What Does Effective Post-Processing of Die Casting Involve?

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In die casting production—whether for new energy vehicle motor housings or 5G base station cooling modules—post-processing of die casting is the final step that turns raw castings into high-performance, market-ready parts. It fixes casting defects, optimizes surface quality, and ensures parts meet design standards. This article breaks down its core goals, procesos clave, quality control methods, defect solutions, and cost-saving tips, helping you build a efficient post-processing workflow.

1. What Are the Core Goals and Principles of Die Casting Post-Processing?

Post-processing isn’t random—it follows clear goals and principles to avoid rework and ensure consistency.

1.1 Core Goals

The work focuses on four key objectives, tailored to part functions:

  • Eliminate Casting Defects: Fix issues like shrinkage, pores, and flash left from casting.
  • Optimize Surface Quality: Achieve smooth finishes or protective coatings for appearance and durability.
  • Adjust Mechanical Properties: Boost strength, dureza, or creep resistance through heat treatment.
  • Meet Design Accuracy: Ensure dimensions, llanura, and other specs match engineering requirements.

1.2 Guiding Principles

To prevent secondary damage and save time, two rules are non-negotiable:

  • “Rough First, Then Fine”: Do heavy-duty work (like cutting sprues) primero, then precision tasks (como moler). This avoids scratching finished surfaces.
  • “Inside First, Then Outside”: Machine internal features (like holes) before external ones. Internal machining is more likely to cause minor deformation, which can be corrected when finishing the exterior.

2. What Are the Key Processes in Die Casting Post-Processing?

Post-processing has five core steps, each with specific techniques and parameters. Below is a detailed breakdown for industrial use:

2.1 Sprue, Riser, and Flash Removal

This step cleans up excess material from casting. The method depends on production volume and precision needs:

Lote de producciónRecommended MethodVentajas claveParámetros críticos
Producción en masaAutomatic Stamping & CizallamientoAlta eficiencia (1000+ piezas/hora); Flat cross-sectionsRetain 1-2mm margin to protect the part body; Cut angle <5°
Small-Medium BatchesGrinding Wheel/Diamond Saw CuttingFlexible (works for odd-shaped parts); Low equipment costUse diamond blades for aluminum alloys to reduce burrs
High-Precision PartsFive-Axis Laser CuttingNo deformation risk; Corta formas complejasLaser power: 500-1000W.; Velocidad de corte: 100-300mm/min

Nota: Usar corte frío for aluminum-magnesium alloys to avoid heat-affected zones that weaken the part.

2.2 Surface Treatment Combinations

Surface treatment improves appearance, resistencia a la corrosión, y funcionalidad. Choose based on material and part use:

Treatment LevelTécnicasEspecificaciones claveMateriales adecuadosBeneficios
Basic TreatmentVibration Grinding (ceramic medium + alkaline solution)- Ardor de arena (ASTM B243 ALMEN standard)- Chemical Degreasing (ultrasound-assisted)Deburrs edges- Ra=3.2-6.3μm (ardor de arena)- Contact angle <5° (desengrasante)All die casting metalsPrepares surfaces for advanced treatments; Removes oil/dirt
Advanced Treatment– Anodizante- Micro-Arc Oxidation- Revestimiento de polvo- Electro ExcripciónCorrosion resistance ×3 (Anodizante)- Hardness HV≥800 (oxidación por microarco)- Prueba de spray de sal >1000h (revestimiento de polvo)- Gloss 90GU (electro Excripción)– Anodizante: Aleaciones de aluminio- Micro-arc oxidation: Al/Mg/Ti alloys- Revestimiento de polvo: Todos los metales- Electro Excripción: Copper/zinc alloysTailored to needs—e.g., anodizing for automotive parts; electroplating for decorative components

2.3 Mecanizado de precisión

This step refines dimensions and shapes. Success depends on clamping strategies and parameter optimization:

2.3.1 Clamping Strategies for Different Part Types

Tipo de parteMétodo de sujeciónExactitudCaso de uso
Thin-Walled Parts (<3milímetros)Vacuum Suction Cup + Honeycomb Support PadPrevents deformationAluminum alloy laptop casings
Irregular-Shaped Parts3D-Printed Custom FixturesError <0.02milímetros5G base station cooling modules
Multi-Process PartsZero-Point Positioning SystemRepeat positioning <0.01milímetrosNew energy vehicle motor housings

2.3.2 Optimized Machining Parameters

MaterialProcess TypeFeed per Tooth (milímetros)Profundidad de corte (milímetros)Velocidad de corte (m/mi)Método de enfriamiento
Aleación de aluminioToscante0.15-0.250.8-1.2N / ALow-temperature compressed air + micro-lubrication
Acero inoxidableRefinamientoN / ARadial <0.580-120Same as above

2.4 Heat Treatment Strengthening

Heat treatment boosts mechanical properties. Utilice esquemas específicos de materiales.:

MaterialEsquema de tratamiento térmicoParámetros claveResultados
Aleación de aluminio A380Envejecimiento de la solución T6535±5°C durante 8-12h; Transferencia de enfriamiento <30sResistencia a la tracción σb=320MPa; Alargamiento δ=8%
Aleación de magnesio ZAM4-1Envejecimiento artificial T6415±5°C durante 24h; Protección con gas inerteDureza Brinell HB=90; Resistencia a la fluencia ↓40%
Aleación de zinc ZA27Endurecimiento por edad90-120°C durante 4-8 h; Temperatura < punto eutécticoDureza Rockwell HRB=95; Estabilidad dimensional

Notas críticas: Las aleaciones de magnesio necesitan gas inerte para evitar la oxidación; Las aleaciones de zinc no deben exceder la temperatura eutéctica. (causa derretimiento).

2.5 Special Processing

Para alivio de tensiones residuales y protección de sellado.:

ObjetivoTécnicasParámetrosBeneficios
Alivio del estrés residualVibration Aging- Tratamiento criogénicoFrequency 2-50kHz; Amplitude 15-50μm- -196°C liquid nitrogen for 48hFatigue life ×2-3 (aleaciones de aluminio); Prevents long-term deformation
Sealing ProtectionSilicone Rubber Impregnation (VIPI)- PARYLENE Vapor DepositionPressure resistance IP68- Film thickness 5-25μmWaterproof/dustproof; Protects electronics (P.EJ., carcasa del sensor)

3. How to Control Quality in Die Casting Post-Processing?

Quality control ensures parts meet standards. Use the right tools and tests:

Quality AspectMétodo de pruebaStandards/Requirements
Precisión dimensionalCoordinar la máquina de medir (Cmm)GB/T 6414 CT7
Air TightnessHE High-Pressure Leak DetectionLeakage rate <1cm³/[email protected]
Aspereza de la superficieWhite Light InterferometerDecorative surfaces: Ra≤0.8μm
Adhesión de recubrimientoGrid Test + Tape PeelingASTM D3359 Method B
Defectos internosX-Ray Fluorescence + CT ScanningISO 17636-1 Level B

4. How to Fix Common Post-Processing Defects?

Defects like shrinkage or pores can be resolved with targeted solutions:

DefectoCausaSolución
Contracción (X-ray cloud-like shadows)Insufficient cooling during castingAdd cooling inserts; Extend holding time to 8-12s
Peeling (separación de capas)Large mold temperature gradientUse mold temperature controller to keep inlet/outlet temp difference <5° C
Pores (tiny air bubbles)Trapped air during castingAdd more exhaust grooves; Adjust backpressure valve
DeformaciónResidual stress releaseManual aging treatment; Use calibration fixtures
Baja dureza (CDH<48)Inadequate heat treatmentLaser cladding with TSN coating (hardness HRC62)

5. How to Control Costs and Cycles in Post-Processing?

Post-processing accounts for a large portion of total costs—optimize to save money and time:

Paso postprocesadoCost ShareCycle ShareConsejos de optimizaciónResultados
Basic Treatment15-25%20-30%Use automatic rolling grinding linesManpower saved by 70%
Tratamiento superficial20-35%15-25%Build coating recycling systemsConsumables reduced by 40%
Mecanizado de precisión30-40%30-40%Adopt turn-mill composite machining centersCycle time shortened by 50%
Inspección de calidad5-10%5-10%Replace manual checks with AI visual inspectionMissed detection rate <0.1%

6. Yigu Technology’s Perspective on Post-Processing of Die Casting

En la tecnología yigu, vemos post-processing of die casting as the “value-adding bridge” between raw castings and high-quality parts. Nuestros datos muestran 70% of part failures stem from rushed or mismatched post-processing—e.g., using heat treatment on porous aluminum parts causes cracking.

We recommend a “process-material matching” approach: For ADC12 aluminum alloy motor housings, we pair T6 heat treatment with precision boring to hit flatness <0.05mm/100mm; For Zamak5 zinc alloy medical handles, we use nano-chrome plating + laser engraving to meet ISO 10993 Normas de biocompatibilidad. By integrating automation (like AI inspection) and material-specific schemes, we help clients cut costs by 25% while improving part reliability.

7. Preguntas frecuentes: Common Questions About Post-Processing of Die Casting

Q1: Can all die casting materials use the same surface treatment?

No. Por ejemplo, anodizing only works on aluminum alloys (it forms an oxide layer), while micro-arc oxidation is better for Al/Mg/Ti alloys. Zinc alloys are often electroplated for decoration, but powder coating works for most metals—always match the treatment to the material and part function.

Q2: Why is quench transfer time critical for aluminum alloy heat treatment?

Aleaciones de aluminio (like A380) need fast quenching after solution treatment to trap strengthening elements. If transfer time exceeds 30 artículos de segunda clase, elements precipitate early, reducing tensile strength by up to 20%. We use automated quenching systems to keep transfer time <25 artículos de segunda clase.

Q3: How to reduce deformation in thin-walled die casting post-processing?

Use three methods: 1) Clamp with vacuum suction cups + honeycomb pads to spread pressure; 2) Use low cutting speeds (50-80m/min para aluminio) to minimize force; 3) Add a cryogenic treatment step (-196°C for 24h) to release residual stress before precision machining. These cut deformation by 60%.

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