Getting the first layer to stick

General discussion of topics that don't seem to fit anywhere else.
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Artlav
Posts: 3
Joined: Mon Aug 03, 2015 7:26 am
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Getting the first layer to stick

Postby Artlav » Tue Aug 04, 2015 7:44 pm

Hello.

I made a top down DLP printer, and am having problems making the first layer stick to the build platform.
Five to ten layers in, corners would unstick and warp up.

I'm using MakerJuice G+, red.
Platform is stainless steel, with 4mm holes drilled in it every centimetre or so.
More exposure on the lower layers make them warp faster.
Much more exposure make them warp and smoke.
Less exposure makes the layers come apart or be incomplete.
Slowing down the dip have no real effect, it still unsticks, only slowly.
The unsticking seem to be sudden, while the corners are still flexible. It happens within one or two layers.

What can be done about it?
I looked around blogs and forums, but most of it talks about bottom-up, or suggests things i already tried (listed above).

Also, if there is some wiki or similar place that lists SLA know-how as good as in the places with FDM know-how, then i'd love to hear about it.

Artlav
Posts: 3
Joined: Mon Aug 03, 2015 7:26 am
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Re: Getting the first layer to stick

Postby Artlav » Wed Aug 05, 2015 5:58 pm

Had a bit of a success by roughening up the platform surface with sandpaper.
The parts no longer just unstick.
But they still warp slowly on long stretches.
Before on the left, after on the right: http://i.imgur.com/MKQ3LV7.jpg

Another issue is overhangs/flat surfaces.
I.E. a LEGO piece - the overhanging top is bulging.
Adding holes to it help, but not all the way.
Increasing settling delay does not do much of anything.
Anything i can do about that?
Or is it exclusively a wiper-soluble problem?
Appearance: http://i.imgur.com/KVgSqua.jpg

newraper1963
Posts: 10
Joined: Mon Jan 19, 2015 6:55 pm
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Re: Getting the first layer to stick

Postby newraper1963 » Wed Aug 05, 2015 9:34 pm

I have found that whether it's fdm or dlp that it's all about positioning. Place your blocks on end. Raise it 5 to 10 on the z axis move section of CW in the 3d window. Rotate it 30 to 45 degrees and have the bumps on the top surface. Add the supports and don't be shy. I won't add the base support as many time the stick supports will do. This will help eliminate your support base from warping. Set you delay for 30 seconds. That's 30000 in the entry box. This cylinder head was done this way.
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