Investment Casting Finishes - Investacast

Investment Casting Finishes

Published - 6th Aug 2020

What finishes are available for Investment Casting?

Regardless of whether you are familiar with the investment casting process, it’s always good to have a helping hand when it comes to choosing the preferred finish for your casting requirements.

There are many different finishing methods available for investment castings, depending on the material being used the finishing can be a critical part of the process to determine its quality and performance. All of which, Investacast are able to provide for you.

Types of Finishes available

Some of the most commonly used finishes are;

Stainless Steel Shot Blast, one of the most common finishes for investment castings, shot blasting is a mechanical post-production finishing service. It uses a rapid impact process onto the surface of the castings with abrasive media, it will remove post casting or heat treatment scaling leaving a uniform even visual finish. This process is faster and more efficient than linishing or fettling for flash or gate removal on investment castings.

Pickle & Passivate is an acid chemical treatment mainly used with stainless steel, which removes any contaminations, scaling or any discolouration. During the process, a passive barrier forms on the metal, this reduces the chemical reactivity of the metals surface. When used on stainless steels, it removes any ferrite from its surface which will prevent any rusting of the metal.

Electropolishing is commonly used to remove a thin layer from the surface of the metal part and leaves a high quality surface, this can improve the surface quality by 50% and is 30 times more efficient than mechanical polishing. Typically used for stainless steel and similar alloys in the food and chemical processing industries. Stainless steel is one of the most common alloys used with electropolishing, but it is also compatible with brass, carbon steels, copper and nickel alloys.

Glass Bead Blast is used to provide a more uniform satin like finish, with a non-directional textured surface. Achieved by high pressure blasting with a silicate glass bead media. No material is removed from the surface of the casting during the process.

E-Cote is an electrophoretically applied paint coating, which was originally developed for the automotive industry due to it being economical and also providing a superior coverage, which is also corrosion resistant. E-Cote can cover any metal that conducts electricity such as, aluminium, zinc, brass and steel.

Light Aluminium Oxide uses a similar process to stainless steel shot blast, but using a more abrasive sand-like media, resulting in less shatter of the particles which produce lower dust levels. Aluminium oxide has a low-iron content, so when used, it will not leave any rust on the surface of the casting. Using aluminium oxide is a cost-effective option to achieve uniform finishes on product.

Powder Coating / Painting is a type of coating which forms a skin over the casting once heated. Using a powder coating is cost effective, environmentally friendly, is tough and produces a high quality finish. Powder coated products are more resistant against impact, moisture, chemicals, ultraviolet light and other extreme weather conditions. It also reduces the risk of scratches, chips, abrasions, fading and other wear and tear issues. A Multitude of colours and textures can be applied by powder coating.

If you would like further information about the content of this blog or to understand more about our casting capabilities, please contact Investacast +44 (0)1271 866200 or email [email protected].

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