Plastic Products Inspection

Guangzhou Huajian Commodity Inspection Co., Ltd. specializes in providing third-party inspection services, third-party factory audit services, and container loading supervision services. It is a professional third-party inspection company, foreign trade inspection company, third-party quality control company, third-party product inspection company, and third-party testing company.

Plastic Product Inspection Standards

1. Purpose

This specification aims to define our company's plastic product quality standards, provide a system for product designers to meet the requirements of product drawings, offer a reference basis for quality inspectors to inspect and judge plastic products, and serve as a criterion for mold and plastic product suppliers to understand our quality requirements.

2. Scope

This specification applies to all plastic products produced by our company and externally purchased (including spray painting and printing on finished and semi-finished products and their surfaces).

3. Responsibilities

This specification is formulated by the Quality Department and the Technical Department, and implemented and maintained by the Quality Department.

4. Definitions

4.1 Defects

Critical Defect (CR): Occurrence of hazards affecting product safety performance or serious potential safety issues, or loss of product functionality.

Major Defect (MAJ): Failure of the product to achieve its intended performance or significant reduction in its utility.

Minor Defect (MIN): Flaws that do not affect the product's utility but impact its appearance.

4.2 Plastic Product Appearance Defects

4.2.1 Short Shot—Insufficient injection material, resulting in incomplete or unfilled parts.

4.2.2 Flash—Plastic extruded at the parting line.

4.2.3 Sink Mark—Surface depression caused by material cooling and contraction.

4.2.4 Dent/Bulge—Surface凹陷 and隆起 caused by squeezing or impact on the part.

4.2.5 Weld Line—Hair-like fine lines formed where plastic flow fronts reunite.

4.2.6 Flow Mark—Silver streaks left on the part surface during injection.

4.2.7 Drag Mark—Scratches caused by dragging the part surface at the parting line or texture during mold opening.

4.2.8 Scratch—Scratches on the part not caused by the mold after ejection.

4.2.9 Deformation—Bending, twisting, or stretching of the part.

4.2.10 Ejector Mark—Whitening of color, often appearing at ejection points.

4.2.11 Discoloration—Localized color差异 defect compared to the surrounding area.

4.2.12 Spot—Dot-like defect with color差异 from the surroundings.

4.2.13 Oil Stain—Contamination caused by release agents, ejector pin oil, or rust preventives.

4.2.14 Burn—Plastic burned and degraded, usually yellowing, severely碳化 and blackening.

4.2.15 Break—Local material separation from the main body.

4.2.16 Crack—Visible cracks in the part body.

4.2.17 Bubble—Hollow formed inside transparent products.

4.2.18 Color Difference—差异 between actual color and standard color.

4.2.19 Poor Trimming—Improper removal of flash and gate, over-trimming or incomplete trimming.

4.3 Spray Coating Appearance Defects

4.2.1 Tear—Tear-drop-like突起 where coating flows downward and accumulates.

4.2.2 Blister—Bubble-like突起 on the spray coating surface.

4.2.3 Droplet—Oil spots splashed onto the product surface.

4.2.4 Inclusion—Dust points or fibers encapsulated in the spray coating.

4.4 Surface Grades

"  4.4.1 Our company uses codes composed of Roman numerals and English letters to indicate different grades of surfaces or areas on plastic products. The importance of the surface is classified by Roman numerals, and the frequency of visual inspection by end users is distinguished by English letters."

4.4.2 Class I: Important external surfaces. Includes: the front, top, or specified surfaces of housing parts, or surfaces of other parts that are exposed on the front, top, or specified surfaces after assembly with the housing.

4.4.3 Class II: Secondary external surfaces other than Class I.

4.4.4 Class III: Internal surfaces.

4.4.5 A-Surface: Surfaces frequently seen by end users.

4.4.6 B-Surface: Surfaces visible to end users but rarely noticed during normal operation.

4.4.7 C-Surface: Surfaces not visible to end users but visible during product assembly or maintenance.

4.5 Time and Distance Inspection

Surface Grade I-A       II-A/III-A  II-B/III-B    II-C/III-C

Visual Distance 250mm   450mm     450mm     600mm

Visual Time  10s         10s             5s               3s

Note: For cases not suitable for the above time and distance, requirements should be specified in the drawings or the "Inspection Guidance Document".

5. Appearance Inspection

5.1 Overview

Plastic product appearance inspection uses a visual inspection method based on "time and distance". When defects are found within the specified time and distance, refer to section 5.3 to determine acceptance or rejection.

5.2 Visual Conditions

5.2.1 Multi-directional, uniform candlelight illumination at 80-120 degrees.

5.2.2 Generally, magnifying glasses are not allowed for inspecting appearance defects.

5.3 Appearance Standards

Item Limit Requirements

I-A II-A III-A II-B III-B II-C/III-C

Short Shot Not allowed According to limit sample

Flash Less than 0.1mm, no scraping feel Less than 0.2mm, no obvious scraping According to limit sample

Sink Mark Not allowed Not allowed or according to limit sample

Dent/Bulge Not allowed Not allowed or according to limit sample

Weld Line According to limit sample

Flow Mark Not allowed 1 place, width less than 0.5mm 2 places, width less than 2.5mm According to limit sample -

Drag Mark Not allowed Not allowed or according to limit sample

Scratch Not allowed 1 place, width less than 0.1mm, length less than 15mm 2 places, width less than 0.1mm, length less than 25mm 4 places, no obvious scraping, width less than 0.4mm, length less than 25mm -

Deformation According to limit sample

Ejector Mark Not allowed Not allowed or according to limit sample or special processing -

Discoloration Not allowed Not allowed Not allowed or according to limit sample -

Spot Slightly visible. φ0.2 or less, 2 points max Slightly visible. φ0.5 or less, 2 points max, spacing greater than 50. Or φ0.2 or less, 6 points max, spacing greater than 20 Slightly visible. φ1.5 or less, 4 points max, spacing greater than 50. Or φ1.0 or less, 8 points max, spacing greater than 30 -

Oil Stain Not allowed

Burn Not allowed According to limit sample

Break  Not allowed

Crack  Not allowed

Bubble  Not allowed or according to limit sample - -

Color Difference ΔE≤1.0 -

Poor Trimming Not allowed Not allowed or according to limit sample

Note: 1. "-" indicates that the inspection item is not required, but if the defect is too obvious, it can be judged as defective.

2. Surface grades should be specified in the drawings or the "Inspection Guidance Document", and dimensional ranges should be set for area surfaces to identify different grade surfaces.

3. For limit requirements different from the above standards, they should be specified in the drawings or the "Inspection Guidance Document".

4. For batch inspection, there should be sealed samples approved by the Technical Department or limit samples approved by the Quality Department.

5. If a defect in a certain part is accepted at the beginning of batch inspection, it can be accepted if easily found within the specified time and distance in subsequent inspections of the same batch, but this does not mean it can be accepted in future batches.

6. Material Inspection

6.1 Overview

Plastic products are inspected according to the material and material performance requirements in the drawings, and acceptance or rejection is determined through testing.

6.2 Material Identification

Identification is done through material burning characteristics, chemical compatibility with organic solvents, and formed product features.

6.3 Flammability UL94 Grade Inspection

6.3.1 Determine whether the flammability UL94 grade meets the required part wall thickness based on burning speed, burning time, drip resistance, and whether drips are flammable in combustion tests.

6.3.2 UL94 Grade Combustion Test.

Grade Combustion Test Requirements and Phenomena

HB Horizontal specimens with thickness<3mm burn slowly, burning speed<76mm/min.

V-0 Vertical specimens stop burning within 10 seconds; no dripping allowed.

V-1 Vertical specimens stop burning within 30 seconds; no dripping allowed.

V-2 Vertical specimens stop burning within 30 seconds;允许 burning drips.