What is investment casting?
Investment casting,also called lost wax casting,is a precision casting process to make net shaped metal parts from liquid steel water.Although the investment casting process has been lasting for many years,for its low production cost,high precision and short lead time,people are still using this technology to make the metal parts they need.For its close tolerances of investment castings,it allows for the highest level of finished shape requirements of all the casting methods. Investment casting can limit or eliminate the need for machining operations after the casting process. Using the lost wax process, multiple high quality molds are created and attached together to form a tree. Molten metal is poured into a runner which then feeds into each of the cavities.
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Investment casting expanded greatly worldwide to meet growing demands for aircraft engine and airframe parts. Today, investment casting is a leading part of the foundry industry, with investment castings now accounting for 50% by value of all cast metal production in China.For price advantages(It is cheap to buy investment castings from China)more and more investment casting purchasers send their PO to Fly investment casting foundry in Ningbo.
What materials of investment castings are used:
Carbon Steel
Alloy steel
Stainless steel
Aluminium alloys
Ductile iron
Gray iron
Investment Casting Process - Overview
Prototype and low quantities of metal investment castings are typically produced from a tooling master and specialty wax patterns. The process can yield production accuracies of +/- .005 inch/inch (.13 mm). Production molds used to manufacture metal investment castings are commonly made using either ceramic or plaster. The ceramic mold is fired in a furnace to drive out moisture. In both processes the wax is liquefied and burns off.
Investment castings are well suited for both long and short runs, and are typically recommended for applications in which fine detail, design complexity and accuracy are required.
The metal casting manufacturing process is also known as lost wax. Today it is often used to rapid prototype metal parts. The investment casting process begins with an investment casting pattern typically made of custom-formulated foundry wax. Wax as a pattern media is a used universally throughout the investment casting and jewelry industry. Quality formulations of wax provide a stable and accurate pattern media. A high quality wax will leave no ash after burn out to contaminate the metal casting. When fired the wax pattern will liquefy and completely melt out of the mold leaving a hollowed out form representing the final part geometry. Molten metal is poured (cast) into the mold, forming the final part. The metal part is then ready for machining and finishing operations.
The Mould
The majority of our metal casting starts with a flexible silicone mould of the object. These can produce upwards of 100 wax replicas before the mould starts to deform.
The Wax
A hollow wax cast is taken using a high quality green casting wax. All wax is new, never re-used which ensures a consistent, bubble free surface. The thickness of the wax is very important; too thick or too thin and the finished metal cast can crack when cooling.
We clean the wax and remove any seams left by the joints in the silicone before passing it to the foundry for investment casting.
Casting
The foundry "invests" the wax cast by dipping it repeatedly in a ceramic shell mixture which gradually cures to produce a tough shell. When hardened this is placed in a kiln or autoclave (depending on the nature of the project) which burns or melts out the wax leaving a hard, heat resistant mold.
Whilst the ceramic shell is still hot the hot metal is then poured into the ceramic shell. When cooled the shell can be broken off to leave a metal cast of the original.
As a fine art fabricator we tend to use partner-foundries to complete the hot metal work for our waxes. This enables us to use the appropriate foundry and appropriate method depending on the metal and grade of casting required. We like to tailor the foundry to the cast so we are able to offer everything from cheap multiples to fine art bronze work to ultra high-end, aviation standard castings. We can offer a range of services few dedicated foundries can offer and due to our close working relationship and large volume of work we are able to offer good discounts on their one-off prices.
We undertake most of the finishing works in-house including: post treatments - the removal of stray flecks from the cast, manually cleaning and polishing the works.
Patination and Treatments
We offer simple selection of patination techniques. Please enquire for details. We are also able to offer a series of surface treatment jobs,like powder coating,painting,ect.
Products Application:
Fluid and chemical machinery, sewing and garments machinery,food processing machinery, packing machinery, printing machinery, agricultural machinery, hardware and tools, medical apparatus, measuring equipment, hydraulic and pneumatic equipment,metal parts of electrical and electronic equipment, telecommunication equipment, power supply engineering works, machine tools, heat treatment equipment, kitchen utensils, internal-combustion engine,oil&gas industry, building and dwelling hardware, precision instrument, marine equipment, auto parts and the equipment related to aviation and astronomy