Laser Marking Accuracy Testing Methods and Standards

It explains in detail the core methods and industry standards of laser marking precision inspection, covering visual measurement, instrument detection, and other practical techniques, to help users master the key points of quality control and ensure that the processing results meet industrial requirements.The book will be of use to laser equipment operators and quality control personnel.

Why is precision testing so important to laser marking?

We use laser engraving machines to etch patterns, text, or QR codes on our products.If the precision falls short of the standard, the product may have a poor appearance, or the entire batch may have to be scrapped, which will directly increase costs.This is particularly true of high-precision fields such as medical devices and electronics, where a difference of 0.1 mm can cause major problems.So learning to measure precision is like giving the equipment a "physical." Only by finding problems as they arise can you fix them in time.

Three precision measurement methods in contact with the ground.

The old fashioned way.

Don't underestimate this method. Many experienced technicians rely on it to quickly find problems.First, a standard grid or crosshatch is applied to the piece, and the difference between the actual size and the design is measured with a magnifying glass.Look to see if the lines are clear and the corners are smooth.It's a good choice for routine checks where precision isn't critical, but it shouldn't be taken as the final word.

Professional surveying equipment is brought in.

If you want more accurate data, then a tool microscope or a 2D image measuring instrument is the only way to go.The samples are then fixed to the machine's platform, and the software automatically analyzes line width, spacing, and position error.For instance, when testing QR codes, the instrument can read the error in module size and generate a visual report.I remember that I had to adjust the equipment before each use, otherwise the data could be "deceptive.

Repetitive marking test.

The same pattern is stamped out 10 times, and the variation in size is measured using a vernier caliper.If the data is inconsistent, it may be because the equipment is loose or the laser power is unstable.This method is especially suitable for newly installed machines or old equipment that has not been maintained for a long time. It can quickly discover hidden problems of stability.

These are the red lines of industry standards that must be understood.

The ISO 9013 international standard specifies that the width of a laser marking line cannot exceed ± 0.05 mm, while the domestic GB / T 19867.4 standard requires a positioning accuracy of at least ± 0.02 mm.But it depends on the industry: for example, the automobile industry requires a depth of cut with a tolerance of less than 5 %, while the jewelry industry is more concerned about the smoothness of the edges of the design.I suggested that we cut the tolerance requirements that customers give us by 20 %, for example if they allow ± 0.1 mm, we would control to ± 0.08 mm internally, and leave a safety margin.

The three biggest traps for beginners.

1. Ignoring the influence of temperature: When the temperature in a workshop exceeds 30 ° C, the expansion and contraction of metals can cause the markings to shift by 0.03 mm.

2. Using the wrong test standard--testing the accuracy on ordinary A4 paper, and then finding that the results are distorted when you use a stainless steel plate.

3. Ignoring focus adjustment: The precision of the same machine on a flat surface and a curved surface can differ by as much as 200 %.

Finally, a piece of advice: Do a complete system check at least once a week, paying special attention to the cleanliness of the lens and the focus of the laser.Precision is like love.