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Wear measurement of roll forming tap

RohanB

Plastic
Joined
Jun 15, 2017
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Hamilton
I have been searching a method to quantify the wear on form taps.

Is there a technique or method to measure wear on a roll form tap?

Is there a standard that can be followed for wear measurement of forming taps?

I am looking at wear particularly over the crest and surrounding flank region of the leading threads.

Kindly suggest.
 
For larger taps, you could track spindle torque, and determine what the "change out" value would be. For smaller taps, perhaps just track tapped hole tolerance changes, and again, figure out where the change is needed.

I think trying to actually measure the taps would be tricky, and could be wasted effort. For the low cost of a tap, I'm not sure you'd see a return on the hours/money spent getting a measurement system in place.
 
Thank you, Milland.
I haven't found any ISO standard so far that instructs wear measurement on taps.
I think torque monitoring will be the easiest in this regard but some stadard to physically to measure wear on form taps considering its huge tool life.
 
I have been searching a method to quantify the wear on form taps.

Is there a technique or method to measure wear on a roll form tap?

Thought some more on this.

Is that a theoretical question or something you'd even considering doing?

I can think of at least 1,000 things that would be better to use your time on.

Just out of curiosity what size of taps are in question?
 
Gage the threads. No one cares about the tap except perhaps you. The point of a tap is make threads in a hole. Its not about how many holes it takes to wear out a tap. Sorry to be so blunt, but. . . .
 
Quality of threads depend on the condition of roll form tap if all other parameters were good. If you are considering one or two holes for threading than gaging might be easy way to detect damaged threads. In case of automotive indusrty, gaging a part which has atleast 100 tapped holes and produced in mass scale is not possible. Monitoring of every 200th part was done on the assembly line. Because of unpredicted failure of taps, every 50th part was inspected which led to increase in cycle time and production loss. In this case, unpredictable wear on taps has become a major issue for my research.
 
@Gordon....Actually, my research is focussed on improving the surface of taps to extend its life till its predictable tool life. Flank wear on cutting inserts is a measurable failure criterion. I couldn't find similar metric for taps. Gaging of taps for pitch diameter tolerance check is done on the formed thread. i am planning some experiments for surface modification of the taps but wear analysis on the tool has become a major obstruction for my study. Presently, I am trying to see if volumetric wear on the crest can be a wear criterion using optical 3D surface metrology. Please feel free to share any ideas for this issue.
 
Hello Gordon...Actually, my research is focussed on improving the surface of taps to extend its life till its predictable tool life. Flank wear on cutting inserts is a measurable failure criterion. I couldn't find similar metric for taps. Gaging of taps for pitch diameter tolerance check is done on the formed thread. i am planning some experiments for surface modification of the taps but wear analysis on the tool has become a major obstruction for my study. Presently, I am trying to see if volumetric wear on the crest can be a wear criterion using optical 3D surface metrology. Please feel free to share any ideas for this issue.
 
Hello Gordon...Actually, my research is focussed on improving the surface of taps to extend its life till its predictable tool life. Flank wear on cutting inserts is a measurable failure criterion. I couldn't find similar metric for taps. Gaging of taps for pitch diameter tolerance check is done on the formed thread. i am planning some experiments for surface modification of the taps but wear analysis on the tool has become a major obstruction for my study. Presently, I am trying to see if volumetric wear on the crest can be a wear criterion using optical 3D surface metrology. Please feel free to share any ideas for this issue.

I'd try to measure the tap major diameter and see how it changes during production. Gut feeling that the wear is going to show up there more prominently vs pitch diameter for example.
 
I'd try to measure the tap major diameter and see how it changes during production. Gut feeling that the wear is going to show up there more prominently vs pitch diameter for example.

I gave MattiJ a "like" as that's the most sensible thing you can do and also by far the cheapest. Probably cost you a good 3 point micrometer.

3p1.jpg 3p2.jpg

A flat is of course better than a "point".

Added:
I can't see what you are thinking of doing as having any practical value IRL.
1. Tap life/wear will vary depending on the material being tapped.
2. Tap life/wear will almost also certainly vary depending on who makes the tap.

It'd be best letting people know the best hole diameter to use before tapping and still keeping the thread within tolerance. i.e. the hole diameter must be over nominal pitch diameter. For that the machinist will need a good set of 3-point micrometers and how many have that?

m3p.jpg
 
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Hello Gordon...Actually, my research is focussed on improving the surface of taps to extend its life till its predictable tool life. Flank wear on cutting inserts is a measurable failure criterion. I couldn't find similar metric for taps. Gaging of taps for pitch diameter tolerance check is done on the formed thread. i am planning some experiments for surface modification of the taps but wear analysis on the tool has become a major obstruction for my study. Presently, I am trying to see if volumetric wear on the crest can be a wear criterion using optical 3D surface metrology. Please feel free to share any ideas for this issue.

It's not just the crest that gives you trouble.
And even if how do you plan to do this inside the production line?
As your process has large variations are coolant concentrations, contaminates, and incoming stock under control?
Are you blaming taps (killing the front line messenger) for the source of variation.
You can't do improvement until you stabilize what you have currently.
I know what you are trying to do... but baby steps. Without the ability to control and classify the old your new will be a shot in the dark that sometimes works.

Don't be that guy. Don't rush forward with improvements, get a serious handle on the variation of the tool in use first.
Why, why, why......
I sense you have a bias of ideas to fix this which is good and bad.

You do not have a stable process now. Why not?
The point of QC should be to eliminate/reduce inspections yet you have had to go to more inspection. This adds no value to a part while increasing costs.
Bob
 
You do not have a stable process now. Why not?
The point of QC should be to eliminate/reduce inspections yet you have had to go to more inspection. This adds no value to a part while increasing costs.
Bob

I couldn't have said it better :cheers:

I've often said that the most important (and often overlooked) part of ISO 9000 is Corrective Action. More inspection is NOT that.
 
Quality of threads depend on the condition of roll form tap if all other parameters were good. If you are considering one or two holes for threading than gaging might be easy way to detect damaged threads. In case of automotive indusrty, gaging a part which has atleast 100 tapped holes and produced in mass scale is not possible. Monitoring of every 200th part was done on the assembly line. Because of unpredicted failure of taps, every 50th part was inspected which led to increase in cycle time and production loss. In this case, unpredictable wear on taps has become a major issue for my research.

If form taps you should just be able to look at the coating for signs of wear, its only a few microns thick, so long as the tap is ground at the minimum or a little more then coated it should be a clear indicator its then undersized.
 
Regardless of how you tap (roll or cut) check the hole diameter. Above tolerance and you have a weak thread. Some make the hole larger than it should be to save money on taps but it isn't a thread I'd buy.
 








 
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