[dmauch]

The stepper motor vibrations will not effect the probe since these will
typically reside in another frequency band.

The electronics involved are completely basic. Cost would be less than $15
including the piezo element.

Testing should be as easy as connecting a function generator to the piezo,
finding the resonant frequency and using a LED to monitor the feedback
will probably work.

1) Because it so super sensitive, it would usually be more prone to false positives. THis could specially happen when the frame/steppers get into resonance and things start to vibrate. This could lead to vibration at the needle point and thus create a false positive.

2) It's just a other way of connecting the piezo element...

Still,
this way of creating a probe is harder to make for the average builder because you need to create some sensitive electronics, not easy to build.

The idea is good still, but needs some clever working out of the electronics and testing. The probe using a switch is much simpler to build, no complicated electronics and can usually be connected to a BoB straight from the switch. THis will be good enough for most hobbyists.

Ries

[MichaelHenry]

Centering the probe involves using on indicator and slowly turning the spindle by hand. You have three adjustment screws to get it as close as possible to zero. If it is off of center your location will not be where you think it is.

Once it is centered, I don't think you would have to recenter it very often unless you crash it like(nuts) I did.(nuts)

I was able to do a probing routine using the digitize wizard included in Mach3.
It worked flawlessly. Arnie's probe is also tough. I was testing a specialized function and drove the probe into my vise at 30 ipm. Good thing my hand was on the e-stop. I bent the end of the probe but nothing broke. I will have to whip up a spare tip or 2. So far so good on Arnie's probe.

As far as accuracy, a quick and dirty test using the DRO on Mach3 and approaching the vise from the same direction to take backlash out of the equation, it repeats to within a few tenths IIRC, definitely well under a thou.

Mike

Thanks for the user report. I have an early version of Arnie's probes and am not sure if he changed the design or manufacturing or not, though it sounds identical. I was having trouble wiring mine and damaged the internals while "dissecting" it. It seems to be working pretty well now but I've yet to verify calibration or accuracy. A few tenths or even a thou would be great.

BTW, I replaced the three cup set screws on mine with self-locking flat nose set screws like these:

http://www.mcmaster.com/#94495a210/=525vfc

I figured the flat nose may minimize gouging and the self-lock feature should help keep the screws from backing out and make it easier to feel how much you are turning the screws in or out. I also use a small Chapman socket wrench with Allen wrench attachment. The wrench has 20 "clicks" so it is fairly easy to adjust in 18° increments.

Mike

[turmite]

Thanks for the user report. I have an early version of Arnie's probes and am not sure if he changed the design or manufacturing or not, though it sounds identical. I was having trouble wiring mine and damaged the internals while "dissecting" it. It seems to be working pretty well now but I've yet to verify calibration or accuracy. A few tenths or even a thou would be great.

BTW, I replaced the three cup set screws on mine with self-locking flat nose set screws like these:

http://www.mcmaster.com/#94495a210/=525vfc

I figured the flat nose may minimize gouging and the self-lock feature should help keep the screws from backing out and make it easier to feel how much you are turning the screws in or out. I also use a small Chapman socket wrench with Allen wrench attachment. The wrench has 20 "clicks" so it is fairly easy to adjust in 18° increments.

Mike

Guys, I think you are talking about two different probes. Arie and Arnie are real close and the $100 probe I am 99.9% sure is by Arnie from up in Montana or Wyoming, or Idaho, or.....well you get the idea!

Mike

[TOTALLYRC]

Here is where I made contact to buy mine.

http://www.machsupport.com/forum/ind...ic,5004.0.html

And since Michael Henry has also posted in the same place recently I will assume we have the same probe.

Merry Christmas

Mike

[turmite]

zarzul on the Mach forum is Arnie Minear from Wyoming. I thought it was but wasn't sure.

He is a super nice person both to email with and talk with.

Mike

[arie kabaalstra]

zarzul on the Mach forum is Arnie Minear from Wyoming. I thought it was but wasn't sure.

He is a super nice person both to email with and talk with.

Mike

hey!.. i'm nice too, but i'm not from anywhere near Wyoming..

My probe design is way smaller, and the adjustscrews don't tilt the PCB inside, but the entire probe-body, which pivots on a ball-bearing.
furthermore, instead of steel ballbearings, i use gold-plated contacts.
instead of a steel stylus, my probe comes with a ruby-tipped stylus as standard

[turmite]

hey!.. i'm nice too, but i'm not from anywhere near Wyoming..

My probe design is way smaller, and the adjustscrews don't tilt the PCB inside, but the entire probe-body, which pivots on a ball-bearing.
furthermore, instead of steel ballbearings, i use gold-plated contacts.
instead of a steel stylus, my probe comes with a ruby-tipped stylus as standard

arie....my most humble apologies! No wait, the little green face did not look humble.....sorry about that! I also apologize for what appears to be an endorsement of one probe over another. That was not the case. It is that Wyoming is a lot closer to me than the Netherlands, and I had the chance to call him. If you have skype, I will be glad to call you and then report back as to how nice you are!

I would love to have one of your probes, but I already have one from IM something or other along with the controller board for encoder feedback that is supposed to make this thing probe at something like 50,000 points per hr.

I am thinking of selling the whole package and getting someting less $$.

Mike

[Drools]

I'm looking at building a TP but I have yet to make anything this complicated with my router. All I have done so far is a few PCBs using Eagle and pcb-gcode. I have purchased a licensed copy of Mach3 but not LazyCAM. I use a Wolfgang spindle and it only accepts 1/8 shank bits. I have a couple of 1/8 end mills and possibily a couple of 1mm to 3mm bits I could use but I'm not experienced enough to do this. I have AutoCAD 2008 to work with and I have downloaded all of the files 10bulls and MrBean have posted.
I would be greateful for any help.

[Drools]

With the help of JayC and his CAM program (as I currently do not have one, a big thanks Jay) I made a touch probe from Delrin. Tough stuff to mill at 16K+ RPM. I used a 1/8 shank, 2 flute end mill. Also I used the dxf drawings from cognitivesolutions.
here is a pic of the almost finished probe and what I started with.
If anyone is interested in the gcode just let me know.
Now I have to figure out how to load the plugin and start digitizing something. I have many somethings in mind

[jalessi]

Drools,

Nice work!

Where are the DXF files posted?

Thank You,

Jeff...

[MyCattMaxx]

Now I have to figure out how to load the plugin and start digitizing something. I have many somethings in mind

With as wide as the tip of that probe is what kind of resolution are you trying to get?
It looks way to big to do lets just say the surface of a coin.

[Drools]

I'm a complete noob to using a touch probe. If I need a new tip then I will make one but at this time I just don't know...
I have seen tips using a ruby, why I don't know.
I downloaded the dxf files from here
http://www.cognitiveinnovations.com/news.php
One thing I would like to add to the dxf files are index notches to the top and bottom so they line up easily. We had to make our own decision on the depth of the bottom as it is not given. We also had to be creative as the bit gets hot and melts the delrin, we add retracts to the code. retract to 1" then to 0 then to the new depth after each long cut. Often the bit will pickup a strand of delrin and act as a fan LOL.

[The Aspirator]

I recently made a touch probe and a touch plate using most of the ideas from arie kabaalstra's design, pics are attached. This was the first real project I machined on my new CNC'ed X2, so I think it turned out great! What a learning experience.

I finally started using it a few days ago after finding the Mach3 center/edge finding button codes that Hoss provided in his DVD's, they're awesome! But I'm having some SERIOUS electrical interference issues, it's falsely tripping every few seconds, and rarely ever making it all the way through a short center finding exercise. I figure it's gotta be a shielding issue, even though I'm using shielded wire, and no combination of shielding or aluminum foil "temp shielding" will result in a trip free setup. My e-stop is also tripping, so it hasn't been wired up. The shielded wiring for e-stop and probe doesn't have any other signal wires in that bundle, but they are zip tied to my stepper wiring (also shielded). The wired thing is that when I ground the probe shield wire, my steppers hiss at a different frequency. This doesn't happen for other shield grounds. So I think I'll have to run a new wiring bundle for e-stop/probe and see if that fixes it. Thoughts anyone? It's totally useless until I eliminate the interference.

I don't have my tach hooked up yet however it does run in the same wiring bundle as the e-stop/limit/probe, so that might cause problems.

If I had to make another probe, or maybe consider these tips for anyone thinking of make one yourself, there are a few things I'd change. First I didn't realize until a few days ago that the Wyoming guy is selling a similar one for $140, that's a STEAL of a deal. But with my design, the biggest thing I hated was soldering those stupid little wires to the pins and managing the wires in the housing. A circuit board would be SOOOO much easier and cleaner, and it would allow you to solder on a proper wiring plug which would make it a lot nicer to work with. I feel like these wires sticking out right off the solder joints are going to break on me one day. If it ever fails I will replace the nylon bottom part with some sort of circuit board. And heck, the fact that you're making it means you have a cnc mill, so whipping up a quick circuit board would take no time at all. I haven't done it yet but I can't wait to whip out a few little helpful boards. By the way those nylon things were machined out a cheap walmart cutting board. You can see that I wired in an LED, just like wyoming guy does on his, what a GREAT addition! You can even use it manually and know exactly when it trips, it's pretty cool. Wiring is shown in his PDF in the first post of the link above. Having it soldered to a circuit board would have been much cleaner. I kind of like how it's pointed down at the workpiece, shines a nice blue light on the edge that I'm staring at. Although having it pointed out towards your face would be just as practical.

The ball beaing adjustment was a great idea incorporated into arie kabaalstra's design, mine seemed to be quite off center so that came in handy. However having the adjustment bolts on top was a bit of a pain, because I'd have to measure for concentricity, then remove it from the chuck, adjust, put it back, and measure again. Took about 30 minutes of dinking around to get it down to 1 thou. Somehow putting the adjustment on the bottom would be much easier. I sort of like Wyoming guy's method, although his use of RTV could be improved upon, I was thinking of a few small springs pushing the board down onto the adjustment screws (not to be confused with the spring holding the center triangle down).

I went out and bought fancy 1/8" drill rod for the contactor pins and turned them to perfect domes and tapers on my cnc lathe, when any kind of steel, even aluminum might work just fine. It sees very very little force, you could machine the entire body out of delrin or nylon and not have any problems, just so long as you can adjust it to be truly centered. I made the 3 different tips out of 4140 steel (machines niiice) just because I didn't know what I would need, but I think the 1/8" ball probe tip will be fine for anything and everything, and if I'm doing a serious digitizing routine then maybe I'd use the pointed one.

Don't be afraid to make it big. arie kabaalstra remarked how small his is at I think 1", which is cool and all, but mine is 1.5" dia and I found it to be pretty cramped inside there to route the wiring and that resistor for the LED. There's absolutely nothing wrong with having it really fat, 2" would be fine and give you way more room. I really like how wyoming guy threaded the different pieces so that they're really easy to assemble, and if I had an internal threading bar I would have done that too. (note to self, buy or machine an internal threading bar!)

I don't have a picture of the assembled touch plate, but imagine the probe without the top and with the stubby plate tip on it facing upwards. The thought is to use it to set up a tool table for an automatic (or manual) tool changer. The crux of this design is that there's no adjustment to make sure that the touch surface is dead flat, and eyeballing it tells me that it's not. I'll use a dial test indicator to see how flat it is, if it's within a few thou then I won't care. Otherwise I might have to build a bit of adjustment in there somehow.

Once I figure out this electrical interference wiring issue I can already see that this tool is going to be used all the time, it'll be SO handy for finding center and edges!

[wmgeorge]

Been watching all these posts with great interest and I've abandon the PC board idea. Yours seems to be the way I am going to go, but with some changes. Instead of using steel rod and ball bearings, I did some checking using my digital ohm meter and some different materials. I seem to get less resistance using a machine screw with the threaded part making the contact, (for the pivot contact) in this case I am using round Phillips head stainless screws instead of the ball bearings. Part of the lower resistance is the fact that you are really passing very little current through the surfaces, and having the screw threads making the contact means several points of contact instead of just one.

Just going to loop tinned hook up wire under the screw heads and solder on shielded stranded 2 conductor cable to my mini plug.

Time will tell. Right now having a slight problem doing much after having surgery on my right index finger.

BTW I am using this probe on a IM service CNC router.

[arie kabaalstra]

i'd stick to PCB design i if i were you.. i sold my design to DamenCNC in the Netherlands, after i altered the design a bit..

the probe is now for sale at : http://www.damencnc.com/damencnc.php...=EN&idComp=230

the copper pins have been replace with a PCB, with Gold-coated contacts soldered to it..

of course i built one for myself ,and that's the one shown in the Youtube Film

[nomedia="http://www.youtube.com/watch?v=5JnDloaC1YQ&feature=channel_page"]YouTube - USBCNC-Porsche 917K[/nomedia]

@ Aspirator, Nice job!, though your's is slightly bigger than mine.. i should have becom a watch-maker perhaps..

[helliman 27]

can you send me the dxf for the touch probe. i tried to find it on that site but no luck thank you.

[aminear]

Great looking job on your probe, but I have to agree with Arie, the pcb is easier to solder to.

If you want to try my design check out my Digital Machinist article Volume 6 #4 Winter 2011.

If it is too much work I do still sell these through CNC4PC.com or [email protected] , Peter Homann - from down under is selling these also for me.

Thanks for the kind reviews of my probe!

Arnie

[rsstesla]

Here's the dxf, cambam and gcode for the PCB bit...

Let the probing commence! :stickpoke

Thank you for sharing, I will try it

[rsstesla]

That's a great job!!, I will build it and share you my results....

[lerman]

Having multiple points of contact instead of one at each element misses the point of the design. The idea is that with three rods and six balls each making contact at a single point (in the ideal case which never really happens), you have a kinematic mount which is fixed with respect to linear and rotational motion in three axes. If you add additional points, you are more like a four legged stool instead of a three legged one. From time to time, you might rest on a different trio of legs.

Ken