horst.w
Posts: 861
Joined: Fri Oct 17, 2014 5:00 pm

Re: PETG Material

First, I show some pictures of a sphere to be print.
There are many many possibility for settings, I limite it to only 2 perimters, with and without Infill and one example with 2 prcesses.

There we go,

a sphere with infill makes normally no problems
Sphere w Infill.png
totally different to this is a sphere, it is not or only with absolute bad quality to close on the top
Sphere without Infill.png
Sphere without Infill Schnitt .png
You can see, the last Millimeters of the top, the perimters and the solid infill have no substructure below. Zhe printer would print the material in the pleine air.

At the end here the sphere with 2 prozesses, the 2nd beginns 5 mm below the top. It needs to set the solid infill to Rectlinear.

Inside of a hollow body S3D doesn't print any bottom or top layers so that the infill of the 2nd process must be bounded to the outside wall, a sufficient overlap is needed.

A visual control of the complete print preview is obligatory, but testprints are not to replaced by any other action.

Finally I attache my factory of PETG. This is only valid for my material, each other printer and each other material must be adjusted-

I regret that only 3 pic are possible!
horst.w
Posts: 861
Joined: Fri Oct 17, 2014 5:00 pm

Re: PETG Material

Here the rest
Sphere process 2  w Infill.png
Attachments
Sphere 2 processes.factory
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eviglotti
Posts: 8
Joined: Tue Feb 06, 2018 3:47 pm

Re: PETG Material

Thanks so much. My actual model is actually a half bowl (factory file attached). And really it's the last 3 or 4 layers that are causing the problem where the hole is showing through the PETG. It sure seems like maybe in my case the easiest solution is to have the last 10 layers have 100% infill that way the walls of the bowl at that point are totally solid such that when the last 3 layers go really quickly and don't completely cover what is below, then what is below is solid infill not infill which naturally has holes...

screenshot.png
Attachments
Bowl factory file.factory
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eviglotti
Posts: 8
Joined: Tue Feb 06, 2018 3:47 pm

Re: PETG Material

Of course, now that I think about it, just increasing the "top solid layers" from it's current value of 3 to something like 10 or 20 would do the same thing :)
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dkightley
Posts: 2405
Joined: Tue Mar 10, 2015 4:09 pm

Re: PETG Material

Printing a sphere always gives the same issue when you print with a thick layer....at the very top, things get "steppy" and can look coarse....and as has been reported here, cause the print to fail. The trick is to use the Variable Settings Wizard to create two, three or even four different profiles....and then gradually reduce the layer thickness as you get closer to the top.
Doug Kightley
Volunteer at the National Tramway Museum http://www.tramway.co.uk
Railway modeller and webmaster at http://www.talkingtgauge.net
horst.w
Posts: 861
Joined: Fri Oct 17, 2014 5:00 pm

Re: PETG Material

The problem is determined by the system of 3D-printing: Layer by layer

While the LayerHeight is fixed, the real LayerWidth groves up and becomes extremly to cover the expanse.

I believe this is only to solve when it is possible to print real bridges by the choice of the users and not only by an algorithme of the program. If we can do so, it will be much better.
Splitting into processes helps but inside a body we cannot print any top or bottom layer what can serve as a bridge.

The preview of the print shows holes but in reality they are not existing. Thats because the preview differentiate between the kinds of inner-outer perimeters, solid infill, infill but this is normally always the same material what makes the optical impression. The surface will always be a bit coarse, but that is also a systematical problem. Printing with ABS or ASA you can smooth it with aceton.

H.
KugelDrucken.png
eviglotti
Posts: 8
Joined: Tue Feb 06, 2018 3:47 pm

Re: PETG Material

Very helpful stuff and very good suggestion on the different settings for layer height towards the end. Thanks!

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