| Since 1991 Clean Earth Environmental Group (CEEG) has manufactured custom
trucks and related equipment for important cleanup jobs such as industrial
waste and municipal sewage. Every truck that rolls out of CEEG must not only
get the job done, but also comply with regulations from city level all the way
up to federal level. Each level of regulations increases the complexity of the
design, providing unique design challenges for each truck.
For years their designs were presented to the manufacturing shop
as hundreds of 2D drawings. However, as the company grew, they found that
persistent design problems were hampering company profitability. CEEG had no
reliable means of detecting potential problems with new or customized designs.
Most customization time was spent rearranging the pieces of a
truck, with a reliance on guesswork and trial-and-error. Even in the final
stages of checking the truck, it was typical to find small problems that had to
be fixed.
Each little piece of a Clean Earth truck that has to be
remanufactured must be cut, welded, painted, and attached to the main truck.
Even the smallest design error costs approximately $180 to fix, and major
revisions could run into several thousand dollars. The company tried analyzing
their 2D drawings to find the source of the errors, with little success. A
solution had to be found.
Paul Comstock, CEEG Director of Engineering, already had some familiarity with
SolidWorks when he decided that 3D models would be the best way to eliminate
their design problems. CEEG computer network consultant John Thomas of TKS
recommended outsourcing the 2D to 3D conversion. He put CEEG in touch with
Engineering Design Automation, Inc. (EDA).
EDA, a SolidWorks Solution Partner with a specialty in design
automation, was able to complete a quick SolidWorks demo showing a simplified
truck with a few moving parts that utilized SolidWorks collision detection.
Since collision of truck elements was one of CEEG's recurring problems, this
ignited their imaginations about the possibilities of a solid design solution.
In spring of 2001, EDA began consulting with CEEG about their project. EDA
President Hiroshi Takaki began by conducting a thorough evaluation of the
current CEEG system. Some of the major problems he discovered:
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Lack of company-wide design standards.
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Missing sub-assembly drawings, resulting in incomplete data about how to put
the trucks together.
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Significant discrepancies between the Bill of Material (BOM) listing from their
MRP system and the BOM listing from the engineering drawings.
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Design bottleneck, where even a fairly standard truck took about four weeks to
design.
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Discrepancies between manufactured trucks and specifications indicated on
engineering drawings.
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The approach that CEEG and EDA decided on was to start by creating "base
assemblies" of the SafeVac and SafeJetVac, two of CEEG's most high-end trucks.
A SolidWorks automation program would automatically assemble standard
configurations of the base assemblies. The assemblies built by the automated
program would become a stable, working foundation for later customization. EDA
got to work building 3D models based on the 2D drawings that had been used to
construct the trucks. Each truck model required more than 600 individual
solids. However, the most difficult work began when the individual pieces were
being joined into assemblies and sub-assemblies. Many necessary drawings were
missing, or lacking sufficient detail for the assembly to be clear. There also
turned out to be even more design errors than CEEG thought. "Things didn't
fit," said Hiroshi Takaki. "We had to go back to Clean Earth to find out if the
mistake was ours or in the drawings. We would go back to the shop and be told,
'yeah, we know this doesn't work, but we've been fixing it on the shop floor.'
That was a typical answer I got when interviewing the production manager." For
example, one hydraulic tank was engineered with sides that didn't actually meet
up when manufactured, so welding was used to bridge the gap. But the welding
would leak because so much of it was used--resulting in costly, inconvenient
repairs.
"Also, it's a cosmetic issue--you see a big old line of weld going
down one side, and anybody who knows anything about tanks knows what that is,"
said Paul Comstock.
Another tank, the SafeJetVac water tank, was being placed into a
cradle with the same radius as the tank, which caused the tank to become
deformed. The boom--a key moving part that swivels around to allow hoses to be
placed where they are needed--was colliding with other parts of the tank.
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This water tank is being forced into a cradle with the same radius
as the tank, resulting in unnecessary wear.
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The solid model of the same water tank shows
interference lines indicating the design problem. |
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EDA staff found it particularly challenging to construct assemblies
from SolidWorks pieces that didn't quite fit together. Easy mating strategies
were often impossible. Instead, they had to create many customized planes and
construction lines to join the solids. It took about two months to complete
each truck design.
"This is the main benefit of outsourcing when you make the leap
to 3D. Our engineers didn't have to stop production and learn SolidWorks. If
they waited for that, they would never have gotten it done," said Paul
Comstock. Also, he knew that EDA had the skills to build 3D models and
assemblies specifically for use by automated programs.
"We really benefited from Hiroshi's knowledge and teaching of
structure," he said.
The conversion from 2D to 3D is an excellent opportunity for companies to
thoroughly examine their designs, to eliminate errors and redundancy, and to
improve consistency. This is an important advantage of contracting a
knowledgeable SolidWorks service provider, rather than using a bare-bones
conversion service that will simply replicate all your 2D problems in 3D.
By late summer 2001, CEEG had their 3D base assemblies and
automated program to dramatically speed development and customization time. The
Truck Configurator program has a simple dialog box interface that allows even
employees who don't know SolidWorks to create standard truck assembly
variations based on tank length, truck chassis, and blower style. This program
makes a selection using built-in SolidWorks configurations. For each
sub-assembly the designer creates 2D drawings of three major views plus the
perspective view. Then, the designer or another CAD operator uses AutoCAD to
add detailed manufacturing information.
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SafeJetVac SolidWorks assembly.
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"When a customer calls us up, 9 times out of 10 he's going to
order the truck in a configuration we've never done before," said Paul
Comstock. This used to mean coming up with new assembly drawings from scratch.
With SolidWorks, it means making modifications to existing base models. The
designer uses the Truck Configurator to create an appropriate design variation,
then copies the SolidWorks files to a different directory. The models and
assemblies are modified as the client requires, and each modification is tested
thoroughly for interference or other problems. Then, the 2D drawings are sent
to the shop.
He estimates that his design time has been cut in half with the
new system, allowing them to unveil new designs with a lot more confidence. "We
know we're not going to be out there at the last minute hacking and burning
trying to get stuff to fit," he said.
Other benefits include better documentation and communication with
the shop, and with their customers.
"We've never been able to do exploded views of our
sub-assemblies before," said Paul Comstock. They are creating a new manual for
truck assembly, to increase the speed with which the trucks are built. They are
also updating an owner's manual, which was five years out of date and not
terribly detailed.
Moving to SolidWorks has speeded up company procedures, and also
opened up new possibilities. "We have never done prototypes," said Paul
Comstock. "We can't afford to build a truck that won't be sold. So if we had an
idea for improving the truck design, we would be calling up our customers and
asking, 'hey, can we have permission to experiment on your truck?'"
SolidWorks allows the company not only to build prototypes of new
truck designs, but also to apply new and powerful analysis tools such as Finite
Element Analysis with the Cosmos package.
"Right now we're making 140 trucks a year, and our owner wants
to increase that to 200," said Paul Comstock. "He's bought another shop like
this one, and wants to increase the total to 800. Last year if somebody had
come and said that to me I would have quit. I'd be out flipping burgers.
"But now it's a possibility. We're already adding seven different product lines
to our current menu--areas we would never have thought of a year ago. The fact
that we have these tools is allowing us to say, 'yes we can do it.'"
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