New to 3D printing, need tips for platform calibration

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samspqr
Posts: 7
Joined: Sun Oct 20, 2013 1:04 am

New to 3D printing, need tips for platform calibration

Post by samspqr » Sun Oct 20, 2013 2:32 am

So, I just bought an up mini, I've read the manual (after downloading it: the printer came with no docummentation or software whatsoever), I've started using it, I've got my first parts working. And some doubts too.

I've followed the instructions from the manual and from a couple of youtube videos, and I still don't know if I should set height a bit higher or lower. As it stands now, ABS sticks quite well to the board, but it may be filling the holes a bit too much: after taking the piece out, many of the holes are left filled with ABS. I can easily get it level with the scraper, but I don't know if leaving those holes covered is good for later prints. If I separate the platform a bit, the raft sometimes fails to adhere to the platform, and I can't imagine everybody cleaning those holes with a pin after each print. Any tips?

Also, do I need to preheat the base before printing? For how long? It would be a lot better if the software could take care of this automatically...
(so far I've been letting it preheat for 15 minutes before printing)

The other doubts I had, I already solved them in this forum: I can't turn the beep off; the LEDs can be turned on in an obscure way (at teast that was the case with older software, I'm not sure I know where the "initialize button" is on 2.0); it can do raftless printing with kapton tape or glass base. Thanks everybody.

roller
Posts: 1622
Joined: Sat Oct 06, 2012 9:09 pm
Location: Brisbane, Australia

Re: New to 3D printing, need tips for platform calibration

Post by roller » Mon Oct 21, 2013 12:45 am

Leave the holes filled - it's too painful clearing them out and the hot ABS sticks just as well to the ABS already in the holes as it does to the empty holes it's squeezed in to... so just scrape it flat like you've been doing.

The Mini heater doesn't get very hot and is a bit too hot in the centre and cool at the edges. I would preheat your heated platform as long as possible to get some heat all through that perfboard and a bit into the chamber even. Look around the forum for a mod to take it up to 80C instead of 50 and your prints will be much more reliable.

samspqr
Posts: 7
Joined: Sun Oct 20, 2013 1:04 am

Re: New to 3D printing, need tips for platform calibration

Post by samspqr » Thu Oct 24, 2013 12:14 pm

Thanks

Going on with my experiments, the biggest problem I have now is that when the ABS cools down, it contracts, and it pulls up the ends of the perf board. For anything bigger than 50x50, the problem is obvious.

I'm experimenting with Kapton tape. I can print raftless, and for small pieces (30x30) it works, and is straightforward to separate afterwards. For bigger prints, the ABS doesn't adhere well enough. I'm dissolving some ABS in acetone to paint over the kapton tape before printing, let's see if this works better... If it does, I will buy a glass base to avoid the warping of the origina perf boards.

roller
Posts: 1622
Joined: Sat Oct 06, 2012 9:09 pm
Location: Brisbane, Australia

Re: New to 3D printing, need tips for platform calibration

Post by roller » Thu Oct 24, 2013 1:25 pm

Yes ... that is the problem with the Mini and why I only had mine a couple of weeks. Kapton is ok and sticking it harder helps but you will always have the stresses with complex prints. Moving to a better sticking platform just resulted in more stresses and cracks in my prints. I never had these issues on my repraps due to the hotter build platform and the same now I have an Up plus. The lack of heat in the build platform is a real problem for contraction oriented prints.

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