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Morton Welding - Productivity And Profit In Short-Run Tube Bending |
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In many manufacturing organizations, production and quality assurance
are not on the best of terms. Q/A people see their counterparts in
manufacturing as so driven to meet production quotes that they take too
many shortcuts, compromising quality and often even violating design
intent. For its part, manufacturing sometimes sees Q/A as nitpickers
and trouble makers. Many production oriented managers feel that Q/A’s
zeal in finding errors (and making manufacturing look “bad”) is mainly
to protect their Q/A cushy jobs.
When production and Q/A are part of the same organization, however, as
at Morton Welding, amazing things happen. Q/A actually boosts
productivity. It should, of course, by helping ensure that jobs are
done right the first time. But this requires tight integration between
Q/A and production.
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Such tight integration is generally seen as feasible only in automated
operations. Morton Welding has managed to do so in the least automated
of production operations, low-volume tube bending. These basically
manual operations turn welded steel tubing and custom-machined flanges
into assemblies for handling water and hydraulic fluid on construction
machinery and large diesel engines.
Most inspections are done by the operators of the bending machines.
Just as in any other production operation, a basic rule in adhered to
faithfully adhered to: If the tooling is correct the parts will be.
This applies whether lot sizes are several thousands or, as at Morton,
just several.
In small-lot-size work, the ability to quickly make low-cost but
accurate tooling is essential to success. All bender operators are
trained to use dimensional measurement arms from CimCore. The portable
CMMs are in the fabrication area where tooling is checked constantly.
Morton has had one arm since mid-1997 and the other since late 1999.
Both machines are equipped with Suprastuff™ and Supravision™
dimensional inspection software. Suprastuff measures standard geometric
features and is used to verify the accuracy of Morton’s modular
tooling. Supravision is specifically for tubing.
The production and Q/A results are so reliable that our primary
customers, seven plants of Caterpillar Inc. and several of its large
distributors, do not inspect Morton’s work. We are, of course,
Caterpillar certified and recently added Deere & Co. certification
as well. We work with our suppliers on the same basis.
All bender operators are trained on the portable CMMs and this is vital
to the company’s success. Each operator is responsible for the quality
of his work and the company uses a buddy system with the arms; two pair
of eyes is better than one. The two machines allow tooling to be
constantly checked for needed adjustments. With the arm this always
takes less than five minutes per piece
and usually less than two minutes. In fact, it takes longer to get the
inspection datums off the drawings than it does to do the work.
With the conventional CMM, 10 to 15 minutes is needed to check a job
and a similar amount of time to set it up. The difference is very
important for the short-run (under 10 pieces) work in which Morton
Welding specializes. Moreover, many jobs are just three or four pieces,
so there is neither time nor money to make inspection gauges. When the
entire job takes less than half an hour, 20 minutes of which is needed
to set up the fixtures, inspection speed becomes critical.
What makes portable CMMs so effective is that the user just needs to
clamp down the part and clamp down the arm. In addition, the arm can
easily reach key points on fixtures when those need to be checked.
There is no need to create work planes, as with a CMM, because the
armarm creates its own. This means operators can find errors right away
and use the information themselves to readjust their bending fixtures.
Inspections with the portable CMM take one-fifth to one-tenth the time
needed with the usual Q/A layout approach on our conventional CMM. That
machine requires a full-scale 3D work-plane layout for each job even in
manual mode. Error-free setups are difficult and verifying them takes
at least 30 minutes.
Tube inspection is actually a very difficult Q/A challenge. Assemblies
have multiple bends in multiple planes, making them awkward to inspect
on a fixed CMM. For anything with an irregular shape, the big question
is, Where do you start?
At Morton Welding, most portable CMM inspections start with the flange
and two of its bolt holes. This provides the datum and inspection plane
necessary to determine if the opposite end’s flange is correctly
positioned and oriented in 3D space. Virtually all of Morton’s tube
assemblies have custom machined flanges on one or both ends. Machining
its own flanges from raw stock is one
of the company’s competitive edges.
However, it’s almost never enough to just have the ends or flanges
right. Every bend and vector in between also has to be right because of
required clearances. Also for one reason or another, some tube
assemblies must be inspected without their flanges. The portable CMM
gives us the flexibility to inspect from the end of the tubing, that
is, without the handy flange datums.
The portable CMM’s speed and accuracy make the fabrication area more
productive. This lets us boost the shop’s capacity at little or no
additional cost. In turn, that makes the operations more profitable. By
speeding everything up, the portable CMMs also increase throughput.
This means we can take on more work without the costs of adding people
or equipment. This makes us more competitive, so we get more work. |
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CIMCORE
a brand of ROMER Inc.
a Hexagon Metrology Company
51170 Grand River Ave.
Wixom, MI 48393
Toll Free Phone: 800.218.7125
Phone: 248.449.9519
Fax: 248.449.9445
sales@cimcore.com
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