Automated Inspection
In current scenario, manual inspection is mainly replaced by automated inspection as errors are decreased to great extent by automation of the process. Economic justification of an automated inspection system based on whether the savings in labour expense and improvement in accuracy shall be more than the investment and/or development costs of the system.
Automated inspection is described as the automation of one or more steps involved in the inspection procedure. Automated or semi-automated inspection might be implemented in the number of alternative ways.
1. Automated presentation of parts by an automatic handling system with manual examination and decision steps.
2. Machine with manual loading parts into the machine doing, automated examination and decision making.
3. Completely automated inspection system in which parts presentation, examination and decisions are performed automatically.
The inspection procedure is carry out by a human worker in the first case, with all of the possible errors in this form of inspection. In 2nd & 3rd case, the real inspection operation is accomplished via an automated system.
As in manual inspection, automated inspection might be performed by using statistical sampling or 100% inspection. Sampling errors are possible while statistical sampling is used. Similar to human inspector, automated system might commit inspection error with either sampling or 100% inspection. Human inspectors might make such errors. Automated system operates along with high accuracy for simple inspection tasks such like automatic gauging of a simple dimension on a part. With enhance in complexity of inspection, the error rate tends to enhanced. Some machine vision applications fall into this category; for instance, detecting defects in integrated circuit chips or printed circuit boards. The inspection tasks of PCB are complex and difficult for human workers. This is one of the reasons for developing automated inspections systems that can do such types of jobs.
As stated before, inspection errors can be classified as Type I and Type II. A Type I error occurs when the automated system indicates a false alarm while the process is in control. The sensitivity of some automated inspection systems can be adjusted by the way of adjusting their "gain" or similar control. While the sensitivity adjustment is low, the possibility of a Type I error is low however the probability of a Type II error is high. When the sensitivity adjustment is increased, the probability of a Type I error enhanced, while the probability of a Type II error decreases.