In my more than twenty years in the vision measuring industry, I have seen all kinds of equipment. Some systems in cleanrooms can run for years and remain stable, while others in mold workshops become blurry in less than half a year. The key difference lies in the maintenance of the optical system.

Lens aging is often underestimated. Most lenses use cemented optics, and when exposed to humid or fluctuating temperatures for long periods, the adhesive layers may gradually deteriorate, causing slight delamination or hazing. These changes are hard to detect with the naked eye, but under magnification they make edges appear blurred. I once had a client in southern China where the factory humidity stayed around 70%. After three years, the repeatability of measurements declined significantly. Upon inspection, hazing inside the lens was found. Replacing the lens immediately restored accuracy. In addition, if the optical axis shifts due to impact or improper installation, the field of view and coordinate system will no longer align, which requires recalibration.

Light source decay has a similar impact. Although LED lights have long lifespans, their brightness and color temperature drift over time. Reduced brightness weakens edge contrast, making extraction less stable. Shifts in color temperature can change surface reflections, leading to inconsistent results on the same part. I recall a case in an electronics factory where PCB traces were measured. After two years, measurement deviations appeared. Inspection showed that the light source had lost nearly 30% brightness and its color temperature had shifted. Replacing the light restored accuracy immediately.

Dust and oil contamination are the most common issues. In many workshops, airborne dust or oil mist attaches to lenses or protective glass, creating artifacts in the image. At one mold factory, workers ran the equipment while grinding parts, and within half a year, oil film covered the lens surface. The images became so blurred that edges could hardly be identified. Cleaning restored clarity, but repeated contamination significantly shortened the optical system’s lifespan.

My recommendations are: under normal conditions, check lens surfaces weekly and clean the system quarterly. In harsher environments, add protective covers or air filters. Light sources should be tested every two to three years and replaced early if necessary. When encountering accuracy problems, always check the environment and optical system before considering lens replacement.

Optical drift is inevitable, but with proper maintenance its impact can be minimized. Precision is not just guaranteed at the factory—it must be preserved through careful management during use.