Daimler AGrelies on

Innovmetricand Leicafor optimalpart fitting

Total Point Cloud Inspection and Reverse-Engineering Solution

The customer

Daimler AG has a product portfolio includingmicrocars, performance coupes, sedans and stationwagons, versatile vans and commercial vehicles.The second largest Daimler AG plant in Germanyis the Bremen plant, which employs nearly14,000 people and has a floor space of 850,000square meters. The SL and the SLK roadstersas well as all versions of the C-class (sedan,station wagon, coupe and convertible) areproduced there.

The business partner

Whether buildingthe fastest car, thebiggest plane, orthe most precisetooling, you needexact measurements to improve quality and pro-ductivity. So when it has to be right, professionalstrust Leica Geosystems Metrology to help collect,analyze, and present 3-dimensional (3D) datafor industrial measurement.

Leica Geosystems Metrology is best known for itsbroad array of control and industrial measurementproducts including laser trackers, Local PositioningTechnology (LPT) based systems, hand-heldscanners, 3D software and high-precision totalstations. Those who use Leica Metrology productsevery day trust them for their dependability,the value they deliver, and the world-classservice & support that‘s second to none.

Companyoverview

C A S E S T U D Y

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Dirk Noffke, a metrology technician atDaimler AG Bremen, inspects the dimensionalaccuracy of the left fender on a Mercedes SLKBody-in-White. The comparison between theactual and CAD data is displayed in realin the PolyWorks Inspector software.

The first thing you’d noticewhile walking up and down theseemingly endless corridors ofDaimler AG‘s sleek, ultra-modernBremen plant is the almost completeabsence of people. Hundreds of

robots go about their work with surgical precision,bringing different sheet metal parts into place,welding them together, moving completed partsonto the next station and transporting finishedproducts overhead to maximize space utilization.Viewed from afar, the ubiquitous robots seem tobe dancing. The few factory workers you do seeuse “old school” bicycles to jet between differentparts of the factory: hi-tech and low-techharmoniously coexist hereside by side.

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Viewed inretrospect, cars

used to be madeof almost square-like

segments which used to fitnicely together without much

hassle. Nowadays, cars aremuch more curvy, with roundareas suddenly changing shapesand meeting other panels at allkinds of angles and lines. Plus,the much higher requirementsfor the nearly seamless fitbetween individual panelsmandate that we work with

very tight tolerances.

Henning Siemers

OperationalEngineer

Technological progress in the manufacturingprocesses has meant that more daring bodyshapes can make the leap from the designers’drawing board to the assembly line. In thenot-so-distant past, cars had relatively simple,square shapes, with individual parts fitting to oneanother along more or less straight-forward lines.On the other hand, modern cars boast far morecomplex shapes than the cars of yore. And the taskof inspecting how these parts fit to one anotherhas gotten increasingly more complex as well.

The Body-In-White (BIW) Rollout and ProcessOptimization Department tackles exactly that task:it is entrusted with the job of inspecting howthe various body parts fit to one another. Moreimportantly, based on their measurements, feedbackis given to the production facilities so specific,targeted adjustments can be made on the tools.

Looking for aperfect fit

Operational Engineer Henning Siemers is involvedin BIW measurement and inspection tasks. Heexplains: “Our job is to assure dimensionalaccuracy of the entire body-in-white. Of course,every BIW consists of many individual parts, andthey must all fit perfectly. Our primary duty isto inspect the entire BIW, both individual partsand the whole vehicle, including the panel gaps,and then analyze the data we get. Based on theanalysis we perform, we then go back to theproduction facilities and make adjustments tothe tools and make sure that what comes out is anautomobile whose parts fit together flawlessly.”

In the past, Mr. Siemers’ department hasrelied on hand-operated measurementinstruments. However, it is the shapecomplexity of today’s cars and theever-increasing tolerancesthat have pushed suchinstruments againsttheir limits.

C A S E S T U D Y

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Deviations fromCAD data arevisually displayedusing the PolyWorksInspector software, with deviations shown either using a color palette or vectors. The information is analyzed in order to yield correction instructions, which are then implemented directly on the tools.

It wasimmediatelyclear to us that theLeica T-Scan and thePolyWorks software werea mighty combination.We already knew that theLeica T-Scan was a greatsensor, and we were alsoshown that the PolyWorkssuite is a worthy match for it.The software is very capable,and we knew we would beon the right track.”

Henning Siemers

OperationalEngineer

Leica Geosystemsdelivers

“With the shapes of our vehicles getting morecomplex, we have been on the lookout for newtechnologies that deliver,” continues Siemers.“Our Quality Engineer, Karl-Heinz Boecker, hasbeen attending the CONTROL trade show inSinsheim, Germany each year, and he had his firstencounter with the Leica TScan system a coupleyears ago, when it was still just a prototype.Based on the announced specs, we knew thiscould be something for us, but we wanted towait until we were positive that the product wastruly ready for the market. The primary issue thatwe saw with many of the other scanning solutionsout there was that the software could not keepup with the hardware. Collecting all those points isrelatively simple, but what do you do afterwards?We were under the impression that manymanufacturers did not award the same attentionto the software as they did to the hardware.“A few months ago Mr. Boecker’s team arrangeda Leica Geosystems product demonstration at theirfacilities. A Leica LTD840 Laser Tracker coupledto a Leica T-Probe and Leica T-Scan – thetop-of-the-line combination – was chosen.And the Leica system delivered.

C A S E S T U D Y

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Changeis good

Since the system delivery, the Leica TProbe/T-Scansystem has been used, among other things, tomeasure panel gaps, examine part curvatures,inspect reference holes and similar. Siemers hasalso been busy testing different applicationsfor the Leica T-Scan system. “One of the newapplications we have found is inline calibration.In the past, BIWs were inspected by beingplaced inside a grid station and measured usingconventional CMM equipment. When you have150 pallets and want to measure with hightolerances, you‘re quickly reaching the limitswith traditional methods. That’s why we wantedto be able to measure inline, both the palletsand the tools, and this is where the Leica T-Scansystem will come into play. Another applicationof interest to us is the inspection of the entirerobot path, and this is something we plan ondoing in the near future.”

A Leica Laser Tracker followsthe position of the Leica T-Probe,

accounting not only for the 3Dcoordinates of the “Walk-Around”

probe but also keeping track ofits pitch, yaw and roll. The position

of the reference holes in the A-pillaris being checked. Outer sheathing

will later attach to the holeslocated in the A-pillar.

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Thanks to the large operatingvolume of the Leica T-Scansystem, which can inspectmeasurement object in therange of 15m, an entire sideof the body-in-white can beinspected without repositioningthe Leica Laser Tracker. Theoperator moves along thevehicle back and forth, andthe Leica Laser Trackermaintains a lock on the LeicaT-Probe/T-Scan within theentire measurement volume.

C A S E S T U D Y

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The LeicaT-Probe/T-Scan combo

measures within a range of15m, giving the technicians a

volume of 30m in which they canoperate. This give Henning Siemersand his team peace of mind in knowingthat should the measurement requi-rements change in the future, theyare well equipped for working in

a measurement volume largeenough to accommodate

several BIWs atonce.

Results

Qualityinformation =Good analysis

Asked about what has changed since theimplementation of the Leica T-Scan system,Siemers is very specific: “By relying on scanning,I am in the possession of much more usefulinformation. The quality of part analysis hasimproved, we are able to get to the root of aproblem much more quickly, therefore coming upwith targeted solutions for what needs to bechanged, for example intervening at the tools atsuch and such point and changing the parametersbased on the results seen in PolyWorks.”

And benefits of using the Leica T-Probe/T-Scansystem are manifold. “We really appreciatethe portability. With the Leica Geosystemsequipment, I can gather all the informationI need in just 2-3 hours and perform theanalysis later. This way, I am not blockingproduction for too long because thesystem lets us work in parallel: whileone operator is taking the measurements,another one can already be working onsorting out the results.” The fact that the system is modular

is important to Siemers’ team. “We purchased a Leica T-Probe at the same time we got the Leica T-Scan. Tactile wireless measurement is of great value to us when we measure easily twistable parts like the hood. We perform a quick measurement with the LeicaT-Probe to get a rough idea about the condition ofthe part. If we were to start scanning immediately,it would take longer to realize that the hood istwisted. With the Leica T-Probe, collecting justa few points will let us know fairly immediatelyhow we are doing. And we are performing thiswithin the same software, merely switchingbetween the Leica T-Probe and the Leica T-Scan.”

TechnicianDirk Noffke

inspects the gapbetween the left

fender and theengine hood.

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