Any ideas or thoughts on making a edge finder come touch off tool

[suesi34e]

Just to say tar very much to you members that have helpedwith various things I now have my mill going and am very pleased with it.

I think my next project other than learning more about Mach 3 will be to make atouch of probe that will double up as an edge finder I have a female socket inthe control box already wired into the break out board.

It would be interesting to see what you guys think or if you have seen goodones. I don’t want a laser pointer kind of set-up. I don’t want to buy a cheap Chinesething of eBay I would rather go to the effort and make a nice one. After all Ihave the female and male socket plus some off-cuts of wire!

All the best

Suesi

[cropwell]

I have got some Quantum Tunnelling Compound pills. These are basically 3x3x1 mm pieces that look like black rubber, but when compressed they change from an insulator to a good conductor with a sharp transition, when I have the time I am going to play with making a touch probe with them. I am intrigued to know how sensitive and accurate they will turn out.

Cheers,
Rob

[JAZZCNC]

What do you want to do.? Just find the edge and surfaces of parts or full 3D touch probe.?

Edge and surface is very easy and requires nothing more than a wire and conductive plate. 3D touch probe requires more work and often work differant regards how they sense the touch.
Simple plate wire plate setup "makes" the circuit so it goes active when High. Most touch probes work opposite and go active when circuit is "broke" or Active low.
Depending on your setup and control software then often the Probe input pin needs to be setup one way or the other so mixing both is a pain.
I practice you'll find the simple plate wire setup more useful has it saves so much time when finding edges and esp when setting material surface or Z height.
I use my plate setup on every single Job and couldn't live without it but can't remember the last time I used my touch probe.!!

[cropwell]

I have a simple brass block with an acrylic piece bonded to it to insulate it from the workpiece. The acrylic and brass were trimmed in the lathe and then the faces of the acrylic and brass were turned parallel. the brass has a 4mm hole in the side for a banana plug to connect to the touch probe input. Mike up the block and that is the tool height offset for Mach3. The BOB has a 10k res to 5v to keep the probe input high until the tool grounds it. A simple macro in Mach3 and I have a tool height setter that is one of my cheapest and most useful accessories.

[Washout]

I use both a 3D touch probe and touch plate i.e. both of the methods Jazz describes. I have a mini toggle switch rigged up to switch between the two circuits, but it does mean going into Mach3 to change from active low to active high depending on which one I am using.

I would say the 3D probe is more convenient once its in the tool collet as my machine laying flat means I would need arms 6 feet long to click the probe button and hold the plate to the part. That said I have had to use the touch plate only and it works fine as its very simple and I still use it to set my tool height.

The 3D probe also gives you the option of "scanning" objects into MACH3/CAD (or it would if I find time to work out how ;-) ).

[Clive S]

I have a mini toggle switch rigged up to switch between the two circuits, but it does mean going into Mach3 to change from active low to active high depending on which one I am using.

Surely there must be a way with a simple transistor so as with the switch the probe would give out the correct level o/p. Or am I missing something? I can hear Irving's brain working in the background ..Clive

[cropwell]

Click, click, durr

http://www.homemetalshopclub.org/new...ation_1202.pdf

[JAZZCNC]

For 3D work these probes are great and inverting the signal is easy enough but just for every day use for setting Z height etc then it becomes a pain swapping out the probe.

Like I say it depends on what your wanting to do and how you use your machine.
For instance routers tend not have tool holders that can be set off the machine so can't use tool offsets. In this case the simple touch plate is great because you fit the tool and probe with the tool for each tool change. You can also use the tool for finding edges etc by putting plate between if non conductive material.

Mill's on the other hand tend to work with holders and can use tool offset's so after initial setting of material height the touch plate isn't so important. It can still be used for edge finding etc same as above.

So IME I find the plate much more useful than the 3D probe. It is possible to permantly fit and offset the 3D probe but would need careful setup and offsets applied thru scripts etc so not exactly simple.

[suesi34e]

Hi Rob,
Very best of luck with that it sounds complex to me! I shall go for something basic.
All the best
Suesi

[suesi34e]

Hi JAZZCNC,

Thanks very much for your help here again with your posts. Yes, I just want tomake a tool to find edges and surfaces of stock perhaps later a center finderfor holes but nothing more at this stage. I am using Mach 3 by the way I justwant something for ease accuracy and to save the eye squinting / problems Icould run into.

Thanks again

Suesi