Precision Casting Parts

Advantages Of Casting

• Casting can produce complex shapes that would be otherwise difficult or uneconomical to make by other methods.
• Features like internal cavities or hollow sections can be achieved.
• Large components can be produced in one-piece cast
• Casting is generally less expensive than other manufacturing processes.
• Casting foundries often utilize recycled materials thereby reducing waste materials that might otherwise end up in landfills.

At Source we use three primary casting methods to mold both metal and plastic parts:

1. Die Casting
2. Sand Casting
3. Cold Casting

Precision Casting Process

Following is a summary of each process and its relative advantages followed by a comparison of various casting methods with other manufacturing processes.

Injection Die Casting

1. Die Casting

Die Casting involves pouring or injecting molten metal under high-pressure metal into a precision metal mold cavity at high speed, and the liquid metal is cooled and solidified under pressure to form a casting. This allows each part to be created with high precision accuracy and repeatability.

The die casting process has significant advantages over other manufacturing processes like machining and stamping allowing us to create complex shapes with complex internal and external features, and with minimal draft angles which minimizes the need for secondary finishing operations. Die casting also produces major cost savings in piece price and the overall cost of production.

Zinc and Aluminum alloys are the most used materials in our die casting factories. Zinc die casting produces parts that are a strong, durable, and cost-effective with a good combination of strength, toughness, rigidity, cast-ability, and superior finishing capabilities. Aluminum die cast parts also have their own advantages which allows us to create parts with complex part geometries that are lightweight, with good corrosion resistance, and high thermal and electrical conductivity.

Die cast parts often need a finishing operation to remove burrs. We commonly use vibration tumbling and sand blasting techniques to achieve the desired level of smoothness. Ultrasonic cleaning is used for high-quality cleaning, utilizing ultrasonic energy to scrub the parts and a liquid solvent to rinse away the residue and loosened particulate matter.

Die casting is an efficient, economical process offering a broader range of shapes and components than any other manufacturing technique. Parts have long service life and may be designed to complement the visual appeal of the surrounding part. Designers can gain several benefits by specifying die cast parts including high-speed production, close tolerances, dimensional accuracy and stability, strength, multiple finishing techniques, and simplified assembly procedures. Dies can be produced for simple to complex parts. Source factories use the latest technologies to ensure superior quality and low unit costs. Our state-of-the-art die casting plants more and more make use of robotics and other automated processes that provide guaranteed consistency in the finished product and cost control advantages.

A good overview of the precision die casting process can be found here.

Sand Casting Process

2. Sand Casting

Sand Casting is a less precise process than die casting with molds which are made primarily of sand with a certain percentage of clay mixed in. The use of sand molds allows for a lower initial set-up cost, and a shorter lead time of product development and first production launch, comparing to other processes. Sand casting can produce very large parts weighing of thousands of pounds.

A master mold is made first and is used to produce the production molds from sand. The sand is formed around this master mold to create the mold cavity and then removed. Next, the molten metal is filled into the sand cavity to form the casting part. After the part cools, the sand mold is broken loose, and the part emerges. Sometimes, a core may be needed to create a more complex feature (i.e. inner hole).

Ductile iron, steel, aluminum, and bronze are the most used materials in our sand casting factories. The sand casting blanks typically require secondary finishing to remove the parting line, smooth roughness, and achieve tight dimension tolerance. Sand blasting, shot blasting, and machining (lathing, milling, etc.) are generally used. After finishing, a surface coating such as black oxide, powder coating, or wet painting can be applied to achieve better corrosion resistance.

Cold Casting Pouring

3. Cold Casting

Cold casting molds are very low cost with production molds made from a master mold which liquid silicone is poured around to create a reverse mirror image. Silicone molds are durable, simple to construct and use, and are capable to reproduce very fine details on the surface of the part. Liquid poly resins comprised of two different liquid parts are mixed and poured into the silicone production molds, where it undergoes a chemical reaction to harden and produce an exact cast replica of whatever was used to make the mold. Vacuum chambers are used to draw any air bubbles from the liquid resin mixture. Similarly, silicone products can be made efficiently by the cold cast process using very thin-walled, low cost steel molds.

Cold cast resins are perfect for quickly and precisely reproducing complex shapes and figures with a low startup and part cost. The repeatability and weight of resin castings makes for a high-quality and cost-effective product, suitable for a multitude of colors, deco options from hand painting to decals. We work in a wide variety of polymers to achieve different flexibilities and textures in cast resin products.