A final inspection checks what the factory made. An in-process inspection checks how it is making it, and when half the order is finished there is still time to change course. It is sometimes called a during-production check, and it suits large orders, long runs, and products where small process changes lead to big quality differences.
The best point is when 30 to 60 percent of the order has been completed, with some finished units packed and others still on the line. The inspector draws a sample from finished goods, much as in a final inspection, and also looks at work in progress and the process behind it. Doing both shows the quality so far and what is likely to happen over the rest of the order.
Thai factories make a wide range of goods, and the checks follow the product. For injection-moulded plastic parts, the inspector looks at cavity-to-cavity variation, flash, short shots, and whether process settings such as mould temperature and cycle time match the approved sheet. A part that measures correctly from cavity one may be undersized from cavity six.
Rubber and latex products, a Thai specialty, are tested for pinholes. Disposable medical and examination gloves are normally checked with a water-tightness test to a standard such as ASTM D5151, at AQL levels set by the buyer. If the pinhole rate climbs through the shift, the inspector asks about the formers, the dipping tanks, and the curing temperature.
For packaged food, the line check covers seal integrity, fill weights, date and batch coding, and metal detector function. A metal detector that is switched on but never challenged with a test piece is a typical finding. Hygiene practices, handwashing, and the separation of raw and cooked areas are visible from the floor.
On any line, the inspector reads the signs of control. Are operators following the work instruction posted at their station? Are gauges and scales marked with a calibration date? Are defective parts put in marked bins and counted, or dropped on the floor? Is rework done at a separate station with its own record? A line with good habits shows them within a few minutes.
Trends matter more than single numbers. A defect rate of 2 percent on the morning shift and 6 percent on the night shift points to supervision and training, not machines. A rate that creeps up through the week suggests tool wear. The inspector records defect type and count by shift where the records allow, so patterns are visible in the report.
As in the initial check, the visit tests the schedule. Output so far, remaining quantity, daily rate, and any bottleneck are compared with the ship date. If the factory is 20 percent behind with ten days left, the right moment to ask for overtime or a second shift is now, not at the final inspection.
When problems appear, the report should say what to do about them: stop the line and fix the cause, quarantine suspect lots and sort them, or adjust the settings and check again within two days. A factory that corrects quickly after a mid-production finding often passes the final inspection with fewer defects than one that never gets a mid-run check.
For automotive and electrical components, which make up a large part of Thai exports, the in-process visit looks at measurement discipline. First-piece approval records show that the setup was checked before each run, and control charts or sampling logs show that dimensions were measured at set intervals instead of once a day. Operators should know the tolerance for the dimension they are checking and what to do when a reading drifts toward the limit. Torque tools and test equipment need current calibration stickers, and the inspector will often take a few readings with a calibrated gauge of their own to confirm the factory’s instruments agree.
Work in progress storage is another useful sign. Parts waiting between operations should be labelled with the part number, lot, and status, and held in marked areas. Unlabelled bins of mixed parts are how wrong components end up in the final carton, and the problem often surfaces only at the customer’s assembly line.
Thailand’s production calendar affects timing, with slower periods around Songkran in April and the year-end holidays. A provider of inspection services in Thailand can fix the dates for the initial, in-process, and final visits at the start of the order. The mid-run check usually takes one inspector for one day, and it is the visit most likely to save the order.
