New toy... economical 3D probe

This little gadget arrived in he post this morning - a 3D probe from China. Neat little design that takes up minimal daylight, has 6mm shank. Works on the original Renishaw principle, available from several sellers on eBay and AliBaba. Prices range from ~£50 upwards, this one cost me ~£59. A few people have used them over on the mycncuk forum and found them very good.

Though I have home-made conductive edge and height finders which I use with probing routines of course they don't work on non conductive materials and the height one is really limited to tool setting.

I'll report back!

I have a similar one used on a Bridgeport mill. It is my go to device for edge finding and for centering.

How easy is it to centre the probe? I have a similar device but a bit chunkier that came with my second-hand CNC mill. Works OK but recentring after changing the probe is a pain. The three adjusters are difficult to see and their thread pitch is a bit coarse. OK, maybe I shouldn't need to change probes that often but I do have a habit of occasionally driving them into the work, to the extent that I now make my own.

That's neat and compact John will it work with Mach 3? Might be just what I need for my KX1

IanJ

If it will plug in to Mach 3 I will be adding one to my Xmas present list!

Haven't tried it yet but I'm assured that it is Mach3 compatible. Just has a NO NPN compatible output.

I have had some issues with Mach3 probing macros. Does it come with any software or a link to where they are available? The issues are powering past the point of contact and damaging probes. I see from looking at the blurb for these they only have a 4mm over run limit in XY and less in Z. I have considered putting a magnetic break point in a probe to avoid damage.

Martin C

I've written my own macros and not had overrun issues.

The problems are not consistent, usually the macros I have work but occasionally they go gaga.

Martin C

Ok, just lashed up for a quick trial, and it works beautifully with Mach3. Mine was set up for NO npn, i.e. expects the probe to assert a low level as if the probe was grounded. Exactly what the new probe does, so no change required. I just needed to provide a 5v supply for which I use an old phone charger.

What interface does the probe plug into normally John, i.e. when not used with a CNC device?

Just needs a 5v supply. It has some cool built in green LEDs that light when powered and turn red when triggered.

But how does Mach3 or whatever you are using know when to touch the surface if the wires only go to a power supply?

Or is it more of an electronic edge finder that simply flashes red on contact with the edge

I was replying to Pete. There is a signal wire too for the probe input to Mach.

I have one. Seems to work great on LinuxCNC using the Probe Basic Subroutines. I have added a resistor to the supply wiring so I can use another input to indicate that the probe is plugged in. I need to modify the routines to check that input before running the rest of the g-code.

Thanks John. I will have to look at getting one of those.

I've looked at my Mach3 macros again and there was a lack of a G91 relative movement code at a couple of places. Now that I have put them in the macros seem to be working as expected. I think in some cases G91 was already set first by another macro running which did not set it back to G90 absolute motion and in other cases the direction of travel was the same for both G90 and G91.

Martin C

After being alerted by someone over on mycncuk I've downloaded a wizard called ProbeIt, the demo version, from Craftycnc. Looks like a good substitute for the macros, though not tried it yet.

I have been using ProbeIt for a couple of years now and it works well. Worth the cheap price.

I use it with my home-made CNC probe.

Finding a hole centre:- **LINK**

Les

Tried ProbIt this afternoon and I have a warning for anyone with a rigid or near rigid probe, don't use it in its current release. I put a piece of aluminium tube in the vice only held loosely as I did not want to make it oval. I decided to try the internal hole probing routine. After the probe has made fast X axis contact with the right hand inner surface it backs off then makes a slow approach for a more accurate contact. Then it does what it should not, it moves towards the material before pulling back again. In the case of my lightly held tube it actually moved the tube in the vice. I also observed it doing the same thing when probing in the Y axis. This is not good and needs to be corrected. I stopped at that point because I didn't need to find it was doing similar things with other probing options and running the risk of damaging my probe.

Martin C