Support doesn't fuse to base layer on long pass

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Vagulus
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Joined: Mon Mar 25, 2019 5:27 am

Support doesn't fuse to base layer on long pass

Postby Vagulus » Sat May 16, 2020 1:50 am

This is a test piece I created to examine a problem with support material not fusing to its base material.
200516 - Tee Test Piece.png

There are three Tee Pieces stacked with gaps between them. My problem is that when my Pro2 starts printing the support material between the layers some of it does not stick to the previous layer. Especially puzzling is that short passes of support material stick okay but long passes do not. This is what happens with the first layer of support between the bottom Tee and the middle one.
https://youtu.be/n_Rkq36sN40
When printing the second layer of support material once again the short passes stick but the long ones do not.
https://youtu.be/oHKEM3T12qI

Does anyone have any ideas for fixing this?

Thanks

I have attached the STL and the template I used to print the model (BIN). I am using 0.8mm nozzles on my Pro2.
Attachments
08 Standard-export.bin
(20.68 KiB) Downloaded 20 times
Tee Piece Test - Copy.stl
(51.06 KiB) Downloaded 17 times
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He did not send a Committee

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Vicky@Raise3D
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Joined: Fri Mar 25, 2016 3:54 am

Re: Support doesn't fuse to base layer on long pass

Postby Vicky@Raise3D » Tue May 19, 2020 9:54 pm

Both videos show private, not able to view.
Would you like to confirm which part of the model was not sticky? Do you mean the first layer of the support or the bottom layer of the model?
Image_20200519144736.png
Image_20200519144736.png (10.96 KiB) Viewed 370 times


With 0.55m layer height and gap between one layer support and model, the nozzle should be 0.55m*2=1.1mm far from the top surface of the model.

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Vagulus
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Joined: Mon Mar 25, 2019 5:27 am

Re: Support doesn't fuse to base layer on long pass

Postby Vagulus » Mon May 25, 2020 12:42 am

Sorry about the delay Vicky. Perhaps this link will work better:
https://1drv.ms/u/s!AvZ9amwal2YXkIBgKnzah_leb2K9Vw?e=CfVzt4

Talking about tip clearance - how do I set it?

Thanks
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God so loved the World that
He did not send a Committee

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Vicky@Raise3D
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Joined: Fri Mar 25, 2016 3:54 am

Re: Support doesn't fuse to base layer on long pass

Postby Vicky@Raise3D » Wed May 27, 2020 2:49 am

From your picture and video, it looks like the gap is too big. There are 0.55*2-1.1mm gap from Nozzle to Model. You can try lower the gap for this support area under Per-layer Settings as the image below.
Image_20200526194845.png

Does the tip clearance you mentioned refer to Extruder Clearance during Sequential Printing?
If so, the following documents may can help you:
https://support.raise3d.com/ideaMaker/4 ... 5-843.html
https://support.raise3d.com/ideaMaker/8 ... 5-713.html
https://support.raise3d.com/ideaMaker/8 ... 5-782.html

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Vagulus
Posts: 184
Joined: Mon Mar 25, 2019 5:27 am

Re: Support doesn't fuse to base layer on long pass

Postby Vagulus » Wed May 27, 2020 3:44 am

Hi Vicky

This (somewhat tattered and bedraggled) honey-loving Teddy-bear of very little brain does not understand a word of what Christopher Robin is saying. :oops: This is probable the result of a badly-phrased enquiry.

Let's start with your clearance equation
There are 0.55*2-1.1mm gap from Nozzle to Model.

Given a standard 0.2 mm clearance between the nozzle tip and the BuildTak at "Home" (done during setup of the machine) and a Layer Height of 0.55 mm then the gap from nozzle to model (by my Elementary School Arithmetic) works out to be 0.55 + 0.2 = 0.75 mm, not the 1.1 mm you calculate. :?:

Secondly, I do not have sequential printing in mind. My issue is obtaining satisfactory results when model parts are printed on support material. Consider a set of shelves - each shelf will be printed one after the other, true, but the gap between them filled with support material and they are parts of one printing process, parts of the one model where the shelves are held together by the frame of the shelving structure. This is the scenario I am attempting to simulate.

Thirdly, in the videos I posted the top of the first Tee-piece has been printed and I am attempting to print support material onto it. This support material will hold up the second Tee-piece.

However, subsequent investigate seems to indicate that the culprit here is the Layer Height. Remember that I am using 0.8 mm nozzles which extrude a 0.8 mm diameter 'sausage'. My 'Elementary School' Nozzle Gap means the tip of the nozzle will be ploughing in the 'sausage' all the time. Perhaps this ploughing created sufficient drag to tear the support fibre off the model before the material had time to stick. Anyway, I have changed to 0.64 Layer Height (80% of nozzle diameter) and the problem has gone away.

There are other issues with using 0.8 mm nozzles. When I have a better handle on them I will post my solutions.

Thanks for the effort. :)
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God so loved the World that
He did not send a Committee

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Vicky@Raise3D
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Re: Support doesn't fuse to base layer on long pass

Postby Vicky@Raise3D » Thu May 28, 2020 5:45 am

1.1mm means the offset in gcode in Z direction. If you are considering the actual physical Z offset, it needs to add extra 0.2mm.
And there is a gap before the top of the model and support so the distance from bottom of first layer of support to the top of the first model is 0.55mm.
But Support has layer thickness, so the nozzle should be current at the top of the first layer of support which adds an extra 0.55mm.
Do you mean that if you increase the overall Layer Height to be 0.64mm, the support issue in video will be gone?


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