and on the 7th day we have movement

yay!!
our machine is moving! it is now possible for us to control the cnc machine with linux cnc … we simply forgot to apply jumpers to the motor control board defining the microsteps that we apply to stepper motors (we thought applying no jumpers meant standard setup, but it turns out, that you had to apply at least one jumper to have an acceptable motor configuration)

setting up the motor control:
setting up the motor control board with EMC2 is really easy — it comes with a setup wizard which allows you to assign specific pins in the paralel port to specific home switches, motor steps etc.

Screenshot-EMC2 Stepper Mill Configuration

on homing difficulties:
we need to set up the cnc machine so it can always find its absolute position — this is done with home switches on the X/Y/Z axes, and should be a simple task, but alas, quoting from the manual:
“Homing seems simple enough - just move each joint to a known location, and set EMC’s internal
variables accordingly. However, different machines have different requirements, and homing is
actually quite complicated.”

so we need to read up on: homing setup: chapter 5.4 homing in the EMC2 manual

also the connection between our motors and the driving shafts are too loose — this can be seen our the first test drawing made with our wonderful machine:

first test drawing

the letters are written mirrored and on top of each other — they should be like the vector layout below

first_drawing_EMC2

the connectors are simply not tight enough to withstand the rotational torque when the machine is moving fast between letters (when drawing the letters are “milled”, so the machine is moving much slower)

but hey: this is all minor tweaks and mechanicals — all very fixable! yeah! what a nice way to start a weekend :D

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