Quality Control, Defect Identification, and Troubleshooting
What the exam tests
Quality control questions test inspection, defect naming, root-cause analysis, and corrective action. You should distinguish a printing fault from a dyeing, fabric, or finishing fault.
Core rules
- Inspect on a well-lit table, face and back, at a defined interval; record defect type, position, size, and frequency.
- Common defects: misfit or off-registration, uneven colour, blotches, bleeding, smudging, finger marks, block cracks, missing print, double impression, and colour variation between lots.
- Root causes map to the process: misfit to registration or block damage; uneven colour to tray, paste, or pressure; bleeding to thin paste or wet fabric; cracks to wood or carving faults.
- Corrective action must address cause, not symptom: re-mark the table, re-level the tray, re-formulate paste, replace the block, or re-train the printer.
- Keep first-piece approval and a running inspection record; quarantine suspect lots.
Worked example
A defect repeats every 30 cm and looks like a faint double edge. Reasoning: the repeat interval is regular, so the cause is likely a damaged block edge or a loose registration pin rather than random paste variation. Check the block face and the pin before changing the paste.
Traps
Do not blame the dye for every colour fault. Do not inspect only the face; back stains reveal penetration problems. Do not record reject without a cause code.