Low-Volume Prototype Manufacturing

Vacuum Casting
Prototypes Services

Production-like vacuum casting prototypes for appearance, fit, and functional validation before committing to production tooling.

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Process Overview

What Are Vacuum Casting Prototypes?

Vacuum casting prototypes are production-like plastic parts created by casting polyurethane into a silicone mold made from an approved master pattern. The process supports multiple consistent parts for design reviews, fit checks, and early functional validation.

Material selection and master-pattern finish define the final surface, feel, and dimensional outcome. After curing, vacuum cast parts can be trimmed, finished, inspected, and assembled for prototype builds or short production runs.

Vacuum casting prototype process placeholder

Why Vacuum Casting Prototypes

Key Benefits of
Vacuum Casting Prototypes

Create a small, consistent set of production-like parts before committing to injection molding tooling or a fixed production material.

Production-Representative Appearance

Replicate approved color, gloss, texture, and detail from a finished master pattern for reviews and customer samples.

Practical Batch Quantities

Produce multiple vacuum cast parts with a lower initial tooling commitment than metal injection molds.

Material & Tactile Options

Select rigid, flexible, clear, or heat-resistant polyurethane systems around fit, function, or user interaction.

Validation Before Tooling

Check assembly, interfaces, ergonomics, and cosmetic requirements while design changes remain manageable.

Master Pattern Options for Vacuum Casting Prototypes

SLA Master Patterns

SLA patterns provide fine detail and smooth surfaces for appearance-focused and geometrically complex prototypes.

Urethane casting part production example

Fine surface detail
Smooth master finish
Complex geometry
Rapid pattern turnaround

CNC Master Patterns

CNC-machined patterns provide stable datums and controlled surfaces for prototypes with demanding dimensional and finish requirements.

Urethane material and finish selection example

Stable reference datums
Controlled dimensions
Durable tooling surface
Repeatable mold results

Customer-Supplied Pattern

Existing patterns can be reviewed and used when geometry, surface condition, and moldability meet project requirements.

Pattern condition review
Moldability assessment
Parting and gate planning
Repeatable casting setup

Pattern Source	Advantages	Considerations
SLA 3D Printing	Suitable for complex curves and fine details. No dedicated machining fixture is required. Fast CAD-to-pattern turnaround. Efficient starting point for appearance models.	Support marks may need removal. Surface finishing may be required. Resin pattern durability is limited. Clear resin does not guarantee optically clear cast parts.
CNC Machining	Stable dimensional accuracy. Metal and engineering-plastic pattern options. High-quality machined surfaces. Suitable for tight fit and finish requirements. Consistent replication performance.	Complex cavities and undercuts can be difficult. Tool access must be considered. Cost and preparation time may exceed SLA. Freeform surfaces may need 5-axis or multiple setups.
Customer-Supplied Pattern	No new pattern is required. Existing parts can be evaluated directly. Useful for legacy parts or projects without complete CAD data.	Pattern condition must be reviewed. Draft and parting suitability must be confirmed. Moldability is approved before production.

How It Works

How Vacuum Casting Prototypes Are Made

CAD & Prototype Review

Review CAD data, target quantity, critical dimensions, material behavior, and cosmetic requirements before process planning.

Master Pattern Preparation

Produce or review an SLA or CNC master pattern based on geometry, interface requirements, and the required surface finish.

Silicone Mold Making

Create an RTV silicone mold with planned parting lines, gates, vents, and demolding access for repeatable prototype casting.

Vacuum Casting

Mix, degas, cast, and cure the selected polyurethane system to produce production-like vacuum casting prototypes.

Finish & Assemble

Remove gates and flash, then add painting, polishing, texture refinement, inserts, or assembly as required.

Inspect & Deliver

Inspect key dimensions, appearance, color, and assembly requirements before protective packaging and delivery.

Vacuum Casting Prototype Materials

Metals

Non-Metals

A rigid polyurethane casting resin for housings, covers, and functional prototypes with ABS-like behavior. It is not ABS thermoplastic.

Two-part polyurethane casting resin
Confirm stiffness, impact behavior, color, and the selected formulation.

Technical Capability

Vacuum Casting Prototype
Capabilities

Defined parameters for production-like prototype batches. Final requirements are reviewed against CAD, material, mold design, and finish targets.

Dimensional Tolerance	±0.3 mm or ±0.3%, whichever is greater.
Surface Detail	≥0.5 mm for raised or recessed details, logos, and texture features.
Minimum Feature Size	Ø1.0 mm holes; 0.5 mm grooves or ribs, subject to demolding direction.
Minimum Wall Thickness	0.75 mm minimum; 1.5 mm recommended for stable filling and dimensional control.
Maximum Part Size	Up to 2,000 × 1,200 × 1,000 mm.
Surface Condition	Ra 1.6–3.2 μm as cast; down to Ra 0.8 μm after polishing.
Recommended Quantity	1–100 parts per prototype program; typically 15–25 parts per silicone mold.
Typical Lead Time	5–10 business days after CAD, material, color, and finish approval.

Design Notes

Vacuum Casting Prototype Design Guidelines

Wall Thickness

Keep walls as uniform as possible. Use 1.5–4 mm where practical; local sections down to 0.75 mm require engineering review.

1.5–4 mm Walls

Draft & Demolding

Use 1–2° draft on vertical walls where possible to support clean release and protect visible surfaces.

1–2° Draft

Undercuts

Silicone molds can accommodate many undercuts, but deep or complex features need a mold-split review.

Mold Split Review

Inserts & Threads

Specify threaded inserts, bosses, and load-bearing interfaces early so their position and post-processing can be planned.

Threaded Inserts

Critical Fits

Mark key dimensions and mating interfaces on the drawing to manage shrinkage, finish thickness, and assembly tolerance stack-up.

Critical Dimensions

Parting Lines

Place parting lines away from cosmetic faces, sealing surfaces, and critical interfaces whenever geometry allows.

Parting Line Planning

Cosmetic Surfaces

Identify visible faces and define gloss, texture, paint, or polish requirements before master-pattern finishing.

Cosmetic Surface Control

Color Matching

Provide a Pantone reference, physical sample, or approved visual target for production-like prototype color review.

Pantone Color Matching

Part Size & Stability

Large, thin, or asymmetric vacuum cast parts require review for filling, shrinkage, and dimensional stability.

Large-Part Review

Finishing & Secondary Operations

More Than Molding.
Complete Your Parts.

Turn vacuum cast parts into review-ready assemblies through coordinated trimming, finishing, machining, marking, inspection, and protective packing—managed as one prototype workflow.

Trim & Degate

Remove gates and flash, then refine edges for clean handling and controlled part presentation.

Insert Installation & Assembly

Fit threaded inserts, bonded components, and specified sub-assemblies in the defined build sequence.

Secondary Machining & Tapping

Machine critical holes, seating features, and threads after casting where the design requires them.

Surface Refinement

Sand, polish, texture-match, or prepare surfaces to the agreed visual standard.

Painting & Color Matching

Apply specified colors, coatings, or cosmetic finishes against an approved sample or Pantone reference.

Final Part Inspection

Check agreed dimensions, appearance, and assembled features before release.

Pad Printing & Marking

Add logos, icons, text, or identification marks to selected surfaces.

Protective Packaging

Pack completed parts to help preserve finished surfaces and keep project sets organized in transit.

Before Secondary Operations

Illustration · As-Cast Part

Gate vestiges and parting-line flash
As-cast surface condition
No post-machined holes or threads
No approved color or graphics

After Finishing & Assembly

Finished vacuum cast prototype placeholder

Illustration · Review-Ready Part

Cleaned edges and specified surface finish
Machined mounting and threaded features
Color, markings, and components applied
Prepared for functional, design, or customer review

Applications

Vacuum Casting Prototype Applications

Illustration of a generic machined housing, shaft and mounting bracket for vehicle development

Automotive

Custom automotive parts for prototypes and low-volume production.

Illustration of metal gripper fingers, a sensor bracket and a precision fixture block

Automation

Custom robotic parts, fixtures, and automation equipment components.

Illustration of a lightweight pocketed bracket, spacer and compact sensor mount

Aerospace

Aerospace prototypes and custom parts for engineering evaluation.

Illustration of an enclosure panel, mounting bracket and white polymer equipment fixture

Medical

Medical device prototypes, custom housings, and mechanical components.

Illustration of a pocketed metal enclosure, circular adapter and conductive connector component

Energy

Custom energy equipment parts, housings, and mounting components.

Illustration of a circular equipment flange, machined fixture plate and rectangular cover

Semiconductor

Custom semiconductor equipment parts, fixtures, and handling components.

Illustration of a sheet-metal bracket, ventilated plastic cover and metal rollers

Office Equipment

Custom parts and prototypes for printers, copiers, and scanners.

Illustration of a molded plastic housing, metal trim frame and formed mounting plate

Electronic Appliances

Custom appliance parts and enclosures for product development.

FAQ

Vacuum Casting Prototypes FAQ

When should I use vacuum casting prototypes?

Use vacuum casting prototypes when you need a small batch of production-like parts for fit checks, functional validation, or customer review before committing to injection molding tooling.

How many parts can one silicone mold produce?

A silicone mold typically produces 15–25 vacuum cast parts, depending on part geometry, material, finish, and handling requirements.

What materials are available for vacuum cast parts?

Polyurethane systems can simulate rigid, flexible, rubber-like, clear, flame-retardant, or higher-temperature production plastics.

Can vacuum casting parts include threads, inserts, colors, or logos?

Yes. Post-machining, threaded inserts, color matching, painting, pad printing, and assembly can be planned during project review.

What is the typical lead time for vacuum casting prototypes?

Typical lead time is 5–10 business days after CAD, material, color, and finish requirements are approved.

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Vacuum Casting Prototype Project?

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