A Case Study in Laser Marking for Automotive Parts

Through the analysis of practical cases, explore how to improve the yield of laser marking on curved surfaces of auto parts.The content of the training program covered such topics as how to deal with the challenges of curved surface positioning, parameter calibration techniques, and improving quality control procedures. This helped the production team solve problems such as blurry markings and off-center positioning, and enabled them to raise the yield rate from 85 % to 98 %.

Why is it that curved surfaces always cause problems?

Many laser marking machine manufacturers have encountered the same problem: while marking on flat surfaces is easy, curved surfaces can result in fuzzy fonts, inconsistent depth, and even misalignment.Last year, when we took on an order for motor housings from a new energy vehicle manufacturer, our first-pass yield dropped below 85 %, and the rework costs were so high it was painful.

After three months of work, we came up with a three-pronged plan for improvement.Now the company's production yield is consistently around 98 %. Even the most complex turbine housings are no problem for the company.

Three ways to improve your game.

The anchor point for a curved surface.

Traditional fixtures use a flat surface as a reference point, making it easy for the workpiece to "slip" if the surface is curved.We designed a 3D module for each part that functions like an alignment frame for a phone case. The module is inserted into a recess in the part, and the laser head automatically recognizes the alignment holes.The accuracy of measurement has been improved from ± 0.5 mm to ± 0.1 mm.

Laser parameters cannot be "set and forget.

Different curvatures require different focal lengths and power combinations.For example, a 30 ° arc is best cut with a 160mm focal length and 85 % power, while a 60 ° slope requires adjusting to 140mm and 90 % power.We made a parameter reference chart and posted it next to the machines so that the operators could look up the parameters just like looking up a word in a dictionary.

It has given the quality inspection system "eyes like a hawk.

Originally, the error rate for visual inspection was as high as 15 %. Now, they are using industrial cameras and AI recognition systems.The camera scans along the curved path of the character, and the algorithm automatically compares the completeness and position tolerance of the character.One time, he discovered that a batch of "8" characters had a slight defect in the lower right corner, and on further investigation found that the lenses had a 0.2 mm buildup of carbon that was completely invisible to the naked eye.

Hidden costs you may have overlooked.

Many people only calculate the cost of materials wasted in rework, but the bigger cost is the idle time on the production line.Before, every batch of parts required two hours of setup time, but now, through the use of pre-stored process parameters, setup time has been reduced to 20 minutes.With three changes per day, a single production line can produce an additional 100 hours of output per month.

Old Chang, the master craftsman in the workshop, says, "Nowadays stamping the trademark is just like stamping a seal. You put it down and it makes a click and that's the end of it.Before, we had to treat them like the ancestors, watching them like hawks to make sure every character was printed clearly.In many ways, this kind of hands-on experience is more persuasive than mere data.