When we need to talk about ‘in-line measurement’ and ‘in-process measurement’, we need to demonstrate and explain each term and show the difference. Both terms are part of manufacturing process that is related to quality control and precision. However, the application process is different. Therefore, it is important to look at them and eliminate the confusion.
The term ‘In process measurement’ means that any measuring process that occurs while the part is machining in the actual manufacturing process. It can provide real-time quality control on deviation or issues and make corrections immediately. This process is applied using sensors or measuring systems, whether it is built into the machine or by monitoring. This process can assist in reducing scrap and rework, improving process reliability and consistency, increasing automation and minimising operator intervention.
While the term ‘in-line measurement’ can be a subset or part of ‘in-process measurement’. With this term, the measurement can be conducted at defined points on the production line. It can be applied before, between or after discrete manufacturing stations. This means that the measuring process is not performing while the part is machining. The measurement is highly automated and can be used when the machining is off. This process is used to approve or reject parts.
It can compare between the terms in different features like timing, location, feedback and integration. The table below shows the key features between two terms.
| Feature | In-process Measurement | In-line Measurement |
|---|---|---|
| Term | Broader term | Subset of in-process measurement |
| Timing | During the machining operation | Between, before or after manufacturing stages |
| Location | Inside the machine | Station on production line |
| Feedback | Direct correction | After operation |
| Integration | In actual process | Production line |
The term of in-process measurement can be wider, which includes other forms of measuring applications. It can include different forms like ‘in-line’ when it is taken on machine while the operation is off, and ‘on-machine’, which has ‘in-situ’ when the data is directly being monitored during manufacturing. It can indicate that the in-process measurement term can be used mostly as it contains different forms, while the in-line measurement term can be used only under specific conditions.