(And the bottlenecks they create)
It was 3 pm on a cold Monday in January and Sleuth had a feeling his iPhone would not be ringing. Last week was hellish and next week he had more than plenty on his calendar. So, what the heck. He plugged in his earphones, threw his feet up on the desk, and dialed up his favorite iTunes, starting with Crystal Gayle moaning “Don’t It Make Your Brown Eyes Blue.” To enhance the experience, he logged into Google images and brought up a slide show of some of his favorite tropical vacation spots.
"When the Veep realizes he can get twice as much cutting out of his expensive CNC machine if he automates set-up with on-machine gaging , he'll buy in for sure," thought the Sleuth.
You know what happened next. The instrument of Sleuth’s pleasure
became a torture device. Quite out of the blue Sam Atkins, a
manufacturing engineer over at Parts ‘R Us was bellowing into his
ears. “Sleuth you’ve got to get over here right away. I’ve got big
problems.”
Sleuth came down from his flight of fancy, pinned on his permanent
visitor’s badge and headed over to his best customer. He found Atkins
in the new aerospace parts manufacturing cell, where the guy had been
living 10 or 12 hours a day, six days a week.
“Sam, I thought you had your manufacturing processes all ironed out and
you were knocking out those little machined air frame components right
and left.”
“Sure am,” he confirmed. “I’m making them so fast the inspection guys can’t keep up with me.”
“So why don’t they get some more capacity over there?” Sleuth said.
“They’re planning on it, but probably not what I need. We just bought
a big, precision CMM and Parts ‘R Us is not likely to be dealing out
those kinds of bucks again any time soon. You see, we cut these
composite parts in families, all on a single fixture. We tried to
refixture them individually on a smaller CMM, but they lost their shape
and we can’t measure them that way. So we have to haul the whole
fixture over to the measurement room and wait for time to free up on
the big machine. That does not happen often because we also have some
contracts for big expensive air frame parts.”
“So measure them right on the machine,” Sleuth said with conviction.
“We’re trying to get that going now with a portable arm, but we still
have to wait for one of the guys who knows how to do it to get over
here with his equipment. Then when he does, it takes quite a bit of
time to set up and measure more than a dozen of these parts at a time.”
“Do the machines in your cell have spindle probes?” asked Sleuth who
was beginning to suspect that Atkins was trying to drag him into a
pitiful game of “yes, but.”
“Yes, but they’re just too difficult to use. I tried to write some
measurement routines using the CNC’s probing macros and then
customizing them. I never got as far as locating the parts on the
machine, let alone measuring them.”
“Hmmmm . . .” thought the Sleuth. “Have you thought about using real
Metrology Software, the same kind you use on your CMMs, to generate
measurement programs you can use on your CNC machines”?
Sad Sam Atkins shook his head and looked down at his feet and mumbled; “Yes, but that’ll never work. Not here.”
Sleuth hated playing yes but. He held his breath until his eyes
started bulging and then he launched his counter-attack: “Of course it
will work. Accuracy won’t be a problem for these parts and since you
are measuring them in place, you won’t lose any of your error budget
like you would if you had to move or worse yet refixture them.
“The software doesn’t cost that much. The programs can be downloaded
from a server to your CNC systems and the data captured and analysed at
the server—so your machine will still spend most of the time cutting
parts. And the same machine measurement server can handle all six of
CNC machines in your cell, so you only have to buy one basic system.
“And programming is done off line using the CAD model—but you don’t
have to learn how to do that because your CMM guys already know how to
do it.”
“That’s the problem,” intoned Sam Atkins morosely. “The Quality
Manager won’t let them. He doesn’t want anything to do with measuring
parts on the same machine that made them.”
“Yike’s,” thought the Sleuth. He was toast. The old
‘can’t-measure-parts-on-the-machine-that- made-them’ wives’ tale had
raised its ugly head. “I’ve had it for today, Sam.”
“I’ll walk you to the door,” he muttered.
While they were walking to the door, Sleuth saw something very
interesting. Over in the far corner of the shop towering over the
Parts R’ Us V.P. of Manufacturing and several others was a gigantic,
newly acquired, million dollar plus Aqua Flash X waterjet cutting
system.
“What are they doing over there?” Sleuth asked.
“That’s one of my problems. Those two guys with the portable arm, who
should be measuring my parts, are setting up one of those 25-foot
structural beams to be cut on the Aqua Flash. They can make an
expensive part in about two hours, but it takes them about the same
amount of time to align it properly before they get started.”
He continued, “The Veep stuck his neck way out to buy that equipment.
So the portable arm guys have dropped whatever they are doing to run
over there every two hours.
“Wait just a minute,” said the Sleuth turning back to Sam. “I think I’ve just solved your problem.” And he did.
A month later, Sam was measuring parts on his CNC equipment using
server-based programs written by the guys in the Quality Department.
Parts were manufactured and measured on the same machine, then shipped
immediately to a happy customer.
“It was a pretty simple sell. I asked him how he would like it if he
could manufacture one of those composite beams on the Aqua Flash every
2 hours and 20 minutes rather than one every four hours. He said he
would like that a lot and asked how that was possible.”
I explained he could use the same on machine measurement software you
were hoping to use—this time not to measure the parts but to align
them. It was something that could happen pretty quickly I added, since
the CMM guys already knew how to write the programs. And so it came to
pass. Convincing him that you could use the same technology on your
machines was a piece of cake.
That day as Sleuth rode off into the sunset, music streamed from his
iPhone to his car stereo. Sleuth’s play list started with “It Ain’t
Necessarily So,” followed by Garth Brook's rendition of “I’ve Got
Friends in Low Places.”
Contributors to this article include: Steve Logee, Business Development
Manager, Wilcox Associates, Inc, Rob Fabiano, Sleuth
iIlustrator, and Joel Cassola, freelance Writer.
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