Monitoring Tool Wear - Seeking: Suggestions on a database for Monitoring Tool Wear

[Dawn]

Can anyone give me suggestions on a database for monitoring tool wear?

[Marc]

I know this is a real oldie which never got a response, but I saw a searchbot hit on it so I figured I'd ask.

How do you monitor tool wear?

[Randy Stewart]

Back in my days with soft tool dies & stampings we used first & last piece off and digital scans. Once buy-off was achieved (per CMM), a digital scan of the die was produced from which a cutter path could be made. The digital scan captured all the dimensional tweaking that went into producing the acceptable panel. Then upon completion of the run, we did another CMM check. By comparing first and last we could calculate how much wear had occured and predict when tool maintenance was needed. These calculations were used for MTBF & MTTR.

[Wes Bucey]

Originally Posted by Randy Stewart

Back in my days with soft tool dies & stampings we used first & last piece off and digital scans. Once buy-off was achieved (per CMM), a digital scan of the die was produced from which a cutter path could be made. The digital scan captured all the dimensional tweaking that went into producing the acceptable panel. Then upon completion of the run, we did another CMM check. By comparing first and last we could calculate how much wear had occured and predict when tool maintenance was needed. These calculations were used for MTBF & MTTR.

IMPORTANT: I think we are making an assumption not in evidence - that the original post is referring to production tools versus inspection "tools" or instruments. The first query is about a "database" setup. Marc's query, on the other hand, asks about "monitoring" tool wear. "Database setup" implies the poster already is capable of monitoring the tool wear and wants a method to store and use the data he/she generates. Let's look at Marc's query first, since it is most recent.

In my machining environment days, tool wear was always a big factor on production runs.

(Note that in manufacturing, "tool" means everything from cutting bits on lathes and machining centers to the big dies used in stamping and injection molds.)

There are two methods of measuring tool wear

1. Direct (remove tool and measure changes from benchmark dimensions - like looking at and measuring gap on worn sparkplugs)
2. Indirect (maintaining tight monitoring of "key" dimensions - not "critical" for function of product, but "key" for revealing tool wear - sparkplug analogy: how does the engine run?)

The choice of which method to use is determined by the production method and practicality - some organizations are capable of routinely lifting 1000 kilogram stamping dies onto a large table CMM and measuring for wear, while others need to do indirect readings of key dimensions on finished workpieces.

In some instances, we removed cutting tools and examined them under optical comparators for wear. In some other instances, we found it simpler and less expensive to factor in the cost of multiple cutting tools and change them out without regard for wear rather than engage in a time-consuming inspection for a ten dollar tool, counting on a rigorous SPC program of the workpieces ("key dimensions) to signal excessive wear or other problem attributable to tool.

Creating and maintaining a database is simply a matter of entering meaningful raw data. The trick is to "massage" that data to make inferences and predictions about tool wear and quality of one material or design versus another.

This is as far as I go as a Mentor. To set up the system, hire me or someone else as a consultant.