The Process

How Vacuum Casting Works

The process begins with a high-accuracy 3D printed master pattern — typically SLA for the best surface quality. Liquid silicone is poured around the master under vacuum, capturing every surface detail. Once cured, the silicone mould is cut open and the master removed. Liquid polyurethane is then mixed, poured into the mould, and cured under vacuum to eliminate air entrapment. Parts are demoulded, trimmed, and inspected. Each silicone mould typically yields 10–25 parts before it is replaced.

Master pattern produced by SLA for finest surface quality

Vacuum during pouring eliminates air bubbles — dense, void-free parts

Silicone mould captures texture, lettering, and fine detail from the master

10–25 parts per mould — multiple moulds can run simultaneously for larger batches

Colour matching available — pigment added directly to the casting resin

Overmoulding possible — two materials cast sequentially into the same mould

Why Vacuum Casting

When It Makes Sense

Polymer vacuum casting occupies a valuable window between one-off 3D printing and injection moulding, particularly when low-volume polyurethane parts are required without the cost of hard tooling.

Pre-Production Validation

Before committing to injection mould tooling, validate your design with production-equivalent parts. Fit, function, aesthetics — all testable with vacuum cast parts at a fraction of the tooling cost.

Bridge Production

When your injection mould tooling is being made, vacuum casting keeps your production line moving. Parts are visually and mechanically equivalent — customers cannot tell the difference.

Low-Volume End-Use

For products where volumes never justify a ₹5–20 lakh injection mould, vacuum casting is the permanent production solution — economical from 10 to a few hundred parts per year.

Marketing Samples

Presentation-quality parts for sales samples, trade shows, and investor demonstrations — indistinguishable from the production article, delivered in days. Test multiple colour options and surface finishes on real production-geometry parts before making tooling decisions.

Spare Parts

For discontinued or low-demand products where tooling no longer exists, vacuum casting is the most economical way to maintain a spare parts supply.

Insert Moulding & Overmoulding

Seamlessly encapsulate threaded hardware, metal bushings, and structural inserts into polyurethane castings for high-strength, production-grade assemblies. Get exceptional mechanical and chemical bonding between rigid substrates and soft-touch elastomers without the high cost of hard tooling.

Material Grade 01

Standard Rigid

A standard rigid polyurethane engineered for vacuum casting — durable, dimensionally stable, and with good thermal and chemical resistance. Closely replicates the look, feel, and mechanical behaviour of injection moulded ABS. REACH compliant and RoHS 1 & 2 certified.

Property	Value
Material resembling	ABS-like, comparable to opaque Polycarbonate
Material	Standard rigid polyurethane
Density (cured mix)	1.14 g/cm³
Pot life	6–7 minutes
Demould time	~45 minutes at 70°C
Compliance	REACH, RoHS 1 & 2, WEEE, ELVs
Surface finish	Replicates master — smooth, paintable, texture-matched
Run size	10–25 parts per silicone mould
Best for	Housings, enclosures, structural components, functional prototypes, marketing samples

Material Grade 02

Soft Flexible

A low-viscosity flexible rubber system with fully adjustable Shore hardness — achieved by varying the ratio of the third component. This means a single material system can replicate anything from firm rubber to very soft gel, covering the full range of soft-touch and sealing applications. Translucent white, pigmentable to any colour.

Property	Value
Material resembling	TPE-like

Shore Hardness	Tensile Strength	Elongation at Break
90A	17 MPa	270%
80A	12 MPa	260%
70A	8 MPa	230%
60A	6 MPa	290%
50A	5 MPa	290%
40A	4 MPa	310%
30A	3 MPa	310%

Overmoulding onto the standard rigid grade possible. Pigmentable to any colour. Curing at 70°C.

Material Grade 03

Clear

A colourless, optically transparent polyurethane with ABS-like mechanical strength — making it the ideal choice when both clarity and structural integrity are required. High transmissivity of 90.75%. Tintable to any colour while retaining transparency.

Property	Value
Material resembling	Acrylic-like
Material	Colourless, optical-grade polyurethane
Shore hardness	82D at 23°C — firm, ABS-like
Tensile strength	58 MPa
Flexural strength	99 MPa
Flexural modulus	2400 MPa
Elongation at break	25%
Heat deflection temperature	72°C
Light transmissivity	90.75%
Transparency	Near-optical for simple geometries — translucent for complex
Best for	Lenses, display windows, light covers, transparent enclosures

Material Grade 04

Glass Filled

A glass fibre reinforced rigid polyurethane — delivering significantly higher stiffness and modulus than standard rigid while retaining the same processing and surface quality. The right choice when structural rigidity matters and the weight or cost of metal is not justified.

Property	Value
Material resembling	PBT-like
Material	Glass fibre reinforced rigid polyurethane
Density (cured)	1.23 g/cm³ (vs 1.14 unfilled)
Flexural modulus	Up to 3500 MPa at 25% filler loading
Stiffness vs standard rigid	Significantly higher — glass fibre reinforced
Pot life	7–8 minutes
Best for	Structural brackets, load-bearing enclosures, stiff housings, under-bonnet parts

Applications

Where Vacuum Casting Excels

Vacuum casting serves industries where production quality is non-negotiable but volumes are too low to justify injection mould tooling.

Automotive

Interior trim, HVAC components, dashboard elements, and under-bonnet housings — production-quality parts for pre-tooling validation and low-volume supply.

Dashboard bezels and interior trim panels
HVAC housings and air distribution components
Gear knob, handle, and interior fitting prototypes
Sensor housings and under-bonnet brackets
Tail lamp lenses and light covers in clear grade

Consumer Products

Packaging, product enclosures, and marketing samples indistinguishable from the production article — delivered in days for commercial presentations and launches.

Home appliance enclosures and panels
Cosmetic packaging and dispenser bodies
Remote controls and handheld device shells
Wearable device and personal electronics housings
Display stands and point-of-sale units

Industrial Equipment

Custom housings, covers, and structural brackets for machinery where volumes are low and hard tooling investment is difficult to justify.

Machine covers, guards, and access panels
Control panel and HMI housings
Pump and valve body housings
Structural mounting brackets and frames
Fluid handling and pneumatic components

Electronics & EMS

Enclosures, bezels, and connector housings with production-quality finish — ideal for pre-production batches while injection tooling is in progress.

PCB enclosures and instrument housings
Front panel bezels and display surrounds
Connector housings and cable management parts
Power supply and converter enclosures
Test and measurement instrument shells

Medical Equipment

Instrument housings and equipment covers where a production-quality appearance is required for regulatory submission samples and clinical evaluation units.

Diagnostic instrument and analyser housings
Centrifuge and laboratory equipment covers
Handheld medical device shells
Equipment front panels and display bezels
Internal brackets and structural components

Aerospace & Defence

Low-volume structural components, cabin fittings, and custom brackets — produced to production quality standards without the cost and lead time of hard tooling.

Cabin interior fittings and trim panels
Instrument housings and display bezels
Structural brackets and mounting hardware
Custom covers and equipment access panels
Low-volume spare parts and replacement components

Common Questions

Frequently Asked Questions

What is the maximum part size you can produce?▾

Maximum part size depends on the selected manufacturing process and available equipment. For FDM, Stratnel can produce parts up to approximately 1 metre in each dimension, subject to part geometry and machine availability.

Larger components may be divided into sections, printed separately, and assembled. Stratnel can design and print dedicated assembly fixtures to help align such sections accurately.

SLA, SLS, and vacuum casting are generally used for smaller components, often around 200 mm, although actual capacity depends on the selected equipment, geometry, and process. Please share your design so that we can confirm feasibility.

Which materials can you print?▾

Stratnel offers a broad range of polymer materials. The appropriate material depends on the application, operating environment, required properties, and manufacturing process. Typical options include:

FDM: ULTEM™ 9085, PA6-CF, ASA, PETG, ABS, PLA, PC-ABS-FR, and other engineering thermoplastics.
SLS: PA12 (Nylon) for rigid parts and TPU 88A for flexible parts.
SLA: Standard, tough, clear, and other application-specific photopolymer resins.
Vacuum casting: Tough, clear, glass-filled, flexible, and other polyurethane resin systems.

Share your application and performance requirements with Stratnel, and we can recommend a suitable process and material. Relevant material datasheets can also be provided.

What dimensional accuracy and tolerances can you achieve?▾

The achievable accuracy depends on the printing process, material, part geometry, orientation, size, and post-processing requirements. Unless otherwise agreed, our indicative process tolerances are:

Process	Indicative Tolerance
FDM	± 0.5% of nominal dimension or ± 0.3 mm, whichever is greater
SLA, SLS & Vacuum Casting	± 0.3% of nominal dimension or ± 0.2 mm, whichever is greater

These are general process guidelines and do not constitute a tolerance commitment for every feature. Please identify all critical dimensions and tolerances in a drawing when requesting a quotation so that Stratnel can review their feasibility and agree on an appropriate inspection plan.

Measurements are typically taken using calibrated vernier callipers and/or a height gauge on a surface plate. Our standard inspection generally covers selected, readily measurable dimensions across the three principal axes; it is not a complete inspection of every dimension in the drawing or CAD model. Full dimensional inspection or inspection of additional characteristics can be arranged when agreed before production.

What is the usual production lead time?▾

Production lead time depends on current machine availability, the size and geometry of the parts, print duration, order quantity, material, post-processing, inspection, and packaging requirements. Finishing processes such as painting may add a few days to the schedule.

We will provide an estimated dispatch date when quoting or confirming your order.

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