Calculating Tool Life?!

Hi fellow Machinists

I am trying to determine / predict tool life. I have various tools that I want to apply this to. I am aware that determining this is very difficult due to the number of variables. But I am simply looking for a prediction.

I am currently working on RFQ's and my tool life expectancy is generally taken from experience aka a random number that pops into my head :L. I want to be able to have a foot to stand on if the question is raised "how did you predict your tool life?" instead of saying "Emmm I guessed it"


I am aware of Taylor's tool life equation but if anyone has anything else that would help me in this matter, I would very much appreciate the guidance


Regards,
TT

Pretty much boils down to experience and educated guesses.
I basically know how long a tool will last for most of the parts we make on our mills only because I'm the programmer and my style hasn't really changed.

Run enough parts to wear out at least three of each cutter, record how much cut time and how many parts.

If it's aluminum, tool life is indefinite.

In all seriousness, are you having problems? Tools 'randomly' breaking?

Taylor96 said:

....
I am currently working on RFQ's and my tool life expectancy is generally taken from experience aka a random number that pops into my head :
TT

Click to expand...

Stand on that and go with "This is what I have seen done and proven."
Bob

For production? Run 5 of them until they explode, or can no longer make a feature in tolerance, whichever is greater.

Average the number of pieces you got per tool. Subtract 10-15% of that.

Boom, tool life.

As others have already stated, it's trial and error.

The same tools in the same holders running the same programs in two similar, but different make/models of machines can have significant tool life differences.

Experience is all you have to work with here.

We get asked this all the time in the field. We know from experience what you can get with our tools, but what they will get is just that, what they will get. The challenge is that I have seen swings of up to 10x in life with tools applied the same way in the same types of materials, with the only difference being the setup, or machine. With small adjustments to the cutting parameters or to the toolpath approach, life can be improved dramatically to get the most out of a given process when you don't get the life you expected with the initial run. When quoting, I'll typically budget for about an hour of tool life in most materials for end milling, and then hope I blow that out of the water, which unless you are cutting Inconel, shouldn't be a problem at all.

TeachMePlease said:

For production? Run 5 of them until they explode, or can no longer make a feature in tolerance, whichever is greater.

Average the number of pieces you got per tool. Subtract 10-15% of that.

Boom, tool life.

Click to expand...

IMHO, instead of taking the average, take the lowest. And THEN subtract 10-15%, knowing that as time progresses, more tools will fail earlier than those in your original n=5 group. The goal here is to find the minimum tool life, not the max.

If the lowest one is a significant outlier, e.g failure at 60 minutes while everything else is 100+, determine if the fault is operator error, material variation, or a bad grind. If it's the grind, then you may have to switch to a different brand of tooling. The carbide market is competitive enough that bad grinds should be exceedingly rare.

Shit still happens though. No process is 100%, and no tooling manufacturer is 100% either. Redundancy can be achieved with tool breakage detection and/or probing the part mid cycle.