Very new at CNC, proofing Z axis...

I don't know a whole lot about CNC, never had the money to play with it but my neighbor who runs a CNC shop was showing me some stuff... basically setting the Z axis after changing tools. He used this device:



And you would carefully lower the tool until it touched and it reads zero, then you typed something (which I do not remember what). And that tells the machine what position is the bottom of the tool so you don't crash the thing. If I remember correctly you always -50 (in mm) because the device is exactly 5cm thick.

If it helps he uses Fanuc controllers, one is a Oi-MF and the other is similar to the Oi-MF.

Is there a good resource on Fanuc controllers? like a manual or something? It's not easy to use like those NYC CNC videos. (and honestly their machines are squeaky clean compared to the ones I work with, so I wonder if they do any real production at all). The controllers are really old, it takes PCMCIA cards and no USB (at least the PC card had a CF card reader in it). So basically no choosing the right field with a mouse but you had to use the right screen options...

Hi Taiwanluthiers! The machine needs to know 1) where the top of your workpiece is and 2) where the tip of your cutting tool is.

The top of your workpiece should be defined in the "Z" register of your work shift coordinate, commonly G54. The value in that register usually either represents 1) the distance from the top of the machine table to the top of your part or 2) the distance from the machine home position to the top of your part.

The tip of your cutting tool should be defined in the "tool length" register in your tool offset table. The value in that register should represent the distance from the spindle nose to the tip of your tool.

When you put your 50mm tool setter on top of your reference plane for your workshift (say, the top of your part or maybe the top of your vice) and bring the tip of your cutting tool down to it you know the tip of your cutting tool is now exactly 50mm above your work shift reference Z value. If your hit the "Z0. + measure" button you are telling the machine that you are touching the top of your part (or vice, etc.) so it can do the math to figure out the length of your tool (since you have already defined the top of your part.) BUT you ARE NOT touching the top of your part...you are 50mm above your part so you need to either type in "Z50. + measure" OR "Z0. + measure" and then subtract 50mm from the resulting offset register as calculated by the machine.

As far as Fanuc Manuals I believe they are available on-line. I don't have any fanuc mills so I am assuming they work similarly to the fanuc lathes and non-fanuc mills we have.

Good luck!
I hope that helps!

P.S. I have read that Taiwan has the COVID virus very well under control because of it's citizen's discipline towards wearing masks, staying away from others, washing hands, etc. Is that true?

If you're just doing rough set ups, I always keep a magazine near. RIP out a corner of a page and bring down your Z till the paper doesn't slide. Like feeler gauge action. No math needed.

Sent from my SM-G950U using Tapatalk

It's a little OT but yea, no lockdowns or school closure and there's been almost a week of zero new cases.

Today the GX710 started beeping an alarm mid job (but no tool damage or anything) yet it wouldn't show me why. Then the second unit beeped an alarm as well saying "low pressure". Turns out the air compressor died so the owner will have to find a way to fix it...

taiwanluthiers said:

It's a little OT but yea, no lockdowns or school closure and there's been almost a week of zero new cases.

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Completely on topic as no health, no work.



To your topic...

...think of your machine as the dumbest thing ever made. You must teach it everything. The machine needs to know where it is in relationship to its home position...in X, Y and Z.


As you asked for Z, we teach the machine by putting the tools you intend to use into the Spindle and touching a common Point.

Simplest point is the top of your work. Many use a paper shim that you come down and carefully touch so you have the slightest of friction.

Depending on your machine the next step differs in the way you go about it. But what always remains the same is the machine need to be given the Value from its Z home position to the position you just came to in Z. That value is entered in your Tool Height Offset. Now your machine knows just where the tip of that tool is in relation to the top of your work.


Now your height gauge takes the place of that paper shim and you must account for its height. That can be done in several ways...changing all tools at once by entering the height in your Work Offset G54, G55 etc OR in the tool offset.

Lots of manuals and teaching aids online...problem is each machine is a bit different in how it wants to learn. I say wants but it really NEEDS to learn in a certain way and it's your job to learn what your machine NEEDS.

Blah blah...for the simplest way to grasp the concept. I'd refer you to Haas Automation. They have the simplest machines to set up, the best manuals and their online tutorials blow away just about everything.
So even if you have Zero interest in buying or using their machines...you can grasp the basic concepts of what needs to be achieved easily. The concept is virtually the same across all machines...just the methods in which you get there changes...but knowing what has to take place and why makes it easier to figure out when learning new machines.

So what do you do about X and Y? I saw the guy use a 600 dollar edge finder (I see it in NYCNC youtube channel too) but I guess you can use a manual mill edge finder too right? But honestly it could be dangerous as I am sure someone has spun those 600 dollar edge finder to death before (you are supposed to use it without the spindle spinning, but a normal edge finder requires the spindle to be spinning).

YouTube

At 2:37...

taiwanluthiers said:

So what do you do about X and Y? I saw the guy use a 600 dollar edge finder (I see it in NYCNC youtube channel too) but I guess you can use a manual mill edge finder too right? But honestly it could be dangerous as I am sure someone has spun those 600 dollar edge finder to death before (you are supposed to use it without the spindle spinning, but a normal edge finder requires the spindle to be spinning).

YouTube

At 2:37...

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It's not just the manual edge finder... Plenty of people have spun a $200 indicator, a $600 haimer 3d taster, a $500 blake coaxial indicator, or a $2K renishaw probe to death, too. It's one of those things that is likely to happen at some point or another, and as the guy in charge of the machine, you do your DAMNDEST to avoid. Also, if you're using a normal edge finder, don't forget to offset by 1/2 the diameter of the edgefinder tip... NOT that ANY of us here has ever done that...

By the way NY CNC seems to be talking about Haas, Tormach, etc. type machines a lot but never talk about Fanuc or Fanuc based machines... and seems to prefer Fusion 360 as their CAM software yet my neighbor uses Fanuc based machines and basically scoffs at Fusion 360 (he uses Mastercam X5). Is it because Haas is more hobbyist level machines while Fanuc is more production level machines (explains why NY CNC's machine seem all spotless when the one I see are covered in grease, the inside has piles of chips, old cooling fluid everywhere, etc.)

taiwanluthiers said:

By the way NY CNC seems to be talking about Haas, Tormach, etc. type machines a lot but never talk about Fanuc or Fanuc based machines... and seems to prefer Fusion 360 as their CAM software yet my neighbor uses Fanuc based machines and basically scoffs at Fusion 360 (he uses Mastercam X5). Is it because Haas is more hobbyist level machines while Fanuc is more production level machines (explains why NY CNC's machine seem all spotless when the one I see are covered in grease, the inside has piles of chips, old cooling fluid everywhere, etc.)

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Actually, cleanliness doesn't directly correspond to production rate.
I have seen filthy, moth-eaten, encrusted machines that get used twice a week,
and also spotless machines that just get cleaned regularly.....

Regarding touching off X and Y...

You can use an edge finder, probe, end mill, anything you know the diameter of. Approach the edge of the part you wish to use as your reference axis and as soon as you touch the edge you know you are the RADIUS of your probe, edge finder, etc. away from your reference axis location. So if you are approaching your part from the left with a 12mm end mill, as soon as it touches you would (probably) type in "X-6.00 + measure" into your work shift for which ever workshift you are referencing in your program...usually staring with G54. Then you would do the same in Y. If you don't want to scratch your part you can wiggle a piece of paper between the cutter and your workpiece and then add the thickness of the paper to what you key in...so maybe "X-6.07 + measure"

If you want the center of some bore to be your X/Y origin you can put an indicator in the spindle and jog the table around until you get in the middle and then you get to type in "X0. + measure" and the same for Y.

Again, I have no Fanuc mills so I am making some assumptions.

Haas machines are not as nice as many other machines out there but their control is very very user friendly and the machines are reasonable for production use, depending on how demanding of an environment they are used in. For instance, when you get to where you need to be in X and/or Y on a haas you just hit the "part zero set" button...easy!

Good luck!

TeachMePlease said:

It's not just the manual edge finder... Plenty of people have spun a $200 indicator, a $600 haimer 3d taster, a $500 blake coaxial indicator, or a $2K renishaw probe to death, too. NOT that ANY of us here has ever done that...

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not in my shop!

SIM said:

Now your height gauge takes the place of that paper shim and you must account for its height. That can be done in several ways...changing all tools at once by entering the height in your Work Offset G54, G55 etc OR in the tool offset.\

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For years our shop would have ZERO in the Z register for all of our work shifts (and touch all tools off to the top of the workpiece)...so our part lengths were -18.1234" or whatever. Of course it didn't really matter...the parts came out right! But lately I've had a real bug up my ass and have been preaching to do it "right" and have the "tool length offset" really be the "length of the tool" instead of compensating for it in the workshift. It's so tempting to adjust the workshift though!