Random piece breaks free of the bed while printing...

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minusbacon
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Joined: Sat Sep 12, 2015 2:52 am

Random piece breaks free of the bed while printing...

Post by minusbacon » Sun Nov 01, 2015 9:18 pm

http://www.thingiverse.com/thing:478336

I've attempted this object eight times with only one successfully completing. The first 1/3 to 1/2 of the print has a lot of small sections that all come together later on in the print. These small sections are breaking free of the bed in the first 15 minutes of the print. It's never the same piece.

After the first two fails I started trying some adjustments after every fail-- lift retraction, more glue/heat on the bed, and print speed. Print speed was the only one that helped and it's the only time I had a completed print, but it was a bit sloppy due to the bridging/overhangs in the print. The second time I tried printing with the same speed settings it failed again, so I think the one success I did have was complete luck.

Based on Thingiverse comments/prints, support, raft, or brim is NOT required to print this. I have no idea what other settings to try. Suggestions? I'd like to keep the speed normal if possible so the the bridging/overhang areas print decent quality.

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insta
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Re: Random piece breaks free of the bed while printing...

Post by insta » Mon Nov 02, 2015 8:03 pm

You can ignore the Thingiverse comments and enable a raft, or you can hose the bed down with hairspray until it finally stops breaking free. I usually opt for the former.
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Jules
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Re: Random piece breaks free of the bed while printing...

Post by Jules » Mon Nov 02, 2015 8:42 pm

Things you can do to improve adhesion on the bottom layer:

Lower the speeds on the first layer to about 50% of whatever you are using now, and make the first layer wider by about 20% to give more surface area contacting the plate.

Increase the temp of the bed by about 5 degrees to keep things adhered better.

Slow down the overall printing speed, but increase the bridging speed to 200% on the Other tab. Then it bridges really fast, but prints slowly overall.

Leave a vertical lift on retraction of about 0.2 mm or greater in there - it might be getting knocked over by the nozzle because of warping. :D

minusbacon
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Re: Random piece breaks free of the bed while printing...

Post by minusbacon » Tue Nov 03, 2015 5:40 pm

insta wrote:You can ignore the Thingiverse comments and enable a raft, or you can hose the bed down with hairspray until it finally stops breaking free. I usually opt for the former.
Does hairspray grip better than gluestick? I applied 3x my usual amount of gluestick for one attempt and it didn't make a difference.

I'm starting to think the cause is some filament oozing at the end of a layer onto a piece, which sticks to the piece on the bed and the nozzle, which causes the nozzle to pull it off the bed when the nozzle moves. Just another theory. Not sure how to confirm it. I should setup a camera to record it printing so I can watch where a piece breaks free. Maybe it'll tell me something.
Jules wrote:Things you can do to improve adhesion on the bottom layer:

Lower the speeds on the first layer to about 50% of whatever you are using now, and make the first layer wider by about 20% to give more surface area contacting the plate.

Increase the temp of the bed by about 5 degrees to keep things adhered better.

Slow down the overall printing speed, but increase the bridging speed to 200% on the Other tab. Then it bridges really fast, but prints slowly overall.

Leave a vertical lift on retraction of about 0.2 mm or greater in there - it might be getting knocked over by the nozzle because of warping. :D
I'm currently using the S3D defaults for the first layer. I tried printing at the same speed that gave me one successful print but pieces still broke loose. So the one successful print I did get was pure luck. Thanks for the bridging speed tip. Will try.

Never had any adhesion issues. I'm thinking it's not a glue/bed head adhesion issue. I'm thinking it's due to the pieces being so small since glue/bed heat hasn't made a difference. I've printed some sphere shapes where the lower part of the sphere printed horribly. Each layer was wavy/curled/warped and I was always nervous that the nozzle was going to bump an area that was curled up and cause issues but it never happened. I think that's because the first layer on the bed a decent size which made it stay in place.

I was thinking about trying a raft but in the past I've used S3Ds default raft settings which made it impossible to remove from the part. Any suggestions on raft settings that would make it easier to remove?

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Jules
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Re: Random piece breaks free of the bed while printing...

Post by Jules » Tue Nov 03, 2015 5:54 pm

I always found the hairspray worked better than glue stick - much easier to get a thick, even coat all across the bed.

Spray until it puddles, then spread it around with a finger and let it dry.

Instead of using a raft, try a brim. Set the distance to zero and the number of outlines to 12.

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