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.
Feet.
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.
Handle.
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.
Scaling
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.
Prototyping
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.
I just got my production boards for my Pololu compatible relay driver. This is a little plug in module that can be used to drive off board relays. It uses the signals that are normally used for step and direction to control two relays with the voltage that is normally used to power motors.
Pololu stepper drivers are great little items. They are inexpensive and very easy to use. You only need a step and direction signal to control them. If you use them in sockets, as I show here, they are portable between projects and experiments. If you accidentally smoke one, you only need to replace the single driver.
There are a lot of carrier boards for these. There are Arduino shields and many other applications. Often, it would be nice to be able to drive a larger external load like a spindle or blower. You can then use the existing step and direction signals to drive the relays. It uses the voltage normally used to drive the motors for the coil voltage. The only wiring required is two wires to the relay.
I chose to put the relays off board because the real estate was pretty limited and I wanted to provide the voltage isolation for AC powered devices. I am also a big fan of DIN rail mounted relays. They are very reliable and inexpensive. They are easy to swap around and have some nice features. The relays shown have a LED indicator and also a manually test button that moves the contacts. The relays shown are about $10 each, including the DIN rail sockets.
I got the boards from Gold Phoenix in 2 sheets of 50. They were not cut out, only V scored. Fortunately I have access to a depanelizer at work and was able to easily separate them. I probably could have snapped them apart too. The depanelizer looks similar to this one. Two slowly spinning sharp disks chop them apart.
The boards have all the components required to drive the relay including a supression diode. I am using a pretty hefty transistor here, but you could substitute a smaller one.
Control connection via terminal blocks or 25 pin ‘D’ connector.
Filtering on all step and direction signals.
Motor disable/enable feature through ‘D’ connector or external switch connected to terminal block.
Socket Mounted Stepper Drivers
The board uses low cost socket mounted stepper drivers. These can be Pololu A4983/A4988 drivers or open source Step Stick drivers. These are easily replaced if ever damaged without any rework to the PCB. A compatible relay driver is planned that also fits this socket. This will allow up to (2) relays to be controlled per board. These are controlled via the set and direction pins associated with that axis and uses the existing terminal blocks for that axis. This is perfect for a spindle on a CNC router or assist air on a laser cutter.
Cooling Fan
There is an integral cooling fan for the stepper drivers. It mounts directly to the board and has a dedicated power connection. It is mounted high enough to allow heatsinks to be mounted to the drivers. This will allow the drivers to run at their full potential of 2 amps per coil.
5V Power Supply
There is a 1 amp 5V switching power supply on board. This will not get hot like a linear regulator due to the voltage drop from the motor supply. This can optionally be 3.3V if your controller requires that. All other items on the board are 5V – 3.3V compatible.
Rotary Switch Resolution Selection.
The resolution of the drivers can be independently set via rotary switches. The resolution is selectable between full step, 2x, 4x, 8x and 16x microstepping. These and the control connector are flush mounted to one side for easy bulkhead mounting.
Control Connector.
The board has a dual pattern for the control connector. There is a pattern for standard 5mm pitch terminal blocks and a pattern for a ‘D’ 25 pin male connector. The ‘D’ connector has a standard pinout for direct PC connection for Mach3 or EMC. The terminal block is perfect for direct connection to laser controllers like the Thunderlaser DSP controller or an Arduino microcontroller.
Filtering.
All step and direction signals are filtered with a RC filter and a schmitt trigger. This is ideal for a noisy environment like a laser cutter or CNC machine. The RC filter frequency is high enough to allow 1uS pulse control of the drivers.
Motor Enable/Disable
You can enable or disable the motors via the ‘D’ connector or via an external switch connected to a terminal block. This can allow hot motors to cool off or allow you to manually rotate them.
The Buildlog.net Open Source Laser cutter/engraver just added 3D printing to it’s capabilities. The printer system uses the existing CNC motion system of the laser cutter along with standard RepRap electronics. A quick release plastic extruder carriage is added to the existing gantry.
The upgrade project is called the Chimera Project because this is a hybrid of two self replicating machines. The parentage of the parts gets a little blurred. A Chimera is a animal descended from two genetically different animals. The laser is self replicating by making all its non off the shelf parts. Adding 3D printing takes that another step forward. The electronics were packaged outside the enclosure for development, but will be moved inside soon.
Changing modes is quick and simple. Swap the control cable, attach the extruder carriage and you are ready to print. You can even leave the printer carriage in place if you don’t need to use the full width machine when laser cutting. The total upgrade cost is less than $200.
The RepRap electronics can actually control the laser cutter with no modifications to the hardware or software, but the lack of acceleration parameters in the RepRap control system limits the speed the laser carriage can move before it becomes to jerky.
Already in the works are a tangential knife cutting head, Pen plotter and Dremel tool head. The entire system is open source and well documented. Starter kits for the laser are available and the 3D printing parts are coming soon.
Yesterday, MakerBot announced they are offering the new Plastruder MK5. The extruder is designed for reliability, low maintenance and ease of use.
It features and all stainless steel hot end that is precision machined to tightly screw together to prevent any leaks. It gets rid of the Nichrome wire heater and replaces it with two power resistors. The resistors draw a lot of power an must be used with a relay board.
The feeder uses the MK5 drive gear that has been available for while and gets rid of the idler wheel. Instead, it uses a thumbscrew adjustable Delrin plunger. he feeder uses the same DC motor as the MK4, but there is a NEMA 17 pattern for the planned upgrade to a stepper.
The design is of course on Thingiverse. It is for sale and in stock at the store for $189.
I have seen this printer various places and it has been mentioned on the forum. It is from UltiMaker.com. They are calling it the Elserbot. It was not clear from the website or other blogs if this was an open source project, so I emailed Martijn Elserman. He responded.
Hello Bart,
The design will be open source when we have finished the complete package hardware, electronics and software.
We will offer DIY kits.
Best regards,
Martijn Elserman
It looks like an interesting design. The two obvious thing that jump out are the large build area and the use of the Bowden Cable style extruder. The Bowden cable idea offers some benefits like reducing the size and weight of the print head and removing vibration. Here are other versions of the Bowden cable.
Engineer Andy Barry has created a new budget open source 3D scanner. He calls it the MakerScanner and hopes to sell it through the MakerBot web site for around $200. It uses the same laser line, offset webcam than many other systems use. He does a good job of explaining on the MakerScanner.com web site. There are even more details on his web site and Thingiverse.
The system uses galvanometers to move a mirror which moves the laser line. A sine wave is output to one galvanometer so it creates a line from the laser diode. The other scans it across the model. All of the parts appear to be printed with a Makerbot.
This is a great presentation of the current and future state of 3D printing. He gives tons of information and mentions a lot of interesting web links.
Singularity University is an interesting sound place. It is based at the NASA Ames campus in Silicon Valley. Their mission statement is…
Singularity University is an interdisciplinary university whose mission is to assemble, educate and inspire leaders who strive to understand and facilitate the development of exponentially advancing technologies in order to address humanity’s grand challenges.
Neil Underwood over at the RepRap Log Phase blog has put together a good guide for the relative costs of the various open source and commercial 3D printers. These are limited to the thermoplastic extrusion types.
It includes basic starter kits, complete kits and fully assembled models. It includes laser cut, CNC machines and printed versions. There are also some rough ideas on complexity and reliability.
I was at the Detroit Maker Faire over the weekend. It was quite a drive from Chicago, but well worth it. The place was full of 3D printers. Most of them were MakerBots and the others were mostly RepRaps (Darwins and Mendels). It is great to see MakerBot Industries having success with an open source product. I almost missed the actual MakerBot “booth”. It was tucked behind a a few bigger displays. They had a couple MakerBots printing away. They were printing a lot of coin bottle openers. They have a slot for a coin that catches on the bottle cap. …quick to print and a crowd pleaser.
Thingiverse
I spent some time chatting with them about all of the DIY digital fabrication going on with printers, CNC machines, lasers, etc. They mentioned that they had a project started to design and build a 3D scanner. It makes a lot of sense because easily getting things into 3D format helps the whole movement along. Below is a scan and print of Bre Pettis, one of the founders of MakerBot and Thingiverse.
Thingiverse
Thingiverse
When I got home I started to look into the Makerscan and 3D scanners in general. Unfortunately the MakerBot people are just getting started. They have a links page, a Google Group and a decent sense of direction and that is about it right now. The links page has a lot of good stuff. I have heard of the David Scanner for a long time. They have a complete kit.
