Daimler loves our high reliability with simple install

To the clear identification the different type classes becomes successful that 2D-Code reader of Omron assigned. That on labels imprinted DATA matrix code replaces that electronic identification system by means of data media, which itself in the production flow as trouble-prone and cost-intensively proved.

Simple and fast integration into the production flow

Simple and fast integration into the production flow The identification system used so far caused disturbances frequently and the spare part costs were high. Besides the assigned data media had to be installed and dismantled within the process. A further substantial aspect was the omission of the installation place used until then. A new identification system was sought, that had to be found within 8 months, to be purchased, installed and that was plug-compatible to the existing mobile RFID system. Interference of the manufacturing wasn’t allowed to arise either by installation or the changeover.

Thereupon different procedures regarding investment volume, operating cost, reliability, degree of possible integration, feasibility and future security were examined. Technically and commercially it was proved that procedure 2D-Code was the best solution. That it could be used in practice was proved in test installations.

According to project manager Walter George Pfisterer the DATA matrix code was selected for the following reasons:

• Largest distribution in Europe and the USA
• High error redundancy in the code by ECC 200
• Both square and rectangular structure possible (A-column narrow but long)
• Very good cost-performance ratio

Data matrix code enables data sets 100 times bigger

The two-dimensional coding of information makes it possible to accommodate substantially larger data sets on a relative small area. In comparison to bar code, in which the information is limited to one dimension i.e., the width of either the bars or the spaces, whereas with 2D-Code  the information is coded in width and height, thus 2D-Code can contain up to 100 times more data.  

For decoding a smaller contrast between background and code print is sufficient, so that the codes can be printed or incorporated directly on the surface of parts with any procedure. The reading reliability is substantially more certain than with conventional code readers, because the recognition is being made by optical camera systems. The position and the turning situation of the code can vary in the image field are compensated.

The 2D-Code reader of Omron can read Data Matrix code ECC200 and QR-Codes and exists of a controller and a camera. The settings take place with a hand console and can be followed on a monitor. A graphic menu controlled surface assists the comfortable communication to the user.

Error free reading of labels at 35m/min

To attach the labels on top with a direct reading from above was ruled out, because a high variety of vehicles, among other things with glass roof and/or combination models are built here. The latter prevented use of the C-column.

Lateral mounting was ruled out, because the reading spots are partly in the work area of the persons. So as the only place to attach the label, existing for all vehicles, A-column remained, which among other things holds the windshields. Some cameras are up to 2 meters removed from the labels. Readings at the driving vehicle take also place at an error free speed of 35 m/min.

An analysis of necessary contents for the manufacturing in the assembly resulted in a sum of approx. 64 utilizable bytes at a high reserve. Additional resources resulted in the possibility to put in the production number in plain text and bar code. As a base for the label an already established plastic label was used, which when painted became according to the matte surface. A thermal transfer printer was used to print the labels.

During the construction it was recognized that the necessary variability by the use of different motor vehicle types can only be attained with a robot. To ensure compatibility to the existing control concept, the software in the interface maps are arranged so that it can convert the label contents on the existing file structure of the still parallel used identification systems. For the installation of the cameras and the lighting an aluminum profile system was assigned.  

Satisfaction of project management

Despite an extremely short term realization date, project management succeeded to select 25 identification places altogether, to plan the execution, to integrate it into the production process and to take it into operation. The reading reliability with the new system increased, both when standing and driving. This led to the fact that a further line, like the new E-class, is likewise reequipped with the DATA matrix code. Thus then 50 systems are used in the double shift enterprise.

About the entire course of project Mr. Pfisterer, project leader at Daimler said: "Co-operation and the implementation occurred unusually well and the systems ran without any problems from the get go."

In addition to these applications, in which the height level of the different vehicles without assembly carriers requires an extended range of vision, a connection for a second camera was realized. The reached plug compatibility makes a conversion to the 2D-Code reader of Omron possible within a few days.

Together with Omron further developments were realized, which will be used with new projects to come. This concerned software-specific changes for integration into existing bus structures, to be able to do without interface maps, as well as desires to larger data sets and changes to the diagnosis of the system.