Electronic tool touch off plates... What? Where? How?

[ChrisInEstes]

I saw this in another post, and didn't want to hijack that thread.

A quick Google gave me the general idea of how these work, and they seem like one heck-of-a-good idea. I use Mach3, will a touch plate work automatically with it? If so, what would the details of using one be? Is it a fairly simple setup process? Which touch plate is the best value?

Thanks!
Chris

[lovebugjunkie]

you have to have a "script" that you can run, you also can add buttons to the Mach3 screen to start it.
The script here will work on any machine,http://romaxxcnc.com/screens.html

Also on the Mach3 forum you can find many versions of the script, I use the one from the Romaxx site as i have a HS1 and using his screenset was easy to get working. (I did not have to set up my own screen)



Just copy and paste the script to your copy of Mach3 if you don't want to see the Romaxx logo and add button or two.

[PaulRowntree]

I must admit that I am too paranoid to let the machine do this automatically, with fear of open circuits, and so my plate is 100% manual. My plate is a two-sided copper printed circuit board, wired up to a 9V battery in series with a resistor and LED. Test the battery by touching plate to tool, make the approach to within a few tens-of-thou by eye, then step it down in steps of 0.001" until my LED comes on showing contact. Type the thickness of the plate into Mach3 (0.060") and it is good to go. 60 seconds to do it all for nervous nellies like me.

I keep promising to get Ger21's screenset ...

[Mick Martin]

I have been using a Z zero touch pad for years ...... the only way to go.

[Adrian]

On my ShopBot I have a touch off bolt that can be adjusted as I skim the surface down for wear. I have automatic routines that go there, touch off, set the z-zero and the maximum retract of the Z (I added an additional proximity switch at the top of the Z).

I also have jigs that use similar routines for setting the X,Y and Z. I often place several of these on my 8x4 table and use routines to automatically record the positions of each one so I can machine batches quickly and easily.

I try to automate as much as I possibly can. I have an irrational hatred of doing something manually more than once!

[zeeway]

I use Mach 3 Blue Screen (Big Tex version)...this has a z zero function built in...you have to enter the thickness of your grounding plate:

This shot shows my hi-tech ( ) z zero plate attached with a clip to the grounding point by the router:

I also have a additional grounded lug (top of hex bolt embedded in table), to use to touch off after a tool change to ensure z zero is the same:

I have used this arrangement for several years and it works well. I have found that your router must be plugged into the same electrical circuit that your control is plugged into - to assure a common ground. I know it should work on any circuit to the same panel, but I would rather make sure.

Angie

[ChrisInEstes]

Wow... lots of great info in such a short time...

I'm with Paul, I'd want to do it manually. One more thing on my list... a touch plate.

Thanks!
Chris

[TReischl]

Different strokes for different folks!

The auto touch off works extremely well. There are actually two probes made.

First the tool comes down at a speed set in a dialog. Then, the tool retracts a little bit and comes down again at a much slower speed (IIRC a percentage of the original speed).

For a simulated "auto tool change" (that means the operator is the tool changer), the first tool is set by using a movable plate on top of the work, or on the spoil board. After that, everytime a tool change is called, the tool moves to a predetermined spot, the operator changes the tool then presses the Run button. The machine moves to a fixed plate on the machine bed and touches off. The macro does some math to figure out the difference between the first tool and the remaining tools to set a proper zero.

I use a gecko with a power supply that is a snap to connect the plates to.

[PaulRowntree]

I'm with Paul, I'd want to do it manually. One more thing on my list... a touch plate.

I should add that as a hobby-type, I don't do this so often that going manual is wasting my time. Slowing down to think is more important at my stage than trying to speed things up to make a living. My less-than-total confidence in my home-built is part of this too...
Cheers!

[daniellyall]

this is the macro I use for hight setting it works extremely well have never had a brain fart with it

Rem Auto Tool Zero Z- Metric Version
DownStroke = -25 'Set the down stroke to find probe
DownFeedRate = 100 'Set the down FeedRate
RetractStroke = 10 'Set the retract Stroke
RetractFeedRate = 300 'Set the retract FeedRate

CurrentFeed = GetOemDRO(818) 'Get the current feedrate to return to later
CurrentAbsInc = GetOemLED(48) 'Get the current G90/G91 state
CurrentGmode = GetOemDRO(819) 'Get the current G0/G1 state
PlateThickness = GetUserDRO(1151) 'Z-plate thickness DRO

If GetOemLed (825)=0 Then 'Check to see if the probe is already grounded or faulty
DoOEMButton (1010) 'zero the Z axis so the probe move will start from here
Code "G4 P2" ' this delay gives me time to get from computer to hold probe in place
Code "G90 G31 Z" &DownStroke &" F" &DownFeedRate 'probing move
While IsMoving() 'wait while it happens
Wend
ZProbePos = GetVar(2002) 'get the axact point the probe was hit
If Abs(ZprobePos) <= Abs(DownStroke)-0.1 Then 'Check if the probe has been found
Code "G0 Z" &ZProbePos 'go back to that point, always a very small amount of overrun
While IsMoving ()
Wend
Call SetDro (2, PlateThickness) 'set the Z axis DRO to whatever is set as plate thickness
Code "G4 P0.25" 'Pause for Dro to update.
Code "G1 Z" &PlateThickness + RetractStroke &" F" &RetractFeedRate 'retract
While IsMoving ()
Wend
Code "(Z axis is now zeroed)" 'puts this message in the status bar
Else
Code "G0 Z0" 'retract to start pos
While IsMoving ()
Wend
Code "(Z-Plate not found, check connection or stroke and try again)" 'puts this message in the status bar
End If
Else
Code "(Z-Plate is grounded, check connection and try again)" 'this goes in the status bar if aplicable
End If
Code "F" &CurrentFeed 'Returns to prior feed rate
If CurrentAbsInc = 0 Then 'if G91 was in effect before then return to it
Code "G91"
End If
If CurrentGMode = 0 Then 'if G0 was in effect before then return to it
Code "G0"
End If
Exit Sub

[Zeropoint]

A bit of old-school tech - a modified dial gauge to set z height for tooling.
It has limitations but after 2 years of use in my shop, generally a very helpful, visual piece of kit.
1st the gauge needs to be calibrated.
Place the gauge on the work piece.
Inch down until the gauge reads zero.
The distance from the work piece to tool tip is exactly 50mm - set up zero z-point accordingly. (Tool tip point z reading minus 50mm.)
Alternately, one can place the gauge onto spoil board or machine bed surface & then subtract the work piece thickness.
The 2nd method allows for more accurate onion-skin cut out profiling & really saves wear on the spoil board.

for details & photo go to http://assets.machine-dro.co.uk/media/c ... gp7249.jpg

Rgds
Mark

[CarveOne]

I have been using Greolt's script and a piece of copper clad circuit board as a touch plate. It works perfectly each time I remember to use it - and attach the ground clip to the cutter or collet. Some routers have an insulated armature shaft and there is no ground path through the router frame to the breakout board. Copper clad circuit board material has lower contact resistance than aluminum.

It is quick to use and accurate. The Mach3 script file can be obtained from CNC Zone in the open source DIY wood router build log forum.

CarveOne

[Norb]

I favour Calypso Ventures' MachStdMill Pro (works in conjunction with Mach3) for Z touch off. It's US$ 70 but well worth it.

Check out the videos, particularily those at the bottom of the page http://www.calypsoventures.com/machstdm ... ideos.html and you will understand why

[bgriggs]

I just saw this topic and thought I would let you know about a couple of video tutorials about using touch plates. The video shows The Makers Guide Triple Edge Finder being used to locate the corner of a workpiece, set the Z zero height. There are a few other free tutorials on my website that explain how to setup a Mach3 Screenset to allow probing. Here is a link to the Tutorial page. Hope this helps.

http://www.themakersguide.com/home/tutorials.

I also include a link to the Youtube video.

Bill

http://www.youtube.com/watch?v=dhmfnea0 ... Q&index=11

[Hermie]

I've made a switch for my touch off so I can use it with a diamond drag or any non metalic cutter. It is accurate to within .0001, not the best but I can live with it, installed an led to make sure it is working (I get a little paranoid like Paul)