Was looking though old posts and seen a guy had a sock over his router
Did not want to revive a post from 4 years ago so started this one just to ask a quick question
I have the Z-Plus and was wondering if anyone could foresee any issues with putting a sock over the Z-axis stepper motor to stop sawdust from getting in there?
Other than the funny look, there is probably no side effect to putting a sock on the Z stepper, but I’m not sure it’s useful, I have yet to hear about a stepper motor failing due to dust. If you have dust collection in place there should be minimal amounts of dust that makes it way up to the top of the Z stepper anyway ? @RichCournoyer has the informal copyright on the “sock on router” trick, who knows maybe you’ll launch a “sock on stepper” trend
I 3D printed cute little snap on caps for all of my Stepper motors…years ago. Why is the hole there? Because the mfg also sells a model with a double ended shaft…since we’re not using it (the hole) there is NO reason to leave it open. Only bad things can happen. As I say…Cap it Mate!
There are some folks who hold that the hole in the motor housing is also useful for ventilation/cooling — and there may be some small metal fragments which will work their way out and need to be removed, so please don’t do anything permanent.
According to most of the vendors the motor should not have air convection through it (as Rich points out), both front and rear bearings are meant to provide a basic seal.
As Julien says though, internal temperature is the major determinant for the working lifetime of the motor windings so whilst plugging up the small hole should make no difference covering the entire motor in something which reduces convective or radiative heat loss to the air is likely not a good idea. There will be some small conduction to the mounting surface but unless mounted with a thermal paste this isn’t going to heatsink the stepper very effectively.
Ahhhh, I saw the first line and, to be honest, didn’t read further because I saw the post with the router he mentioned.
Hey, I am up there in years. Thats my excuse and am sticking with that.
More seriously though, the motor will tend to do this on it’s own. The motor has two holes, one of which the spindle comes out through. As moisture gets into the stepper there is a constant process to manage this, assuming you turn the machine on reasonably frequently.
The air outside the motor will have some specific humidity (g water per kg air) which will translate into a relative humidity. Thanks to the way the vapour pressure of water varies with temperature, for any mass of air with a constant mass of water vapour in it (Humidity Ratio), if you raise the (dry bulb) temperature of the air, the relative humidity (RH) will reduce. If you cool the air down then the RH increases, at some temperature you hit the dew point and moisture condenses out of the air (thus dew and fog and possibly wet stepper internals). When you heat the air up the mass of water which can be carried as vapour also increases.
The motor is not airtight, it’s not designed to be. This means that it will exchange air (and water vapour) with the surrounding environment. When you power up the machine, as the motor heats up, some fraction of any condensed moisture inside the motor will evaporate into the air inside the motor. This causes expansion of that internal air (much more expansion than happens with just temperature rise of dry air), which pumps some of that now wetter air out of the motor, carrying moisture out (just like the vapour permeable membrane in GoreTex type fabrics).
So, unless your motors are hermetically sealed and able to be pressurised, you’re going to be constantly exchanging small amounts of air with the environment, there’s a tendency for the air leaving to carry any condensate out of the motor as vapour. This is why small electrical heaters in electrical cabinets and similar environments work so well to keep them dryer inside than outside.
I don’t know if it was me or not but I put a sock over my Makita on my CNC. Based on the amount of dust I vacuum off the sock everyday, I think it was a smart move. I’ve had it on for 2.5 yrs now and never had any issues.