OmioCNC report

[VisualConduct]

I use the probe and it does work but mine is uneven, I think there is around 0.1mm deviance across it (I can't remember exactly) which shows when probing a larger tool and cutting on the same height surface, as the larger tool always catches a higher spot. To use the probe you have to set the offset in the offsets page. I leave my probe fixed in place and do this by chucking up my DTI and measuring the difference between the top of the probe and the top of my stock, it works ok, but I'm in the process of making a small fixture plate whereby I will use the top of the fixture plate as the offset point and start setting up my CAM using that as the Z zero point, it will save messing about at the start of each job. It doesn't take long but it gets tedious.
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Thanks Mmpie,

Yes that probe is kind of a nonsense I guess, maybe better to use a more precise all or copper plate instead.
I have it working now, but only with the original screenset, when I use the (most excellent) 1010 screenset by Mach3 2010 Screenset I start to have problems....
For now I try to have this working, but when I will be organised and have things working, I will dive into the method that you are speaking about.

Kind regards, Robert

[Mmpie]

I've gone off bourbon, it was getting too expensive. Not that I've stopped making ill considered eBay purchase decisions just because I've switched to scotch...

Heh. $400 on 6061 stock today, all I wanted was some 10mm plate to make my tooling mounts for the 4th axis and tailstock but I may have gotten a bit carried away.

Looking forward to see if the real thing looks anything like the render!

I have the opposite problem with everything, I buy too little and end up paying more in delivery charges


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[RCaffin]

Do you mind Roger to share the link of that shop with us?
Um - that was some time ago. I think I bought all of them from CTC when he was in Hong Kong. He has since moved to Europe somewhere, and we have seen recent reports from quite a few unhappy customers.
The secret back then was that the owner of CTC was actually able to pop over to the mainland and visit the factories which made the stuff. That way he could avoid all the dodgy brothers. I have to say that seemed to work.

I have also bought a few imperial-sized collets from Mari-Tool, but their single-collet prices were similar to the Chinese full-set prices. At the time though I could not find Chinese collets in imperial sizes, only USA ones.

Looking at a 'typical' Chinese ER25 set on eBay, the specs say
Style: ER25
Hardness: 46-50HRC
Standard: DIN6499b
Accuracy: 0.005mm
The ones I bought did seem to meet the DIN Standard.

'Do you feel lucky?'

Cheers
Roger

[RCaffin]

Hi Harmic

I found that the tailstock was far more important than I had expected - and a bit more difficult as well.

Cheers
Roger

[dharmic]

Yep, I watched with horror as my super chinesium alloy head stock nodded visibly when confronted with the mighty load of a 6mm cutter trying to skim 0.2mm off a bit of brass about an inch from the chuck. Tailstock fixed it.

Making the subplates for the tailstock and head has been pretty easy, getting the slider rails for the tailstock is proving a bit more painful. Still learning about proper clamping etc, made somewhat more challenging by the lack of a decent vice. And 140mm gantry height on these machines would mean, even if I had a Kurt or similar, I'd not be able to use it most of the time.

[extent]

Finally done (enough) with my probes

5mm ball for setup and 2mm ball for digitizing. Only about 84mm offset for the longer one so it fits great in the short Z travel under the gantry, clears the vice on the fixture plate with maybe 6mm to spare. Repeats pretty easily to within 1 or 2 steps, around 3 micron, the rest of the machine is a bigger source of error, makes it hard to tell.

The digitize sample was done at .1 mm step size, lit to highlight imperfections as strongly as possible. 50k ish samples. The vertical banding is along the direction of travel during the probing routine, so the results stayed fairly consistent until the machine had moved in 2 axis. Took about 74 hours to complete so it could even be temperature shifts.

[dharmic]

very nice!

[RCaffin]

Interesting design for the probe interior. Looks good.
You might be interested in MYOG probe tips as well: see
http://www.cnczone.com/forums/calibr...ml#post1956342

Cheers
Roger

[Stigoe]

Finally done (enough) with my probes

Is this a homemade probe or a commercial probe? If it is a homemade probe, do you have drawings and schematics you're willing to share?

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[Mmpie]

I want a manual edge finder, just something cheap that's quicker and easier than chucking up a rod and feeler gauges.

Anyone used one of those LED ones or should I go for one that's like a dial gauge with the hinged prong instead of a plunge?


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[dharmic]

I made a touch probe as well. A little simpler, without the electronics in the probe so I could keep two wires back to the black box. Of course, I have to flip the polarity when I swap between this and tool height plate but it's still pretty handy. Sort of. It'll be a lot handier when I've written some macros to touch off a corner of a workpiece, find the centre of a hole and a couple of other things.

In the meantime, I find a lot of what I'm doing at the moment is getting an edge aligned with X or Y axis of the machine and you can't beat a little run-out gauge for that. I ended up getting a bigger mag base and I can use the arms that came with it in a collet in the spindle to hold it in place, with a lathe dog on the collet nut pushed up against the bottom of the Z ways to stop the spindle from spinning and throwing the readings off.

[extent]

You might be interested in MYOG probe tips as well: see
http://www.cnczone.com/forums/calibr...ml#post1956342

Thanks for that, it was a big inspiration early on. Bit too lazy to chase that rabbit hole further right now with qmark styluses being priced not too bad and easily available, but it's certainly in the back of my mind.

Is this a homemade probe or a commercial probe?

all home made, not decided if I want to put up the cad and board files for it yet, but I'll be doing a step through of the design within a couple weeks on my YT channel at the very least. Not really anything different from other reneshaw clones aside from using a comparator to allow me to use a conductive contact vertex. Side benefit of the particular comparator also being a push/pull driver so the input doesn't need a separate pull up/down, but I'm not really taking advantage since it all goes through a little multi probe board to get the tool setter, probe, and touch plate all working together.


For a manual edge finder I like the Little Machine Shop 1/4 shank edge finder well enough. Not sure what you mean by hinged prong, like a dial test indicator or a Haimer 3d taster? A test indicator really isn't meant for that kind of thing, it would be way fiddly to keep adjusted on axis, a regular manual edge finder would be far simpler. Haimer I'm not sure if you could get one small enough for your average benchtop gantry machine, and they're really expensive comparatively.

I had been thinking about putting a steel plate on the spindle holder for a mag base, just chucking up an arm in a collet sounds a lot simpler.

[dharmic]

Once you have a PCB that does the logic and power (yah, it's on my project list) the touch probe is a handy dandy little add on. But it's not the be-all and end-all of measuring on your machine, I only mention this because it surprised me. Sure, it replaces my wobbler/edge finder and being able to do a G31 move which stops at deflection is great for touching off a zero. But I still get a tonne of use out of a cheapo dial test indicator when setting things up - the touch probes aren't great at letting you run along an edge and seeing how far it deflects as you go along.

[extent]

oh ya, I probably use a test indicator more than anything, so many things that a contact probe just can't touch (heh) I'm really curious to try coord system rotation works out for dealing with alignment issues, but I only have really simple probing routines written right now.

For doing a rough setting I did find it pretty handy to put a led on your main screen that shows the probe activity status if there isn't an indicator light on the probe body itsself. Really quick to probe a zero just above a fixture pin, move the gantry down the axis you're trying to align to and pivot the work piece until the probe triggers without having to do a full probing routine. When 'close enough' is all you need.

[dharmic]

Dragged out the touch probe today to do a bit of zero setting, it's really nice for that. Gave it a go getting something square and there it's not great, but it is good for confirming that something's set properly in a fixture before hitting the big GO button

Got my sub-plates sorted for the 4th axis today. No more stuffing around getting everything aligned, it now takes 3 minutes, four dowels (two for head and two for tail) and eight bolts that I can reach with a cordless driver from "I need the 4A" to chucking up a part in a properly aligned, ready to rock and roll rig. Very pleased.

[VisualConduct]

Looking at a 'typical' Chinese ER25 set on eBay, the specs say
Style: ER25
Hardness: 46-50HRC
Standard: DIN6499b
Accuracy: 0.005mm
The ones I bought did seem to meet the DIN Standard.

'Do you feel lucky?'

Cheers
Roger

Thanks Roger, your link is not working, but I found something quite decent I think:

ZJchao ER20 Precision SPRING COLLET set 13 pcs 1mm-13mm CNC MILLING LATHE CHUCK | eBay

They have a runout tolerance of less then 0.008mm, they don't provide hardness, but honestly I have no clue how hard it matters.

Kind regards, Robert

[VisualConduct]

I now want to square things up on the table.
The X axis ends up aprox. 1mm to high (or to low, don't remember) compared to the Y axis.



I was thinking to widen the holes on the side panels and adjust as necessary, also using epoxy under the bolts to hold things in place.

Good idea, or are there better solutions to this?
Is this something more people where running into?

Regards, Robert

[Mmpie]

Mine was out, the big plate the gantry sides bolt onto isn't flat. Once you've surfaced a spoilboard, or like Dharmic got a flat bed and shimmed it square with the spindle, the uneven ness doesn't matter anyway as your work surface is level relative to the tool. The bed is worse than any other part of the machine, one of my bed panels is almost 1mm higher than the next! The frame isn't flat and level either. Personally I wouldn't bother, and just face mill a nice flat surface to clamp your work down to.

Also the normal t slot bed bows like a banana when any sort of force pushes down on it, so getting things accurate in Z is like trying to piss in the wind.


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[VisualConduct]

Mine was out, the big plate the gantry sides bolt onto isn't flat. Once you've surfaced a spoilboard, or like Dharmic got a flat bed and shimmed it square with the spindle, the uneven ness doesn't matter anyway as your work surface is level relative to the tool.

Thanks Mmpie, maybe I did not make myself clear, I was not speaking about the bed but the angle between X and Y.
I need to be able to cut square parts and now they are way off.
I check the levels of the bed, its better then I was afraid off: 0.3525mm.
I will deal with that later, first I want to be able to cut square parts.

Regards, Robert

[Mmpie]

Ah I see, I would investigate where the problem is before drilling them out, it might be something that can be shimmed or some such easy fix, opening up the holes I think could leave that joint more susceptible to vibration/wobble.


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