Printing cylindrical shapes

[zews 1]

This is my first post. I have only had my Ultimaker 2 a couple of days.

I needed to print a part that contained a cylinder. The part needed to be printed with the cylindrical part laying flat on the bed, and the rest of the part with supports (I haven't figured out yet how to print support that remove cleanly) When I printed the part, the side that touched the bed, was not round as I wanted, but had a flat spot along the length of the cylinder. The same thing happened this evening when I printed another cylindrical part laying flat on the bed. Instead of following the curve of the cylinder, the section in contact with the bed was flat. I printed that second cylinder again, but now vertically. That cylinder came out much better, not flat area along the length of the cylinder. Unfortunately I cannot always print parts situated on the bed like that that.

I am working on a prototype of a bracelet with which I will have the same issue. The bracelet is a bangle type bracelet in the rough shape of a large thick O-ring. Obviously this part will have to be printed laying down flat on the bed. How do I avoid the same flat section from happening with rounded shapes like that?

I wonder if it is possible to upload images to illustrate what I am trying to say.

 

[anon4321 16]

I believe that will always be the case when you have a cylinder on it's side.

The first issue is that I believe Cura slices the bottom layer differently using a thicker slice based on the first layer setting.

See page 23 here: https://www.ultimaker.com/spree/uploads/38/original/Cura_User-Manual_v1.0.pdf

I'm sure your first thought would be to reduce that value but the value is chosen to help with the second part of your problem which is bed leveling and distance to nozzle. In order to use a smaller first layer value, you would need to precisely adjust the level of the bed and it's distance to the nozzle. This is almost impossible to do down below .2mm

Here are two suggestions that might help. Print the object on a raft. See page 27 at the link above. Or use MeshMixer to levitate the part about 2-3mm and then use it to add support under the part. See

 

[yellowshark 153]

Hi guys, I wish someone could come on the forum and say this how you do it, never seen it and have never been able to figure out how to crack this one. I do not think the problem is layers, although they might contribute. My mind sees it as the nozzle width, i.e. your first layer will always be at least 0.4mm wide (assuming that is your nozzle width). Also the first few layers will have a serious overhang.

The problem with support/raft is that unless you can dual extrude a soluble support material, you will need a lot of post print sanding etc. to get back a perfect finish. If you really have to do this then I would suggest – go slow i.e. 20mm/s max; turn on cooling 100% after layer 1. This may help but after my first attempt I have subsequently only printed cylinders vertically, so cannot be sure. Maybe you can break the part into subparts, print the cylinder vertically and then stick the subparts together?

 

[illuminarti 18]

I think a picture would help. Here are the instructions for picture posting:

http://umforum.ultimaker.com/index.php?/topic/4525-how-to-upload-an-image-to-the-forum/

However, it's an inherent limitation of this type of technology; the print is built up in layers off a base platform. You can't have an infinitely small contact area with the platform; indeed you need quite a large contact area to get the print to stay stuck down during printing.

Printing off a raft or support might help. Finding ways to orient the part differently and/or assembled it from multiple prints is probably a more viable option. In any case, some amount of post-print finishing/clean-up work is going to be necessary.

 

[skint 61]

This may prove to be a good simple example for the " monthly challenge " thread.

 

[zews 1]

I believe that will always be the case when you have a cylinder on it's side.

The first issue is that I believe Cura slices the bottom layer differently using a thicker slice based on the first layer setting.

See page 23 here: https://www.ultimaker.com/spree/uploads/38/original/Cura_User-Manual_v1.0.pdf

I'm sure your first thought would be to reduce that value but the value is chosen to help with the second part of your problem which is bed leveling and distance to nozzle. In order to use a smaller first layer value, you would need to precisely adjust the level of the bed and it's distance to the nozzle. This is almost impossible to do down below .2mm

Here are two suggestions that might help. Print the object on a raft. See page 27 at the link above. Or use MeshMixer to levitate the part about 2-3mm and then use it to add support under the part. See

 

 

Page 23 of the Cura manual deals with uploading models to YouMagine.com

I will try printing with a raft.

I had seen the video you mention, and tried to lift the part to put us ports under it. This did not work on my computer. When I try to make any changes to any of the parameters in the Support Generator of try to lift the part (Y-offset), asll I see is "Sampling .. ", or "Sampling surface ... ", but nothing happens. The program either crashes or I have to Force Quit out of it.

When I tried to do this again in MeshMixer a couple of hours ago, the same thing happened, and in a new way. When I saw the "Sampling ... " window again I decided to wait a long time. Finally I saw a progress bar. It took forever for the bar to move until finally, ... my computer crashed to a black screen. The only way I was able to get out of this was to reboot. BTW, I am running Mac OSX 10.7.5 on an iMac with 6 GB of RAM