Increased milling space for R-CNC, the printable milling machine by ewald

Last crawled date: 3 years ago

I am currently building a modified version of R-CNC, the printable milling machine. Since the original design is too small for my woodworking needs, I intend to blow it up a bit:
Increasing the width is easiest: add 200mm to all the original measurements.
More depth is a bit trickier as sturdiness degrades by the power of two when just increasing the length of the side tubes. In a first step I will go with the original 25mm tubes but 1200mm length and then test bending. So just adding 450mm to all the orginal measurements. If bending turns out too bad, I will either swap the corner pieces with holders for 40mm tubes or I will add a second 25mm tube below - which is more complicated and less likely to happen. So the 40mm solution is already part of this upload.
Another simple solution might be to insert a matching flat bar vertically into the tube and glue it on the full length of the corners. Maybe just flooding the corners with epoxy resin.
Adding more clearance below the router requires stretching the x-fixations and shifting them upwards. All the original measurements are increased by 50mm, except the two side pieces which will probably need at least additional 80mm. Since the resulting X-fixation was too big for common 3D printers like mine, I cut the piece in half and added small hooks. You probably need to file the hooks a bit once printed.
There is also an updated drilling template for paper prints. You will need to scale it correctly: print it, calculate the required scaling factor by dividing real measurement on paper by the printed value. Then print the second time. Afterwards fold it at the designated line and place the fold at the front sides to mark the locations. Be sure to shift equally on both sides.
Please note that as of now this is work in progress and the one the or the other detail might change for better performance.
Update 2017-07-23:
I am mostly done ;-)
Contrary to first assumptions, a 40mm tube is too big, is covers part of the space for the belt. So I added a second tube with 25mm below the original one. Additionally there are screws in the bottom board to support the second tube.
This project now contains virtually all my files. Each STL is accompanied by a JPG of the same name so you have an idea about the intended purpose and location. I omitted the Sketchup files. Should you want them, drop me a note.
I hacked the Marlin files a bit to make the endstops work and to display the current state on the otherwise empty space on the LCD.
I also added support for a Z probe which acts as a second ZMIN for homing. Now I can wire up the router bit and place a thin piece of wired metal on top of my stock and have it homing.
Update 2018-03-04:
The sources with my modifications are all on Github
Since Marlin was not intended as software for a CNC, it does not understand every such gcode file. My current workflow comprises FreeCAD and the LinuxCNC or GRBL preprocessor. Just make sure, the output is not shortened as each line is required to contain X, Y, and Z-code like the following. There was a switch to accomplish just that bad setting, but I can't reproduce it right now.
G0 X109.8144 Y548.0000 Z13.0000