totalitarian
Posts: 44
Joined: Sun Dec 18, 2016 1:42 am

Gaps in top layer

Thu Jan 26, 2017 7:30 am

Here is my test piece, as you can see I have gaps in the top layer. Recently I calibrated my extrusion multiplier by creating a thin walled part (0.4mm cube) Measured the width, which initially was 0.43mm, then lowered the multiplier until it measured 0.4mm

What I am seeing now is gaps appearing on the top layer. If I move my multiplier back up, yes it closes the gaps a little (not fully) but then my walls on the 0.4mm cube go back to being oversized.

https://goo.gl/photos/HwU43YdU6GCJZvsk9

Any advise? I'm using a Flasforge creator pro @ 0.2mm height, 50mm/s and 3 top solid layers.

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dkightley
Posts: 2339
Joined: Tue Mar 10, 2015 4:09 pm

Re: Gaps in top layer

Thu Jan 26, 2017 8:36 am

Its difficult to advice what settings to adjust when you don't know what they currently are!

Can yo supply a factory file for this part, please. File menu....Save factory file
Doug Kightley
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Railway modeller and webmaster at http://www.talkingtgauge.net

jonsnow43
Posts: 7
Joined: Mon Jan 16, 2017 11:24 am

Re: Gaps in top layer

Thu Jan 26, 2017 12:09 pm

Hi

It seems that you print with PLA so you should have an extrusion multiplier of 0.92 or close to this (1 with ABS).

What is your infill ? Did you try to follow the instructions on the quality guide ? https://www.simplify3d.com/support/prin ... nd-outline

For me the outline overlap was set to 15% and when I increased to 20 I got better results and parts are not oversized.

totalitarian
Posts: 44
Joined: Sun Dec 18, 2016 1:42 am

Re: Gaps in top layer

Thu Jan 26, 2017 12:53 pm

dkightley wrote:Its difficult to advice what settings to adjust when you don't know what they currently are!

Can yo supply a factory file for this part, please. File menu....Save factory file

Sorry, everything else not mentioned in my first post is factory default. Here is my factory file
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totalitarian
Posts: 44
Joined: Sun Dec 18, 2016 1:42 am

Re: Gaps in top layer

Thu Jan 26, 2017 2:11 pm

jonsnow43 wrote:Hi

It seems that you print with PLA so you should have an extrusion multiplier of 0.92 or close to this (1 with ABS).

What is your infill ? Did you try to follow the instructions on the quality guide ? https://www.simplify3d.com/support/prin ... nd-outline

For me the outline overlap was set to 15% and when I increased to 20 I got better results and parts are not oversized.
This is it bumped up to 30% outline overlap

https://goo.gl/photos/pDFLrzHTerrQ6gpc9

Not much difference i'm afraid

totalitarian
Posts: 44
Joined: Sun Dec 18, 2016 1:42 am

Re: Gaps in top layer

Thu Jan 26, 2017 3:00 pm

Ok here it is with stock 0.9 multiplier. Still can't see any difference

https://goo.gl/photos/2pTT8xuP7yoM9sUC8

totalitarian
Posts: 44
Joined: Sun Dec 18, 2016 1:42 am

Re: Gaps in top layer

Thu Jan 26, 2017 4:22 pm

Here is a comparison using the stock settings but with a different filament

https://goo.gl/photos/t8To3nHmGqMdcVyAA

billyd
Posts: 223
Joined: Mon Jan 19, 2015 12:13 pm

Re: Gaps in top layer

Fri Jan 27, 2017 7:11 am

You are under extruding.

I don't think you can calibrate extrusion based on wall thickness, especially to 0.0x of a mm. 3D printing is typically good to about plus or minus .2mm (some are better than others, but I don't think any can hold 0.0x mm).

Calibration needs to be done with outside dimensions of a printed part and again you are hoping to get that within 0.2mm of the desired dimension. Your x, y and z steps/mm should be correct from the factory (assuming you didn't make your printer). Typically all a user needs to adjust is their extruder steps/mm of filament travel. From there it's a matter of measuring your filament correctly and making sure your nozzle diameter is correct in the slicer. Use extrusion multiplier to tweak the flow depending on results. Usually you won't have to touch it if you have everything else correct. But if you change the extrusion multiplier to get wall thickness perfect you will probably end up way off in volume of plastic extruded, either over or under. In this case you are under extruding. Again you can't achieve that level of accuracy in wall thickness (single).

billyd
Posts: 223
Joined: Mon Jan 19, 2015 12:13 pm

Re: Gaps in top layer

Fri Jan 27, 2017 7:21 am

ps I typically print something like a 20mm square about 3mm high with about 20% infill and 4 layers top and bottom. I adjust my extruder steps/mm until my top surface is perfectly smooth with no gaps. I leave extrusion multiplier at 1 for all prints. Make sure you measure your filament diameter exactly and get all other information controlling plastic flow volume correct. After you do this your prints will always be perfect as long as you measure filament diameter accurately for each spool.

pss if the outer measurements of the cube are wrong your printer's x y or z steps/mm might have to be tweaked (assuming your plastic flow is perfect). It also could mean you are printing too fast or with too much acceleration.

totalitarian
Posts: 44
Joined: Sun Dec 18, 2016 1:42 am

Re: Gaps in top layer

Fri Jan 27, 2017 8:23 am

billyd wrote:ps I typically print something like a 20mm square about 3mm high with about 20% infill and 4 layers top and bottom. I adjust my extruder steps/mm until my top surface is perfectly smooth with no gaps. I leave extrusion multiplier at 1 for all prints. Make sure you measure your filament diameter exactly and get all other information controlling plastic flow volume correct. After you do this your prints will always be perfect as long as you measure filament diameter accurately for each spool.

pss if the outer measurements of the cube are wrong your printer's x y or z steps/mm might have to be tweaked (assuming your plastic flow is perfect). It also could mean you are printing too fast or with too much acceleration.
Thanks. Here is my 20mm test cube with my multiplier set back to the default 0.9

https://goo.gl/photos/kc5ty9wxEX8xRD6R6

As you can see, the top layer isn't perfect in the top left and bottom right corners of the face. The corners also seem to be a little bit bulbous. As for the dimensions, X=20mm and Y = 19.85mm. Acceleration is down to 200mm/s

Only some of my filaments seem to under extrude, so I can I get away with just adjusting the multiplier or do I have to change the steps each time?

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