MegaMax has been and continues to be my main project for the last 2+ years. I am currently working on some upgrades that will make him more Mega and even more Max. The Y axis is being converted from belt drive to screw drive and the round guide rails are being replaced with linear guides and bearing blocks. The X-axis will also get converted to linear guide and bearing block and change from 5mm pitch belt to 2 mm pitch belt drive. I feel confident saying that once these modifications are complete the flaws/errors in prints will be due primarily to the nature of liquid plastic squirting through a nozzle, not positioning system errors.
I recently updated my web site with a sort of historical look at the project, including all the mistakes I’ve made along the way and the often failed attempts at correcting them. Here is the page that shows how it all started, how it has ended up, and where it is going. http://mark.rehorst.com/MegaMax_3D_Printer/index.html
As part of my effort to reduce the noise and vibration in the Y axis, I am going to try using a screw drive instead of the 5mm pitch belt. I rescued a screw drive assembly from a big XY table but it uses a 200W servomotor for which I have neither power supply nor drive electronics. Never fear! The motor was a NEMA-34 size, so I designed an adapter to mount the NEMA-23 stepper that MegaMax uses in the NEMA-34 motor mount. Next I needed a shaft coupler- the screw has a 9mm diameter attachment and the NEMA-23 motor has a 1/4″ shaft.
Adapter plate on NEMA-23 motor
I used DesignSpark Mechanical to design the motor mount adapter and flexible shaft coupler. I uploaded the motor adapter to Thingiverse (http://www.thingiverse.com/thing:526424) and it proved surprisingly popular so I designed another that adapts a NEMA-23 mount for a NEMA-17 motor (http://www.thingiverse.com/thing:526443). I had to make two attempts at the flexible shaft coupler- the first design proved a little too springy and flexible, so I tried again with a more beefy design. It turns out it is pretty easy to design this sort of thing in DSM. I probably spent 30 minutes on the first one and about 10 minutes on the second one.
I sliced in Cura because Slic3r was having some problems. The prints look a little rough because of all the support material required to print the springs, but they work fine.
Flexible shaft couplers- not-so-springy and super-springy.
Adapter and shaft coupler on motor
Motor mounted on screw assembly
I’ll post an update when I get the screw mounted on the machine.
Several months ago, a humorous request went out for a Zamboni that could be used on the Nerdy Derby track.
Last year the Milwaukee Makerspace held a Maker Fest and a Nerdy Derby track was made for the occasion. The design allowed the track to be disassembled in 4 foot long sections.
When the track was reassembled, earlier this year, for the South Side Chicago Maker Faire, it was found that the joints did not match up as well as when it was first put together. Small ledges, that went up and down, would cause the cars to bounce off the track or hit the bottom of the car. Both of these scenarios prevented the cars from traveling freely down the track.
As many of you know, we just had a GREAT Maker Faire here in Milwaukee last month and the Nerdy Derby track was needed again!
We produced, and ran, over 1000 Nerdy Derby cars over the 2 day event. Wow!
A month or so before the event I started working on an idea for a Zamboni type of device. My first thought was of a custom contoured planer that could be used at each joint to smooth them out. This idea seemed like too much work so I proceeded forward with my second design. This consisted of a simple sled hat used a drum sander, which smoothed out the high spots. Wood putty was then used to fill in any low spots.
We’re planning on setting up a Nerdy Derby track at the upcoming Maker Faire Milwaukee so to that end we are preparing car parts. We recently received a generous donation of filament from Inventables (thank you!) so MegaMax and others went right to work printing wheels for the Nerdy Derby cars. The goal is to print 4000 (!) wheels before the Maker Faire.
A small batch-test run of twelve wheels
Starting a batch: printing 40 whimsical wheels and once!
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:
Join us for The Greatest Show (& Tell) on Earth at Wisconsin State Faire Park September 24th & 25th, 2016. Admission is free. A joint presentation by Milwaukee Makerspace and the Betty Brinn Children's Museum.
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