Text Size

Auto Tool Zero Method for XYZ Axis Using Mach3 - Part 1

Auto Tool Zero Method for XYZ Axis Using Mach3 - Part 1

Postby airnocker » Sat Aug 21, 2010 12:44 am

Are you looking for a simple, sequential method to set the work piece XY axis to “0,0” and the work surface Z axis “0” location on your CNC mill? The method I devised makes it simple and easy and requires only one touch plate device, the existing Auto Tool Zero button on the Mach3 screen and my custom Visual Basic code for the button macro. In addition, the code includes the following execution user prompts: Confirm touch leads are connected to continue (y/n)? where "n" aborts entirely, Zero X & Y (y/n)? where "n" skips to Z confirmation, Zero Z (y/n)? where "n" aborts and ends macro.

Prerequisites
First, you should have your home position switches and travel limit switches setup and operational because the first requirement to utilize this method is that you Home your X,Y and Z axis.

Second, the tool should accurately move in all three axis without any positional errors or inaccuracies.

The All-In-One XYZ Touch Plate
The touch plate used consists of a 90 degree piece of 1/8” x 1 1/4” angle aluminum that measures 1 3/4” long. It is important that the end of the angle aluminum that will serve as the XY base be a clean, smooth , perpendicular cross-cut.

The inside faces of the aluminum should be checked to ensure they are square with each other and flat. A hole is drilled and tapped for a short, 8-32 machine screw as shown in Figure 2. Pieces from a 1/16” copper clad circuit board are cut to match the dimensions of the inside faces of the aluminum angle. The circuit board material must make a butt joint with each other in the corner. The circuit board material is Super Glue'd with cyanoacrolate glue to the inside faces of the aluminum angle and held by compressions clamps for an hour. Using a digital micrometer, the thickness of the Z-axis touch plate side is then measured in multiple places to note any thickness variations and written on the face of the copper with a Sharpie pen. Mine in uniformly .180" thick.

TouchPlate-1s.JPG
Figure 1
TouchPlate-2cs.JPG
Figure 2


As Figure 1 above illustrates, the top, inside corners of the copper faces are soldered together. A small gauge wire is also soldered into the corner weld and bent around to the opposite side, stripped and tinned on the end. The Touch Plate signal lead is made from 16 Gauge silicon wire terminated with a Banana plug on one end and a lug crimp connector on the other.

The small wire is clamped between the lug crimp connector and the aluminum backside by the screw.
Figure 1 and 3 illustrates the “standing” position of the touch plate for XY zeroing.

TouchPlate-5cs.JPG
Figure 3


Figure 3 shows the XY touch plate against the intended work piece's XY 0,0 corner while Figure 4 shows the Z touch plate resting on the work piece.

Figure 4 illustrates the “sitting” position of the touch plate for Z-axis zeroing.

TouchPlate-6cs.JPG
Figure 4


Tip: The copper surface will tarnish over time from handling it with you hands. You should periodically clean the surface with alcohol to remove oils then burnish the copper with a pencil eraser. This is especially critical for XY touching. When doing the XY “touch” press the angle aluminum against the work piece's corner if necessary.

My Mach3 Ports and Pins Settings
Figures 5 and 6 shows my Mach3 Ports and Pins settings for Inputs. I am using the Probe input for the Touch Plate but any unused Input could be used.

M3 Ports & Pins-Input.jpg
Figure 5
M3 Ports & Pins-Probe Input.jpg
Figure 6


For the logic ground terminal I am using the Port 15 Common terminal on the Break Out Board (BOB).

I will include the details of the Visual Basic Macro along with how to do Mach3 version compatibility pre-testing and macro implementation in a separate posting.
Last edited by airnocker on Sat Aug 21, 2010 2:32 am, edited 1 time in total.
airnocker

Everything depends on everything else
airnocker
 
Posts: 620
Joined: Thu Mar 25, 2010 9:43 pm
Location: Wellington, CO
CNC Machine: Custom

Re: Auto Tool Zero Method for XYZ Axis Using Mach3

Postby michaelthomas » Sat Aug 21, 2010 2:11 am

Interesting.....I'm not quite to this point yet, but thanks for posting this.
michaelthomas
 
Posts: 180
Joined: Sat May 22, 2010 2:37 pm
CNC Machine: RedFrog

Re: Auto Tool Zero Method for XYZ Axis Using Mach3 - Part 1

Postby JayCop » Wed Dec 28, 2011 9:45 pm

Im having a problem in Mach3 where the probe light is constantly on. Any ideas why it would not go out? I have active low set and the proper pin selected. (pin 15)
JayCop
 
Posts: 3
Joined: Wed Dec 28, 2011 9:42 pm
CNC Machine: RedFrog

Re: Auto Tool Zero Method for XYZ Axis Using Mach3 - Part 1

Postby airnocker » Thu Jan 05, 2012 12:09 am

JayCop,

When I first posted this topic I failed to mention an important piece of information. I am using the CNC4PC C1R10 Opto-Isolated Break-Out Board. The input port pins on this board can be individually jumpered to be either Pulled-Up to 5vdc or Pulled-Down to Gnd.

How your BOB input port pins are setup may yield different results than what I've described.

I'll be more than happy to help you figure out what is happening.
airnocker

Everything depends on everything else
airnocker
 
Posts: 620
Joined: Thu Mar 25, 2010 9:43 pm
Location: Wellington, CO
CNC Machine: Custom

Re: Auto Tool Zero Method for XYZ Axis Using Mach3 - Part 1

Postby JayCop » Thu Jan 05, 2012 12:24 am

I believe that my BOB is the C10 and that the jumper sets all inputs to the same settings.
JayCop
 
Posts: 3
Joined: Wed Dec 28, 2011 9:42 pm
CNC Machine: RedFrog

Re: Auto Tool Zero Method for XYZ Axis Using Mach3 - Part 1

Postby airnocker » Thu Jan 05, 2012 1:24 am

Here is the thing to consider on any touch plate implementation. (let's assume your system and Mach3 is powered up and reset)

1. One of the leads used connects from the touch plate to a BOB input. So is your BOB input normally pulled HI or normally pulled LO with nothing connected to it, and when measuring between it and circuit ground with a volt meter? In your case the BOB input is pin 15, so measure between pin 15 and ground. Does the meter read close to 5v or 0v?

2. The other lead that will connect from either circuit ground or 5vdc depending on the answer to item 1 above. This lead will be connected from that point on the BOB to an alligator clip of some sort at the other end that will be clipped on the router bit during the Auto Tool Zero execution. My preference is to connect the "Ground" lead to the router bit, thus making the touch plate the router bit will come down and touch have to be normally HI or at 5v.

3. Now, if pin 15 is normally LO, then to make it "active" it would have to connect to a HI (5v source), but if it is normally HI then to make it "active" it would need to connect to a LO (Ground source). This is how you determine whether in Port and Pins > Input Signals the Signal line is set to Active Low (Green Check) or not (Red X) .

Does this help?
airnocker

Everything depends on everything else
airnocker
 
Posts: 620
Joined: Thu Mar 25, 2010 9:43 pm
Location: Wellington, CO
CNC Machine: Custom

Re: Auto Tool Zero Method for XYZ Axis Using Mach3 - Part 1

Postby JayCop » Fri Jan 20, 2012 1:10 am

I picked up a grecko g540 and the setup block is working great with that.
JayCop
 
Posts: 3
Joined: Wed Dec 28, 2011 9:42 pm
CNC Machine: RedFrog

Re: Auto Tool Zero Method for XYZ Axis Using Mach3 - Part 1

Postby airnocker » Fri Jan 20, 2012 1:43 am

Glad to hear you found a solution, JayCop.
airnocker

Everything depends on everything else
airnocker
 
Posts: 620
Joined: Thu Mar 25, 2010 9:43 pm
Location: Wellington, CO
CNC Machine: Custom


Return to Tutorials

Who is online

Users browsing this forum: No registered users and 2 guests

Who is online

In total there are 2 users online :: 0 registered, 0 hidden and 2 guests (based on users active over the past 5 minutes)
Most users ever online was 158 on Thu Mar 08, 2012 8:54 pm

Users browsing this forum: No registered users and 2 guests