Validation des plastiques conducteurs : granulés, plaques et pièces réelles
L’approbation d’un plastique conducteur ne doit pas s’arrêter aux données fournisseur ou aux plaques plates. La pièce réelle révèle variation injection-fin de remplissage, lignes de soudure, nettoyage et risque procédé.
FAQ acheteurs et ingénieurs qualité
Questions avant validation des données de plastique conducteur
Pourquoi les données granulés et plaques ne suffisent-elles pas ?
Elles sont mesurées dans des conditions contrôlées ou simplifiées et ne capturent pas injection, lignes de soudure, orientation des charges, skin-core, nettoyage ni contraintes d’assemblage.
Quel niveau de validation est décisif ?
La donnée pièce réelle. Les granulés filtrent, les plaques donnent une référence, mais la pièce réelle confirme l’application.
Quel produit DEYU est lié ?
Le cas parle de sockets de test en PA66 conducteur. Il n’existe pas de page produit exacte, donc la référence proche est DGK-PA66 CF15L-CF40L.
Combien de pièces tester ?
Un protocole pratique moule 20-50 pièces, les conditionne, mesure 5-10 points par pièce, puis ajoute nettoyage, cycles thermiques, usure et contrôle dimensionnel.
Hiérarchie de validation en trois niveaux
Pour qualifier un plastique conducteur ESD, l’ingénieur reçoit trois preuves : données granulés fournisseur, données plaques/coupons moulés et données pièce réelle. Chaque niveau sert, mais aucun ne suffit seul.
Niveau 1 : données granulés
Les données granulés viennent de fiche technique et COA. Elles servent au screening, à la spécification achat, au contrôle entrée et aux plages de référence, mais pas variation injection-fin, soudure, nettoyage ni contraintes montage.
Niveau 2 : données plaques
Les plaques utilisent des coupons moulés du même lot. Elles vérifient les données fournisseur et comparent des candidats, mais une plaque plate ne reproduit pas nervures, bossages, skin-core complexe ni effets d’injection.
Niveau 3 : données pièce réelle
La pièce réelle capture géométrie, flux, procédé, skin-core, contraintes résiduelles, nettoyage et montage. Dans le cas socket semi-conducteur, la référence DEYU proche est DGK-PA66 CF15L-CF40L carbon fiber reinforced PA66 pellets; aucune nouvelle page produit n’est créée.
Tableaux de validation de référence
Les tableaux gardent les données source anglaises sur hiérarchie, critères et cas client. Les lignes de catégorie sont remplies pour éviter les cellules vides.
| Level | Data Type | Source | What It Tells You |
|---|---|---|---|
| Level 1 | Pellet data | Supplier datasheet | Intrinsic material properties under ideal conditions |
| Level 2 | Plaque data | In-house testing on molded coupons | Material properties in a standardized geometry |
| Level 3 | Real part data | Testing on actual molded parts | Material performance in the actual application geometry |
| Property | Test Method | What It Shows |
|---|---|---|
| Surface resistivity | ANSI/ESD STM11.11 | Intrinsic surface conductivity of the material |
| Volume resistivity | ASTM D257 | Intrinsic bulk conductivity |
| MFR (melt flow rate) | ASTM D1238 | Processability, flow characteristics |
| Tensile strength | ASTM D638 | Basic strength under tension |
| Flexural modulus | ASTM D790 | Stiffness of the material |
| Notched impact strength | ISO 180/ASTM D256 | Toughness, brittleness |
| HDT (heat deflection temperature) | ISO 75 | Thermal stability |
| UL94 flammability | UL94 | Fire safety rating |
| Density | ASTM D792 | Weight per unit volume |
| Limitation | Why It Matters | Example |
|---|---|---|
| Idealized conditions | Lab conditions differ from production | Pellet data shows resistivity at 23°C/50% RH; production may be 35°C/30% RH |
| Standardized geometry | Coupons are not parts | Flow conditions, gate effects, weld lines, and skin-core structure are absent |
| Single-point measurements | No consideration of variation | Pellet data shows one value; actual parts vary across the part and across batches |
| No processing effects | Molding conditions affect properties | Injection speed, temperature, and pressure change filler orientation and resistivity |
| Purpose | Why It Matters |
|---|---|
| Verification of supplier data | Confirms that the material batch meets specification |
| Incoming quality control | Checks consistency of incoming shipments |
| Comparative evaluation | Compares different material candidates under the same conditions |
| Process development | Establishes baseline processing parameters |
| Gap | Plaque Data | Real Part Reality |
|---|---|---|
| Geometry | Flat, uniform thickness | Variable wall thickness, ribs, bosses, weld lines |
| Flow conditions | Simple, balanced flow | Complex flow with gates, weld lines, flow front variations |
| Filler orientation | Less oriented (some orientation) | Highly oriented in flow direction; varying across part |
| Skin-core structure | Present, but simpler | Complex skin-core structure with variable thickness |
| Gate effects | Minimal (often edge-gated) | Significant near-gate effects on resistivity |
| Stress distribution | Minimal residual stress | Significant residual stress from cooling and packing |
| Environmental exposure | Lab conditions | Cleaning, thermal cycling, chemical exposure, UV |
| Factor | Why It Matters |
|---|---|
| Complex geometry | Flow patterns, filler orientation, and resistivity vary with geometry |
| Gate-to-end variation | Resistivity can vary by 1–3 orders from gate to end-of-fill |
| Weld lines | Resistivity is significantly higher at weld lines |
| Skin-core effects | Surface resistivity may differ from bulk resistivity |
| Processing sensitivity | The material's response to your specific processing conditions |
| Application-specific performance | The only way to validate ESD performance in your application |
| Test | What It Validates | Method |
|---|---|---|
| Multi-point surface resistivity | Uniformity across the part | ANSI/ESD STM11.11 at 5–10 locations per part |
| Critical surface resistivity | Performance on functional surfaces | ANSI/ESD STM11.11 on contact surfaces |
| Resistance to ground (if applicable) | Grounding performance | ANSI/ESD S4.1 (for work surfaces) |
| Post-cleaning resistivity | Cleaning resistance | 50–100 IPA wipe cycles |
| Post-thermal cycling resistivity | Thermal stability | -40°C to +85°C, 100+ cycles |
| Post-wear resistivity | Abrasion resistance | 10,000+ wear cycles |
| Dimensional stability | Part geometry after processing | Precision measurement |
| Assembly performance | Snap-fit, press-fit, or other assembly | Assembly fixture testing |
| Step | Action | Sample Size | Acceptance Criteria |
|---|---|---|---|
| 1 | Mold parts under production-equivalent conditions | 20–50 parts | Consistent process parameters |
| 2 | Condition parts at 23°C / 50% RH for 48+ hours | All parts | Environmental control |
| 3 | Measure surface resistivity at 5–10 locations per part | All parts | All locations within specification |
| 4 | Measure resistance to ground (if applicable) | 3 parts | < 1×10⁹ Ω |
| 5 | Perform cleaning resistance test | 5 parts | Resistivity remains in specification |
| 6 | Perform thermal cycling test | 5 parts | Resistivity remains in specification |
| 7 | Perform wear resistance test | 5 parts | Resistivity remains in specification |
| 8 | Measure dimensional stability | 10 parts | Within drawing tolerances |
| 9 | Analyze data (mean, range, pass/fail) | All parts | ≥ 95% pass rate |
| Aspect | Pellet Data | Plaque Data | Real Part Data |
|---|---|---|---|
| Reliability | Low (idealized) | Medium (standardized) | High (application-specific) |
| Cost | Low (no testing) | Medium (molding plaques) | High (molding parts, testing) |
| Time | Immediate | Days | Weeks |
| Predictive value | Low | Medium | High |
| ESD performance validation | None | Partial | Complete |
| Measurement | Pellet Data (Supplier) | Plaque Data (In-house) | Real Part Data |
|---|---|---|---|
| Surface resistivity (gate area) | 10⁷ Ω | 10⁷ Ω | 10⁷ Ω |
| Surface resistivity (center) | 10⁷ Ω | 10⁷ Ω | 5×10⁷ Ω |
| Surface resistivity (end-of-fill) | 10⁷ Ω | 10⁷ Ω | 3×10⁸ Ω |
| Surface resistivity (weld line) | Not measured | Not measured | 5×10⁸ Ω |
| Surface resistivity (after cleaning) | Not measured | Not measured | 8×10⁸ Ω |
| Part-to-part variation | Not measured | ±0.3 orders | ±0.8 orders |
| Phase | Activity | Data Level | Purpose |
|---|---|---|---|
| Phase 1 | Review supplier datasheet | Pellet data | Initial screening, specification setting |
| Phase 2 | Mold and test plaques | Plaque data | Verify supplier data, establish baseline |
| Phase 3 | Mold real parts under production conditions | Real part data | Validate performance on actual geometry |
| Phase 4 | Test real parts after environmental exposure | Real part data | Validate durability and long-term performance |
| Phase 5 | Analyze data and make final decision | All data | Material approval or rejection |
| Level | Acceptance Criteria | Action |
|---|---|---|
| Pellet data | Within supplier specification | Proceed to plaque testing |
| Plaque data | Within ±0.5 orders of pellet data | Proceed to real part testing |
| Real part data | All locations within specification; < 5% part failure | Approve material |
| Environmental data | Remains within specification | Approve for production |
| Data Level | Documentation Required |
|---|---|
| Pellet data | Supplier datasheet, COA (Certificate of Analysis) |
| Plaque data | Test results with environmental conditions (temperature, humidity) |
| Real part data | Test results with part identification, locations, environmental conditions |
| Environmental data | Test results before and after exposure |
| Aspect | Plaque Data | Real Part Data | Difference |
|---|---|---|---|
| Surface resistivity (gate area) | 10⁵ Ω | 10⁵ Ω | 1× |
| Surface resistivity (center) | 10⁵ Ω | 10⁶ Ω | 10× |
| Surface resistivity (end-of-fill) | 10⁵ Ω | 10⁸ Ω | 1000× |
| Surface resistivity (weld line) | Not measured | 10⁹ Ω | Not measured |
| Part-to-part variation | ±0.2 orders | ±1.2 orders | 6× |
| Parameter | Plaque Data | Real Part Data (After Correction) | Specification |
|---|---|---|---|
| Surface resistivity—gate area | 10⁵ Ω | 10⁵ Ω | <10⁶ Ω |
| Surface resistivity—center | 10⁵ Ω | 10⁶ Ω | <10⁶ Ω |
| Surface resistivity—end-of-fill | 10⁵ Ω | 10⁷ Ω | <10⁶ Ω |
| Surface resistivity—weld line | Not measured | 10⁸ Ω | <10⁶ Ω |
| Part-to-part variation | ±0.2 orders | ±0.4 orders | <0.5 orders |
| ESD failure rate | 0% | 0.5% | <1% |
| Level | Data Type | Purpose | Sufficiency |
|---|---|---|---|
| Level 1 | Pellet data | Initial screening, specification setting | Insufficient alone |
| Level 2 | Plaque data | Verification of supplier data, baseline comparison | Insufficient for complex parts |
| Level 3 | Real part data | Performance validation on actual geometry | Essential for qualification |
Scénario de validation client
Un fabricant de semiconductor test socket a approuvé un PA66 conducteur avec datasheet et plaque. Trois mois plus tard, 5-8% des sockets avaient des défauts ESD et la résistance variait de 10^5 à 10^9 ohm. Le protocole trois niveaux a réduit le taux à 0.5%.
Informations à fournir
Fournir plan ou 3D, injection et soudures, spécification et norme, exigences pellet, géométrie plaque, points de test pièce réelle, essais environnement, échantillon, paramètres, service, montage, critères, volume, matière actuelle et défauts.
Conclusion
Les données granulés et plaques sont nécessaires, mais insuffisantes. La qualification doit se terminer par des données pièce réelle sur la géométrie moulée et en exposition réaliste.