consistent diameter

[951Michael]

Hello,

If I want a very accurate diameter circle, what settings in the slicer should I be changing. I keep on getting small bumps in the circle that mess with the diameter.

Thanks

[951Michael]

I should mention that the bumps are not too bad; I just need a very accurate circle. So I think everything is operating as it should. I just am not sure what would be the best settings in the slicer to try in order to improve.

Thanks

[Garyg]

Hi

I’m thinking that maybe the STL file and original drawing may be creating your small bumps in the circle.

What software are you using to make up your original drawings?

If you are picking files from Thingiverse, usually I find they need some help to clean them up.

gg

[951Michael]

Hello gg,

I appreciate the reply. I am using sketchup. Basically I just make 2d circles in a rectangle and then push/pull the surface up to create a 3d surface, very basic. The only thing that can think of is to change the settings in the slicer.

Thanks,

Mike

[Garyg]

Hi again

I also use Sketchup and I think I’m understanding your problem.

You really cannot fix incorrect stl files in a slicer.

You can only fix problems like holes in the stl file.

–

Your source file from Sketchup, I believe is your problem.

Sketchup does not make true circles.

Sketchup makes polygons that have the circle transcribed about the outside of the polygon.

You can change the polygon count of circles in Sketchup.

I’m not sure if this works in all versions of Sketchup, but it does work in SketchupPro 2014 thru 2016

When you select the circle tool, take a look at the lower right hand side of your screen.

There, It will say how many facets the circle will be built from.

The default is 24 facets.

You can change that.

If I need a circle that looks round when the diameters are greater than about 2 inches, I usually us a 60 facet count, Sometimes 80.

That definitely improves the 3D printed output.

…

When I export a model I’ve designed in Sketchup to STL, I always reload the STL back into Sketchup and check it with

Solid Inspector plug in to be sure there are no reversed faces or holes in the STL.

I hope this helps you in some manner

gg

[Asad3D]

Hey @951Michael, what kind of printer are you using?

[951Michael]

I appreciate the replies everyone,

I am using a fusion f400. Slicer is simplify3d. Yeah, I have tried going all the way up to 144 sides to have a smooth curves surface. Maybe I am overdoing it though. I am thinking that the slicer has the settings. I did decrease the mill thickness in the slicer and that did help some. There are so many settings in the slicer; I feel like I am in a maze.

thanks,

Mike

[Garyg]

Hi again

I realize you are attempting to resolve an issue you are having.

Is your goal to have a circular part that is visually perfect?

Is your goal to have a circular part fit into something well?

I’ve used several 3D Hubs people and I now have a TAZ printer.

My fit issue is always the same.

I think that the stl is the path that the toolhead takes.

The extruder width is divided between outside and inside of the noodle of plastic made by the extruder.

My parts always come out slightly larger than my drawing

My bores always come out slightly smaller than my drawing.

I leave the outside dimensions however they are.

I always make my bore dimensions larger by about 0.020 to 0.025" larger than

what I want.

When I look at the drawings, things look like they have too much clearance.

When printed, the parts fit good.

Very tight fit is 0.020" oversize

Slip fit I usually make to 0.025 oversize.

…

Just trying to be helpful

gg

[Perry_1]

Simplify3d has a problem with internal circles. You can read it all over their forums.

The issue is they do not compensate for the fact that internal spaces - squish inward when printed.

Think of it like this- if you know what a pool noodle is. (those long foam tubes people/kids play with in their pools)- if you take the pool noodle and form a circle, it will be wrinkled inside, because there is no place for the foam to go.

The same thing happens when you take circles and print them. The outside is stretched, the inside is squished.

It is something many have complained on the s3d forums about, but it has not been resolved in their slicer. So you need to compensate in your design.

[951Michael]

I have no idea how I can compensate on my design. Where do I even start?

Or maybe I should just get another slicer? This is very disappointing

thanks

[Garyg]

Hi

I believe you missed one of my posts.

Please look back thru the entire message thread.

I did not realize that entering my posts on the main box would

get my posts out of order.

Let me know if my previous post helped you in some manner.

gg

[951Michael]

Hello Gary,

Yes, you are right. I did miss your post. It does help. And I suppose my main concern is fit. I believe I will experiment some and get back to you if I find out anything more. Perhaps at a 6.25mm radius hole it gets harder for the tool head because it is a tighter radius.

Thanks,

Mike

[951Michael]

Hello,

I wanted to update this thread to let everyone know that I solved my problem. Interesting enough there were TOO many facets in the circle for its small size. I guess you can have too many. I new that the default was 24 so I increased it to 144, simply because I figured the more the merrier. For a 6mm radius circle and for my particular application I found that the best amount of sides was only 12 sides.

Mike

[951Michael]

I was going to update this forum with the solution to this problem but forgot to. Apparently the circle that I had had too many sides to it that caused problems. So if you have a problem like this just reduce the amount of sides. I had 144 sides; but for a small hole like that 12 sides works good.

Also, I purchased a fusion f400 printer and they were the ones that helped me out on this one. So yeah, they do have good customer service over there.