MM3 Build Progress

Started with a box of parts and assembled some of them as seen in my last post. I built the X-axis, Y-axis and Z-axis carriages, they roll on beveled 2020 extrusions with dual bearings in polycarbonate wheels, very smooth with no play.

Once the extrusions from Misumi arrived I could start building the bottom frame. I did the final tightening of screws on a glass table to make sure it was square and everything was flat. Then it was on to build the Y-axis. This is the carriage that will move the heated glass build plate.
This part took a bit of work to get square in all axes:
First, get the two extrusions parallel. Did this by spacing them equally between the outer frame
extrusions, measuring 76mm from each Y-axis to the frame extrusion.
Tighten the two extrusions to the front plate to fix this geometry.
Measure the distance beween the two Y-axis (148.29mm) at the front plate
and then adjust the extrusions at the back plate to have the same spacing.
They are now parallel, but not necessarily square.
To square them, adjust the top plate and rails to be flush with the back plate, and square to it.
Check from both sides that the frame is square using the big carpenter’s square
Tighten the two back rail screws first, then the two front ones.
Measure the rail spacing, it must be the same front to back, or the carriage will bind at one end.
then tighten the rest of the rail screws and then the 8 stiffener screws under the extrusions.

Removed the Y-axis and placed the Y-axis plate on it with wheels and checked for free running motion.
Here it is mounted and all squared up into the base frame, I’d just installed the X-axis which holds the extruders and the Z-axis uprights and both Z-axis carriages which move the X-axis and attached extruders up and down.

So, now the Z and X axis have to be aligned. The instructions were not really detailed, so I kept a log of what I did to line them up.
Squaring up the Z and X axis
Install Y Axis plate to square the frame with 4 screws to extrusions and front, back frame plate only.
With mounting finger tight on Z 2040’s square them to the frame extrusions with a square, tighten the 2 screws on each 2040
pull rear support 2020-300’s back from 2040s while tightening the 4 mount screws on each side, need clearance for Z-axis wheels at top.
check Z axis uprights for squareness across y-Axis rails, slide the glass carriage out of the way.
Gently bend to get close as possible to square.
Measure spacing at bottom of Z and top of Z, should be 34mm at the frame, +/- 1at top without the top bar mounted
Tighten down all frame screws now

Line up the right angles on the Z axis carriages and tighten them down, use T-nuts
Install the X-axis 2060, center the X carriage and let the wheels rest on the Y-Axis.
Measure the distance from 2060 to frame 2020’s, approx 35mm on each side, tighten T-nuts.
Last bit of X-Axis skew can be taken out by adjusting the Z lead screws
Bring up the X-Axis and tighten down the top plate

Step 19A – not going to remove the X-Axis, spent to much time squaring it.

So now it’s 95% mechanically complete and all aligned so my prints will be accurate.

Next: Electrical Setup
And a quick shot of of the dual extruder setup 🙂