Quality Control System
Integrated Quality Assurance Across Raw Materials, Coating Lines, and Export Logistics
01 Raw Material Inspection
Substrate thickness, width, zinc mass & mechanical hardness verification before processing.
02 In-Process Inspection
Online paint film thickness, spectrophotometer color check (ΔE), and mechanical adhesion tests.
03 Packing & Final Check
Inkjet coil marking validation, seaworthy waterproof packaging, and final moisture check before loading.
Raw Material Inspection
Thickness & Width
Precision micrometer validation of base substrate thickness and width matching order specs.
Surface Inspection
Thorough surface check to ensure zero rust, heavy oil contamination, or mechanical scratches.
Hardness Test
Hardness testing to check required substrate properties (Commercial vs. Full Hard).
Weight & Heat Number
Physical weight verification and raw material heat number matching against order specifications.
In-Process Inspection
Paint Thickness
Continuous online gauge testing top coat and primer thickness against target order specs.
Color Match
Precision spectrophotometer testing for color consistency against standard RAL codes or physical master samples.
Gloss & Surface Finish
Optical gloss meter verification ensuring required surface reflection status (Matt, Semi-gloss, or High-gloss).
Impact Test
Impact resistance testing to check paint film integrity and resistance to cracking under mechanical stress.
Adhesion & T-Bend
Cross-hatch tape and T-bend testing verifying paint adhesion quality during profiling.
MEK Curing Test
Solvent double-rub testing to verify full paint film curing in the baking oven.
Packing & Final Inspection
Custom Inkjet Marking
Verification of customized inkjet marking content, brand name, and dimensions as requested by buyer.
Seaworthy Packaging
Standard export packaging with anti-rust paper, plastic film, metal outer wrap, and strong steel strapping.
Weight & Tag Check
Verification of gross/net coil weight, outer shipping labels, and packaging integrity prior to dispatch.
Pre-Dispatch Inspection
Final visual check in factory warehouse to ensure finished coils are clean, undamaged, and ready for dispatch.
Buyer Quality Concern & FAQ
Q: How does PPGI.LTD ensure consistent quality for pre-painted steel coil exports?
A: PPGI.LTD implements a structured quality control process covering raw materials, inline production, and final export packaging. Each coil batch is monitored through continuous micrometer thickness checks, spectrophotometer color matching, paint adhesion testing (T-bend and solvent rubs), and seaworthy packaging inspection before loading.
Q: How are substrate thickness and paint coating tolerances controlled?
Q: How do you manage color consistency and surface gloss across production batches?
A: Color alignment is verified using digital spectrophotometers to match target RAL color codes or customer-approved physical master samples. Surface gloss levels (Matt, Semi-Gloss, or High-Gloss) are routinely checked with optical gloss meters during continuous coating runs.
Q: What inline tests are conducted to verify paint adhesion for roll forming?
A: To evaluate paint adhesion and flexibility, sample strips from each production lot undergo cross-hatch tape adhesion testing, T-bend testing, and solvent double-rub testing to confirm full paint curing prior to profiling. For detailed test requirements, feel free to contact our technical team.