Ironing / Sanding Expectations and Best Practices

[DennisV 1]

Hi folks. I'm continuing to refine how to get the best top layer without any post print processing. I've read quite a bit about ironing / sanding, but am not seeing the results I'm expecting. I wonder if I misunderstand its purpose, or am not configuring it correctly.

 

I find that my results are actually worse when I check "Enable Ironing" in Cura. In the attached photo, the printer (Ultimaker 2+) and material (Ultimaker ABS), are the same. The key difference is Enable Ironing is selected in the bottom example. You can see circled in green, where it results in little blobs of material. I'm not seeing this when it's turned off.

 

I appreciate there is a "Me: Dr. it hurts when I do this. Dr.: So stop doing that." approach. Though I expect I'm probably just misusing the feature. Insight and suggestions appreciated. @neotko

 

[gr5 2,098]

It probably doesn't work for ABS.  The technique was created by @neotko and Ultimaker included it into Cura without consulting him (he was annoyed I think because they know him personally but didn't get clarification from him on how to do it right).  So you could google "neosanding" and get more info maybe.  Anyway I'm guessing it only works well on PLA because it has to reheat the surface and PLA only needs to get up to about 60C for this to work but ABS has to get up to about 120C for this to work and so you basically would have to move the nozzle at maybe half the speed on these ironing passes.  I'm guessing.

 

When @neotko does it himself he uses S3D (simplify 3D) and he changes a bunch of things including the speed and he also extrudes a tiny bit (something like 5% or one twentieth normal extrusion - or maybe less) although it works without any extruding also.

 

Instead since you are printing with ABS you could try sanding with sandpaper followed by acetone vapor deposition.  Get a paint can or sealable container large enough for your printed part.  Put 1 cm of acetone in the bottom and then put some kind of spacer to keep your part from touching the acetone - metal spacers are good like aluminum.  Then put the part on top of that and seal it up.  Google how long to leave your part in there - I think an hour at room temp maybe?  I think just a few minutes if you heat it - not sure.

[neotko 1,417]

1 hour ago, DennisV said:

Hi folks. I'm continuing to refine how to get the best top layer without any post print processing. I've read quite a bit about ironing / sanding, but am not seeing the results I'm expecting. I wonder if I misunderstand its purpose, or am not configuring it correctly.

 

I find that my results are actually worse when I check "Enable Ironing" in Cura. In the attached photo, the printer (Ultimaker 2+) and material (Ultimaker ABS), are the same. The key difference is Enable Ironing is selected in the bottom example. You can see circled in green, where it results in little blobs of material. I'm not seeing this when it's turned off.

 

I appreciate there is a "Me: Dr. it hurts when I do this. Dr.: So stop doing that." approach. Though I expect I'm probably just misusing the feature. Insight and suggestions appreciated. @neotko

 

 

Most probably the issue is the concetric skin pattern is messing with the order the ironing is done. Try normal typical non concetric style, it should look better, also for this kind of prints on S3D I use 1 perimeter for the last layer, it makes things cleaner, concentric for that fonts sure will look decent without ironing, but Cura 'redo' the last print on the oposite angle, and that's not compatible with a concentric style, so probably it's doing the ironing mostly on the small parts that are actually infill and making a bit of a mess for the final look

[gr5 2,098]

Good points.  Also keep in mind this is ABS.  I don't know if ironing works on ABS @neotko

[gr5 2,098]

Maybe I should instead ask:  why ABS?  Does this need to withstand high temperatures?  how high?  You might want to try PLA.  I printed the number for my house in PLA and it has done very well out doors for the last 2 years.

 

 

[neotko 1,417]

5 minutes ago, gr5 said:

Good points.  Also keep in mind this is ABS.  I don't know if ironing works on ABS @neotko

 

You think so 2D, you need to think like a slicer for this. Ironing works with abs as abs is easily sanded. Nozzle pushes residual plastic that goes beyond the -0.01 layer that was printed. The difference between doing that on A or B material are

 

a) Can be sanded?

b) Does it suffer from too much temperature? (PLA needs high sanding speed to avoid damaging the overhangs, but slow temperature increases the gloss of the finish while fast makes it more matte)

c) Can the nozzle beat the surface? Olsson ruby nozzles are specially great for this since it doesn’t suffer from being scratched against almost anything.

 

So for example neosanding Nylon problably is a bad idea (but nylon I don’t know how would behave)

 

The easiest way to know how would a surface behave neosanding it is by the common scratches we have always seen on past Cura releases (they have do a very good on the travel path planning to avoid this on most scenarios if you know what to adjust).

 

So abs? Indeed it can. Also his photos show that a) material was dragged to the center of the print area due spiral style. That’s probably the less useful print style to get sanding by the nozzle since it increases the drag on the nozzle, while zigzag style has more chances of filling the gap holes of the printed layer. 

 

This reminds me a thing. Cura sanding does actually extrude a bit. For my latest tests for 2 pass sanding it works much better to not extrude. I suppose Cura team left an option to lower the extrusion rate while ironing, that should remove the issue the user has, but the finish look won’t change much except the blob on the inside of the letters. 

[DennisV 1]

4 hours ago, neotko said:

 

Most probably the issue is the concetric skin pattern is messing with the order the ironing is done. Try normal typical non concetric style, it should look better, also for this kind of prints on S3D I use 1 perimeter for the last layer, it makes things cleaner, concentric for that fonts sure will look decent without ironing, but Cura 'redo' the last print on the oposite angle, and that's not compatible with a concentric style, so probably it's doing the ironing mostly on the small parts that are actually infill and making a bit of a mess for the final look

 

Thank you for your thoughtful reply.

1. I see a Ironing Pattern: Zig Zag option. I will try that. Do I also need to alter the Top Surface Skin Pattern? It has a Concentric, Lines, or Zig Zag option.
2. You mention "I use 1 perimeter for the last layer". Can you please clarify? I see several options for altering Top surface, which I assume is synonymous with "last layer".

I appreciate you sharing your time and expertise.

 

Edited January 18, 2018 by DennisV

[neotko 1,417]

2 minutes ago, DennisV said:

 

Thank you for your thoughtful reply.

1. I see a Ironing Pattern: Zig Zag option. I will try that. Do I also need to alter the Top Surface Skin Pattern? It has a Concentric, Lines, or Zig Zag option.
2. You mention "I use 1 perimeter for the last layer". Can you please clarify? I see several options for altering Top surface, which I assume is synonymous with "last layer".

I appreciate you sharing your time and expertise.

 

 

Nice clearly Cura team doesn’t let down

 

zigzag Indeed will improve the result for that print. Ironing flow to a lower amount than default 10% will yield better finish also specially for last toplayer if you want to keep the concentric style

 

so try a) cut ironing flow to the lowest possible 

 

or b) changing to zigzag Ironing style

[DennisV 1]

1 hour ago, gr5 said:

Maybe I should instead ask:  why ABS?  Does this need to withstand high temperatures?  how high?  

 

 

I will mount this on a car. ABS is very common for this type of application, so I'm using it for consistency. Thanks.

[gr5 2,098]

Google "acetone smoothing abs".  See if the pictures that come up interest you.

[DennisV 1]

22 hours ago, neotko said:

zigzag Indeed will improve the result for that print. Ironing flow to a lower amount than default 10% will yield better finish also specially for last toplayer if you want to keep the concentric style

 

so try a) cut ironing flow to the lowest possible 

 

or b) changing to zigzag Ironing style

 

Thanks for the continued suggestions. I did another print with the following changes:

• Ironing Pattern: Zig Zag
• Ironing Flow: 2%

The blobs of material are gone, but you can see lines matching the path of the print nozzle.

 

Definitely an improvement over the previous ironing attempt. Still not as good as good as when I turn ironing off and do Concentric Top Surface Skin Pattern. Given the success others seem to have with Ironing / Sanding, I still feel like I'm not doing something right. I'm attaching more of the settings that seem relevant, in the event someone can identify what I'm doing configuring correctly.

 

[DennisV 1]

21 hours ago, gr5 said:

Google "acetone smoothing abs".  See if the pictures that come up interest you.

 

Acetone smoothing is on my radar. For consideration of minimizing production time, and everything that goes along with handling chemicals, I'm considering it a last resort.

[gr5 2,098]

I strongly recommend you do these experiments with just a single letter.  And make it very thin - say 1mm.  No reason to print an entire part for these tests.  If you can get 10X as many tests in the same amount of time then you can learn 10X faster and get 10x more done before potentially getting discouraged.

[geert_2 557]

For acetone smoothing ABS, I have seen videos on Youtube where people put kitchen tissue paper, or an old newspaper, all over the sides of the container. Then they poured in some acetone and let it soak into the paper. And then they hung the model in this container, without touching the walls. In this way, the acetone vapour comes from everywhere around the model, not just from the bottom of the jar. This gave a much more equal distribution, and thus better smoothing result, without need to cook the acetone (thus less risk of explosion, but be carefull anyway, since acetone is more explosive than fuel).

 

Dipping ABS in acetone was not a good idea, if I remember well, since that dissolved the ABS too fast, and caused "tears" and deformation.

 

For use on a car, you need ABS indeed, or another high-temp material. PLA will deform in summer, or even in spring or autumn on a nice day. Don't ask me how I know... 

 

[DennisV 1]

I've continued my experiments. Posting here in case my trial and error might help someone else down the road. I've twiddled:

• Top Surface Pattern to Zig Zag, to match Ironing Pattern zig zag
• Ironing flow: 0%
• Top surface skin layers: 2

The blobs are not present, but continue to see ironing / sanding path lines. Best seen in the top example of the attached photo. Perhaps hard to tell, but the results are pretty much the same across them all.

 

[neotko 1,417]

6 hours ago, DennisV said:

I've continued my experiments. Posting here in case my trial and error might help someone else down the road. I've twiddled:

• Top Surface Pattern to Zig Zag, to match Ironing Pattern zig zag
• Ironing flow: 0%
• Top surface skin layers: 2

The blobs are not present, but continue to see ironing / sanding path lines. Best seen in the top example of the attached photo. Perhaps hard to tell, but the results are pretty much the same across them all.

 

 

Indeed curved paths are the hardest to get sanding correctly due pth planning. A solution could be that Cura team makes an ironing planner (complex I assume) that forces one direction sanding. I force this on s3d using horizontal expansion for the process but it has downsides, ofc filing by hand the edges is worth for me since I mostly use this to presand the object and make the realword sanding easier faster and with a cleaner look (and specially faster)

[DennisV 1]

I have made some good progress, through trial and error of applying what I've read elsewhere and advise from @neotko above. My best result so far appears to have come from a combination of:

1. Reduce Ironing Flow to 2%
2. Increase Ironing Speed to 90 mm/s
3. Increase Infill Density to 50%

Counterintuitively, setting Enable Gradual Infill was a little bit worse than the above. I would have thought the settings that come with Gradual Infill (even higher Infill Density of 90% and Gradual Infill Steps 5), would have been better than uniform Infill Density of 50%.

 

I'm not sure where to go from here, other than to push the values of these settings a bit further. Maybe this is as good as it gets?

 

[neotko 1,417]

Probably that’s as good as it gets atm in cura yea

 

For surfaces where the area can’t be sanded in one direction alone its hard to get more uniform look. 

 

Check this test I did on s3d.

 

 

I forced the sanding layer so it did go beyond the print area, this way the slicer does a uniformly sanded direction. Ofc is just a test on greentec, I been doing more progress and with 2 pass sanding it looks better