The benefits of inspection as close to the part as possible include fewer bottlenecks delays. By Daniel Brown, senior product manager at Creaform.
For many production managers, measuring parts directly on the production floor means fewer alignments and manipulations, which is one of the keys to more efficient production processes.
However, quality control teams may be more reluctant to inspect on the shop floor and prefer to redirect measured parts to the lab, where the control will be performed on the coordinate measuring machine (CMM). This article is intended to demystify why, when, and how inspections can be performed efficiently on the production floor.
Better Control & Workflow
- To unload the CMM
Because CMMs are very accurate metrology instruments, they are very popular for inspection and quality control. Therefore, they are extremely loaded. Among the tactics employed to unload the CMM is prioritising inspection directly on the production floor, especially if the measured parts are large and cannot be moved easily.
- To enable measurements at intermediate steps
Waiting until the end of the production to inspect the manufactured parts may be risky and hazardous. It is usually not easy to locate where specific issues occur, especially if the manufacturing process comprises many steps. Thus, deciding to wait may save time in the short term, but can quickly become a headache later on. Action today can prevent a crisis tomorrow. Measurements at intermediate steps, therefore, are paramount to better quality control. In addition, they must be performed on the production floor to minimise manipulations of parts, especially when they are large and heavy.
- To enhance the quality of the products
Because more measurements can be done on the production floor than on the CMM, more parts can be inspected. The inspection frequency can also be increased due to the availability of measuring tools. All this has a major impact on the quality of the products.
Independence & Autonomy
Whenever you want! Inspection on the production floor gives production teams more autonomy, better capabilities, and greater independence. They no longer need to rely on the CMMs, which are already extremely loaded, nor do they have to wait for a quality control department, which is very busy.
They can use another metrology tool, one with a level of accuracy that is not overkill for the tolerances typically required in the industry. With the possibility of measuring parts whenever they want, at any intermediate step, production teams can perform better quality controls.
Inspection on the production floor requires a tool suitable to take measurements in an industrial environment. The metrology tool must be portable, compact, and easy to use.
Some metrology tools are more sensitive to environment instabilities than others. In those particular cases, it is important to track any vibrations that could impact the measurement system and to minimise the induced error.
Another solution is to use an optical technology. In addition to being portable and suitable for industrial conditions, optical metrology provides measurement accuracy that is insensitive to the instabilities of the environment.
Remember, if the measured part moves, vibrates, or oscillates during the measurement, then the inspection and quality testing are not valid. This enhances the importance of having a rigid measurement setup or a reference system that is locked to the part itself. Dynamic referencing gives this flexibility by optically tracking the measured part and the measuring tool at the same time.
Inspection on the production floor, therefore, requires fewer manipulations, which means less error accumulation and less pressure on quality control operators. It also reduces the amount of back and forth in the lab, which means fewer bottlenecks at the CMM. All tooling remains available for production, which minimises delays and accelerates customer approval.
For all of these reasons, inspection done directly on the production floor leads to more efficient production processes, saving time and money.
— Info Box —
Portable Measuring Devices—An Important Change In Metrology
Over the past 30 years, one of the most important changes in metrology has been the development of portable measuring devices, according to a paper titled “21st Century Measuring Challenges” that was presented at the Coordinate Metrology Society Conference.
Portable measuring devices have brought inspection right into the production line, as close to the part as possible. The change was sparked by the development of portable measuring arms in the early 1990s and the emergence of laser trackers shortly after.
It also made it possible to take measurements more quickly and more often, fostering huge improvements in response time and quality. Far from the comfort of metrology labs where qualified inspectors operate digital CMMs with their heavy, stable granite tables, portable measurement is still facing several major challenges.
Obstacles faced by portable measurement solutions users in production environments include:
- Permanent vibrations generated by production equipment.
- Requirements for rigid equipment set-ups.
- Changes in temperature and humidity levels.
- Different operators’ experience and skills level.
One of the conclusions observed was that human error is a major factor in poor quality measurements. Dynamic referencing could actively contribute to reducing some of the human errors identified, such as inadequate operator assessment of the risks that derive from an unstable environment, heavy traffic, or an unstable part.