2nd Generation CNC Mill

NexMill 15 -Part 7

Z-Axis assembled and Controller wired...

Between school and some misc other castings the Z-Axis Spindle mount finally was cast, failed and had to be cast again.

This is the casting as it came out of the sand as well as a spare foam pattern in case this one also had defects.

With a bit of clean-up, some file-work and grinding the spindle mount is drilled tapped and ready to start the process of alignment and mounting to the Z Axis.

The lettering and rib work at the top washed out a bit and ironically the "qualitycasting.ca" lettering looks shitty...

The driving nut had to be machined a couple of times until it fit perfectly.

The metal plate on the table is a spacer that allows the spindle mount to clear the rod caps at the top and bottom.

The 5TPI lead screw is coupled to the stepper with a length of 2 ply 1/4" air hose.

The motor mount was marginally undersized (due to shrinkage of the casting) so the stepper was chucked in the lathe and the edge of the face turned down for a snug flat fit.

The Z-Axis has been assembled and dis-assembled so many times, I can do it in my sleep.

But finally it is ready for paint.

The parts are sprayed down with the remains of the blue that went over the Gantry.

This week I was able to wire up the motors, and start ty-wrapping down the lines.

This view from the back has the Y-Axis cable encased in a harness that I cannibalized from the Gorton mill last fall.

The controller was tested with a simple 555 timer as a pulse generator prior to connecting to the PC. The Stepper voltages are initially tested with 5VDC. Once the controller is verified to move all three axis it is hooked to the PC. Once the PC is verified to move all three axis I wired in the Current limiting resistors and switched the Stepper Supply to 12VDC.

The Controller housing is a gutted Computer Power Supply, and the Controller Supply is another PC Power Supply. Note the dual fans on the controller housing. After about 6 hrs of testing and a few hrs of idle time (energized) everything is still running cool.

So the NexMill-15 is functional, I've spend 2 days and a night just on the wiring and testing (my original mill took almost a month to get to this point).

It can run up to 90 IPM (Inches per minute) with no load, but realistically 45 IPM (Full Step Mode) on dense material like softwood or MDF.

The 1 (one) TPI lead screws are amazing, but reduce the resolution to 0.005" unless I get into a controller that can handle micro stepping.

The work area is 15" x 15" X 2.25"

For the near future, a speed controller for the router, side mounting the controller & PS... Now to start drafting up some "Super-Sized" patterns to mill.

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