I repaired the Budaschnozzle hot-end over the weekend and bolted the SnakeBite extruder to it and then to MegaMax and tested it last night. There’s plenty of tuning to do, but the first print looks promising:
After building the box for MegaMax I decided to try a big print. The blue 3 face cup is 130mm tall and took a little over 15 hours to print. No delamination! It’s a miracle the extruder kept working!
Well, OK, not the whole enclosure, just the parts that hold it together.
MegaMax can print big stuff but he’s had problems with large prints delaminating. The answer seems to be enclosing the printer to keep the prints warm while printing. I designed this box and 3D printable parts to hold it together so that I can take the box apart easily to work on MegaMax or move him to other locations and put it back together when I’m done. The box is 38″ D x 28″ H x 32″ W.
The box is made of 1″ PIR foam with corners suitably notched to accommodate the printed parts. MegaMax has a 450 Watt heater in the printbed so the box gets super-toasty inside. I suspect it gets a little too toasty but haven’t made any measurements yet. I’ll soon be moving the electronics out of the box. I didn’t do anything to seal the seams in the box because it doesn’t seem to be necessary. I did tape the edges of some of the foam boards with clear packing tape to prevent damage.
Design and stl files are available at http://www.thingiverse.com/thing:269586
When I recently was at the thrift store and saw a pair of ice skates next to a kick-scooter, it got my mind going. “What would a scooter look like with skates in place of wheels!?”
The next time I was at the Makerspace, I saw my old electric scooter over on the Hack Rack. This was a scooter I originally rescued from a dumpster. Although it didn’t have batteries, just adding power and a little tinkering got it up and running again. A few of the EV Club and PowerWheels Racing guys played around with the scooter a bit, but eventually the controller got toasted, and who knows what happened to the front wheel.
Oh well, I’d be replacing that front wheel with an ice skate anyways.
Turns out that the heel of an ice skate is actually sturdy enough to drill right through and use as a mounting point. I simply drilled through the skate, inserted a spacer, and then ran a 3/8″ bolt through the skate and the front fork of the scooter. I finished it off with a couple of washers and a nut.
Then next thing to fix was to get the motor going again. Turns out that it’s a brushless motor. While I have a fair amount of experience now with BRUSHED motors, this was my first experience with brushless. I did a little research, and then ordered a 24V, 250 watt generic brushless controller from a mail-order scooter parts company. Unfortunately, it used a different style of throttle than what was already on the scooter, so I had to order a throttle to match.
Connecting the controller was pretty easy, three wires to the motor and the black and red one to power. I first bench-tested it with an old printer power supply, and once everything was working right, bit the bullet and bought a brand new pair of 12ah SLA batteries. The two batteries are wired in series, along with a 20 amp fuse, and then go to the controller.
I still needed a deck for the scooter. I dug through some scrap materials and found a pair of cabinet doors that were about the right size. I cut them down just a bit and bolted them to the scooter. I even re-mounted a cabinet door handle to have as an attachment point for towing a sled.
With that, I was ready to go for a test ride, so it was off to the lake. Once I was on the ice, I turned on the scooter and gave it a go! What fun! It really zipped along, but it was almost impossible to steer, as the back tire would slip right out from under me! Time for more traction!
I decided to make a spiked tire. I removed the rear wheel, then disassembled the two-part rim and removed the tire and inner tube. I stuck 1/2″ self-tapping, pan-head, sheet-metal screws through the tire from the inside, so that their points stuck out. I evenly spaced out 24 screws and alternated them to be slightly off-center side to side. Next, I put some old scrap bicycle inner tube over them as a liner to protect the scooter tire inner-tube. After that, it was just a matter of reassembling everything.
Now for test #2 out on the ice. Remembering how much it hurt to fall on the ice, I was prepared this time by wearing my motorcycle jacket (which has padding built-in) and my helmet. Good thing too, as I would learn while steering with one hand and holding a GoPro camera in the other…. (Note to self, keep both hands on handlebars at all times.)
Overall, the Ice Scooter works great! I still have a few little things to do on it. For example, the motor is running “sensor less”, and I’d like to learn about how brushless motors use the sensor system. I’d also like to get a small 24V dedicated charger. As it is right now, I have to remove the deck and manually charge with a little 12V charger.
From thrift store idea, to hack rack, to life on the ice, it’s always fun to see what you can do with just a little ingenuity. I hope you like this project. If you want to see more on it, please check out the write-up I did on Instructables. It’s even in a few contests there, and I’d love your vote!
Keep on Making,
5 years old have many things in common. A penchant for poor personal volume control, meth-addict levels of energy, and an OCD like compulsion to make noise. Mine in particular has the “drummer” variant of that condition and so loves to bang on anything and everything. This affliction made manifest is the Blue Man Group, naturally his favorite musical group. So when he needed a new headboard for his bed, we decided to see what we could do let him exercise his inner Blue Man.
The math behind the right lengths for the right tones are pretty straight forward – I just followed the recommendation from a PVC instrument instructable by tallman1996 – there he explains:
“I got an equation from nate true that will give you the length of the pipe you need when you plug in the frequency: Tube Length (in) = (13300/(2*Frequency))+(Tube Diameter/2)
For the frequencies of the notes in the range of the piano go here: http://en.wikipedia.org/wiki/Piano_key_frequencies
My low note was number 16 (C2) in the list on the wikipedia page.”
Drilling the holes through the 4 inch pipe was easy, just lay two parallel lines opposite each other on either side of the pipe and mark your drill holes on either side at equal distances from one end. The 2 3/8 hole bit went through easily but you had to keep it completely perpendicular to the pipe or it would jam. I highly recommend you use a drill with a torque setting so you don’t snap your wrist or have the pipe turn and crack you in the head when it jams. Don’t ask me how I know this.
Also, PVC power / flecks have amazing static cling powers so be aware that it’s rather messy.
Since I was worried about the pipe length hitting the ceiling and didn’t want a spaghetti mess of pipes on it I opted for a C3-C4 whole note scale with an extra C2 at the bottom for a nice low note.
It turned out well, we need to paint and glue the PVC together and drill the elbows to the lower cross member but even with the dry fit they stay together pretty well. With the 90 degree elbow on the end, he could continue to stick pipes on it and change or add notes if he’d like.
Paddles for now are just a pair of old flip-flops that will be modified to have handles. Any dense foam rubber will do.
This was also a great excuse to try out my new GoPro 3 on Time Lapse, so here is a video I did of the build:
After a long series of manipulations, the CT scan derived face was successfully used to make a pencil holder (of all things!). It is about 100mm high and took about 9 hours to print. You can find files that you can use to make your own mash-ups of my face on thingiverse: http://www.thingiverse.com/thing:203856
While investigating software to extract bone data from CT scans and turn it into 3D printable STL files, I played with a CT scan of my own head that was used to treatment plan orthodontics. I have been using DeVide to process the data and finding it is not only easy to use, but a lot of fun!
The animated gif was made by sweeping the lower threshold of a dual threshold module from -800 to 900 in steps of 100 with the upper threshold fixed at 1400. The effect is to strip away the lower density tissues leaving only dense bone at the end of the sweep. I saved the result of each run as a png file then converted to an animated gif using an on-line service.
As someone who has gone to GenCon quite a few years and knows several of the GMs of major events, I’ve started getting asked to make props… This year I have decided to expand my experiences in molding and casting in order to make one of the props. The prop requested was a “Bracer that looks like it is made of Amber – part of the shell of an insect”. Thankfully I was afforded quite a bit of creative leeway beyond that.
In the past I have used Smooth-on products, but one of the members of the Makerspace mentioned they were a distributor for Alumilite, so I thought I would give them a try. This was my first experience with most of the Alumilite products.
I ordered the following supplies:
Other items I used:
3” Diameter PVC Pipe – Approximately 18” long
3” Diameter Hose Clamp
Disposable Mixing Containers
Steel Wire (to hold the mold together)
I wanted to make a “generic” bracer that would fit either arm, not a right or left arm bracer, so I didn’t want to do a life cast of my arm first – it would be too specific. Instead I picked up a piece of 3” pvc pipe, cut a section out of most of it (leaving a part connected) and then used a hose clamp to tighten the open end down. It turned into a really good stand-in for a human arm. The shape is close enough that it is recognizable, but is not left or right arm specific. (Note that the screws in the picture were added at a later stage)
Once I had the basic form for the arm, I used the synthetic clay to create the shape of the bracer. I was going for an organic look, so I wanted curves and no sharp edges. The biggest challenge I had was trying to smooth out the sculpt. I still need to figure out the right technique. Sadly, I forgot to take pictures of the sculpted bracer.
Once I had the sculpture complete, I added some screws around the edges as alignment points. I was careful to make sure the heads were close to the PVC so they would not get stuck in the molding material. Then I got to try my first new material – the Mold Putty. I really liked the idea of it – take two parts, hand-mix, then just push it onto the original. It essentially worked exactly that way. I thought the mixed consistency was almost perfect for my application. Unfortunately, the biggest difficulty is being sure not to trap air in it – particularly when placing a second mixed batch next to an already placed batch. I ended up with some imperfections in the final mold because of this. Would I use it again? Yes, but I think I may also try other approaches – either a box and pourable rubber, or brush-on rubber.
Given the way I wanted to cast the bracer – standing vertically – I wanted to make sure that I was able to hold the rubber mold to the arm form well. So, using the plaster bandages, I made a two-part “mother mold” for the rubber mold. First, I coated everything with Vaseline as a release agent, then I covered half of the arm piece with plaster bandaging, making sure the edges were particularly strong, and that the top edge, where I would be creating the second half of the mold, was also quite smooth. After the first half of the mother mold cured, I then coated the edge of the plaster with Vaseline to make sure the other half would not stick to the first half. Once I was done placing the Vaseline, I then coated the other half with plaster bandages.
Once all of the plaster dried, I used a sharpie and drew lines across the edges of the plaster. These lines are so that I could realign them easily after I took the mold apart to remove the original sculpt.
After I removed the original sculpt, I realized I forgot something major… A way to get the resin into the mold. Oops! After a bit of thought, I decided the easiest way to get the resin in would be to drill some holes through the PVC pipe and pour it in that way. Ideally, I would have designed pour holes and vent holes into the original design of the sculpt. Something to remember for the next one! In order to try to control the fluid a bit better, I used straws to extend the holes out. Bendy straws would have been good – I’m not sure how effective straight straws were.
Using the volume of clay from the original sculpt, I did a rough guess at how much resin would be needed to fill the mold (~12oz). I measured out 6oz of each of the two parts, added one drop of red and six drops of yellow to one of them, then mixed it. I used a syringe to suck up the mixed resin and transfer it into the mold. It worked quite well, although it was a bit disconcerting because of the number of bubbles that were exposed during the suction process. Thankfully, as soon as the resin reached normal pressure the bubbles disappeared.
The resin takes 24 hours to cure. 24 hours wondering if it turned out.
And after that full day of waiting, I de-molded it. Quite the pleasant surprise! I think it may have slightly too much red, so I’ll have to correct that for my next iteration. I’m still debating about sanding and buffing it in order to get it to be more glass-like.
After a year’s work designing, building, scrapping, redesigning, building, and working through software and firmware issues, the MegaMax 3D printer is now functional. It has some common 3D printing issues like printed objects peeling up off the glass printbed. Tweaked settings in Slic3r, ABS “juice”, and Aquanet hairspray have all been tested with moderate success in attempts to improve adhesion to the printbed. Finally, have_blue gave me a block of foam out of the Stratasys printer to try out and it seems to work better than the other methods and doesn’t require heating the bed! Further experiments to be conducted post-haste.
More info on this project can be found here: http://wiki.milwaukeemakerspace.org/projects/megamax_3d_printer
September 27-28 at Wisconsin State Fair Park, the same weekend as Harvest Fair. Admission is free. Maker Faire Milwaukee's Call for Makers is now open.
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