Using Laser Marking to Improve the Traceability of Automotive Parts
In the 1960s, “National traffic and motor vehicle safety act”, the first law about recalling car, was instituted in US. It makes strict requirements traceability of auto parts. Then the development of marking automotive parts technology started.
Now common methods of auto parts marking are: die casting, electric corrosion marking, stickers, screen printing, pneumatic and laser marking. Although the laser marking technology was the latest, but it got attention for its eternal marking.
The main advantage of the laser marking on auto parts is quick, programmable and non-contact, and not affected by the required steps in the process of production and bad environment. Of course, laser marking has some shortcomings, such as the initial cost of laser marking device is higher, and marking on some materials like plastic is lack of contrast.
How to choose laser device?
Usually, there are two types of laser device when marking auto parts:
CO2 laser device uses carbon dioxide gas to make monochromatic light, marking with 1064nm wavelength. It is suitable for marking on non-metallic materials and metal surface paint layer.
•Nd3+: YAG laser.
Nd3+: YAG uses doped silicon carbide crystal material, as the dielectric, to produce near infrared light, marking with 1064nm wavelength. It is suitable for marking on metal materials and part of non-metallic materials.
With the development of researching Nd3+: YAG, lack of contrast on plastic materials is solved by using plastic additives for laser marking. Nd3+: YAG can mark clearly on the surface of plastic materials. (Figure 1)
Figure1:Nd3+: YAG can mark clearly on the surface of plastic materials
Laser bar code and QR code
Bar code and QR code is popular on the traceability of various forms of product, and fully applicable to all kinds of auto parts.
In the past, traceability depends on marking serial number on auto parts. Since bar code was invented, it was quickly applied to the identification of auto parts (figure 2), but bar code isn’t popular due to the less amount of information and low fault tolerance. The appearance of QR code technology solved this problem.
Figure2: Car tags based on laser marking and bar code technology
QR code is 2D graphics, like a tessellated pavement. It contains a large amount of information in a tiny area. Because of QR code 2D graphics only requires less than 50% contrast ratio, the application of QR code graphics increased the number of laser application.
Figure3: Marking QR code on metal to realize traceability of products
QR code coding also has a built-in correction function, even some damaged part code is still readable. QR code can also be used in several different forms of decoding encryption, by placing protection device in data to make this type of marking on components which have patent rights more valuable. HGLASER LSY50F laser marking system can not only generate bar Code automatically, but also support Data Matrix, PDF417, QR Code technology, etc.
Figure4: Common QR code
The importance of database and network support
The traceability of auto parts is based on marking database on products. Before computers were born, the database cost a lot of manpower due to using manually and retrieval. With the increasing development of database, it brought heavy burdens to retrieval work. Then the birth of computer and network has brought the new model for this work.
Because of using computer controlling model in the laser marking system, the database can generated and retrieve automatically and easily. Considering the demands of auto parts enterprises, HGLASER, as the earliest domestic laser company focusing on auto industry, has applied database and network function in marking software, such as connecting the database network of auto enterprises, setting up a marking database, and communicating related database, to realize the traceability of the whole manufacturing process.
How about the cost?
The initial investment of independent or online laser marking system is generally higher than that of most traditional marking systems.
But by comparing the owning cost, laser marking system is actually a better investment, because it has lower consumption, no repeat processing cost, or the cost of order delivery, inventory and new products. CO2 and diode, solid-state laser marking systems rarely need maintenance due to its long service life and gas proof. And in most processing of auto parts, the laser marking system has development to the direction of automation, that without manual operation, and not affected by the operator.
October 1, 2004, China started to institute the system of recalling cars. It means that the traceability of auto parts should be improved. Once the quality of auto parts has batch problems, the company's reputation, responsibility and future business depends on the solution of the fault and correction measures. Using laser marking based on the QR code technology can be convenient to realize product traceability in the whole life cycle.
Reference：Laser Marking Enhances Assembly Traceability by Joyce Laird