Wednesday, July 1, 2020

YAFL: Yet Another Fractal Lamp

My brother, the distiller, built a bar in his living room, and I thought that he might like a bar-worthy lamp for it, so I got busy.

I recently bought a couple 5 lb spools of transparent PETG filament (edge glow glass from Keene Village Plastics) that has some bluing in it to make it look like the glass that old Coke bottles were made from- I thought it would be great for a lamp shade, especially for colored lights because the bluing in the filament emits a beautiful, pale blue fluorescence. I've used PETG filament before, but this is the best I've used. It printed without a lot of hairs or charred blobs ending up all over the prints. I will be buying more. I suspect that all the "edge glow" colors they sell are fluorescent.

In a single wall, the stuff really does look like glass:

I searched through my collection of fractal based designs and settled on one I had previously used. I made some changes to make it more printable and for esthetic purposes, and sliced it for the new filament.

The print failed twice with the controller complaining of a heater fault. The first time I thought it might be because of a power outage (that's not a heater fault, is it?) due to a local thunderstorm, so I examined the printer and restarted the print. It got to about 23 hours and failed again. I took the cover off the printer so I could access the controller board and found that the screw terminals on the PT1000 interface board were stripped and had let the pressure off the wire enough to make the connection intermittent. 

The nice thing about prints like this is that even the failures can be useful, and no one knows they're failures if you don't tell them!

I replaced the cable and switched to the other PT1000 input on the interface board, then restarted the print. It made it all the way this time- 564.5 mm. It used 759 g of filament.  I printed it with a 0.4mm nozzle at 50 mm/sec, 3 perimeters, 0.25 mm layers. Total print time was 36 hours, 13 minutes and 57 seconds. Print time was included about 2 seconds per layer in order to make the layer synchronized time lapse video. 564.5 mm x 4 layer/mm x 2 sec/layer = 4516 sec = 75.27 minutes.

The camera had a problem when shooting the photo sequence that would become a layer synchronized time lapse movie. Even though I locked white balance, focus, and exposure, the brightness of the images varied a lot resulting in some really annoying flickering in the video. This only seems to happen when the print is lit by UV. I couldn't see any brightness variation or flickering of the light in the printer, so I checked the EXIF data of some of the brighter and darker images and found that the camera was varying the ISO value. Maybe a bug in Open Camera? I also found that the Mooni button suddenly isn't reliably working with the camera. Sometimes it triggers the camera and sometimes it tries to change the speaker volume setting. Hmmm. More problems to solve...

Here are some still photos shot while the print was running and almost finished:

This lamp has a round base, printed with black PETG. Unfortunately, the filament pigmentation wasn't consistent so parts of the print look lighter than the deep black color it started with. I used concentric top solid infill that makes the base look like a stack of vinyl records.

The light source is the same type Feit Electric 1600 Lumen, multicolor, wifi controlled LED bulb that I used in the last lamp, treated the same way- the two PCBs were separated and laid flat. The LED board is clamped to the top of the base by three screws that go through the heatsink plate inside the base. Yeah, I know it isn't going to be very good at dissipating heat that way, but the original heatsink was smaller and covered with plastic, so how warm is it going to get?

Pink/purple light, which is a combo of light from red and and blue LEDs, looks particularly nice. The bright center of the lamp looks pink while the rest of the shade fluoresces a pale blue color because of the blue LEDs. This photo doesn't quite do it justice:


Leave comments or a questions here and I'll try to post a response as soon as I can.