Higher definition, higher warp?

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sTaLa
Posts: 43
Joined: Tue Jun 14, 2016 3:01 am

Higher definition, higher warp?

Post by sTaLa » Sun Jun 26, 2016 5:18 am

Hello,

I just began using my M2 Rev.E. After printing the bracelet, my first project is the Gear Cube available on thingyverse. I figured since it has a lot of similar parts, I would be able to print each one of them separately and play with S3D's setting in order to learn.

I had to use a large Brim in order to avoid having all the points of the splines warping from the bed. It worked beautifully at first and was done at 0.200 mm layer.

I did the second print using a 0.100 mm layer. While I can see the higher resolution on the edge of the part, it seems all the points of the splines had issues during the print (attached pictures show the difference). What I think is that the layer is so thin on that point of the spline, that it is unable to stay stick on the underneath layer. The nozzle, going pretty fast, kind of resets the warped points every it passes over them; thus giving me that bad result on those splines.

Is there a way to print those splines using a high resolution?
Thanks,
Attachments
2016-06-25 23.41.48.jpg
Second part at 0.100 mm
2016-06-25 23.41.24.jpg
First part at 0.200 mm

Slipshine
Posts: 182
Joined: Sun Apr 13, 2014 3:02 am

Re: Higher definition, higher warp?

Post by Slipshine » Sun Jun 26, 2016 4:30 pm

1. The thinner you print the less tolerant overhangs will be.

2. On your first layer settings when printing at .100
Set your first layer height to 200%.

That being said you can try printing at a slightly lower temp it will help some.

.100 is a bit tricky. You may want to try at .150 layer height . Its quite a bit easier to dial in and the quality difference is negligible. Then if you still want to try .100 go for it.

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Jules
Posts: 3144
Joined: Wed Jan 21, 2015 1:36 am

Re: Higher definition, higher warp?

Post by Jules » Sun Jun 26, 2016 4:32 pm

Short answer is....you need a 0.25 mm nozzle to do it right.

There are a couple of rules that hold true when 3D printing, no matter what layer height you are using.

1. You want to keep the layer height at roughly half of the filament width. That is so you will have the correct extruded shape on the filament that provides proper bonding between layers and threads.

When you printed the first time, with the layer height at 0.2 mm, I'm betting that the filament width was 0.4 mm. So that ratio was maintained. When you switched to 0.1 mm layer height, did you reduce the width on the extruded thread? If you did not, then you were over extruding, and the smeared filament will glob up on the outside edges, which is exactly what you see there. It's got to go somewhere.

2. Unfortunately, the second rule prevents you from getting a perfect 0.1 mm layer height with a 0.35 mm nozzle.

The second rule says that in order to correctly place the thread, the extruded width must be larger than the hole size of the nozzle, and less than the OD of the flat surface on the nozzle.

For a 0.35 mm nozzle, you want to choose an extruded thread width in the 0.36 mm - 0.50 mm range, in order to get control over placement. So the lowest layer height that you can get a perfect print with using a 0.35 mm nozzle is 0.36 mm /2 = 0.18 mm

So you're limited by how fine you can go with that nozzle. Any layer height smaller than about 0.18 mm requires a 0.25 mm nozzle.

That's not to say that it can't be done physically. But the results are going to look like your print. If you want to fix it, you need a smaller orifice on the nozzle. :)

sTaLa
Posts: 43
Joined: Tue Jun 14, 2016 3:01 am

Re: Higher definition, higher warp?

Post by sTaLa » Mon Jun 27, 2016 4:22 am

Thanks for those answers!

I made sure my first layer was at least 0.250 mm in both cases by increasing the percentage for the percentage.
I did not reduce the extrusion width though.

The point about the nozzle tip makes sense physically. I was going according to what I understood from the Beginner Guide for the Rev.E. I thought that, since 0.35/0.1 = 3.5 which is greater than 1.8, I was fine. So I did not look into that.

I guess I'll fine tune my skills with the 0.35 mm nozzle and might order a smaller one at some point.
Thanks again!

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