After I bought my first printer and began printing for friends, I felt I could use a 2nd printer. Instead of just buying a 2nd one, I came up with the idea to build a reprap. I had a printer, so I could print the parts. You could buy the other parts everywhere on the internet, so that wasn't a problem either. I began creating a design that was easy to built, compact, cheap and still accurate. Continue reading to see if I succeeded!

Step 1: The Idea

When looking online for repraps, I did not find any that I really liked. They all looked complex with nuts and bolts everywhere. None of them were what I was looking for. I began thinking of designing one myself.

There were a few requirements my printer had to meet:

- Compact: I wanted a large build platform, but an as small as possible printer.

- Cheap: I was on a budget, I didn't wanna go over €400. I would have to use allot of 3D printed parts to do this.

- Simple: It had to be straight forward, simple to build

- Accurate: It had to produce high quality prints, as high or higher then 3D printers on the market. With this in my mind, I went creating.

Step 2: The Design

While designing, there were allot of problems that came up. A compact design, while still keeping a rigid frame for high quality prints. It was allot harder to accomplish than I expected.

To keep costs low, I did not want to use 2 motors for the Z-axis. But I really liked how the prusa's were made, they were allot more compact than those big box printers. So I just went for a prusa style, but I left away the other motor and the rod on the other side of the bed. This gave me allot of things to think off. The frame had to stay rigid and balanced, so I went for thick 12mm rods for the Z-Axis. This gave me a lot of stability, but the weight of the 2 rods for the Z-Axis would still make this axis sag, so I placed the X-Axis motor and the extruder motor on the opposite site of the Z-Axis rods, compensating the weight of the X-Axis. This way the whole Z- and X-Axes was a lot more stable.

The extruder was another problem. Direct drive extruders were pretty expensive, even on Ebay. This would bring up the price, wich is what I had to avoid. By designing my own extruder, that is printable, I could get rid of this cost too. I went for a direct drive extruder, driven by an MK8 gear. The design is simple, but effective.

After tweeking and tweeking and redrawing pieces, I was finally ready after a few weeks from beginning this project. At this point, I still didn't knew If I met all my requirements or, worse, if he would even work...

Step 3: The Parts

To keep costs low, I had to search for cheap parts. I ordered allot of my parts from AliExpress and Ebay. These sites were good for allot of stuff: bearings, belts, pulleys, fans, cables, motherboard, powersupply,... But I had to keep the quality in mind, so for rods, linear bearings, motors,... I went for known brands. These were more expensive, but this way I could make sure there wouldn't be any quality loss because of low quality parts.

Step 4: The Assembly

When all the ordered parts where here and the to-be-printed parts were printed (that took my a lot of time...) I was ready to assemble. This was a part I knew would go easy. I focused on this when designing. The hardware build took me less than 2 hours! Shortening cables, setting up Marlin,.... took a little longer. I was ready for a first print after a few hours.

Step 5: The Printing

From the first print I was impressed already. It was surely not perfect, but I was so happy he actually printed! It was a simple cube.(pic.1) The corners curled up, so I added a fan and the problem was gone. I experienced some backlash to, but I implemented an easy belt tension system so by just tuning a screw, this problem went away. I began using this printer allot, and it always gave me awesome results. I'm now using it more than my first printer, because it is a lot quieter and it sits on my desk, so I can always have an eye on the print.

Step 6: The Verdict

For me, this was a very successfull project. The printer accomplished all the requirements and is now printing on a daily base for a few months already and I haven't had a single problem with it yet. The printer prints up to 200x200x170mm. It's equipped with a heated bed and E3D clone hotend. As far as the price goes, I came up with a total of about €300, this is €100 under my budget. I couldn't be any happier!

Thanks allot for reading my instructable. If you have any questions, just shoot!

Step 7: Make One Yourself!

Now, after reading what it is capable of, it is time to make one yourself! If you are interested, I uploaded all the .STL files and a parts list (parts you need next to the printed parts). You can just download them, buy the other parts and begin to build! How awesome is that?

Because this is still a work in progress, that will probably never be finished, I have no manual or build plans. Because of the simplicity of the design it shouldn't be to hard to assemble. Run into problems? Send me a private message and I'm happy to help. If you find faults in the design while building, please also send me a message. This way I can edit the parts so that future builders won't run into these problems. Thanks for reading and happy building!