The 3D printer has a compact size so that it can fit in a large backpack. It was essential for me that the printer has a reasonable print volume despite the requirement to be portable.
The outer dimensions are 300x330x105mm (folded), and the build volume will be 160x220x150mm (XYZ).
As you can see in the renderings, the printer will unfold during printing. The printer will be built out of CNC machined aluminum parts and 3d printed ones. I chose aluminum in the first place because I wanted to build the printer as rigid as possible (proof of concept).
To obtain rigid joints, the printer uses a combination of axial and radial bearings. Three screws then preload each axial friction bearing.
Einsy Rambo Board
small, low profile board
MGN9 linear guide
UHP-350-24 Mean Well power supply
350W 24V power supply which will be integrated into the printer
I managed to wire everything up. It is not the best wire management, but it works. I added a LED-strip at the front for better looks and usability. The power supply and EinsyRambo are mounted under the 3d printer between the Z-slider and the printbed.
In the back, there are a power switch, a USB-port and a power connection + fuse.
First print :
The first prints are looking very promising. I printed the test cubes with a 0.2mm layer height.
On the other hand, the first layers are still pretty bad. I lifted the printbed 6mm as I thought this would improve it, but it didn't. Without a heated bed, the print adhesion ist not good, which could be a factor as well. The Z-slider has some flex which leads to some looseness in Z-direction. It is made out of 3mm Aluminum(7075), but it is still not rigid enough. I want to try to reinforce it, maybe this will help.
Here is a video of the homing procedure. X and Y are homed sensorless and Z with an regular endstop.
With the help of Uzair Patel I was able to solve the non-linear Z-Axis firmware problem. I decided to use marlin 1 instead of marlin 2, because marlin 2 takes way longer to compile in the arduino IDE than marlin 1. I added the extruder and the Bowden tube to the printer.
And here is a picture of the "folded" Bowden tube.
On the bottom side are holes for high-temperature magnets which are required for the removable printbed. At the rear right corner is a cutout for the printhead, because the nozzle needs to be below the print surface so that different nozzles or print surfaces can be attached. Later I want to add a heatbed, but because of the cutout in the printbed, I can't use a standard one. I plan to build one by my self out of copper tape and capton tape.
I use 3mm MDF to insulate the printbed from the base frame.
All sidearms are mounted. The main structure is almost done. In the video, you can see the folding process, which looks very promising. The printer weighs already 4,3Kg, but the aluminum parts pay off because the construction is quite rigid.