A New 3D Printed Lamp

Several years ago I made a 3D printed lamp for my son using guts from a WIFI controlled RGB LED bulb. The lamp had a large 3D printed fractal vase. He recently reported that the electronics had failed and asked if I'd make him another lamp. Sure!

I designed a new vase using a 3rd order Julia set with swept parameters. About 600 fractal images were generated using ChaosPro. The images were imported into ImageJ where they were stacked and converted to a solid and exported as an STL file. I sliced it using Cura's vase mode (did they ever fix vase mode in Prusa Slicer?) and printed it on UMMD. The top and bottom of the vase are the exact same tri-lobe shape, but rotated 60 degrees. At the middle layer the outline of the vase is almost a perfect circle. The vase has a very interesting surface texture that results from the limited resolution of the math used to generate the fractal shapes.

The new vase is 638 mm tall, printed in about 13 hours using 930 g of Keene Village Plastic's Edge Glow Glass PETG filament with 1 mm walls, and 0.25 mm layer thickness.

The Edge Glow Glass filament is a transparent filament with some "bluing" added to make it look like glass under normal lighting conditions. But if you light it with blue light, the material fluoresces a very cool looking pale blue color.

This is what it looks like in daylight. The bluish color that makes it look like glass comes from some dye that's added to the filament. 

In the original lamp, I took apart a normal shaped LED bulb so I could put the LEDs as close to the bottom of the vase as possible. That required making a very odd shaped heat sink to mount the LEDs on. Since I made that first lamp for my son, LED bulbs have become cheaper, much more widely available, and in many different configurations. For the new lamp, I used a WIFI controlled GX-53 RGBW LED bulb and didn't need to take it apart as it is pretty flat and sits very close to the bottom of the vase. I just bought a socket for the bulb and installed it. 

The only way to get "white" light from the old lamp was to turn on all the R,G, and B LEDs and the color temperature that resulted wasn't very nice. You could tweak it a little by adjusting the relative brightness of the LED colors, but it never produced a pleasing white light. The new bulb is an RGBW type that includes warm and cool white LEDs and the control app allows you to set the color temperature anywhere between a warm yellowish light to a cool bluish white. 

I like to set the bulb to a purple color. That turns on red and blue LEDs. The blue light makes the vase fluoresce the beautiful pale blue color and the red light shines through and looks pink through the glowing blue vase. It's a very nice effect that's not fully captured by the camera. The blue light also makes nearby fluorescent objects glow nicely, too.

The new lamp, set to purple light, making its own vase glow blue and the one next to it glow green. There are no glass pebbles in the bottom of the vase in this photo.

Wiring couldn't be simpler. I drilled a hole in the side of the vase near the bottom, fed in an 18 gauge line cord, split the end of the cord and tied it in a knot so it couldn't pull out of the lamp, stripped the ends of the wires, and soldered them to the wires from the lamp socket, then used shrink tubing to cover the solder joints. Finally, I put some hot-melt glue on the bottom of the lamp socket and mounted it in the bottom of the vase. Done!

The vase is large, tall, and relatively light weight so it can be moved or knocked over pretty easily. I added a few lbs of glass pebbles to the bottom of the vase to help keep it stable. I haven't decided if I'm going to epoxy them in or just leave them loose.

Surface texture results from the low resolution math that generates the fractal shapes that get stacked to make the vase. The print came out with a very shiny surface- like glass.

A look into the lamp- the wiring is as simple as can be. The GX-53 socket is hot-melt glued to the bottom of the vase. Wires are soldered and covered with shrink tubing. There's an on/off switch on the power cord, but it's mostly used to put the light bulb into pairing mode. Once paired, you can program schedules and control colors, brightness, and on/off with the phone app.

The nice thing about this lamp, unlike the original, is that if the bulb ever fails the dead one can be easily replaced - assuming they are still available. GX-53 bulbs are commonly used for under-cabinet lighting, so I think they'll be around for a while.

I added some rubber "feet" to the bottom of the vase to make it less likely to slide if bumped. These feet are some soft silicone material that is sticky on one side but not the other. The stickiness comes from the plastic, not an adhesive, and they don't leave any residue if you peel them off. They also don't seem to damage the finish on furniture. If they get dirty and "unsticky", just wash them off and they're sticky again.

Rubber feet on the bottom of the lamp.

A Stand for the SVS 3000 Micro Subwoofer

I recently got an SVS 3000 Micro subwoofer to add some low bass to my stereo system. It's amazing what 265 mm cube box can do. It's available in shiny "piano" white or black finish. I went with white so it wouldn't show cat hair.

Ms. Kitty's fur gets everywhere, so I have a robot vacuum cleaner that scoots around and cleans most of it up between vacuuming jobs with a real vacuum cleaner. I didn't like the idea of the robot vacuum cleaner bumping into the subwoofer over and over (or even once), so I decided to make a small stand for it. I measured the vacuum cleaner and found that 100 mm of lift was all the sub needed.

I made a CAD model of the sub for this project and maybe others in the future, then designed the stand. The sub's feet are set at the corners of a 196 mm square.

This is a CAD rendering of the sub sitting on the stand. This is how I often make CAD drawings- just enough detail so see what I need and to design 3D printed parts like the end caps for the verticals. Eight 1/4-20 button head cap screws hold the whole thing together.

I dug out some left over 1" t-slot aluminum and took it to the makerspace and cut and milled it to size (4x 170.6mm and 4x 100 mm), then drilled some tool access holes and threaded the center holes with a 1/4-20 tap. Finally, adding some 3D printed TPU end caps for the vertical t-slot pieces prevent the sharp edges of the t-slot from damaging the sub's feet or the floor.

Printing end caps on UMMD using white TPU to match the sub. With the 1 mm nozzle printing in 0.5mm layers, prints are a little sloppy but finish in about 20 minutes. A diagonal cutter quickly cleans off the blebs and hairs.

I assembled the pieces on a granite counter top that is pretty flat and everything came out square and very solid. The TPU end caps fit tightly and stay put without any screws or glue.

The sub on the stand. Vertical t-slot pieces are 100 mm long and horizontal pieces are 170.6 mm long. I used white TPU to print jam-fit end caps for the verticals.

Now it's safe from the robot vacuum cleaner!

Update 8/3/24: I forgot that I had ordered some screw-in rubber feet for this project and they were delivered today. I installed them and now the sub sits just a little higher off the floor. The screw -in feet are nice because the floors in the old building I live in are neither flat nor level, so now I can make adjustments as needed.

It's hard to see them, but they are there- black rubber screw-in feet. They have 1/4-20 threads and I tapped the frame parts before I assembled them, so they were ready for the feet.

Disco Shroom!

 A friend gave me a mirrored mushroom that threw many light beams when hit by the morning sun streaming through my east window. Nothing exceeds like excess, so I looked around and found a small, 4 rpm turntable powered by a USB dongle. I didn't want any wires for Ms. Kitty to chew on, so I also ordered a couple 5V solar cells to connect to it with the shortest possible cable. 

The Disco Shroom. Pen for scale (I didn't have a banana...)

I designed a base to hold both the solar cell and the turntable with wires hidden so Ms. Kitty can't chew on them. You can see it all below.

CAD render of the base for the disco shroom. The solar cell is mounted at about 45 degrees and wires feed through the tunnel that connects the hollows in the print. The whole thing sits 75mm above the window sill so the window frame doesn't cast a shadow on either the solar cell or the disco shroom.

Printing the base on UMMD. I printed with 1 mm nozzle, 2 mm walls, and 15% triangle infill. It took about 18 hours to finish the print and used 1200 g of PETG filament.

The finished print.

Wires stripped, twisted, and soldered to the solar cell. I put some hot melt glue over the solder points to protect them- probably not necessary.

Double sided foam tape (red) used to hold the solar cell in place.

Wires are fed through the tunnel to the turntable mounting position.

The Turntable opened. The table (right) is mounted using a single screw through the center.

Be careful when you open up the turntable. There are five little wheels/bearings that can fall out of the base and get lost if you're not paying attention.

This is probably the most expensive part in the turntable- a 6003RS bearing!

Cut the battery leads from the terminals, strip, and solder them to the solar cell leads. I put heat shrink tubing on them to prevent shorts and used a screw to hold the wires down inside the base.

Underside of the turntable base. I threw away the battery cover and ran the wires from the solar cell into the turntable base through the battery cover latch hole.

Completed assembly, ready to go on the window sill.

Another view of the completed assembly.

Yet another view of the completed assembly.

Video here

More video here.

CoreXY X-Axis Wobble Revisited

A while back I noticed that the X axis would wobble a bit when the magnet in the Arrakis sand table was moving only in the X direction. This got me thinking the same could be happening in UMMD, my corexy 3D printer. I mounted a gauge on the Y axis rails and measured the movement of the ends of the X axis and found slight wobble with a period of 40 mm which I attributed to a a poorly drilled 20 tooth pulley on one of the motors:

One of the results when the cheapo pulleys were used in the printer. Note the 40mm period of the "waves" corresponding to one full rotation of the 20 tooth drive pulleys.

I could see the belt wobble slightly as it went on/came off the A motor (left side) pulley, implying a poorly drilled hole in the pulley. Poorly drilled means either not centered, not aligned with the axis of the pulley, or too large. Any of those conditions could cause some wobble. A poorly drilled pulley acts like a cam and as it turns, it slightly modulates the belt tension. The belt tension modulation causes the X axis to wobble relative to the Y axis.

At the time I built UMMD, Gates belts and pulleys were only sold through industrial distributers who had large minimum purchase requirements. IRIC, I had to buy 50' of belt to meet the minimum sale requirement. I ordered pulleys via Ali-Express or bought them from other sources, definitely not Gates-made parts. 

Recently, someone on a forum mentioned that Filastruder sells genuine Gates pulleys. I decided to order some to see if they were better than the cheapo stuff I used. The pulleys I ordered arrived in about a week. The packaging is unmarked and there are no Gates logos on anything, so I was a little skeptical and a little disappointed. I decided to install the pulleys on the printer and see if they were any better than the cheapo Ali-Express pulleys that I've been using.

I pulled the old pulleys off the motors and compared them to the new Gates pulleys- the new pulleys had thicker flanges, and the finish on the teeth was visibly smoother. Then I tried them on the motor shafts. Wow! Big difference- they fit very closely on the shafts, unlike the originals that fit loosely. I had to lightly sand one motor shaft to get the new pulley to fit (old pulley set screw galled the shaft, or maybe a little hardened lock-tite caused interference).

Chinese pulley on the left, Gates pulley on the right (I didn't take a picture of the 9mm long Gates pulley before I mounted it on the printer). Note the thicker flange at the top of the Gates pulley and the thicker base where the set-screws go in. It's hard to tell from the picture but the Gates pulley tooth finish is better than the Chinese pulley (though the Chinese pulley has been in use for several years, so maybe not a valid comparison). My caliper says the Chinese pulley has a 4.97mm hole diameter, the Gates pulley reads 4.95mm.

Next I installed the digital gauge and reran the test file with one modification- I ran it at Y=5 and Y=-3 instead of Y=5 and Y=-35. With the old pulley, I could see visible run-out as the pulley rotated. There wasn't any visible runout with the Gates pulleys. 

Gauge mounted on the right side Y axis rail to measure deflection of the end of the X axis as the extruder carriage moves along the X axis. After running tests on the right end, I ran the same tests on the left end of the X axis.

Here are the results of the test with the new pulleys mounted on the motors:

Interesting results here. There is relatively large wobble of the left end of the X axis (attached to the left side Y axis bearing block), but it no longer has the 40mm periodicity that was evident using the original pulleys. 

The right side looks a lot better, with almost no deflection except for when the extruder carriage is at the far right side of the bed (at X=140 and X=145mm). I would attribute that deflection to an error in the position of the pulleys on the right side Y axis bearing block or the belt clamp on the right side of the extruder carriage that is causing the belt to go out of parallel with the X axis rail.

I don't know how to account for the greater variability measured on the left side of the X axis compared to the right side. I'm going to have to think about that for a while. If you have any ideas, post them in the comments below.

Does it matter? It's hard to say. I never saw any print quality problems I could attribute to the old pulleys, but maybe it's because I never looked for it. There are many potential sources of error in the mechanism that could lead to print quality problems. Using quality pulleys eliminates one of them. The Gates pulleys from Filastruder cost about $5 each, so using them isn't going to break anyone's budget. In future projects I'll use Gates pulleys. Filastruder also sells Gates belts in 100mm increments.

Note: I bought the pulleys myself and received no compensation for this test/post from Gates, Filastruder, or anyone else.

The data and graphs are here.