> -----Original Message-----
> From: Gene Heskett [mailto:ghesk...@shentel.net]
> Sent: July-14-19 8:26 AM
> To: emc-users@lists.sourceforge.net
> Subject: Re: [Emc-users] Work holding machining Techniques
>
> On Sunday 14 July 2019 09:46:02 andy pugh wrote:
>
> > On Sun, 14 Jul 2019 at 14:43, Roland Jollivet
> > <roland.jolli...@gmail.com>
> >
> > wrote:
> > > Jogging up is better, backlash notwithstanding.
> > > Use an accurate rod or the shank of an endmill, say 10mm
> > > Jog upwards while you gently try to roll the rod under the cutter
> >
> > Yes, I should have perhaps gone in to more detail of the touch-off.
> > The way you describe is what I do when I want accuracy, I use some of
> > my massive stock of broken end-mills as the reference.
> >
> > But for a skim cut to start a job, especually with the big shell mill,
> > I often simply jog down until it starts to cut, and call that my
> > surface (it soon will be)
>
> Another technique I've used, works well on the G0704 as its spindle is
> well grounded, and when making a "box" of parts, is to plant a small bit
> of pcb at some fixed and findable point on the jigging with super glue,
> and run the machine to above it. The top of the pcb is connected to the
> probe input, I start the spindle in reverse so the contact is not
> destructive either to the copper or the tool, go down to the probe trip,
> then back upwards at about 10% of the down speed until the probe opens.
> This point is recorded as the #<_tlo>, and that becomes z=0 for the rest
> of the time that tool is in use. Unforch I've got to figure out a
> better way on the 6040 as theres no way, with all the epoxy paint, and
> apparently ceramic bearings in the spindle motor to assure a good ground
> on the tool. So I've both a spindle mount probe and a contact
> pad/switch. Now my problem is a solid mount for it... Due to the wires
> stiffness, and its low weight it cannot be convinced to lay dead flat on
> the table. Combine that with the lack of a grounded tool needing to have
> a ground clipped onto the tool and a PITA is what it is ATM. But I'll
> figure out something.
>
> Just saying there's more than one way to skin this cat.
>
> Cheers, Gene Heskett
> --
For my CNC router I use the PCB with a very thin flexible wire soldered to it
and to an input on the BoB. When I press the tool zero button on MACH3 it runs
a customized macro I wrote that throws up a dialot telling me to put the ground
clip onto the tool. It expects the tool tip to be within a specific distance
of the PC board which I lay on top of the work I want as Z Zero. Once I've
done that I click on OK and it goes down probing for contact with the PCB.
After it's found that it adds the PCB thickness to the Z axis position and
retracts to the Safe Z location. Then throws up another dialog telling me to
remove the clip from the tool. Nothing runs until I click OK on that.
John
_______________________________________________
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users
