Good morning. I am a new to 3D and having a frustrating time printing a gear that has an inner recessed floor.
I’ve tried printing it with the gear laying flat and standing up.
When flat, the first few layers of the middle sink because there’s nothing under it.
When printed upright, it get’s 3/4 of the way to the top when the printhead knocks it loose from the bed. Also the bottom is flat and not truly round.
Any tips on how to print this?
Things I’ve tried:
- printing Normal Quality for slower work speed
- increasing the Build Plate Temp to 65
- printing part flat and upright
Thanks!
Jaime
I just discovered the Support section Luban, which is probably what I need to use.
I’ll turn that on and see if I can get a successful print.
I see that the front of the gear is hollow. Is the back also hollow? If the back is flat, I would rotate it around the X axis to put the flat back on the build plate. Then you should be able to print without supports.
If the back is hollow, you’re going to need those supports. The supports do mar the surface, so I wouldn’t suggest printing in the orientation you’re displaying above. It would affect the gear’s teeth, and that’s usually bad for gears. I would still rotate it so it’s flat, and use Support: Touching Buildplate. The inner flat surface of the gear can generally handle more imperfections that the teeth. Depending on your tolerances, you may may need to sand the surface were the supports touched.
You didn’t include the size of the gear, but I’m assuming the diameter is more than 25mm. If it’s about that size, you might try printing flat and faster. I did a few bridging tests when I first started, and it does a better job bridging distances without support when the print head covers the distance more quickly. Unfortunately, there’s not a separate setting for Bridging Speed. The software does recognize that it’s doing something different, because it behaves differently when bridging gaps. If you want to target just the speed for bridging, you might try increasing the inner wall speed. That’s just a guess, but that seems the most likely to control the speed it uses when bridging.
Regarding printing upright, and the print head knocking the piece over. That can happen with parts that are tall and narrow. You can improve build plate adhesion by changing the Adhesion config (just above the Support section). I generally have good luck with brim, but raft offers the best adhesion, even though it affects the surface finish more. You can get an idea of the difference between the two by generating the GCode without actually printing. Pay attention to the print time, the amount of filament used, and look at the first few layers. I don’t think you’ll need either option for this particular print, but it’s good to know for future prints.
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I would go with printing flat using supports.
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Thanks for the responses! I was able to print laying it flat and using supports, although after removing the support, I found the bottom is not smooth.
Is this just how it works out?
Support side
Normal side
Yes there is probably no other way. You can sand the rough surfaces a little to get a smoother surface again.
You can try to clean up the support contact points with an exacto knife or sand paper. The knife will probably be difficult to get inside though. I think I’d try a strip of sandpaper laid over the end of a pencil eraser. That should let you get some sanding done without too much effort.
Depending on your strength requirements, you might be able to slice it it half. That will give you two pieces, each with a flat back. Print them both on the flat side without supports, then super glue them together.
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Alternatively, you could try to play with your bridging settings to improve the print quality of the section that is supported, to do this you will need to set up Cura or another 3rd party slicer.
I would only suggest you do this after getting more familiar with customising your print settings.
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I had thought about printing the gear in halves, but wasn’t sure how you do that.
Is that something you can do within Luban or do I need a CAD program? This gear is one of 55 parts that I downloaded from an author, so I don’t have the original design; only the SDL files.
If the part is symetric you should be able to use the Windows 3D Builder to cut off one half of the part and print it twice.
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Fantastic! I was able to use 3D Builder to split the object.
Thanks!
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With Cura, its a good idea to use at least a brim to make that object stick. On 3Dlac, for me.
Stable support is a must, best with 1-2 solid millimeters on top so the part gets a smooth surface. One has to carefully adjust the vertical gap between support and part, so the comes off from its support easily. 0.15 to 0.2 mm were fine for me. But that depends on the material. I’ve been printing small (M1/32T) gear in ABS with good results. Thin walls require 50% and up infill.
