PP Vacuum Casting

PP Vacuum Casting

Polypropylene, known as PP, is a thermoplastic polymer often used as plastic components, storage containers, and consumer products packaging.

Vacuum casting PP parts are made for applications that require high strength, high toughness, moisture absorption resistance, low friction, and light weight.

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Material Performance

Material Performance

  • Strong Fatigue Resistance
  • Good Chemical Resistance
  • Good Electrical Insulation
  • Low Moisture Absorption
  • High Flexural Strength
  • Overall Toughnesss
Material Performance


  • Slippery surface. With this property, PP is highly suitable for low friction applications, and PP is a good substitute for other plastics, for example, POM.
  • Saving cost. PP is inexpensive and easy to access and it is relatively low density and weight.
  • An excellent insulator. PP cannot conduct electricity well, making it a great material for electrical insulation.
  • Malleable. PP can be repetitive bending and without cracking or breaking, making living hinges with PP is feasible.


> Automotive Components

> Consumer Product Packaging

> Water Bottles and Containers

> Household Goods

> Food Trays

> Luggage


How to PP vacuum casting?



1. Master Model Building.
First of all, producing vacuum casting prototypes require a high-quality master model with high dimensional accuracy. To ensure the final vacuum casting parts are the same as expected, creating flawless master model is the vital foundation. Master model can be created by 3D Printing or CNC Machining, and dedicated post-processing, grinding, for instance, is necessary. These steps make sure that the master model is perfect to use. At Wenext, we will go through all details before making the master model, like design file checking to guarantee a manufacturable master model.


2. Silicone Mold Making.
Master model is ready to use. Then it’s time to pour liquid silicone into the casting box and fully immerse the master model. It takes several hours to cure the silicone naturally. After the mold is cured, cut open the mold and take the master model out of the mold. You will see a hollow space in the middle of the silicone mold, which fits the dimensions and specifications of the master model. Later on, the silicone mold needs to be cured again at a high temperature in an oven because the mold is still soft and sticky. Curing time would be based on size of the mold.


3. Parts Producing.
The final step is casting parts with the silicone mold. Before casting, clean the surface of the silicone mold again is necessary. Then spraying the silicone mold internal structure with special release agents, attach tape to the edge, and even insert steel bars inside for large mold. All these steps make sure that mold release without damages. Prepare polypropylene (PP) in advance, then fully fill the mold with PP, the process is done in a vacuum chamber for degassing, ensuring air bubbles are removed. Afterwards, move the PP part in an oven for curing. Curing time is based on part size as well. The vacuum casting PP part can be removed from silicone mold after cool down.

Frequently Asked Questions

1. Why would you choose vacuum casting over 3D Printing?

The major consideration when choosing vacuum casting over 3D Printing is material performance and quality. Vacuum casting provides higher performance materials than better mimic those used in commercial products. If material performance and product appearance are on top priority, vacuum casting should be the alternative.

2. Why would you choose vacuum casting over injection molding?

The critical consideration is cost and quantity. Vacuum casting is more affordable and cost-effective for rapid prototypes to low volume production.

3. How much does it cost to vacuum casting polypropylene (PP) parts?

Prices are based on the structure of the part, order volume, machining processes, etc. You can use our instant quoting engine to get price, or you can email hello@wenext.com for more information.

4. What is polypropylene (PP) vacuum casting?

Polypropylene (PP) vacuum casting is the process of casting PP parts by using vacuum to draw the PP into the mold, thus making PP parts with desired structures and geometries.

5. What is polypropylene (PP)?

Polypropylene (PP) is a tough, rigid, and crystalline thermoplastic. It is made from propene (or propylene) monomer. This linear hydrocarbon resin is the lightest polymer among all commodity plastics.

6. How to choose between polypropylene (PP) and nylon?

Both nylon and polypropylene are durable and resistant to stress, but polypropylene is stronger than nylon. Besides, if parts will be used underwater, moisture resistant polypropylene vacuum casting parts are waterproof.

7. Which is better, polypropylene or polyethylene?

Polypropylene and polyethylene are similar. PP is slighter stiffer, more heat and chemical resistant.

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