upsm
Posts: 151
Joined: Sun Mar 12, 2017 5:37 am

Re: Bridging Issues with PETG

Fri Aug 18, 2017 4:00 pm

For start I believe you are using part that is "too complex" and "too big" for this test. You are fighting with Simplify3D properly recognizing bridging, time to print the fairly big part with the unknown of the "new material".

May I suggest you try something simpler, like this for e.g.: https://www.thingiverse.com/thing:12925

https://www.thingiverse.com/download:41992
btest.JPG
It is perfect bridging test, prints fast, Simplify3D properly recognizes the bridge, so you remove all the obstacles you have and just focus on the bridging thing. Running it at 0.25mm layer would in my opinion be optimal for test. There is also a scad file so you can shorten it to 3cm if you don't want 5cm for testing (in my opinion 5cm is perfect).

Furthermore, you can drop 5-6 copies of the same model on the bed, set each of them to be printed with a different process and create 6 "same" processes with a single change on each of them. For e.g. you put 5 of them, 5 processes, all same except speed is 50, 55, 60, 65 and 70% for bridging. You find the best one, next session you print 5 again but speed is same (whatever you find in prev run is best) and you select different values for multiplier 80, 90, 100, 110, 120% .. do a run etc etc ...
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upsm
Posts: 151
Joined: Sun Mar 12, 2017 5:37 am

Re: Bridging Issues with PETG

Fri Aug 18, 2017 4:12 pm

for example, try this factory file
Attachments
bridge-torture-test.factory
(31.59 KiB) Downloaded 201 times
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  • Custom (darwin) / Replicape

gwhite
Posts: 156
Joined: Wed Jul 19, 2017 9:37 am

Re: Bridging Issues with PETG

Fri Aug 18, 2017 5:22 pm

Thanks for the suggestions. When I revisit this, I will probably make up a dedicated bridging model that is much simpler. At present, my setup can't really do a clean job going more than a few mm, so it doesn't need to be very big. The idea of trying to test over more than a centimeter is a pipe dream at this point.

I'm still new to S3D, and I can use this as an opportunity to learn how to set up different profiles for multiple models. That will allow me to run a range of options. I can sweep two variables in a grid of models.

Just to do a quick checkout, I ran the same bridging test model using the eSun PLA Plus I just installed for the current job. Using the default settings from MakerGear, It had a lot of the same issues the PETG did initially. The MakerGear profile pre-dates Version 4 of S3D, so they didn't have some of the bridging options that are available now. I may start by tuning up the PLA Plus as long as it's on the printer. I can't really expect PETG to do a good job if I can't get PLA working well.

gwhite
Posts: 156
Joined: Wed Jul 19, 2017 9:37 am

Re: Bridging Issues with PETG

Fri Aug 18, 2017 9:25 pm

Thanks for the file, I'll check it out this weekend.

Here are the results of my latest bridging speed tests. Both were run with the perimeter bridging option turned on. The 65% speed was done with a Bridging Extrusion Multiplier of 150%, and the 50% was done with 120%.
Bridging Speed Test.jpg
50% is still the best I've tried. 25% is too slow, and 65% is too fast.

craftyham
Posts: 6
Joined: Sun Dec 01, 2019 11:17 pm

Re: Bridging Issues with PETG

Mon Jan 04, 2021 4:15 pm

gwhite wrote:
Fri Aug 18, 2017 9:25 pm
Thanks for the file, I'll check it out this weekend.

Here are the results of my latest bridging speed tests. Both were run with the perimeter bridging option turned on. The 65% speed was done with a Bridging Extrusion Multiplier of 150%, and the 50% was done with 120%.

Bridging Speed Test.jpg

50% is still the best I've tried. 25% is too slow, and 65% is too fast.
@gwhite Thank you for posting this write up! It was a huge help. I did as you did to a degree; Speed 50% Bridging Extrusion Multiplier 83%(is this being based off your normal Extrusion Multiplier?) Mine is currently 0.93. I have the Fan set to 60% a couple layers before too & a few layers before drop the T0_Temp_245--->240 then return T0_temp_245 .The results are out standing for a .6nozzle @0.72 Extrusion Width using Esun Transparent PETG. I will post pictures of how well it came out possibly later this evening. :?: :!:
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