Top 5 factors affect the investment castings surface quality

Investment casting process has long history, It is the proven technology to economically produce metal parts with low tolerance , complex geometries and superior surface finish, So it is still widely applied in many industries, such as chemical and food machinery, Marine and Aerospace, heat treatment fixtures and etc.

Investment castings can be used directly in most of applications, no need for further machining. Even for mechanical equipment parts which need precision dimensions, the machining allowance is also small, as a result, it saves machining cost. But it’s not easy to achieve extraordinary surface quality,

Today let’s talk about the top 5 factors which have main affection on the surface quality:

1, Tooling quality

Tooling is the first process to make investment castings, its quality is very important, a good tooling interior wall is smooth, all the angels, radius and transition section of structures is smooth too. For special castings used in medical or food industry required extraordinary smooth surface, the tooling must be polished, it’s directly responsible for the fine surface finish of the castings that it will eventually produce.

2, Filled pattern Wax quality

Filled pattern wax must have excellent flow properties and consistent dimensional stability with superior surface finish, so the wax pattern is strong and flexible, no shrinkage and tiny line will be created during the wax is cooled from high temperature.

3,Slurry quality and coating process

Slurry must be heat resistant in order to resist the hot molten metal corrosion, a fine primary coat is critical to the surface finish of castings.  The operation of slurry coating is also important, workers must break up every bubble during slurry coating and then coat the edges, angles, holes, grooves and other important sections with fine brush carefully.

4, The quality of molten metal

The metal before melting must be free of greasy dirt, if further machining or polishing required after casting, return scraps should be used as less as possible.

Rapid slagging and covering thermal insulating agent on molten metal in order to prevent black spot or other oxide on casting surface

5,Shot blasting

Use small grain size stainless steel ball and multi-angle shot blasting machine to shot blast the castings, ensure every spot of castings are cleaned entirely.

Beside the above factors, quality control is the most important. Shinning Metals inspects its products at every stage of the manufacturing process, Our engineers have first-hand experience on how to produce castings with fine surface. This benefit can prevent time and money being wasted as a result of products being rejected, ensure that components can be manufactured to the required standards efficiently and with minimal waste. So we call our castings are cost-effective.

Do you have any trouble with your investment casting surface quality? You are welcome to leave send e-mail to evakong@shinningcorp.com, we are happy to discuss how to solve the problem.