Quality Control Standards

1. INSPECTION REQUIREMENTS

1.1 Purpose: This inspection protocol is used to assess plastic components at various stages, including research and development, trial production, incoming inspection (IQC), and finished product shipment inspection.‍

1.2 Scope: Applies to metal, plastic products, painted parts, electroplated parts, and silicone products used by our company.

1.3 Inspection Requirements:

• 1.3.1 Sampling Plan: We utilize the MIL-STD-105E II sampling plan, with a general Level II single normal sampling approach. Based on the importance of inspection criteria, items are categorized into three levels:
  • Critical Defect: Acceptable limit = 0
  • Major Defect (MAJ): Acceptable limit = 0.65
  • Minor Defect (MIN): Acceptable limit = 1.0
• 1.3.2 Defect Definitions:
  • Critical Defect: A defect that may compromise safety or significantly impact product performance.
  • Major Defect (MAJ): A defect that considerably affects the product’s appearance or performance.
  • Minor Defect (MIN): A defect with minor impact on appearance or performance.

2. Appearance Standard Reference – SPI

COSMETIC SPECIFICATIONS OF INJECTION MOLDED PARTS

2.1 Purpose: To establish quantitative definitions and recommended methods for inspecting and measuring the cosmetic quality of injection-molded plastic parts when customer specifications are not provided.

2.2 Scope: Covers cosmetic quality standards for molded plastic parts and related post-molding activities.

2.3 Defect Definitions:

• Bleeding: Color overlap or pigment spreading.
• Blush: Discoloration or gloss change, often at gate locations.
• Broken: A defect with minor impact on appearance or performance.
• Bubbles: Void pockets, typically in transparent parts.
• Burns: Brown marks or streaks.
• Cold Slug: Solid or semi-solid material with a distinct border.
• Contamination: Discoloration due to foreign matter.
• Cracking: Splitting caused by stress.
• Crazing: Tiny cracks from stress.
• Delamination: Peeling of plastic layers.
• Discoloration: Unintentional color change.
• Drag Marks: Scratches from plastic dragging in the mold.
• Flash: Excess plastic along parting lines.
• Gas Marks: Dark streaks from incomplete venting.
• Gouge: Abrasive damage removing material.
• Grease: Machine lubricant residue.
• Haze: Cloudiness on transparent parts.
• Insert Problems: Errors with insert installation.
• Jetting: Off-colored streaks.
• Lint: Foreign substance in coating.
• Marbling: Colored streaks from incomplete mixing.
• Nicks: Small gouges from impacts.
• Non-Adhesion: Lack of paint or coating adhesion.
• Orange Peel: Rippled appearance from under-pressurizing.Pin Push: Protrusion from ejector pin.
• Pitting: Crater-like imperfections.
• Pulling: Distortion from plastic catching in the mold.
• Runs: Drips or sags in paint or ink.
• Scratch: Surface abrasions.
• Shine: Glossy areas on textured surfaces.
• Shorts: Missing plastic from incomplete mold filling.
• Sink: Surface depression from uneven solidification.
• Smearing: Excess ink or paint from rubbing.
• Specks: Small discolored spots.
• Splay: Off-colored streaks from moisture or degradation.
• Weld lines: Lines where molten plastic converges.

2.4 Surface Identification and Classification

• Grade 1: Highly polished, clear transparent, fluid contact.
• Grade 2: Low-grade polish, textured, clear translucent.
• Grade 3: Painted parts.
• Grade 4: Ink stamped, printed, silk screened, other decorative processes.

2.5 Surface Identification

• A Surface: Most viewed surface.
• B Surface: Front edge and sides, less viewed.
• C Surface: Back and bottom surface.
• D Surface: Internal surfaces, generally not inspected.

2.6 Standard Viewing Conditions

• Lighting Intensity: 80-120 footcandles in white fluorescent light.
• Viewing Angle: some text
  • A Surface: 30° from horizontal, rotated 30° left and right.
  • B Surface: 90° from horizontal.
  • C Surface: 90° from horizontal, 45° below eye level.
• Viewing Distance: some text
  • A Surface: 18 inches.
  • B Surface: 24 inches.
  • C Surface: 30 inches.
• Inspection Interval: Varies by surface area.

2.6 Color Matching

• Decisions regarding color matching are made by comparison to known standards using a spectrophotometer, color meter or suitable color matching light booth.
• Color standards and tolerances shall be provided by the customer. In the absence of a customer supplied color standard, standards shall be developed based upon the material manufacturer's color chip set and tolerances shall be set using a Delta E (ΔE) limit of 1.00, unless otherwise stated by the customer.

2.7 Gloss

• Measured with a glossmeter or visually compared to customer-approved standards.

2.8 Surface Finish and Texture Matching

• Compared to SPI Mold Finish Guide plaque or Mold-Tech texture plaque unless specified otherwise.

2.9 Adhesion

• Applied finish must withstand a tape test without removal of the finish coat.

2.10 Cosmetic Quality Summary Sheets

• Summarizes cosmetic requirements by grade for use as work instructions.

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THE FOLLOWING FOUR SECTIONS ARE SUMMARY SHEETS OUTLINING THE COSMETIC REQUIREMENTS BY GRADE

3. Structural/Dimensional Standards

3.1 Inspection is conducted according to the customer’s 2D requirements.

3.2 If the customer does not provide documented 2D requirements, we adhere to the internal tolerances outlined below. 

3.3 Testing Tools: When not specified by the customer, we use the following measuring equipment for general dimensional checks: calipers, projectors, CMM, needle gauges, altimeters, feeler gauges, tape measures, steel rulers, and other standard instruments.

4. Reliability Standards

4.1 Hardness Testing: For silicone or soft products, we adhere to a specification of ± 5A, measured using a durometer hardness tester.

4.2 Colorimeter Testing: We use a color difference meter with a Delta E (ΔE) tolerance limit of 2.00 or follow the customer-provided data as the standard.

4.3 Surface Adhesion Testing (Spray Painting, Screen Printing, Electroplating): For post-processed surfaces, we use Scotch 3M adhesive paper model 610 (or equivalent). The adhesive is pulled at a 90-degree angle to check adhesion. Any adherence of the paint, screen printing, or electroplating to the adhesive paper indicates an issue.

5. Packaging Standards

5.1 Packaging Condition: Packaging must be clean, intact, and free from damage, softening, moisture, mold, indentations, or deformation. Outer box labeling must be accurate and legible.

5.2 Packing Method: Follow customer requirements. Protect products with plastic bags and arrange each layer consistently and orderly within the box. If parts are non-cosmetic, parts will be bulk packed.

5.3 Labeling: Once packed, apply material labels to the outer box, including both front and side views.