe down the screws EVERY DAY of use...so that would likely never be a problem.

[damonlayne]

Using a pocket toolpath, I am attempting to make a simple rectangle which I have done many times over the past month. As the picture shows, the rectangle started just fine; however, the Y started to head in one direction. I stopped the toolpath and attempted to re-home the machine. Now, the Y-/+ only moves in one direction until it reaches the end of the machine. There is a grinding noise like a slipping clutch from the stepper motor under the table. The screws are wiped with 3n1 weekly. The coupler is tight. I don't run my machine hard, probably 50-60 IPM. I checked all the connections inside the box and the plugs are seated tightly. Thoughts?

[Axiom Tool Group]

Damon, I'd worry more about communication problems than something mechanical.

If you have not already called support, we are happy to help.

I'd start by looking through some electrical connections...for instance, the cable between the handheld and control box.