I'll be an expert when I've made every mistake

[johnridley]

After a couple of hours of printing, I went downstairs to see this:

The glass slipped. I think it slipped because the head hit the object during a move, and I think the reason that happened is because the object warped, and that was because the glass is so thick that 110* on the bottom only results in 95 on the top in the middle and less at the edges, according to the IR thermometer.
To combat this I'm setting the bed temperature at 120 and I may go to 130.

I've also decided to video record long prints that I'm not personally watching so that I can try to determine the actual cause of unexpected axis slips rather than guessing and tweaking stuff at random.

Also I'm clipping the glass to the board underneath:

Comments

[rono-60103.livejournal.com]

Is there a danger of the binder clips becoming a burn hazard. If they are in contact with a hot part of either surface, they'll be hot.

If this works, it may be wise to remove the parts that let you remove the clips.

(Now can someone get this safety officer I'm channeling out of my head)

[johnridley.livejournal.com]

The entire thing is a burn hazard. The first thing you do when you put one of these things on your desk is to place a fire extinguisher within reach.

Binder clips are actually standard equipment for these printers, they're what has been used to hold down print beds since day one.

The assumption is that anyone who uses one of these is an adult.

Besides, the surface is only about 110*C, and the binder clips are thin metal open to the air, they're probably more like about 60*C. Not a burn hazard unless you hold your skin to them.

Honestly, I touch the print surface lightly and quickly to flick off stray bits of plastic during printing, and the IR thermometer reads it at 110*C at times, and it doesn't burn. I just don't touch it for long.

[bwittig.livejournal.com]

So the purpose of the heated bed is to stick the part in place, and once it cools the part comes loose? I was reading the temps as F not C--110C is MUCH different from 110F--I did not realize it ran that hot.

[johnridley.livejournal.com]

Yeah, degrees C. One thing this project has done is to bring to the surface my deep-seated hatred for US/SAE measurements. I never liked them and wish we'd gone metric in the 70s when we had the chance. This entire thing is designed in metric and making one with SAE parts is kind of a pain. You wind up with some metric parts anyway because some stuff like linear bearings are dirt cheap in metric an expensive as hell in SAE.

[kevinnickerson.livejournal.com]

You can't make *every* mistake. More than one of the possible mistakes are fatal.