Hei-Cast 8743 Vacuum Casting Material
For functional prototypes that must operate in punishing thermal environments without losing their shape, Hei-Cast 8743 is a top-tier solution. This advanced polyurethane resin is engineered to simulate the thermal and structural properties of semi-crystalline plastics like PBT (Polybutylene Terephthalate) and PA (Polyamide/Nylon). Offering a higher heat deflection temperature than standard high-temp resins, it ensures dimensional stability even under significant thermal load. At JUCHENG, we recommend Hei-Cast 8743 for the validation of automotive engine components, industrial heater housings, and electronic assemblies where thermal management is critical.
Hei-Cast 8743

Basic Characteristics & Composition

Hei-Cast 8743 is a two-component system formulated for high-rigidity applications.
  • Superior Thermal Resistance: Capable of withstanding temperatures up to 120°C, making it one of the most robust thermal resins available for vacuum casting.
  • High Stiffness: It exhibits a high flexural modulus, simulating the rigid feel of glass-filled engineering plastics.
  • PBT/PA Simulation: Matches the mechanical profile of industrial thermoplastics used in injection molding.
  • Dimensional Accuracy: Low shrinkage rates allow for precise fit-checks of mating components.
Hei-Cast 8743 prototype

Color Options

  • Standard: Beige / Pale Brown (Natural).
  • Finishing: The surface is hard and dense, providing an excellent base for sanding and painting. JUCHENG can apply heat-resistant coatings if required to match specific aesthetic needs.

Key Technical Parameters

1.Mechanical Properties (Typical values):
Property Value Unit Standard
Hardness 82 - 85 Shore D JIS K 7215
Flexural Modulus 2,300 - 2,500 MPa JIS K 7171
Tensile Strength 65 - 75 MPa JIS K 7113
Elongation at Break 5 - 8 % JIS K 7113
Heat Deflection Temp (HDT) 115 - 120 °C JIS K 7191
Impact Strength (Izod) 4 - 6 kJ/m² JIS K 7110
Linear Shrinkage 0.3 - 0.4 % -
2. PROCESSING 
  • Vacuum Casting: Must be processed under strict vacuum conditions. Any trapped air will expand during the high-temp post-cure, causing defects.
  • Pot Life: Approx. 6-8 minutes. Requires efficient pouring techniques for larger parts.
  • Demolding: 60-90 minutes at 70°C.
  • Post-Curing: Mandatory. To achieve the 120°C heat resistance, parts must undergo a stepped post-cure cycle (e.g., rising from 70°C to 120°C over several hours) while supported on fixtures.
3. PRECAUTIONS:
  • Warpage Risk: Due to high heat treatment, unsupported thin walls may warp during post-cure. JUCHENG engineers design custom fixtures to prevent this.
  • Brittleness: High rigidity comes with lower impact strength. Avoid designing sharp corners or thin snap-fits.
4. STORAGE:
  • Conditions: Store in a cool, dry place. Keep containers nitrogen-purged to extend shelf life.

Application Scenarios & Fields

Hei-Cast 8743 is designed for "hot zone" testing:
  • Automotive: Intake manifolds, thermostat housings, lighting internal bezels, engine covers.
  • Industrial: Casings for motors, pumps, and compressors generating operating heat.
  • Electronics: Heat sink mounts, projector housings, power supply enclosures.
  • Appliance: Internal structural frames for coffee machines, irons, or hair dryers.

Vacuum Casting Process Compatibility

  • Silicone Tooling: Compatible with standard silicone. High-temp resins can reduce mold life slightly faster than ABS simulants due to chemical aggression.
  • Machining: Excellent machinability. Cured parts can be drilled, tapped, and faced to tight tolerances.
  • Inserts: Ideal for heat-staking inserts or casting brass inserts in place.

Advantages vs. Limitations

Advantages Limitations
Excellent Heat Resistance: HDT ~120°C. Low Impact Strength: More brittle than PP or ABS simulants.
High Stiffness: Great for structural loads. Color: Limited to beige/brown; not transparent.
Dimensional Stability: Holds shape under heat. Cost: Higher material and processing cost (due to post-cure).
PBT/PA Feel: Simulates engineering plastics well. Lead Time: Post-curing adds time to the production schedule.

Manufacturers & Alternatives

  • Manufacturer: Hei-Cast (H&K Ltd., Japan).
  • Alternatives at JUCHENG:
For even higher heat resistance: We recommend Hei-Cast 8570.
For a black alternative: We recommend Axson PX 223.
For better toughness (lower heat): We recommend Hei-Cast 3012.
Learn more about ABS type materials
Jucheng Precision Factory
Request Your DFM & Quote – Upload Your Drawings
ㆍFill in your requirements and upload your 2D&3D file, we will feedback your project quotation and DFM within 24 hours.
ㆍFile types: STEP, STP, IGES, IGS, SLDPRT, 3DM, SAT or X_T files File size: < 128 MB Part size: < 1500*1500*1500 mm
ㆍPrivacy: We respect your privacy. Here you can find an example of a non-disclosure agreement. By submitting this form, you agree to our terms & conditions and privacy policy.
Choose File