INVESTMENT CASTING PRODUCTION STAGES

Investment casting, also known aslost wax casting,is an advanced metal casting method used to manufacture components withhigh dimensional accuracy and complex geometries. The production processconsists of carefully controlled stages, starting with wax pattern preparationand continuing through ceramic shell formation, metal casting, cutting,finishing, quality control and shipment.

Wax Injection

The first stage of theinvestment casting production processis wax injection. Special casting wax is injected into precision moldsspecifically designed according to the geometry of the metal part to be produced.The injection process is carried out under controlled temperature and pressureconditions to obtain accurate wax patterns.

Thewax injection process is extremely important for achievinghigh surface quality and dimensional accuracy. Injection temperature, pressureand cooling time are carefully controlled so that fine channels, corners,cavities and complex geometric details inside the mold are reproduced accurately.

After removal from the mold, the wax patterns are visually and dimensionallyinspected. Patterns that do not meet the required standards are removed fromproduction, while approved wax patterns proceed to the wax assembly stage.

Wax Assembly

Once the wax injection process is completed, the wax patterns are attachedto a central gating system to ensure an efficient and controlled casting process.The resulting structure is commonly referred to as awax tree or casting tree.

Positioning the wax components on the main runner at the correct angles anddistances is essential for ensuring that molten metal can flow evenly intoall areas of the ceramic mold. A properly designed gating system helps controlmetal flow and reduces the risk of potential casting defects.

In thelost wax casting process, the completed wax assemblyis subsequently coated with ceramic materials to create the foundation ofa high-temperature-resistant casting mold.

Investment casting ceramic coating and ceramic shell formation

Ceramic Shell Building

The prepared wax tree is coated with special ceramic materials to createa mold capable of withstanding high casting temperatures.During theinvestment casting ceramic coating process,the wax assembly is first immersed in a liquid ceramic slurry and thencovered with suitable refractory material.

This process is not completed in a single coating. The dipping, stuccoingand drying operations are repeated several times until the required ceramicshell thickness and mechanical strength are achieved. Each layer is driedunder controlled environmental conditions before the next layer is applied.

The resultingceramic shell must have sufficient mechanicaland thermal strength to withstand the high temperature of the molten metalpoured into it during the following stages. For this reason, ceramic shellbuilding is one of the most important stages affecting investment casting quality.

Investment casting autoclave dewaxing process

Autoclave and Dewaxing

After the ceramic coating and drying stages are completed, the wax patterninside the ceramic shell must be removed. This operation is carried outinside a high-temperature and high-pressureautoclave system.

Under the effect of heat and steam, the wax melts and is removed from theceramic shell in a controlled manner. Once the wax has been eliminated,a hollow ceramic mold remains, accurately reproducing the geometry of themetal component to be manufactured.

This stage is the reason the process is commonly calledlost wax casting. Controlled dewaxing is essential forpreventing cracks, deformation or surface damage in the ceramic shell.After inspection, the dewaxed ceramic molds are prepared for the metal casting stage.

Investment casting molten metal pouring process

Metal Casting

Once the ceramic molds have been brought to the appropriate temperature,the selected metal or alloy is melted and the casting process begins.Molten metal is transferred into the ceramic mold through the preparedgating system in a controlled manner.

During theprecision metal casting process, metal temperature,mold temperature, pouring time and alloy characteristics are carefully controlledto achieve consistent product quality. The molten metal fills the fine detailsof the ceramic mold and reproduces the geometry originally created duringthe wax injection stage.

Depending on application requirements and customer specifications,investment cast parts can be manufactured from stainless steel,carbon steel, low-alloy steels, high-alloy steels and various engineering alloys.After pouring is completed, the metal is allowed to solidify under controlled conditions.

Ceramic Shell Removal and Cleaning

After the cast metal has completely solidified and the required coolingprocess has been completed, the ceramic shell surrounding the componentsis broken and removed. This exposes the metal casting tree and the individualcomponents attached to it.

Theceramic shell removal process can be carried out usingmechanical methods, vibration systems or other suitable cleaning techniquesdepending on production requirements. Any remaining ceramic material onthe component surfaces or in difficult-to-reach areas is also removed.

At the end of this stage, the casting tree and metal components are fullyexposed. The surfaces are then subjected to preliminary cleaning operationsto prepare the parts for cutting, finishing and subsequent manufacturing processes.

Investment cast parts cutting from the gating system

Cutting and Finishing Operations

Once the ceramic shell has been completely removed, the metal componentsare separated individually from the main gating system.During theinvestment casting cutting process, appropriatecutting equipment and methods are selected according to the geometryand dimensions of the components.

After cutting, remaining gate connections and excess material are removedusing grinding, deburring or other finishing processes. Depending on productrequirements, additional operations such as shot blasting, surface cleaning,heat treatment, CNC machining or other secondary processes may also be applied.

During final inspection, the dimensions, surface characteristics and conformityof the components with technical specifications are evaluated. As a result,ready-to-useinvestment casting parts suitable for applicationsrequiring high precision and complex geometries are obtained.

Quality Control, Packaging and Shipment

After production and finishing operations are completed, the componentsundergo quality control procedures before shipment. Depending on technicaldrawings and customer specifications, dimensional inspections, visual surfaceinspections and other required quality checks are performed.

Approvedinvestment casting products are packaged usingsuitable methods to protect them from damage during transportation and storage.Depending on the geometry, weight and shipping requirements of the components,boxes, crates or pallet systems may be used.

In this way, thelost wax casting production process,which begins with wax injection, is completed with quality control,packaging and shipment. Thanks to carefully controlled production stages,metal components with complex geometries, excellent surface quality andhigh dimensional accuracy can be delivered to customers ready for use.