Quality Assurance

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QUALITY CONTROL

Qualitätskontrolle & Optical Inspection

Plastic optical injection molding

This manual specifies the quality control (QC) requirements, testing equipment, and inspection methods for the entire production process of plastic optical components (z.B., lenses, Lichtleiter) manufactured by injection molding. Its purpose is to ensure consistent optical performance, dimensional accuracy, and surface quality of final products, meeting customer and industry standards.

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Illustration of optical lens inspection with a measuring head and technical drawings
Optical inspection & measurement
01Optische Leistung
02Maßgenauigkeit
03Surface quality

Quality control across production

Pre-production quality control

  • Raw Material InspectionVerify the conformity of optical plastic materials (PMMA, PC, COP, COC, etc.) with technical specifications, including purity, moisture content, Schmelzflussrate (MFR), and optical transmittance. Reject materials with impurities or inconsistent properties.
  • Mold QualificationInspect mold surface finish, dimensional accuracy of cavities/gates, and cooling system uniformity. Sicherstellen, dass die Oberflächenrauhigkeit der Form ≤2 nm für optische Bauteile beträgt.

In-production quality control

  • Überwachung von ProzessparameternEchtzeitüberwachung der Spritzgießparameter (Formtemperatur, Schmelzetemperatur, Spritzdruck/-geschwindigkeit, Halte- bzw. Nachdruckzeit, Kühlzeit) zur Vermeidung von Eigenspannungen und optischen Fehlern (z.B., Doppelbrechung, Verzug).
  • Stichprobenkontrolle während des ProzessesRegelmäßige Stichproben von Halbfertigprodukten zur Kontrolle der vorläufigen Oberflächenqualität (keine Kratzer, Blasen, oder Fließmarken) und kritische Abmessungen.

Final inspection

  • EndabmessungsprüfungÜberprüfung kritischer Abmessungen (z.B., Linsenkrümmung, Dicke, Durchmesser) und geometrische Toleranz der Fertigprodukte.
  • Optische LeistungsprüfungBewertung der wichtigsten optischen Eigenschaften zur Sicherstellung der Einhaltung der Spezifikationen.
  • OberflächenqualitätsprüfungUmfassende Kontrolle auf Oberflächenfehler, die die optische Leistung beeinträchtigen.

INSPECTION & MEASUREMENT

Inspection and testing equipment

Equipment types are grouped below by inspection purpose. The instrument selection, test availability, measurement conditions and acceptance requirements should be confirmed for each project.

Optische Leistung & coatings

Spectrophotometer
Spectral transmission and reflection
Transmittance / haze tester
Light transmission and haze
Polarimeter / birefringence meter
Stress-related birefringence
Goniophotometer, reflectometer and abrasion tester
Light distribution, reflectance and coating durability

Surface & dimensional inspection

Laser interferometer
Optical surface form and curvature
Optical profilometer / atomic force microscope
Surface topography and roughness
Coordinate measuring machine / Dickenmessgerät
Critical dimensions and geometry
Optical microscope / optical comparator
Surface appearance, edge profile and visible defects

Materials & process monitoring

Moisture analyzer
Moisture content of molding materials
Melt flow index tester
Material flow behavior
Temperature sensors / Druckaufnehmer
Molding-process temperature and pressure
Process monitoring / visual inspection systems
Process records and defined in-process checks

Reliability & application testing

Temperature / thermal-shock chambers
Temperature exposure and thermal cycling
Humidity chamber / vibration test bench
Humidity and vibration evaluation
Application-specific optical testers
Lighting distribution, endoscope imaging or AR/VR field of view, as applicable
Project-specific test scope
Test availability, conditions and acceptance requirements to be confirmed during review

Inspection methods & acceptance reference

The inspection reference below preserves the existing quality-control manual. Applicability and acceptance limits should be reviewed for the specific component, material and application.

QC Stage
Inspection Items
Prüfgeräte
Inspection Methods & Standards
Vorproduktion
Rohmaterialdurchlässigkeit, moisture content, MFR
UV-Vis-Spektrophotometer, Feuchtigkeitsanalysator, Melt-Flow-Index-Prüfgerät
  • Transmittance: Prüfung bei 400–760 nm, ≥90% für PMMA/PC
  • Moisture content: ≤0,02% (Karl-Fischer-Methode)
  • MFR: Entspricht den Spezifikationen des Materiallieferanten
Vorproduktion
Formoberflächenrauheit, dimensional accuracy
Rasterkraftmikroskop (AFM), Koordinatenmessmaschine (KMG)
  • Surface roughness: ≤2 nm (AFM-Scan)
  • Maßgenauigkeit: ±0,001 mm (CMM-Messung)
In-Produktion
Spritzgießprozessparameter
Prozessüberwachungssystem, Temperatursensoren, Druckaufnehmer
Echtzeit-Datenerfassung; Abweichung ≤±5% von den Sollwerten; Alarm bei Sollwertüberschreitung
In-Produktion/Endkontrolle
Oberflächenfehler (Kratzer, Blasen, Fließspuren)
Hochauflösendes optisches Mikroskop, Automatisierte Sichtprüfung (AVI) System
  • Microscope: 50–100x Vergrößerung
  • AVI: 100% Prüfung, Fehlergröße ≤0,01 mm abgelehnt
Endgültig
Maßgenauigkeit (Krümmung, Dicke, Durchmesser)
Präzisions-KMG, Laserinterferometer, Dickenmessgerät
  • Dimensional tolerance: ±0,002 mm
  • Curvature: Abweichung ≤0,001 mm (Laserinterferometrie)
Endgültig
Optische Leistung (Transmission, Doppelbrechung, Lichtverteilung)
UV-Vis-Spektrophotometer, Polarimeter, Goniophotometer
  • Transmittance: ≥90% (400–760 nm)
  • Birefringence: ≤5 nm/cm
  • Light distribution: Entspricht den Konstruktionsvorgaben
Endgültig
Beschichtungsqualität (falls zutreffend: HC/AR-Beschichtung)
Abriebprüfgerät, Reflektometer
  • Abrasion resistance: ≥6H Bleistifthärte
  • Reflectance: ≤1% (AR-Beschichtung)

Quality assurance & traceability

Gerätekalibrierung

Alle Prüfgeräte müssen jährlich von autorisierten Institutionen kalibriert werden, um die Messgenauigkeit sicherzustellen, mit Aufbewahrung der Kalibrierungsunterlagen.

Personalschulung

Qualitätskontrollmitarbeiter müssen eine professionelle Schulung zur Gerätebedienung erhalten, Inspektionsstandards, und Fehlererkennung, Qualifikationstests bestehen, bevor Posten übernommen werden.

Datenrückverfolgbarkeit

Ein vollständiges Qualitätssicherungssystem einrichten, einschließlich Rohmaterialzertifikaten, Prozessparameterprotokollen, Inspektionsberichten, und Aufzeichnungen über den Umgang mit nicht konformen Produkten, um die volle Rückverfolgbarkeit jeder Charge zu gewährleisten.

Umgang mit nicht konformen Produkten

Nicht konforme Produkte müssen markiert, isoliert, und überprüft werden. Disposition (Nacharbeit, Verschrottung, Nachinspektion) müssen von der Qualitätsabteilung genehmigt werden, mit vorbeugenden Maßnahmen, um Wiederholungen zu vermeiden.

Continuous improvement

Qualitätsdaten regelmäßig analysieren (Fehlerquote, Kundenbeschwerden, Prozessstabilität) um Verbesserungsmöglichkeiten zu identifizieren. Interne Audits vierteljährlich durchführen, um die Wirksamkeit dieses Handbuchs zu überprüfen, es gemäß den Industriestandards aktualisieren, Kundenanforderungen, und technologische Fortschritte.

CUSTOMER QUESTIONS

Before samples, production and delivery

What information do you need to review my quality requirements?

Please provide the current drawing revision, 3D model where available, Materialanforderungen, critical dimensions and functional optical surfaces. Include the required optical performance, surface appearance criteria, inspection methods, quantities and any coating or assembly requirements. Acceptance limits and measurement conditions should be agreed for the specific component before production.

What should incoming-material inspection cover?

Incoming-material inspection considers conformity with the specified material and the properties relevant to molding and optical performance. These may include material purity, moisture content, melt flow rate and light transmission. Identify the required resin grade, any specified supplier and the operating conditions in your inquiry so the material requirements and verification scope can be reviewed together.

What inspections are relevant during molding and before shipment?

The quality plan should connect process monitoring with in-process and final inspection. Relevant checks include molding temperatures, injection and holding conditions, Abkühlzeit, critical dimensions, surface appearance and optical performance. Inspection items, sampling frequency, test conditions and acceptance limits need to be defined for the project rather than assumed to be identical for every component.

Which measurement methods are used for different optical requirements?

The appropriate method depends on the feature being evaluated. Interferometry assesses optical surface form; profilometry evaluates surface topography and roughness; dimensional metrology checks geometry; and spectral measurements assess transmission or reflection. Polarimetric methods can evaluate stress-related birefringence. Confirm the required method, measurement conditions and test availability during project review.

How can our incoming inspection be compared with supplier results?

Agree on the measurement method, measurement area, optical and mechanical reference datums, fixtures and relevant test conditions before evaluation. Identify critical optical zones and request a comparable report format. Also distinguish acceptance checks on the supplied component from validation of the completed optical system.

Can I request inspection reports and traceability records?

Please identify the records you need at quotation stage. These may include drawing revision references, material identification, trial sample evaluations, dimensional results and optical test results. Confirm the available documentation, required lot references, report format and any additional testing in the agreed project scope.

What should be reviewed for repeat orders and different production batches?

Identify the approved drawing revision, material and coating requirements, acceptance limits and any changes since the previous order. Where batch comparison is required, specify the lot references and comparable inspection records needed in the project scope.

How should defects or nonconforming parts be handled?

The project quality plan should define how nonconforming parts are identified, segregated and reviewed, along with approval requirements for rework, scrapping or re-inspection. It should also define how findings and corrective actions are recorded. If you identify a concern, contact us with the relevant part or order reference, drawing revision and inspection evidence so the issue can be reviewed against the agreed requirements.

What quality requirements should I specify for coated optics?

Include the substrate material, coating function, operating conditions and required optical performance. Depending on the application, evaluation may address spectral transmission or reflection, surface appearance and coating durability. The applicable test methods, acceptance limits and any environmental testing should be confirmed for the project.

How are packaging and delivery requirements agreed?

Include handling, packaging and delivery requirements in your inquiry, particularly where exposed optical surfaces need protection. These requirements should be reviewed alongside coating, assembly and inspection needs before production release. Send your project information to sales@silveroptics.net or use our Contact Us page. Please arrange confidentiality requirements before sharing sensitive design files.

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Send your drawings, optical specifications and inspection requirements for review.

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