Pressure Casting
Low-volume production parts with injection-molding quality β without the tooling cost or lead time.
What is Pressure Casting?
Pressure casting (also known as vacuum casting) is a manufacturing process in which liquid polyurethane resin is poured into a silicone mold under pressure, then cured to produce a high-fidelity replica of the original master pattern.
The master pattern is typically produced via SLA printing, which means the final cast parts inherit the same fine surface detail and dimensional accuracy as the original 3D print. Silicone molds can yield 20β50 parts each β making this process ideal for low-volume production runs of 10 to 200+ units.
Compared to injection molding, pressure casting requires no expensive steel tooling, no minimum order quantities, and can be ready for production in days rather than months β all with comparable surface finish and mechanical properties.
How the Process Works
Master Pattern Production
A high-precision SLA master pattern is produced from your 3D file. This master defines every surface detail that will be replicated in the final cast parts.
Silicone Mold Creation
The master is placed in a frame and encapsulated in liquid silicone. Once cured, the silicone is cut open along a parting line, and the master is removed β leaving a perfect negative cavity.
Resin Mixing & Degassing
Two-part polyurethane resin components are measured, mixed, and placed in a vacuum chamber to remove air bubbles before pouring. This ensures void-free parts with consistent mechanical properties.
Casting Under Pressure
The mixed resin is poured into the silicone mold and placed in a pressure vessel. Elevated pressure during curing eliminates any remaining micro-voids and ensures the resin fills every detail of the cavity.
Demolding & Post-Processing
After curing, the part is removed from the mold. Sprues are trimmed, and parts can optionally be sanded, primed, or painted to a production-ready finish.
Quality Inspection
Parts are inspected dimensionally and visually. Wall thickness, surface finish, and critical dimensions are verified against your specifications before shipping.
Technical Specifications
Dimensional Tolerance
Β±0.2 mm
Parts per Mold
20β50 shots
Max Part Size
500 Γ 500 Γ 300 mm
Minimum Wall Thickness
1.0 mm
Surface Finish
Replicates master (Ra ~1β3 Β΅m)
Lead Time
5β10 business days
Available Polyurethane Resins
Rigid PU β Standard
ABS-LikeThe workhorse casting resin. Rigid, paintable, and dimensionally stable. Ideal for enclosures, brackets, and structural components.
Rigid PU β High Impact
ToughEnhanced impact resistance for parts that take mechanical abuse. Drop-test grade quality for consumer electronics and industrial handles.
Rigid PU β High Temp
Heat ResistantHDT up to 130 Β°C. For engine bay components, lighting housings, and parts exposed to elevated operating temperatures.
Flexible PU β Shore 40A
Soft RubberVery soft, high-elongation rubber for seals, overmolds, and grip surfaces. Excellent tear resistance.
Flexible PU β Shore 60A
Medium RubberMedium hardness rubber for gaskets, buttons, bumpers, and protective covers. Good compression set.
Transparent PU
ClearWater-clear rigid cast for light pipes, display windows, and optical covers. Can be tinted with pigments.
Common Applications
- Low-volume production runs (10β200+ units)
- Pre-production pilot batches before injection molding
- Enclosures and housings for electronics
- Automotive interior trims and prototypes
- Medical device housings and ergonomic grips
- Consumer product development and market testing
- Architectural models and scale replicas
- Replacement parts for discontinued components
How It Compares
| Pressure Casting | Injection Molding | 3D SLA Printing | |
|---|---|---|---|
| Tooling Cost | Low (silicone mold) | Very High (steel tool) | None |
| Lead Time | 5β10 days | 6β12 weeks | 48β72 hours |
| Volume Range | 10β200 units | 1,000+ units | 1β50 units |
| Surface Finish | Excellent | Excellent | Very Good |
| Material Options | Wide (PU resins) | Wide (thermoplastics) | Wide (photopolymers) |
| Part Complexity | High | Very High | Highest |
Design Guidelines
Wall Thickness
Minimum 1.0 mm. Uniform wall thickness prevents sink marks and warpage during curing.
Draft Angles
1β3Β° draft on vertical surfaces greatly improves part release from the silicone mold.
Undercuts
Silicone is flexible enough to handle moderate undercuts without slides β an advantage over rigid injection molds.
Texture
Any surface texture on the SLA master is faithfully reproduced in the silicone mold and transferred to every cast part.
Inserts
Threaded metal inserts, magnets, and other hardware can be placed in the mold before casting for embedded components.
File Format
STL or STEP. Ensure the model is watertight. Scale in mm. Tolerance allowances for mating parts should be added to the CAD.
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