A 100% quality assurance check is often not done. Only a portion of large batch is analyzed or every few samples after every hundred or thousands are inspected. However, a 100% quality inspection is not far from reality. It is possible with the use of advance machinery, intelligent and fast computers or lots of time and patience.
While molding PET bottles. The molding machine is capable of producing 800 bottles a minute. A built in camera takes picture of every bottle which is then analyzed by a computer. Every defective mold are taken out for recycling.
While making aluminum cans for soft drinks. Each can pass through a multiple photo inspection. Any item with deviating color, dimensions and with other defects are blown out for recycling.
Adequately filled soda cans. It is easy for PET bottles. The content level can be seen with a naked/machine eye. Underfilled and overfilled are tossed off. However, the method is impossible for canned soda. Checking for properly filled cans is done by gamma ray scanner – a method similar to X-ray.
Medicine capsules. Each should have a precise weight. Every capsule pass on a weighing machine. Overweight and underweight are ejected.
Above examples are performed at a very high speed and accuracy while the following can be done manually with lots of time and patience.
Glass molding. Broken glass can be recycled endlessly – break and mold into bottle again. They are cleaned well before the process. Broken pieces are pass on a wide conveyor while a staff is removing paper and other debris that may contaminate the glass.
Potato Chips. After frying, it pass under camera that can see every single chip. Chips with brown and black spots are thrown out with a trigger. Non conformities can also be removed by series of human hand.
Harvesting coffee. Only red cherries should be harvested. They are carefully hand picked to leave the green and allow it to ripen. Or harvesters try their best not to include more than two green for every 100.
Manual selection of coffee defects. Coffee defects has bad effects on overall coffee quality. Defects such as black, broken, too small, stones, woods and hollow beans. Those are sorted out using human eye and hands.