In the video measuring machine industry, the mechanical structure often receives less attention than optics or software, but it has a significant impact on measurement accuracy. Some machines remain stable for ten years, while others show positioning errors after just one or two years. The difference usually lies in the condition and maintenance of the mechanical components.

Guide rails and ball screws are the core components of the motion system. No matter the quality level, wear is inevitable with use. Initially, it may go unnoticed, but over time, backlash gradually increases, resulting in inconsistent repeatability.

I recall a mold factory where repeated measurements of the same part varied by around 5 μm. At first, the problem was thought to be user error, but investigation revealed worn ball screw nuts causing backlash during reverse movement. Replacing the nuts and applying minor software compensation restored measurement stability. Many users underestimate the importance of lubrication and cleaning, and wear often accumulates faster than expected.

Mechanical structures are also sensitive to temperature. Granite bases are relatively stable, but aluminum frames, transmission components, and even ball screws expand or contract with temperature changes. Large environmental temperature fluctuations can cause measurement drift.

For example, in an electronics factory, a machine measured accurately in the morning but showed overall deviation in the afternoon. The cause was frequent air-conditioning cycles, which caused temperature swings and prevented the machine from reaching thermal equilibrium. Maintaining stable temperature and allowing sufficient warm-up time can avoid most of these issues.

Sudden stops or rapid acceleration/deceleration can impact the transmission system. Over time, screws may loosen and couplings develop gaps, which often leads to positioning drift.

Once, a client reported slight shaking of the worktable during measurement. Inspection revealed loose screws at the ball screw mounting end, causing axial movement. Tightening the screws resolved the problem immediately. Such issues are not uncommon but often go unnoticed until they affect measurement results.

Mechanical drift cannot be completely avoided, but proper maintenance and compensation can keep its impact within acceptable limits:

Software compensation: Correct backlash and thermal expansion effects;

Regular calibration: Use gauge blocks or measuring tools to check repeatability;

Environmental management: Maintain stable temperature and humidity, minimize dust and vibration;

Proper operation: Avoid sudden stops or forcing the worktable;

Routine inspection: Clean, lubricate, and tighten components regularly.

Mechanical drift accumulates slowly, unlike optical issues that can appear suddenly. In many cases, accuracy is not “lost instantly” but gradually “worn away.” Consistent maintenance and environmental management are key to keeping video measuring machines reliable over long-term use.