Die Casting Finishing and Quality Assurance

About Die Casting Pressure Testing

Many die castings are used in pressure tight applications or as pressure vessels.  If you part is designed for this function then we need to know what the application will be and also what pressure levels you expect your part to work with in the application.

As a result, we use pressure testing to test for porosity which is a root cause for leaks in die casting that are used in pressure applications. Porosity is the presence of small pockets of air, or bubbles, that develop in the metal during die casting. There is an acceptable level of porosity in a metal die-cast part, but anything beyond that level could affect the integrity of the part. It is very important to keep porosity to a minimum.

We do that through either a hydrostatic or pneumatic pressure test. The hydrostatic test uses water and the pneumatic test uses air or some other non-toxic gas. The function of the test is to subject to part to the chosen medium in order to locate potential air pockets. In this way, we can make sure the porosity of any part is low enough to meet our high standards of quality.

Part Finishing and Plating

There are two phases of the finishing process to consider: surface finishing and external finishing (or plating). While you will typically always opt for some kind of surface finishing, plating is often reserved for components that either require some kind of decorative finish or where corrosion resistance is a higher priority.

Surface Finishes

The purpose of the finishing process is to smooth out the surface of your part, remove imperfections and generally make sure the part appears suitable for use. There are many different methods for effectively finishing a part. The finishing options we commonly use at Premier Die Casting include:

• Vibratory Deburring: This process uses vibration to remove imperfections and sharp edges from the surface of your part and prepare it for painting or other finishing processes. It is often the finishing process of choice if an operator will be handling the part pre-plate, as it creates smooth edges, as well as removing oils that may end up on the part from the machining process.
• Shot Blasting: Shot blasting is a finishing process involving blasting particles at high speed across the surface to strip imperfections from it. Some part sellers are fond of the appearance of the sandblast finish, which can come in a variety of textures and can finish your part with a bright metal appearance. Other shot blasting options include wheel blasting and air blasting.
• Robotic Sanding/Polishing: Our automated finishing robots can quickly and efficiently sand, brush and polish your part for a smooth and bright finish.

We also have an automated painting process and can apply a powder coating, which adheres the paint cleanly and efficiently through electrostatic attraction, or we can accurately finish with a wet spray-painting process.

Plating

If you need an external finish, or plating, your options include:

• Chromate: A thin coating with tremendous corrosion resistance.
• E-Nickel: Electroless nickel. We can add a nickel coating with no electrical current required.
• Cadmium: A soft white metal plating that has been popular for aerospace applications.
• Silver: A beautiful plating material with low electrical resistance.

Finishing Classes

For your convenience, there are five different classes your finishing requirements may fall into:

• Utility Grade: These parts will probably not be customer-facing and have no cosmetic requirements. Imperfections on the surface are not a concern.
• Functional Grade: These are parts that may have decorative coatings. Any imperfections can easily be spot-polished or painted over.
• Commercial Grade: Used for structural parts in high-stress areas. Slight surface imperfections with some reasonable means of removal are okay.
• Consumer Grade: High-class decorative coated parts with no noticeable surface imperfections.
• Superior Grade: Surface finish applied to limited areas of casting and are alloy-dependent. Superior grade finishes must have a maximum value in microinches, as specified.

At Ustar Die Casting, we take great pride in our quality assurance process and finishing methods. We know that providing our customers with great-looking, high-quality metal parts every single time is what has kept us in business and flourishing for over 70 years. We would love to put our commitment to quality metal workmanship to work for you in your business, whatever your industry.