Nylon wheel tension screws

[Flash]

Hello

I was wondering if anyone could give me a detailed explanation of what the 2 screws do with regards to the nylon running wheels.

one of my screws is cross threaded and therefore useless, to compensate for this I had to unclip the snake like plastic clip that holds the wires as the forwards and back action was causing the top head than runs over the rail to become at an angle, therefore i lost lots of laser power.
all was fine really as i could use it with this setup, however last night the top peice would not stay in a level posistion so i tighted up the one nylon screw on that side that works and also the top screw that inserts into nylon wheel and since then its been to tight!, I have unscrewed all screws on the side where it is to tight, but its still too tight, this in turn is causing my laser jobs to start in the wrong posistion as the head is getting stuck on the rails.

Thats why I thought if I understood what these screws did then it might help me?

Cheers
John

[Flash]

Just an update..

I rang HPC today and spoke to simon about this, he informed me (if I heard correctly!) that the screw going though the nylon wheel need not be touched and holds the bearing in place, the other screw going into the side is what holds the wheel in place and only need to be pinch tight.

The intersting bit that solved my problem was that the the brass bit that the side screw is keeping in place is 'egg' shaped and not 'round' which is were I was getting my problem from, I had turned this so the top of the egg was facing the rail, therefore it was much tighter on the rail and not allowing it to move freely, once I had turned this a quarter I could immediately tell a difference and hopefully this will solve the problem

hope this helps someone, and thanks si

John

[MC Design]

I think im having the same problem with mine.
While engraving the gantry sounds like its getting stuck, then the engraving will skip and be off. Very frustrating, will take a look at my bearings and see whats up

[JohnStevenson]

I had the same problem with my 3040 and it was sorted back at base to my satisfaction as it was still a new machine.
Can't say enough about the service from Chris and Co but as a design engineer I feel the overall design of the gantry is poor, nothing to do with HPC unless they can get a design change at the factory and after working closely with another Chinese factory I know from experience that it's not easy getting them to change their mind.

The whole set-up is the Vee rail, 4 rollers, 4 bearings and support hardware must cost more than a simple linear rail with one bearing.
some of the other Chinese machines use this method and it makes sense engineering wise.



Something like this.

Hopefully mine is cured but if I do get problems later and I feel i must given wear on rollers etc I will probably change to this design.
Another thing I have noticed is that the motor on that axis is far smaller than the motor on the X yet each has roughly the same job to do. I feel that is the motor was stronger, and the driver will support it, then any sticking will be overcome instead of it loosing steps