By Ben Lopez
Description: Velleman K8200 3D Printer
Assembly Time: 32 hours
The Velleman K8200 3D Printer Kit is an awesome (and relatively cheap) option to get you into the 3D printing game. There is a bit more assembly involved in this kit than with some other 3D printers on the market, but the end result is definitely worth it. Although the instructions provided are clear and simple, the execution can still be time consuming, and the electrical assembly is just as lengthy as the mechanical assembly. The entire kit comes in a 22" x 10" x 8.5" box that's packed with all the carefully spec'd-out parts to build this machine.
Build your own 3D Printer.
What is unique about this printer is that the platform for your printed part actually does most of the moving while the printer head only moves up and down vertically. The base of the printer consists of four aluminum bars, an x- and y- translating stage, and four rubber feet. Two aluminum bars also run vertically up both sides of the printer with another aluminum bar that moves between them, to provide a frame for the printer head to move about. As far as components, there are only four motors that you have to mount throughout the process, as well as corresponding "stop-switches" to limit the printer's range of movement for each degree of freedom.
Mechanical assembly begins with the base frame and fitting the xy-stage within it. This stage will look like the Fig. 2 above.
You might want to take out the flat metal parts in the early stages of your build to file down any sharp edges – they may have a rough finish from the machine shop. Most of the fastening in this kit is the trademark 3D printer method of fitting one piece onto another, then clamping them together by tightening a screw. You'll want to have a good set of Allen keys, screwdriver and at least two wrenches.
Pay close attention when putting the xy-stage together and make sure you have fastened everything on the correct side of your plate. I learned first hand that these parts become difficult to move later in the build.
A very small heat sensor gets soldered onto the heated bed that comes with the kit, and then this heated bed is assembled on top of the stage. The purpose of the heated bed is to prevent your hot parts from bonding with the bed and to allow you to remove them from the platform without damaging them.
After the base frame is ready, you will build the vertical frame onto it as well as the printer head or "extruder" parts. The frame is fairly straightforward to construct, but your extruder may take some extra work as mine did. You should have a decent file to use to grind down the length of two particular screws in the extruder hardware, otherwise the components will not fasten together correctly.
On the left is the bearing housing with the screws that need their excess length filed down, and on the right is the assembly that the housing must fit into:
A threaded shaft, as shown in Fig. 5 below, is controlled by a motor (at the bottom) that rotates the shaft and moves the extruder vertically.
A nice feature of the Velleman 3D printer is a spool positioned at the top of the printer that keeps the plastic filament feeding into the printer with very little resistance, which is sometimes problematic for other printers.
While the wiring for this machine is simpler than the previous steps, it is still just as time consuming. Much of the wiring is repetitive, so it is unlikely that you will wire something incorrectly. There are four motors, three switches, a fan, the heated bed and thermistors (temperature sensors), so you know that you just have to connect them all to the main PCB board somehow.
Here are some of my thoughts and tips about the wiring:
Be careful when stripping the wires from the ribbon cable. The actual metal in the wire is very thin in diameter and can easily be sheared or pulled off with the insulating material. I ended up with a few wires that were a bit shorter than others.
Soldering gets tight around the heated bed and switches that you have already placed in cramped areas, so mind the surroundings – especially the rubber pulley belts – when wiring these components.
Be conservative with your heat shrink tubing or you might run out like I did.
Velleman provides plenty of zip ties for wire management in this kit.
Most of the wiring is conveniently hidden in the recesses of the extruded aluminum frame.
To prevent the risk of damaging the sensor, be sure to finish tightening the extruder components together before attaching the thermistor to it.
You will have about a dozen small harnesses that meet at the controller board. Once this wiring is finished and the connections are made at the extruder head, you are done! Your finished machine should look like the Fig. 6 above.
Stay tuned for part two of the build, where we'll calibrate this printer and finally print an item!
Build the Velleman K8200 3D Printer.
Ben earned his bachelor's degree in Mechanical Engineering from UC San Diego, where he learned about robotics and electric vehicles. Originally from Monterey, CA, Ben currently lives in the Bay Area where he works with the Product Marketing team at Jameco Electronics. His interests include innovative technology, music, tools and anything automotive.