From 70 % to 95 %: The Story of a QR Code Laser Marking Process

By analyzing real cases, the book explains how to optimize the core methods of the micro QR code labeling process, covering equipment adjustment, parameter settings, and process improvement. It helps production teams to increase their yield rate from 70 % to 95 %.The content focuses on solutions to user problems, and provides reusable operational experience.

Why does the laser marking of QR codes always cause problems?

Many in the industry have run into this problem: even with imported equipment, the QR codes are blurred, missing a side, or even unreadable.Last month production was stuck at a 70 % yield rate, and we discovered that the problem was caused by three things: laser power fluctuations, inaccurate positioning, and uncontrolled temperature and humidity in the factory.

The secret to fine-tuning the equipment.

Don't be lazy about laser head maintenance.

Every week you should clean the surface of the lenses with a special cleaning rod. Never use alcohol-soaked cotton balls to wipe the lenses.One time, an engineer discovered that a 0.1-millimeter layer of dust on a lens could result in a 3-micrometer difference in the depth of the etching, which would directly affect the QR code's readability.

Vibration-proof work table.

Two 5-millimeter thick rubber mats were laid on the concrete floor, and the equipment vibration was reduced by 40 %.Don ’ t underestimate the impact of this vibration, because if the marking head shakes even a little bit, the 0.3-millimeter edges of the QR code will appear blurred.

Practical experience with parameter setting.

More power is not necessarily better.

After testing 20 materials, they discovered that 18W was just sufficient to produce a 0.05 mm groove in 304 stainless steel, but that 22W would cause the edges to become carbonized.I suggest that people prepare a chart of the various power ranges for different materials.

The balance between speed and accuracy.

When the speed is reduced from 800mm / s to 650mm / s, positioning error is reduced from ± 0.03mm to ± 0.01mm.Although efficiency dropped 8 %, the pass rate went up 15 %, which made the whole thing a good deal.

Key points in controlling the workshop environment.

After installing two industrial dehumidifiers to keep the humidity at 45 %, the pass rate for the marking of aluminum oxide material rose from 82 % to 93 %.Temperature is even more important. On one occasion, when the air conditioning broke down and the temperature in the workshop rose by five degrees, the scrap rate doubled overnight.

Three things to check every day.

Before starting work in the morning, they first check the diameter of the laser beam. After lunch they check the focus accuracy, and before leaving work for the day they record the total working hours of the equipment.These three sets of data, recorded for two weeks, will enable the best period for maintenance to be determined.

A simple way to keep improving.

They have a shared document where operators can upload photos of products that are out of spec, and at weekly quality meetings, photos of typical defects are projected onto a three-meter screen.In three months, he had accumulated more than 200 examples of case studies, which are now used as materials for training new employees.