Cat 40 Offline tool length measurment

[Chipmakr]

I need to get the exact length of a gage pin that I have mounted up in a CAT 40 holder. I will use this to calibrate the tool calibration sensor mounted on the table. How do you guys measure a CAT 40 tool to get the actual tool legth from the gage line?

[McLaren]

Why not put a test indicator in the machine, zero out on the bottom of the pin, then zero out your position page. Z down to the spindle face?

[Craig-B]

All of our tool are set offline we use a Zoller pre-setter, http://www.zoller-usa.com/ We only use the one in the machine for Tool breakage detection during cycle.

[Chipmakr]

Is the flat face on the spindle the gage line? I didnt think it was because it doesnt look like a precision surface on our spindle. I am familiar with the Zoller, but I just need to do one tool. I found a spec that said 1.75" was the ggae line diameter on the taper, so i guess i could just get the distance on the cmm knowing that. I figured that had to be an easier way to do it. either on the machine or on a surface plate.

[Craig-B]

No its not on the face, You can try using a optical comparator and get the diameter of the taper and, then set the length.

[McLaren]

Is the flat face on the spindle the gage line? I didnt think it was because it doesnt look like a precision surface on our spindle. I am familiar with the Zoller, but I just need to do one tool. I found a spec that said 1.75" was the ggae line diameter on the taper, so i guess i could just get the distance on the cmm knowing that. I figured that had to be an easier way to do it. either on the machine or on a surface plate.

 

Yes, the flat face is BASICALLY the gage line. 1.75" is correct (for a 40 taper). But the tolerance is ±.015" in Z off of that. Since tool length offset and fixture z offset are relative, the exact number isn't really all that critical. Unless you are doing 5axis work I think.

[MotorCityMinion]

'the exact number isn't really all that critical" Huh?

 

The spindle nose (Flat ) is usually ground and is the Zero point / gage line for gage length's. Master gages in 40/50 taper can be purchased. If you already have a pre-setter in house, you can test with the master from that unit.

[McLaren]

Yeah, it's not that critical, unless you know of a reason to state otherwise. Like I said, the gage diameter of 1.75" is the critical dimension. But the face of the spindle is ±.015" from that. And like the OP said, his spindle face doesn't appear to be precision ground. What happens when you have a spindle reground? Do they also regrind the face?

 

EDIT: Those are actual questions. And keep in mind we aren't talking about dual contact stuff. Also, does anyone have a reason on why the exact gage line would be critical?

[YoDoug®]

Yeah, it's not that critical, unless you know of a reason to state otherwise. Like I said, the gage diameter of 1.75" is the critical dimension. But the face of the spindle is ±.015" from that. And like the OP said, his spindle face doesn't appear to be precision ground. What happens when you have a spindle reground? Do they also regrind the face?

 

EDIT: Those are actual questions. And keep in mind we aren't talking about dual contact stuff. Also, does anyone have a reason on why the exact gage line would be critical?

 

Exact gage line would be best for simplifying offline presetting. Otherwise your pre-setter needs to have a configuration for each machine tool. Also if you are using Balfuff RFID chips with a tool offset stored in the chip you don't want to have to re-measure the tool if you switch it from machine to machine. In some FMS systems with shared tool magazines you would prefer the same base offset for each tool regardless of which machine it is in. I always use a ground master bar to calibrate tool probes, pre-setters and any other tool offset related measurement.

 

 

 

[MotorCityMinion]

Perhaps I'm missing something here or don't understand the statement.

 

Our Makino gage dia. and spindle nose are dead nuts. I can touch the spindle nose off any flat face, set the wpc z, pre-set the tools and go. Formerly ran Mazak HMC's for years, same set-up, 50 taper. Spindle nose to CL of rot is fixed (varied between machines a few thou). Tools were pre set off the machine, and usually good within a thou.

 

Edit: Doug beat me to it and said it more betterer, lol.

 

 

 

[YoDoug®]

Perhaps I'm missing something here or don't understand the statement.

 

Our Makino gage dia. and spindle nose are dead nuts. I can touch the spindle nose off any flat face, set the wpc z, pre-set the tools and go. Formerly ran Mazak HMC's for years, same set-up, 50 taper. Spindle nose to CL of rot is fixed (varied between machines a few thou). Tools were pre set off the machine, and usually good within a thou.

 

 

 

Makino is a high quality builder. They were most likely already grinding theoretical gage line to spindle face to a tight tolerance. That is not the case with all builders.

 

 

 

[McLaren]

I kind of understand where you are coming from, but;

 

Wouldn't the fixture 'Z' offset zero out the error?

For the sake of argument the tool length on your presetter is exactly 4.0000".

This is measured from the true gage line at precisely 1.750" diameter.

You have 3 identical machines.

Machine #1 gage line is exactly at spindle face, tool jogs down to top of probe, measures -16.0000"

Machine #2 gage line is +.015" from spindle face, tool jogs down to top of probe, measures -16.0150"

Machine #3 gage line is -.015" from spindle face, tool jogs down to top of probe, measures -15.9850"

 

Isn't the tool going to go to the top of probe when you program Z0 on all three?

[McLaren]

And MotorCityMinion, it seems we are in agreement that the face of the spindle should match up with the gage diameter. The problem is that they have tolerance on it. Check the Machinery's Handbook, section on machine spindle tapers.

[YoDoug®]

I kind of understand where you are coming from, but;

 

Wouldn't the fixture 'Z' offset zero out the error?

For the sake of argument the tool length on your presetter is exactly 4.0000".

This is measured from the true gage line at precisely 1.750" diameter.

You have 3 identical machines.

Machine #1 gage line is exactly at spindle face, tool jogs down to top of probe, measures -16.0000"

Machine #2 gage line is +.015" from spindle face, tool jogs down to top of probe, measures -16.0150"

Machine #3 gage line is -.015" from spindle face, tool jogs down to top of probe, measures -15.9850"

 

Isn't the tool going to go to the top of probe when you program Z0 on all three?

 

I'm not sure I follow what you are saying. However if you are using a tool probe in the machine then yes it will comp it correctly.

 

The scenario I am describing is this.

 

1. you use an offline tool pre-setter to measure the tool to exact gage line.

2. you use the machine tool spindle face to set work offset.

3. your error will be the difference in tolerance of the machine tools spindle face to actual gage line.

4. now put that tool in a different machine using the same offset and using the spindle face to set work offset. Unless the two machine have the spindle ground to the exact same tolerance then there will be error.

 

 

 

[McLaren]

AHA! Now I understand. Thanks Doug! I've never used the spindle face to touch off though. I always used the surface of my edge finder. Hand tight in a collet so it'll slide up in case of accident. Slide it back and forth and when it hits it'll stop moving.

 

EDIT: Well, not always. I started doing it that way a few years back. Edge finder is already in there for X and Y, figured use it for Z too.

[YoDoug®]

I don't use the spindle face either. I use a tool with a known length. That is unless I have a probe available.

[GoetzInd]

The best thing to do is just buy a master. It will cost a few bucks but you'll always have something to reference. Especially if you start doing a lot of 4 and 5 axis work. Here's one.... http://www.tacrockford.com/datasheets/gauges/steep-taper-master-setting-gauges/

 

Mike

[McLaren]

So Dwain Dyer, what's the verdict?

[Chipmakr]

I have been away for a few days and I am glad to see some more discussion on this. By my thinking there is a "actual" length for each tool. No matter if this length is obtained offline on a presetter, at the machine, or by some other means there is still only one correct "actual" value. I understand the point of view that of its used on one machine and the "error" is relative and its not 5 axis work that it won't really cause a problem, but its just not the way I like to do things. I belive I will mount up a .5" gage pin and go to the CMM probe the cone in the holder and create a plane at the 1.75" diameter. It will be easy enough to accuratly measure the disatnce from this plane to the end of the gage pin. I will look at picking up a master setting gage or a test bar, but with the CMM method we wouldn't have to purchase anything to try this out. Thanks to all of you who chimed in. I'll let you know how it goes.

[McLaren]

That'll do it! Then once you have the number you can check the spindle face to see the difference in position. If you do report back, I'm curious to know where it's at.

[Chipmakr]

I haven't gotten around to doing this yet but I will let you know what the difference in position to the spindle face is.

[Chipmakr]

I did end up doing this with our VM3 and had good success. There was a significant difference between the spindle face measurement taken at the machine yielded and what the precision approach of going thru the gage pin/CMM steps yielded. I believe it was around .075". I had the exact # written down to post on here but lost it somewhere along the way. So basically what I did was.

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1) Mount gage pin in a good quality holder.

2) Go to CMM and measure cone of the CAT40 taper, and measure the end plane of the gage pin. Create a theoretical intersection between the CAT40 cone and a theoretical plane @ the 1.75'' diameter location of the cone. The "gage" length of this tool assembly is the distance between the theoretical cone/plane intersection and the end plane of the gage pin.

3) Go to the machine and calibrate using this number.

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If you don't have a standard or a test bar this works great to accurately calibrate your on machine tool touch off devices.