POM Vacuum Casting

POM Vacuum Casting

POM, the abbreviation of polyoxymethylene, also known as Delrin or acetal, is a naturally white semi-crystalline that belongs to engineering thermoplastic. POM can produce high precision parts with vacuum casting.

Vacuum casting POM (Delrin) is suitable for creating parts that require high strength, high resistance to heat, abrasion, and moisture absorption, excellent dimensional stability, and overall toughness.

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Material Performance

Material Performance

  • Excellent Wear Resistance
  • Superior Impact and Creep Resistance
  • Good Chemical Resistance
  • High Tensile Strength
  • High Fatigue Strength
  • High Rigidity
  • Low Moisture Absorption
Material Performance


  • Strong material performance. Vacuum casting POM (Delrin) parts own high material performance and they can be an alternative to metal parts.
  • Chemical resistance to fuels and solvents. The excellent resistance to chemical makes POM parts withstand harsh environments.
  • Robust and durable. Vacuum casting POM parts have a longer lifespan than other plastics.
  • Cost saving. Compared with other plastics, POM (Delrin) is less inexpensive and durable, making the material a cost-effective option.


> Automotive Components

> Household Appliance

> Pump and Valve Parts

> Gears and Bearings

> Bushings

> Fittings


How to POM 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 POM (Delrin) in advance, then fully fill the mold with POM (Delrin), the process is done in a vacuum chamber for degassing, ensuring air bubbles are removed. Afterwards, move the POM (Delrin) part in an oven for curing. Curing time is based on part size as well. The vacuum casting POM (Delrin) 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 POM (Delrin) 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 POM (Delrin) vacuum casting?

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

5. What is POM?

POM (Polyoxymethylene), also Delrin, acetal, polyacetal, and polyformaldehyde, is an engineering thermoplastic. POM has excellent physical and mechanical properties, it is also widely known as metal plastic, super steel, etc. POM plastic has good comprehensive properties and machinability.

6. Is POM the same as Delrin?

Delrin is the trademark name for a series of acetal resins which are semi-crystalline thermoplastic polymers which are also known by the abbreviation POM or polyoxymethylene.

7. Is POM the same as acetal?

Acetal, also called polyacetal and polyoxymethylene (POM), is a semi-crystalline thermoplastic. Two general types acetals are acetal copolymer (POM-C), and acetal homopolymer (POM-H). Acetal homopolymer is commonly called Delrin.

8. Are acetal and Delrin the same thing?

Delrin is one type of acetal, acetal homopolymer, having a uniform backbone with a larger crystalline block structure than acetal copolymers providing better chemical bonding. So, Delrin has stronger properties and performance than acetal copolymer.

9. Does POM crack?

Featuring high strength, good fatigue strength, and superior rigidity, CNC POM parts resist cracks and deformation from mechanical stress over time.

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