After thinking about it for a long time I bit the bullet and ordered myself a smallish CNC router/mill. Having a small lathe at home already made a lot of nice things possible, but adding a mill to the workshop would really allow me to get creative. I’ve been a CNC machinist for about 10 years, working my way up from Heidenhain TNC135 through Maho CNC432 to Mazak Mazatrol 640MT controls over the years. So I’m not exactly new at machining… this does also mean I might do things in a way I’ve done it for years, which might not always be the best way.
Being a Linux system administrator I of course wanted to use LinuxCNC. So as soon as the box was arrived, everything was set up in place and I had the pre-installed PC turned on I started up LinuxCNC. Setup indeed was a breeze, although I immediately learned a few not-so-good things…
The spindle is only controlled by a relay : I can’t set RPM’s , can’t switch spindle direction and can’t even turn on/off the spindle in a program. This is something I definitely will change soon… right now toolchanges are not possible and that’s just not acceptable.
The machine so far appears to be very stable and accurate. I’ve yet to get my dial indicator mounted to check for accuracy, repeatability and everything being square and true but so far I’ve got good faith in it. Using a normal vernier caliper (0.05mm accuracy) I can’t detect the machine being off.
Being an engineer I always want to peek under the hood. So I opened the control box and was to say the least quite surprised at especially the earthing configuration… almost nothing is properly grounded!
I immediately got to work, installed earth wires from the filter to the VFD (NowForever D100 model), to the spindle motor socket (need to replace spindle motor cable, it’s 3-wire now) and to the (fake, cheap copy) Meanwell 350W 24V power supply. I also made sure that I scraped enough paint away that the case metal is now actually properly earthed.
I already had out the LPT breakout board (marked YooCNC 685JKB , 4-axis but no PWM sadly) to fit the 0.1″ header pins for the home switches.
The pinout of the 685JKB is
1) Spindle enable (drives the relay)
2) X step
3) X dir (inverted in my case)
4) Y step
5) Y dir
6) Z step
7) Z dir
8) A step
9) A dir
11) Home X
12) Home Y
13) Home Z
15) Tool probe
So hopefully I can extract pin 14,16 or 17 and have it do PWM to drive the VFD instead. The relay could then drive a solenoid for the air nozzle I intend to mount on the Z block for tool cooling and chip clearing. The power regulator chip can handle up to 40V maximum.
In a next post I’ll show how I made my endstops, from some aluminium L-strip 20*20*1.5 and flat 30*3 using the X4-800 for the shaping / drilling.