I plan to build a desktop CNC machine capable of milling aluminium.
The “Mostly Printed CNC” (MPCNC) machine is what I will be building.
This will be a long term project and a bit of a journey.
For long I considered 3D printers somewhat of a toy. 3D printers together with M3 M4 M5 bolts and nuts, 608-2RS skateboard wheel bearings and Thingiverse / Fusion 360 open up a world of possibilities for manufacturing and rapid prototyping. I will need to learn how to 3D print. I purchased an inexpensive 3D printer with the following features:
Metal clips clamp the glass plate and the aluminium hotbed together. Metal clips are not glued and can be easily removed. When removing the clips be careful not to scratch the insulation of the hotbed exposing the copper traces(!) I noticed the metal clips on the bed were actually mounted sort of upside down. It is best to mount the clips as follows in my view:
Without a heated hotbed the corners of your prints will warp and lift when the plastic filament cools down and shrinks. For simple and inexpensive bed adhesion printing PLA on a glass hotbed use the following method:
Update: Changed “G1 E-1 F300” to “G1 E-30 F300” to retract the filament 3cm instead of 1mm. This allows me to easily remove the filament after printing for storing without having to heat the nozzle to 180+ degrees Celsius. I also moved the “G28 X0 Y0” homing instruction up so it will return to the origin before performing the slow retract operation. Without this, the hot nozzle will leave an imprint on the object printed.
“This geometry is best with short legs and a short z axis. It was designed first and foremost as a cnc mill/router. If you think about it on those terms standard bits are no longer than 1″-1.5″ so you actually only need that much travel in the z axis, any more is just for material clearance and there are other ways to deal with that, like a drop table. Keeping a short z axis and short legs keeps the machine as rigid, accurate, and as fast as possible. This is the same for laser, drag knife, foam cutting, plotting, ect.”
” I recommend starting with a foot print of 24″ X 24″ (600 x 600mm) Outer Dimensions with a 3-4″ (75mm – 100mm) usable height.”
My goal is to be able to mill up to 10mm thick aluminium sheet metal, but also 1″+ (25mm+) wood / foam using up to 1″ (25mm) tall cutting bits. 800mm x 600mm x 85mm (X * Y * Z) seems like a good compromise for a desktop CNC router. I want to keep the sides open to be able to slide in larger work pieces i.e. engraving long narrow timber signs letter by letter.
I am using the metric calculator:
In a next episode we will start 3D printing and cutting round tube.