For a recent project I needed to make helical threads which would allow multiple parts to be screwed together. After completing this I thought I could adapt the thread-making technique to the design of an LED desk lamp. I have made many LED lamps of different types and shapes, but they all had solid sides and I thought one with helical open & closed sides would look interesting.  Here is the design  came up with (this image is a 3D rendering from Rhino3D):

I realized this would be a difficult print to make because of the inherent overhangs cause by the helical geometry, so before attempting a complete print I made a short test:

This looked pretty bad so I posted my results on the Facebook 3D Printer group and got some helpful feedback.

The best advice was to reduce both print speed and layer height. (My normal settings are 100 mm/sec and 0.200 mm.) So I tried a new test with 50 mm/sec and 0.100 mm and got this:

Clearly this was not a good solution, plus it had the problem of quadrupling the estimated print time to around 40 hours. Even with good results I didn’t think many people would want to make a 40 hour print.

Someone suggested increasing the pitch of the helix in order to reduce the size of the individual  layer overhangs. Doing this did accomplish that, but it also increased the space between each helix. So I added more helixes to make the spaces thinner. My final design looks like this:

Here is a rotatable 3D view of the lamp:

[canvasio3D width=”500″ height=”500″ border=”2″ borderCol=”#F6F6F6″ shine=”1″ backCol=”#000000″  mouse=”on” objPath=”threadlight1” objScale=”0.43″ objColor=”#fc9400″ lightSet=”1″ reflection=”on” refVal=”2″ ambient=”#888888″]  Help=”off”] [/canvasio3D]

You can download the STL file by clicking this link.

Once again I made a test print, this time using a layer height of 0.140 mm and a print speed of 100 mm/sec. I figured this would be a pretty good compromise that would yield reasonable results and a manageable total print time.  Here’s the result of this test:

I felt this was good enough to make a real print, so I used these settings and the print completed in just under 36 hours:

Here are 3 images of the final print, the first with the LED off, second with LED on, and a close-up of the helixes and intervening spaces:

If you want to print this part yourself you might get better results with the recommended 0.100 layer height and 50 mm/sec print speed.

Last Update: 03 Sep 2017