Manual inspection operations are not effective and should be a last resort. If a process has low capability to meet a specification, then the process needs to be improved. As a containment action, 100% testing or visual inspection may be used.
Full Answer
As products move from raw ingredients you process all the way to the loading docks, 100% Inspection is key to ensuring quality and increasing brand protection. As such a critical process in your organization, you shouldn't trust it to just anyone:
The 100-hour limitation may be exceeded by not more than 10 hours while en route to reach a place where the inspection can be done. The excess time used to reach a place where the inspection can be done must be included in computing the next 100 hours of time in service.
Figure 11: The effectiveness of 100-percent inspection when limits are widened by two probable errors (Click image to enlarge.) This widening of the specifications on the X axis has the effect of making virtually all of the PGS values reasonably close to 1.00.
It doesn't matter if your work space is completely spotless with everything in line, your inspector needs to find something wrong or you need a new inspector. You can't have 100% on a grade because everything is prone to error. You can pass with high scores, but your inspector should not.
Therefore, 100% inspections are generally adopted for life-supporting products, expensive products, and products that are not consumed or damaged by inspection. This means that a variety of products undergo sampling inspections in different processes.
A 100% QC inspection is just what it sounds like: a method that inspects the ENTIRE shipment instead of a few random samples. The benefit here is that the inspection is more thorough as every last item is inspected for defects. The drawback is the expense and the amount of time/labor it requires.
As you can imagine, 100% Inspections can be extremely labor-intensive. Not only do inspections require extreme concentration, but repetitive checking of the same products can get mundane and boring. This often leads to fatigue, human error, and consequently poor quality detection.
Complete inspection is used when inspection cost is high. c. Sampling inspection is used when the cost of passing a defective unit is high relative to the cost of inspection. 63.
So usually an inspection during production is done after 10-30% of the products are finished. Inspecting the goods after they are made and packed is the standard QC solution of most importers.
A point to remember is that the main purpose of acceptance sampling is to decide whether or not the lot is likely to be acceptable, not to estimate the quality of the lot. Acceptance sampling is employed when one or several of the following hold: Testing is destructive. The cost of 100% inspection is very high.
Results: Inspectors correctly rejected 85% of defective items and incorrectly rejected 35% of acceptable parts.
acceptance samplingExplanation: When there are many items to be inspected and the inspection error rate is sufficiently high, that 100% inspection might cause a high % of defective units to be passed, the procedure of acceptance sampling is adopted.