Update: This is now available at Inventables.com
I was invited to this really cool event called ORD Camp. ORD Camp is unique, yearly event put on by Inventables and Google in Chicago. It brings together 200 people with a far range of interests. The common thread is a exceptional passion for what you do.
You are encouraged to bring a “creation /invention” you are working on. I did not want to bring the 2.x laser because it is hard to move around, it takes up a lot of space, and is not real conducive to just operating in the middle of a room. I will probably bring the camera slider, but I really felt like using the opportunity to create something new and cool with the MakerSlide material.
I was recently inspired by this Kickstarter Printrbot 3D printer. It seemed like a real ‘outside the box’ look at 3D printers. Brook of printrbot contacted me recently about collaborating with some of the people he is working with on some projects which got me more inspired. I decided to try a similar concept using Makerslide.
MakerSlide has these main features. It is a linear bearing. It is a structural element. It is accurate and it is cheap. The concept is, if you keep some of this laying around and have access to a few tools, you can quickly brainstorm an idea and fabricate it right away. This project was hashed out in about 3 hours, fabricated in about 2 hours and assmebled in about 2 hours. That includes cutting all the custom parts.
The result is the ORD Bot 3D printer platform. The structure and linear bearings are 100% MakerSlide. The motion is smooth, ridged and accurate . The parts are cheap. This uses less than $60 dollars worth of MakerSlide rail, wheels and idler pulleys. The rest are off the shelf items or fabricated by CNC router, laser cutter, 3D printer or other means.
A huge feature of this design is the scalability. It can scale in X,Y, Z or any combination by simply using different lengths of MakerSlide. All brackets stay the same. You might need to change belt lengths, but all the belts are open ended belts, so you don’t need the exact length, just some belt stock. The lead screws also need to change if the Z changes, but that is standard cut threaded rod. The version I built is probably as small as you would ever want to go, so I called it the Quantum ORD Bot. The build area is slightly larger than a standard MakerBot.
The frame is extremely ridged. Cut squareness does not matter very much. Every parts has multiple adjustable points and does not rely on the quality of any cuts. Parts can be aligned with a square and bolted down.
I initially had some screw on leveler feet in the design, but after some design tweaks, extra bracket were going to be needed to mount them. I made these feet out of HDPE. They are soft and will not scratch any surface. I added the holes at the bottom to get a little spring to them, but I also think it brought in a nice design element. The rounded end and three point contact make them self leveling. The rear feet also act as a secondary brace for the Z axis.
The handel is not required, but adds a lot of strength, can be used to mount electronics and also serves as a gauge for alighning the uprights. If you use a handle and scale the X axis you would need a hew handle. An alternative is to use a standard 20×20 t-slot piece across the top.
Here is the build area increased by 100mm in each direction. I put a 20×20 extrusion across the top instead of the handle. I just did it as an example to show a more easily scaled version. This cost would be $4 higher for the MakerSlide about $3-$4 more from Misumi, about $2 more for longer lead screws and about $5 more for the longer belts. You would also need a bigger build platform (not shown). The total increase is easily less than $20. The increase in Z weight is about 4 ounces (0.1kg). At very large widths you might want to add a second Y axis extrusion, but that would just be a repeat of the existing one.
The pictures above are mostly renderings. Here are some real pictures of the prototype. I cut all the parts on my CNC router. I could have used my laser cutter, but I wanted to make a few counter bores for some screw. I don’t think that is needed, but it looks cool. I also used some optional non laser cuttable materials like carbon fiber and HDPE.
I came up with this idea about 6 days before the ORD Camp date, so I was a little rushed. The biggest problem was lack of motors. I also was so busy that I really could only allocate about 6 hours to the project. I let the delivery time of the motors set the schedule so only worked an hour or so a day over the week.
This design is very strong. I could stand on it or hang from it without damaging it. It is quite light at about 6.25 lbs. I am very happy with it and hope to get some good feedback at ORD Camp.
Where Are The Wires?
The element I really liked when I did some initial renderings was the clean look. I knew it would quickly turn into a RepRap hair ball as I wired it, so I decided to take advantage of the built in passage ways in the MakerSlide. I drilled some holes into the faces in some areas to pass the wires from extrusion to extrusion. The wires to the gantry had to be exposed because they move with the gantry. I put the wires into an extrension spring. This is a 1/4 O.D. 0.018 wire springs. If you stretch a spring the diameter reduces. I used this feature to mount the spring. I drilled holes slightly less than 1/4″ and stretched the spring through the holes. When I released the spring the diameter expanded to fit snugly in the holes. I tried to find a tap that matched a spring pitch so I could just thread the spring in, but couldn’t find a match. This mod falls into the “its not worth doing, unless you overdue it” category. I also wanted to reinforce the extreme rigidity look, by using carbon fiber parts, but the budget limited me to just the small thin parts. Again, this was overkill and just for fun.
What is Next?
If there is any interest, I might add this as a kit to the Makerslide store. I would like to quote all the carriages and brackets in aluminum, so I don’t have to fabricate much. I would probably need a 50 piece buy to justify the work and cost.
You can get the source files at Here.
Here is the ORD Bot running at 160mm/sec, but the current print speeds are exceeding 400mm/sec with 1000mm/sec rapids. The limiting factor right now is the extruder, but we have preliminary prints close to 500mm/sec.