Another Harrison Milling machine

[Fastdruid]

That is a really clever idea. Check that the rubber sheet is not EPDM. Oil has EPDM for breakfast.

It's a 1 ply reinforced SBR/NR blend rubber. I think this is the correct page

Textile Reinforced Insertion Rubber | Camthorne Industrial Supplies

Textile Reinforced Insertion Rubber for a number of sealing/waterproofing/vibration & sound reduction applications made from an SBR/NR rubber compound.

www.camthorne.co.uk

 

[Fastdruid]

Lots of wiring later....

It is all colour coded, although probably not to any standard colour codes.
Using shielded cables for the high frequency signal stuff, tri-rated cable for everything else.

I ended up not using the 8-relay module as I thought of another way to do things and because they didn't easily work with the 7i76 (because the outputs are sourcing while the relay module is sinking). Unless I think of something to use it for I'm probably going to remove it, although it does leave an annoying space I could have used.

Not 100% done yet as still waiting on a two way switch (rather than a three way), some lights and some connector strips. Also have some printable self-adhesive plastic that I plan on making up some labels with.

Controls are top row left to right: Spindle disable, E-Stop, Stop, Start
Left column top to bottom: blank, Axis disable, blank, Coolant on/off/auto.

Think I might actually move the spindle disable to the top blank on the left and fit a (mains) power light in its place. That will leave a single blank (for future expansion!)

Relays are (top to bottom): Axis Enable, Axis Enable, Axis Enable, Coolant, Spindle running, Spindle up to speed.
(these will sit inside the cabinet on a section of rail).

The Axis Enable relays are all run off the same 5v supply as the 7i76 uses for the drivers and are NC with the 7i76 providing power and earthed through the E-Stop.

The E-Stop cuts the ground to the 3 axis "enable" relays and they send a 5v (Dis)[en]able signal to the drivers and hence drives, halting motion. As previously mentioned, I'm loath to just remove power as the table will drop unpowered and that's arguably more dangerous than halting and holding position. Long term I'd like to stick in a brake on the Z at which point I can do a timer and cut all power on E-stop.
The E-stop also cuts the DCM on the VFD wiring which will halt the spindle motor.
Finally the E-Stop also connects to an input on the 7i76 so that the software "knows" the E-stop has been pressed.

I brought the DB25 out to the front so I wasn't trying to run a cable through a slot or anything else. The PC will just connect to the front there.

I'll bring an extra axis connection on the board out to a DB9 connectors as well, lets me plug in a 4th axis (or something else) at a later date. I put in a second one as well but unsure what that will be. Lets call it future expansion!

Next up, even more wiring!

 

[Fastdruid]

Front panel wired and labelled up

Have a few more holes to drill in the case for mounting things and the mount for one of the Y axis limit switches then it's final connecting up all the wiring.

 

[Fastdruid]

Final limit switch sorted. That joins the others...which I've realised I haven't pictured before so here they all are.

Lower Z (slight risk it may false trigger off swarf but we'll deal with that later).

Upper Z (as previously mentioned, [re]movable to allow for removing the vertical head and using the horizontal spindle.)

Rear Y

Front Y

Right X

and of course finally left X

All now need wiring up!

 

[Fastdruid]

Well it's only a year later. Finally getting round to the final steps of getting it working.

Had to reconsider the swarf shield for the front of the Y axis as the rubber got in the way of the X axis motor. Changed to just a metal shield.

Lots of wiring today and then initial tentative testing.

All axis working from LinuxCNC (well, the MESA configuration tester anyway). Enable relays work. The only issue I have is that using on the Z axis when I disable the axis (ie disable the relay which puts +5v across the "Enable" pins) the table drops slightly. I may have to reconsider a brake but for now I'm going to have to reconfigure it so it's always on instead of being an "Enable" relay

Next up is wiring in the limit switches and then can have a proper play.

 

[Bitterend]

What has happend to the pictures from halfway down page 5 onwards?
I have one of these milling machines and was particularly interested in the X axis ball screw. Now I am thinking about full CNC conversion. It does mean learning about the control side of things though.