Limit Switches

Finished running wires, then soldered them to the six limit switches.

Next, tested each switch.  The all work!  Red wires are all connected to 5V supply and green wires are brought to 5V when a limit is hit.  Each pair of switches has its own port on the board, so the computer will know which axis has hit the limit - but not which switch.  When a switch is triggered, the CNC routine will stop.

Usually, with this many wires and connections, I find I did something wrong.  This is worth celebrating.

Wiring Motors and Stops

This morning, I finished wiring the motors.

Roughed out the stop wiring - two wires to each of six stops.

Motor Controller

Made a DIN-rail mount for the controller.

Hooked up the 24-V power supply and printer cable.
Tested the motor, identified the common pins, then pins 1-4.  (1=Green, 2=Yellow, 3 = Red, 4 = Blue)
Hooked up the motor (Z-axis) and tuned it.  160 rpm works well without load.

Mill in Machineroom

Cut the baseboard (39" by 45" on 3/4" plywood)

From Big Machine

Attached the large ballscrew and rails.

From Big Machine

Moved to desk in the "darkroom."

From Big Machine

Today's progress.

The old machine had a 7" by 7" work area.  The new machine will have 21" by 30", so about ten times as much area in XY plane.  The vertical travel will be greater, too (about 7" vs. 2.5" for the old machine).

Today, I'm cutting a sheet of walnut plywood for the base, then will mount the Y rails and ballscrew.  After that, will carefully keep everything square and add the gantry, which holds the X and Z rails and screws.

Some yet-to-be-resolved issues:

• Need to get new 3-axis controller, as it will just be too much hassle to borrow from the old machine.  Besides, the old machine is still quite useful.
• Need to figure out what kind of motor, chuck, etc., to do the carving.  High torque?  What voltage (steppers are 12V)?  Will probably need a separate power supply.  How to control motor speed?
• Another computer?  Maybe I can have the machines in same room, then use a 15-foot printer cable to drive the big one.  Is 15-foot cable too long for good signal / control?
• Is it time to buy Mach3 software?  So far, my programs have been less than 50 lines of code.  Can go up to 500 with free version of the software, but fully-loaded software has lots more bells and whistles.
• Run to RadioShack to replenish supply of wires, parts for switch box, E-stop switch.  Rail mounts?

Building a Bigger Milling Machine

My small (7" by 7") milling machine just isn't big enough...so I'm using it to build a bigger machine.  If I did this right, the link below should take you to the photo album.  The machine still needs lots of work: 

• beefing up the supports
• adding a strong base
• strengthening the horizontal piece
• adding stepper motors
• adding two stop switches per axis
• adding emergency stop switch
• hooking up all the electronics

Big Machine