The pre-production inspection is the second most commonly used inspection after the Pre-Shipment inspection.
A Pre-production inspection is carried out, when the manufacturer has received all the raw materials and components for your product but has not put them on the production line yet. This is a great way to ensure that the supplier is using the components/raw materials that were agreed as changing components over orders due to different reasons (to cut costs, unavailability of components, etc.) is by far the single biggest QC issue that we see.
By the time these components have been assembled into a finished product, it can be too late or expensive to change them. Therefore, a pre-production inspection helps avoid that scenario.