Manufacturing Process

Manufacturing Process

1. OEM part identification

2. Modeling and drawing

3. Casting engineering

4. Rapid Prototyping

5. Tooling

6. Investment Casting

7.Machining

8.coating

9.Quality Control

1. OEM part identification phase

In the first stage, a number of used or new parts are received from the client. The more the number of parts, the more accurate data will be extracted. The following inspections will be carried out on the parts.

- Sampling and determination of the Chemical Composition of main part.

- Sampling and determination of the analysis of the coating.

- Metallographic analysis to investigate the microstructure.

- Macro etch and determination of grain size.

- Hardness Analysis.

- FPI (Fluorescent penetrant inspection) testing to detect surface defects

- RT testing to detect internal surface

- laser scanning for extracting cloud of point

- CMM (Coordinate Measuring Machine) measurement for more precise dimensional inspections

2.  Modeling and drawing

The 3D model will be designed after obtaining the dimensional data including the cloud of point analysis, CMM measurements, etc. In this step, the final models and drawings of machining part, Casting part, ceramic core, insert and other component is designed.

3. Casting Simulation

The production of casting part is a time-consuming and expensive process that may sometimes result in the production of a part with metallurgical defects. To prevent such defects and save time and cost, simulation of the casting process is performed before production.

In casting simulation, stress, thermal, and fluid analyses are performed. The results of these analyses provide useful data, which are presented below.

Based on the results obtained from the simulation, the gating system is optimally designed, and changes may be made to the initial casting model. The simulation process is repeated until the casting parameters, including melting temperature, shell thickness, and the design of the gating system ant etc., are optimized.

Based on the obtained data, all casting parameters are set with high precision. These parameters will be provided to production stations in the form of special forms

4. Rapid Prototyping

Before the production of main tools, including wax injection molds, setter molds, ceramic core molds and machining fixtures the first samples are produced using rapid tooling and rapid prototyping. In this method, the sample is produced using 3D printers from material that can be easily cast.

Rapid tooling such as Low melt alloy and Alufix are also used as fixtures for milling and turning processes to investigate the machining process.

5. Tooling

In order to manufacturing part by investment casting, machining, and finishing processes, special molds and fixtures are required. High quality product is the result of high-quality tools. Therefore, the design and manufacturing of tools, especially in the field of gas turbines, require high technical knowledge. The following are some of the tools required in the processes of investment casting, machining, and finishing.

.

6. Investment Casting

Investment casting, also known as precision casting, is a process used to manufacture specialized metal components. In this method, the mold is created by layering expendable patterns with ceramic slurries and powders. The pattern (usually made of wax) is then removed from the mold by burning or melting it out.

Due to its unique features, the investment casting method is the only method for producing many gas turbine components such as nozzle vane and rotary blades. These features are as follows:

- The ability to produce mass quantities of complex-shaped parts that cannot be produced by other casting methods.

- The ability to repeat the production of parts with dimensional accuracy and high surface quality so that it is possible to produce parts with minimal need for machining and finishing operations.

- A wide range of produced alloys.

- possible to produce parts with better metallurgical properties.

- The possibility of using molds for casting in a vacuum (for special alloys that need to be cast in a vacuum such as nickel and cobalt-based superalloys)

- The ability to produce parts with complex geometry that cannot be produced by machining.

- High repeatability in production with high cost and time savings.

1. 1. Ceramic Core Production

Since many gas turbine components have internal cooling channels, ceramic core technology is used to create these internal surfaces.

ceramic injection molding (CIM) involves the injection of special ceramic paste into molds to produce ceramic cores. The green ceramic cores are placed in an alumina powder box to be debinded and sintered in an electric furnace.

Ceramic Core Quality control:

1. 2. Wax Pattern Production

the main method for producing a lost model is wax injection into metal mold. The wax model is a same replica, of the final metal part.

If the part has internal cooling passages, it is necessary to first place the ceramic core inside the injection mold.

Then, the wax models are removed from the mold and placed in a setter to prevent any changes in overall shape. Additionally, at this step, other wax components such as gates, runners, and other necessary items are injected.

1. 3. Wax model cleaning:

After the wax model is completely frozen, it undergoes a cleaning process. the existing flash in the parting line is removed, and if there are any surface defects on the wax model, they will be corrected.

1. 4. Assembly (wax tree):

the wax feeds are assembled onto the wax model and then installed onto the sprue. The assembly process is carried out based on the designed gating system. The wax tree is also cleaned again.

1. 5. Ceramic Mold Production

A ceramic mold is made by applying layers consisting of slurry and ceramic powder on a wax assembly model. To produce a uniform shell molding, The wax tree is first dipped into a ceramic slurry, then withdrawn from the slurry, and manipulated to drain off excess slurry. The wet layer placed under the rain of sand with ceramic particles. After drying the process of slurry dipping, stuccoing, and hardening are repeated several times, until the required shell thickness is achieved.

1. 6. Removal of Pattern

In order to remove the wax from ceramic molds, they are subjected to autoclave or flash fire processes.

1. 7. Mold Firing and Burnout

Green ceramic Shell are fired to sintered and strengthened. Also, this step is to remove moisture and burn off residual pattern material.

1. 8. Ceramic Mold Inspection

Non-destructive analyzes on molds and destructive analyzes on accompanying samples are performed in order to guarantee the quality of ceramic molds.

1. 9. Wrapping

Wrapping Process of ceramic molds is done in order to control heat transfer and solidification process to adapt to the simulation conditions with optimum microstructure and mechanical properties. Wrapping is done by ceramic wool (Blanket) which acts as thermal insulation.

1. 10. Casting

At this step, ceramic molds are placed in a preheated furnace in order to prevent thermal shock. Casting of nickel and cobalt base supper alloy is done in vacuum induction furnaces. For this purpose, the virgin ingots are charged in the furnace and after melting alloy, the preheated ceramic mold should be transferred into the VIM mold chamber the casting process is done under vacuum.

1. 11. knockout &

The cooled molds are knocked out by a pneumatic hammer to break the shell molds. Then, the metal tree are transferred to the cutting station to separate the parts from the gate and runners. Afterwards, grinding is performed to remove any remaining feed. For components with ceramic cores, the parts should be leached out by high-temperature alkaline chemicals and water-jet pressure.

1. 12. Finishing

1. Sand Blasting
2. Ultrasonic cleaning
3. Nickle Blasting
4. Ceramic Peening
5. Grinding
6. Welding
7. Brazing
8. Heat Treatment:

7. Machining

After the casting part is prepared, it is necessary to carry out the machining process in order to create parts with the final dimensions according to the defined tolerance.

In the following, the usual machining process of gas turbine blades and Vanes are presented.

8. Coating

In order to increase the durability, thermal, corrosion and wear resistance, many parts of gas turbines are coated with specific materials.

Badr engineering system factory, many coatings such as HVOF, APS and CVD can be implemented .