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
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.
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.
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 building||We 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.
Rubber/TPE resin. Variable hardness, 40 - 85 Shore A. Can be over-molded.
PP resin compound - living hinges possible (typically 30 to 50 bends before breaking).
This is the classic and most popular ABS compound.
Transparent. Mainly simulates filled ABS or POM.
UV stable. Great for glossy, clear parts. Can be tinted or colored.
This is the classic acrylic and PC substitute.
Ultra rigid material.
High temp, most popular ABS compound in the EU. Auto/medical/chemically stable - up to 40 parts per silicone tool.
Transparent rubber substitute. Variable hardness, 45-70 Shore A.
Translucent colors possible.
Vacuum Casting Material
Vacuum Casting Processing
Vacuum Casting Technical Specifications
|Typical lead time||Up 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 thickness||To 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 dimensions||The 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 quantities||Up to 25 copies per mold (depending on the mold's complexity and the casting materials)|
|Color & Finishing||Pigment is added to the liquid polyurethane prior to casting, custom painting and texture.|
Vacuum Casting FAQ
Q: Can Vacuum Casting parts machined in color & texture ?
A: The casting urethane part can be a full set aesthetic model with various colors, textures and finishes under the same design idea. If having no idea about what color would be the most suitable for a product, you can make a silicone mold to produce 10-15 castings and paint each with your design colors and textures to discuss internally during meeting among design departments or even management meetings.
Q: Why would I choose vacuum casting over injection molding?
A: Vacuum casting is a more affordable alternative to IM, especially in low volumes. It also offers unique advantages like an excellent surface finish.
Q: Can I make production-quality parts using vacuum casting?
A: Vacuum casting is best for making visually impressive prototypes, but it can also be used for non-mechanical end-use parts like cases and covers.
Q: What happens to the silicone mold(s)? Can I keep them?
A: The silicone molds used in vacuum casting have a short lifespan, typically around 20 moldings, so we dispose of them after use. If you wish to keep the 3D printed or CNC machined master model, talk to us directly.
Request Your Free Vacuum Casting Quote Today
Our improved algorithm decreases Vacuum Casting quotation times by up to 90%. Most quotes are delivered within 24 hrs. and usually much less, depending on project details.
Your customer support partner will contact you directly to ensure you’ve received and understand all aspects of your quotation and to answer any questions you may have.
Vacuum casting is a prototype manufacturing process that uses silicone molds to quickly create urethane casting parts for the production of small series of functional plastic parts.
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