Use Loctite (or similar product) for some screws. See: loctite.com
As anywhere within the official manual this is not written down anywhere… something is missing here. This is absolutely clear to do that and it should be within the official manual as well. BUT IT’s NOT.
In our experience, it is not mandatory.
Feel free to add glue if you wish, but keep in mind that this makes changes more difficult or even impossible. Only do this when the unit is fully calibrated and operating properly.
I think it’s no problem to use BLUE glue (non-permanent). Also this glue will harden over night, not within minutes.
Use BLUE low or medium strength so you can loosen the screws again later on.
For the small headless screes on the wheels on the motor axes you should use some BLUE Loctite.
Of course you need to limit de movement about some parts, every industrial design do it. Red nail enamel is enought and this option let you:
1.- Block these parts
2.- Optical control about possible maladjusted when the time pass.