The LowRider CNC
The LowRider CNC is my answer to you that want a full 4’x8′ sheet router, or of course you can go smaller. If the MPCNC is not big enough for you this picks up where that left off.
This CNC router can handle any length, the Y direction is only bound by your table length.
Width (X direction) seems to be just about maxed out at a little over 4′ using .065″ thick stainless X rails. I see no reason to push it further if you try it out let us know how it goes and why you did it.
The Z direction (height) is best kept to a 3″ maximum for wood, with that being said, you can make the usable z length as much as you want you will be working from the bottom up, so go to town.
Feel free to round up to whole numbers.
All quantities shown in the drawings are for each assembly, not total quantities.
More details to come.
Ideal table thickness is 4″.
Of course there is more to come. This is how I use the machine.
1)Square it up. After mounting your work piece (making sure the mounting hardware is not going to interfere) I check to make sure the sides (Assemblies with the wheels on them) are the same distance from the nearest end. You can do this by making sure the wheels are hitting the end piece on your table, or if it is in the middle I just measure to the nearest end with a measuring tape.
2) Double check. You only need to do this the first few times until you understand the machine. Use the LCD to control the machine. Lift the gantry high enough as to not drag the bit across your material. Drive the machine The entire length of what you will be cutting. This is to make sure the machine does not hit the table and you are parallel with it.
3) Set your starting position. Use the lcd to position the bit at your zero position in all three axis.
4) Beginning gcode. If you use the Fusion 360 post processor this is done for you but make sure your beginning gcode resets all your axis to 0,0,0, you can use this command, G92 X0 Y0 Z0.
5) Ending gcode. What should happen is your job ends above your last position, meaning your bit should not drag across the surface if you move it. With the bit above the last position, telling the machine to go back to the starting position will return the machine to where you started it. and then making sure the steppers do not turn off is a good idea as the LowRider will drop under it’s own weight. The last few lines of your gcode should look like this.
G1 Z7 F420 (this is my clearance plane and is already in my gcode)
G1 X0 Y0 F2100 (I add this to have the machine drive its self back to the start)
At this point you can use the lcd to move the machine clear of your material and lower it, then power off.
Or, if you leave a little room you can drive past your starting point and lower automatically.
G1 Z7 F420 (already there)
G1 X-15 Y-15 F2100 (drive 15mm past your start)
G1 Z0 F420 (Lower the machine)
M84; Turn steppers off