Touch probe available at sparkfun


(kirby) #1

I have been waiting a long time for the touch probe to come back in stock. It looks like sparkfun is selling it now and in stock https://www.sparkfun.com/products/14806


(jason) #2

I was just racing here to say the same. had to buy it first though :slight_smile:


(Patricio Suarez) #3

Thank you @keebie81!!!. Can’t believe I finally got one!!!.


(Kevin Conway) #4

Did any of you actually order/receive one of the probes from Sparkfun? The green ball says in stock but no way to add them to your cart.


(Stephen Taylor) #5

Yea I’d like to know that

Going to be upppppset if they sold out already :frowning:


(Stephen Taylor) #6

@patofoto where did you click buy? Says it’s in stock but no where to purchase it


(kirby) #7

I was able to order it when I posted this. But a few hours later I got an email from sparkfun that its not really in stock yet at the 3rd party selling it and it will be around 10days before it ships.

Seems sparkfun has started selling some items through drop shippers which is disappointing


(Stephen Taylor) #8

Ahh gotcha… So damn frustrating. I’m so tired of using the paper method :confused:


(Neil Ferreri) #9

Can anyone share the practical advantages of the Carbide 3D active probe vs a passive probe? I know there are theoretical gains in precision, but are those less than the machine tolerances anyway. I’m ok with passive homing switches. What do I gain with an active probe beyond the built-in integration with Carbide motion?


(William Adams) #10

It works as a nice power indicator for the machine (I made a mount which hangs it off the front of the machine: https://cutrocket.com/p/5a6bbc6cdbea4/ )

I find the red light / test functionality invaluable for ensuring that I actually have the clamp in place.


(Kevin Conway) #11

I contacted Sparkfun and they never had any in stock, just a glitch on their website.

sigh


(mikep) #12

This has nothing to do with the homing switches. The homing switches tell the machine where machine zero is. The probe helps determine where the work zero is. Without a probe, you’re doing so manually (or with some sort of reference like the thickness of a piece of paper, or by Mk1 Eyeball)

Here’s my take:

  1. I like the build quality on my Carbide 3D probe. It looks nice, and is a good size.
  2. I like that it works nicely with Carbide Motion. But I don’t use carbide motion any more for various reasons, so this isn’t really relevant to me any more. With UGS for example, you can use whatever size probe you want for XYZ. CM only supports the one size.
  3. I like that the Carbide 3D probe has a light on it that changes color when in contact with the endmill/ground.
  4. I can’t tell ANY difference between a cheap passive probe and this “active” probe with actual accuracy on the machine, which has been claimed. I think the “active” part of the probe is a solution looking for a problem. I don’t believe it is temperature compensated (Someone correct me if it is)
  5. Like every other aluminum probe, it expands a bit when warmer, and contracts a bit when colder. Because of it’s dimensions, that happens in a non-obvious way. Mine is currently .9835-.9840 inches thick at the “thick rim” right now (midsummer Minnesota in my uncooled garage) measured with a temperature compensated caliper (mitutoyo). The probe dimensions (much thinner than it is wide) and soft material (aluminum) means that gets thicker on it’s short dimension as it gets smaller across it’s long dimensions (it “squashes”). Last winter it measured 1.006" thick in the same place. I’m sure these are 1" thick when made in their shop at their shop temperature. There’s a whole discussion to be had on temperature effects on the machine (they’re relatively large), and I suspect (I’m guessing) the probe size change is relatively small in that scope.
  6. The alligator clip ground is just as awful as everyone else’s. For the expense of the Carbide3D probe, I would prefer a magnetic ground.

(Neil Ferreri) #13

I get that. I was just saying that if I’m ok with the precision of a mechanical switch, what advantage in precision does an active probe give me. I’m thinking the gain in precision is smaller than the tolerances of the machine.
It just seems like a lot of hype and money for an indicator led. I have a corner probe I made myself out of aluminum. More often than not, I only need to probe Z, and I’ve used everything from aluminum chunks to steel straps to aluminum foil to feeler guages, and, as long as I know the thickness, they all work well.
I’m really just curious on the design advantages of an active probe.

The reason for my initial question.


(Phil Thien) #14

They can’t be moving in excess of .02” from temp swings.


(Patricio Suarez) #15

OMG, trying to get this probe is really one of the most frustrating things ever!!!. Such a letdown. Nothing has shipped yet. Just checked my order. Waiting for third party to ship.


(mikep) #16

In my garage, I think it would. I have about a 50 degree F swing (from about 40 to about 90 - it’s not so much heated as “warmed” in the winter). I’ll use a smaller Tdelta in this example (30 degrees F).

Steel: 0.000008 inches per degree per inch. That’s about .007" over the front and back frames for an XL (30") over 30 degrees F.
Aluminum: side rails is quite a bit bigger, at 0.000012 inches per degree per inch, or roughly .008" (for a 20 inch rail).
Rubber: (belts) is about .000043 inches per degree per inch, which again, over 20 inches and 30 degrees(F) is .026". (!)

Given that the machine “measures” distance in belt teeth, it could easily be off .020" across the bed in Y, and about twice that in X: .038" (on an XL).

The expansion of the steel and aluminum decreases the error from the belts.

Given that, and the actual measurements I have of the probe (which seem to be further off from nominal than I would expect, but I’m quite sure they’re accurate, I’ve confirmed them with both a caliper and a micrometer). I think the temperature changes are significant to accuracy of both the probe and machine. Just like the additional of weight to the table can easily move it .005"+, which -can- be an issue. Will you see them? Maybe, maybe not. If you’re cutting parts at about the same time, they’ll fit fine.

I think this is all kind of academic - all it really does is call out that you need to periodically recalibrate when things are not meeting the specific tolerances you need.


(system) #17

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