PETG not sticking

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MikeA
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Joined: Fri Apr 22, 2016 1:58 am

PETG not sticking

Post by MikeA » Fri Jul 01, 2016 7:46 pm

I'm having a problem with PETG overhangs when using PLA support.The red is PETG and the Black is the PLA support. The support has 2 100% dense support layers. The problem seems to be the nozzle is to high above the support for the PETG it to stick. If I turn the manual Z adjust clockwise one click just as the 1st layer of PETG above the the support material starts it sticks fine. It's printing 2 passes of red and then 2 of black. I'm using S3D and have the upper and lower vertical separation layers set to zero. Any suggestions?
IMG_0686.JPG

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Jules
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Re: PETG not sticking

Post by Jules » Fri Jul 01, 2016 8:40 pm

I see from the corner clips that you have the new Rev.E dual?

Is there some part of that design that keeps you from flipping it over and printing it with fewer supports required? Because that is going to be your best bet. Supports are a last resort, and you always want to place as much of the design flat on the plate as you can. (Or cut the design into parts so that support is not needed, then glue it together after. instructions here: viewtopic.php?f=3&t=3431)

The things you can try to make it stick better:

1. Change the Starting Height in the Z-Adjust App so that the gap is a little bit smaller.
2. Slow it down.....a lot.
3. Increase the temperature a little. That is going to increase the oozing on the PETG, but it might make it hot enough to stick better.
4. Put a pause into the print (there's a way to code one in....described here: viewtopic.php?f=3&t=2132) and apply an adhesive of some kind on top of the support. Let it dry, then resume the print. (Elmer's glue, hairspray, gluestick.)
5. Keep adjusting it by hand using the Z-knob if that is working for you, cause it sounds like it might be the easiest option.

MikeA
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Re: PETG not sticking

Post by MikeA » Fri Jul 01, 2016 9:05 pm

Flipping it over would result in even more support. I was hoping there was some setting I was unaware of, but it seems like the best option may be to just edit the G code to reduce the gap only on the 1st layer after the support material.
The printer is a pre E rev that I removed the bed springs from and tapped the holes for corner leveling as well as moving the Z-home switch. I also had to change some wiring on one motor and the Z home as well as a couple of things in the firmware to enable the REV E firmware to run on it.

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Jules
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Re: PETG not sticking

Post by Jules » Fri Jul 01, 2016 9:24 pm

Ahhhh! That's too bad. Some of them really do present a challenge. :|

Bratag
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Re: PETG not sticking

Post by Bratag » Sat Jul 02, 2016 1:19 am

Does it have to be printed as one part for strength - if not use simplify3d to mirror the print along the mid point and print it flat on that mirror line

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jimc
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Re: PETG not sticking

Post by jimc » Sat Jul 02, 2016 3:16 pm

There is a horizontal and vertical seperation distance in your support settings. Horizontal is only for perfectly horizontal surfaces. Vertical applies to everything else.

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