Mighty Mill

Mighty Mill
Side View Back View
Side view of the mill. Back view of the mill.
Overall System A precisely bent aluminum corner.
The tool with an offboard EMC-based controller. Tight bends in the tube were achieved using a custom bending tool.
Cement filling port. Inside Corner
Ports in the top of the X axis frame provide a fill point for pouring the cement. Precision guide rails pierce the aluminum frame thru oversized holes.
Joint between X and Y axis frames Grommet at the wire entry point into the frame.
The X and Y frames are butt joined with an internal aperture allowing cement to flow. This and a set of threaded rods reinforce the joint. Motor wires run internal to the frame to minimize cable clutter.
The work surface. One hole in the table.
The work surface is machined from cast aluminum and has 104 mounting/locating holes for aligning and fixturing work. The upper section of each hole is reamed for a locating pin, and the lower section threaded for a screw.
The Z Axis from behind. An epoxied bushing.
The Z axis is mounted to the X axis in a stacked configuration. Each carriage has a set of fixed and floating bushings. The floating bushings are epoxied in a way intended to resist shear.
Leadscrew preload assembly. Foamcore mockup.
Leadscrew preload assembly. A foamcore mockup of the machine architecture.
Competitor size-to-work-volume study. Work volume study.
Work began with a size-to-work-volume study of the competition. This set of cubbies helped determine a good working volume for the machine by testing which objects would fit.
V cutting the tube. The machined frame tubes.
V-cuts in the thin-walled aluminum tubing were machined for locating accuracy. The X and Y axis frame tubes post-machining.
Threaded insert insertion tool. Threaded inserts.
A tool was made to assist in press-fitting inserts into the tubing. Press-fit inserts create mounting features in the tubing.
Bending knife. Bending a tube.
An impromptu press-break using a Bridgeport milling machine and a custom knife and die. Bending the aluminum tubing.
Carriage blocks. Folding the y axis frame.
Each carriage block was machined, with the intention of eventually extruding the profile. The Y axis frame during assembly.
Machining the casting fixture The casting fixture
The casting fixture was too tall to machine with an end-mill in one piece, so blocks were added as the machining progressed. The complete casting fixture is comprised of multiple assemblies.
Dry-fitting guide rails in the fixture. Creating a pass-thru for the lead screws.
Dry-fitting the guide rails to the fixture to test parallelism. Paper tubing (originally for model rockets) was used to create pass-throughs in the frame.
Masking around the guide rail entry points. Y frame mounted on fixture.
Temporary masks seal the gap between guide rail and frame during casting. The Y axis frame fitted onto the fixture.
Leadscrew locating pin. Guide rail biasing clamps.
Locating pins set the alignment between the motors and the carriages. Clamps repeatably bias the rails in their fixture seats.
Frames mounted on fixture. Pouring cement into the frame.
Everything mounted on the fixture and ready for casting. Pouring cement. This photo is of a trial run conducted without the fixture.
The cast frame as it came off the mold. Underside of cast frame.
The frame just after coming off the fixture. Mounting the table to the Y carriage.
Z axis isolated. Unpainted electronics enclosure.
The Z axis stage. The electronics enclosure was bent from a sheet of waterjet-cut steel.
Painting the electronics enclosure Mounted drive electronics.
Painting the electronics enclosure late at night. Originally, the control and drive electronics, and the power supply, were housed inside the machine.
Stepper controller. Stepper driver.
Motion control would have been done using custom firmware and driver boards. Close-up of a custom Allegro A4982-based stepper driver (same as used in prior projects).
All wired up! Machine on the bench.
All wired up! Driving around the machine for the first time on my workbench.
Switching to offboard control.
Due to noise issues, the switch was made to a LinuxCNC EMC2 based control system.