Quality Control
Measured at every stage, from sand to shipment.
PT Tri Sinar Purnama operates in-process quality control across the full malleable iron production sequence — raw material preparation, casting, annealing, galvanizing, machining and final packing. The checks below are the procedures applied in our Semarang plants, with their measurable acceptance criteria and inspection frequency.
In-process and final inspection procedures
| Inspection | Method & acceptance criteria | Frequency |
|---|---|---|
| Sand inspection | Compactibility testing of moulding sand | Every 30 minutes |
| Hit test | Fracture surface visually observed | Three periods per operator, per day |
| Tensile & elongation | Minimum tensile strength 350 N/mm²; minimum elongation 6% | Every unloading process |
| Spectrometer | Chemical composition, minimum 5 surface test points | Four times per day |
| Pressure test | Sample strength testing — applied in particular to other casting products | Early casting process |
| QC sorting | 100% visual inspection | After production |
| Zinc coating thickness | Elcometer, 10 spots per sample, minimum 65 µm | During process |
| Dimensional test | Calibrated vernier caliper and thickness tester, against the required standard | According to order instruction |
| Alignment | Maximum deviation 1.5 mm per 300 mm, or 1 mm per 200 mm | 3 pcs from each machine, every 30 minutes |
| Thread test | Plug gauge and ring gauge | 3 pcs from each machine, every 30 minutes |
| Leakage test | Minimum 7 bar, held over 3 seconds | 100% of products, before packing |
| AQL inspection | Visual, gauge, alignment and packaging accuracy | Before shipment |
Criteria and frequencies above are TSP's own in-process procedures. Applicability varies by product family and by customer order specification — the pressure test in particular applies chiefly to casting products rather than to every threaded fitting.