Vacuum Casting - Urethane Casting

IDEAL is fully capable of handling your vacuum casting and silicone molding needs. With years of expertise in the field, we can fabricate your plastic parts to the highest standard, as well as cost-efficient and with fast turnarounds.

Vacuum casting is a great method to make rigid or flexible parts, and is ideal for high quality prototypes, function testing, concept proofing and display demos. Urethane casting parts can be made from a few to hundreds as required.

Advantages of Vacuum Casting

  • 01

    Low cost & Repeatability

    Cast urethane parts are made of cheap silicone molds, eliminating the need to invest in expensive and time-consuming metal tooling. Up to 50 functional cast urethane parts can be produced in 10 to 15 days.

  • 02

    Wide selection of materials

    Urethane casting materials range from soft and flexible to rigid and impact-resistant, also provides end-use parts with  fine details of production-level quality.

  • 03

    Color Options

    Urethane casting can provide better surface quality compared with CNC prototyping or 3D printing, as well as colored and clear.

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How Vacuum Casting Works?

The urethane casting process has three steps: master pattern, molding, and casting.

Step 1: Master buildingWe can paint parts surface for texture or satin effect to simulate the final mold texture of the product. Thesilicone molds will copy the details and textures from the original master, so the cast urethane parts wilcome out the same as the master without any extra finish on the surface. Casting molds are made from liquid silicone resin, also known as RTV molds. The chemical stability, self-re-leasing properties and flexibility of silicone rubber are excellent that it gives minimal shrinkage and carriesfine details effectively from master to mold.The silicone mold making steps are as follows: Paste tape in flat position around the master, so that it is easy to open the mold later, which will also becomethe parting surface of the final mold.
Step 2: Mold making

The master model is suspended in a box and place plastic rods to set gates and vents. Silicone is poured around the master and vacuum is used to remove all air. This then is cured in an oven, at atemperature of 40℃. lt generally takes 8-16 hours depending on the volume of the mod.

Once the silicone rubber is cured, remove the master from the silicone to form a cavity and the silicone mold is made.

Step 3: Cast the parts

The process of vacuum casting parts is as follows: First, put the silicone mold into the oven and preheat it to 60-70°℃. It is very important to choose a suitable release agent before closing the mold and use it correctly to avoidstickiness and surface defects. Then prepare the polyurethane resins to preheat it to about 40℃ before use.

Mix two-component resins in exact proportions, and then fully stir and degas for 50-60 seconds undervacuum.

The resin is poured into the mold inside the vacuum chamber under computer control, and cured again inthe oven.Average cure time: 1-3 hours for small parts and 3-6 hours for big parts. Remove the casting partfrom the silicone mold after curing. Prepare to repeat this cycle.

Vacuum Casting Materials

Urethane resins are polymers with a wide range of properties and uses. IDEAL offers various urethane materials to meet your applications, including Hei-Cast from Japan and Axson from France. Materials with certain properties are similar to engineering production plastics, such as ABS, PMMA, PC, PP, PA, and so on. Casting parts can be varied from transparent, translucent to colored, and from soft rubber to hard plastic. Various materials contain those impact-resistant, high-temperature resistant (120℃) or fire-resistant (UL94-V0), and glass-filled resins, and different hardness silicone.

  • PU Rubber

    Rubber/TPE resin. Variable hardness, 40 - 85 Shore A. Can be over-molded.

    UPX 8400

  • UP 5690

    PP resin compound - living hinges possible (typically 30 to 50 bends before breaking).

  • UP 4280

    This is the classic and most popular ABS compound.

  • PX 527

    Transparent. Mainly simulates filled ABS or POM.

  • PX 5210

    UV stable. Great for glossy, clear parts. Can be tinted or colored.

    This is the classic acrylic and PC substitute.

  • PX 245

    Ultra rigid material.

  • PX 223-HT

    High temp, most popular ABS compound in the EU. Auto/medical/chemically stable - up to 40 parts per silicone tool.

  • (HeiCast)T0387

    Transparent rubber substitute. Variable hardness, 45-70 Shore A.

    Translucent colors possible.

  • Vacuum Casting Material

    Vacuum Casting Material

  • Vacuum Casting Processing

    Vacuum Casting Processing

Vacuum Casting Technical Specifications

Typical lead timeUp to 20 parts in 15 days or less, depends on the part specification and volumes.
Accurate±0.3% (with lower limit on ±0.3mm on dimensions smaller than 100mm)
Minimum wall thicknessTo ensure that the mold is filled properly, a wall thickness of at least 0.75 mm is necessary.For best results, we recommend a wall thickness of at least 1.5mm.
Maximum part dimensionsThe size of the mold is limited by the dimensions of the vacuum chamber (1900 x 900 x750 mm) and by the volume of the product (maximum volume: 10 liters)
Typical quantitiesUp to 25 copies per mold (depending on the mold's complexity and the casting materials)
Color & FinishingPigment is added to the liquid polyurethane prior to casting, custom painting and texture.

Vacuum Casting FAQ

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