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G54 Z offset? Avoid teaching every tool, every part?

Higgins909

Aluminum
Joined
Nov 19, 2018
I'm a very basic operator at this point and I sometimes work with HAAS mills. Some don't have tool setters and even the ones that do might be broken or are just not used for whatever reason. There is a lot of tool stealing from the machines as one part on another machine might need X tool(s) that happens to be in X machine(s) and not in use. (Limited tooling)(We also have a habit of storing unused tools in the machines and still have all the old tool data set)

Usually we teach each tool for each operation, even if it uses the same tools. I recently setup a machine and touched all the tools to the top of the raw material of the part, for the first op. When I got to the 2nd op I chose tool 1 and found it's 0 spot (Machine position?) and set the operator screen's Z to 0. I noticed if I switched tool, the operator Z zero would change, this is because it is set based on the machine position? (In other words, to find the difference I need to use the same tool?) Then I went and found the difference for the 2nd op and in this case it was 0.5004" added to the G54-57 Z column. The problem I found with this, if the jaws/part were different, I couldn't reteach a tool, if it were to break. I was thinking what if I put a 123 block on the table and set the tools from the 3" length.

I also noticed that you can "Part Zero Set" for the Z column in G54 offsets. (In addition to the XY that I was taught) How do you properly use this? Is this for a tool setter? It would be super nice to just press that if all the tools were already taught to say the 123 block. How would you do this?

For those that wonder how I'm doing with the Lathe canned cycles, I haven't gotten far. I tried the book and am always tired (Like I should probably see a doctor but... yeah...) and never have a good place to study...

Thanks,
Higgins909
 
...I was thinking what if I put a 123 block on the table and set the tools from the 3" length.

I also noticed that you can "Part Zero Set" for the Z column in G54 offsets. (In addition to the XY that I was taught) How do you properly use this? Is this for a tool setter? It would be super nice to just press that if all the tools were already taught to say the 123 block. How would you do this?
If you set your tools to a 123 block, the G54 Z value will be the difference between the 123 block and the part zero. Recommend you review these recent threads:

Fanuc tool length offset, compensating for fixture offset.

Problem setting tool/workoffsets with Haimer and 123 block
 
I still find it baffling that anybody would choose to put a value other than actual tool length on a mill. I'm aware of the advantages to using arbitrary reference points, etc... But it makes life a lot simpler when you can quickly double-check lengths with a tape measure or eye-crometer.

The simple way to get you down the right path would be to touch the spindle face off on a 123 block. Set this position as Z0. Put a tool in the spindle and touch it off in the same way in the same spot. The difference between Z0 and current position is the length of the tool. For steep taper this isn't actually the correct length (stupid gage line), but it will be close enough. Once all your tools have been measured, you can just set Z0 at the top of the part/stock/whatever using any of the measured tools.

This method has the added advantage of making it easier to preset tools offline, or move them between machines. For better accuracy you could use a test bar or standard to get your reference length, instead of touching off on the spindle face.
 
But it makes life a lot simpler when you can quickly double-check lengths with a tape measure or eye-crometer.
.

I for one do not buy that argument.
I don't see a difference in having a .05 discrepancy in a large negative value or having an un-calibrated tape measure being off by .05.

End result is the same.

On a Haas it's stupid easy to use the 1-2-3 block on the table and only shift the work Z0. All without ever having to hand-type ( I HATE hand typing ) any tool offsets.
Though, I don't recall getting a straight answer in the other thread about how to do that on a Fanuc.
 
I reference all of my tools to the bed. I have one of the dial tool setters and have a work offset set up to take it into account. I load up my toolsetting program, it calls my work offset and moves to the location I set tools at. Change tool, jog down, tool offset measure. Repeat for all tools.
Tool offsets end up negative.

Now my z work offset is a positive length from the table. I can use my haimer to establish z offsets, or work up from the table. My vises are 3.000" tall to the vise bed, so then I just add the parallel height to that and I'm all set with the origin at the bottom of my part. Any z offset can be checked with a tape or scale, and any tool can be used for any setup.
 
As I am sure it has been stated above (didn't read through):
Tag all your tools off a 123 or a 2" height gage. Every time.

The number that goes in the G54 is the difference in height of your part and your chosen height/ tag gage.
 
I'm not sure why this discussion comes up so much, and it seems like everyone is doing it the difficult, non-intuitive way.

My tool offsets represent the height between the spindle nose and tool tip. Positive number.
- With no tools in the spindle, establish a reference height (off any surface), and zero the Z reading. Use a 1-2-3, touch off gauge (Pro Touch Off Gage 04-000 - Edge Technology), etc...
- Load a tool and then use that same surface and touch off method. Look at your Z reading, and tada! There is your tool height which goes into your tool table. Same value for every program you will run. No need to modify. Repeat for any other tools you need to measure.
- Install your workpiece/fixture, measure your XYZ origin, and you're done...
 
I'm not sure why this discussion comes up so much, and it seems like everyone is doing it the difficult, non-intuitive way.....

During the years that I did field service and applications, I did lots of training for new CNC users. As far as being intuitive, I found most folks grasped the concept of negative offsets easier than they did positive offsets. I have no preference, either gets the job done.

I saw that shops using a tool presetter machine often had operators that had no understanding of how tool length offsets were determined.

........There is your tool height which goes into your tool table. Same value for every program you will run. No need to modify. Repeat for any other tools you need to measure.
- Install your workpiece/fixture, measure your XYZ origin, and you're done...

Works the same if one is using negative offsets as well.
 
I for one do not buy that argument.
I don't see a difference in having a .05 discrepancy in a large negative value or having an un-calibrated tape measure being off by .05.

Usually more like spotting a 1 or 2 inch discrepancy with the eye-crometer, then verifying with a tape measure. Not that it's ever happened. :D
 
unless your running a horizontal with zo coming out of the center of the pallet, or if your running mindless production. why you would want to use anything other than touching off the top of a part?
how long does it take to touch 5-6 tools? 2mins? if that is a problem, i wouldn't want to work there. i just think its personal preference, or if your shop does it a certain way.
 
.....how long does it take to touch 5-6 tools?......

I'd guess it takes longer than not touching them off. Am I right?

Yes, it is about personal preference and in many cases what an individual understands.

Unless a tool is a new assembly, I never touch them off. I'm a lazy SOB and anything that saves a tiny bit of work is a good thing.
 
Off the part? what part? the one ran last week? last month? last year? tomorrow? how many tools in that machine were set off different parts? if you set every tool every time a new part comes and then remove them all at the end, ok maybe, but if most your tools stay in there all the time like they do for some of us and run many different parts/jobs and different heights, touch them off something that is always the same.
123 block off the table here.
 
I'd guess it takes longer than not touching them off. Am I right?

Yes, it is about personal preference and in many cases what an individual understands.

Unless a tool is a new assembly, I never touch them off. I'm a lazy SOB and anything that saves a tiny bit of work is a good thing.

I'm thinking that if I had an employee that thought setting the Z Height for each tool for each setup on the top of the part was a good use of time, I wouldn't want him working here. I'm not real sure of the math, but I have a feeling that whenever my spindles aren't turning, they probably aren't making any money :)


I use (when possible) common tools in all of my machines. All tool lengths are set 4 inches above the bed. All vises are the same height, all jaws are a common height. Any tool that is installed in the tool changer and not set to that height is damn near a firing offense. All vises and fixtures are probed when installed and offsets are written down on a clipboard. All parts are programmed (when possible) to use common XY offsets.

All of these OCD habits save us bunches of time. Usual setup is less than 5 minutes of door open time.

I'm in this business to make money. Any place that I can save a couple minutes is worth looking at.
 
i wouldn't work for you, your sound really OCD yourself.
try a job shop, running one or two of something. Or the place you work does it that way.
but, im sure all of you talking who are here everyday are always right...........people who do
things different are always wrong, your's way is always right.
 
i wouldn't work for you, your sound really OCD yourself.
try a job shop, running one or two of something. Or the place you work does it that way.
but, im sure all of you talking who are here everyday are always right...........people who do
things different are always wrong, your's way is always right.


Gotta be JW...
 
i wouldn't work for you, your sound really OCD yourself.
try a job shop, running one or two of something. Or the place you work does it that way.
but, im sure all of you talking who are here everyday are always right...........people who do
things different are always wrong, your's way is always right.

Judging by your interesting use of grammar and lack of punctuation, I'm guessing you are the same person that posted as "skywalker" above.

I do run a job shop and consistently build complicated prototypes and short run production. My average day is five to ten setups on the three axis machines and a couple on the 4 and 5 axis machines. I own the company so I look at every step as an opportunity to add to my bottom line. When I started out, I did my setups just as you described. Then one day, I realized I was re-setting tools that already had known Z heights and radial offsets. I finally figured out that if I set my tool offsets at a common datum (4 inches off the table), and used common tooling as much as possible, I could save time and make more money. Not only that, but because the tools stayed in the machine, I could greatly refine the axial and radial offsets and make more accurate parts without running a "set-up" part. Pretty good system. It does require a bit of discipline and attention to detail, but it is still way better than the old way I did it in the '90s.

For instance, I have one machine that has been running 8 different injection molds. Since the first one, I have not changed an offset or switched a tool. Change over from one mold base to another takes about 5 minutes. That is a money maker. On another machine I am running a family of similar parts: two vise ops and one forth axis op (hitting it from 9 sides). I programmed using the same tools, and the same XYZ&A offsets. Runs non-stop and change over is about ten minutes.
 
judging by you, your still an asshole, who trolls everyday looking for some smartass thing to say, instead of just stating your opinion.
go back to your ocd shop and piss some of you employees off, they must hate you. jerk
i don't know any skywalker, so fuck yourself on that to.
 








 
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