The Magic of Investment Casting
Investment casting has a long history, which allows creating high precision components with minimal surface defects. It requires molding a wax pattern, casting it in ceramic shells, removing the wax to form an empty space and eventually filling up that cavity with molten metal. After solidification of the metal, the ceramic shell is removed leaving the finished part with very limited post-processing.
Investment Casting Process at CFS Foundry: A Step-by-Step Guide
Investment casting process in CFS foundry is operated with the most advanced technology in China. We can produce top level investment castings in a variety of dimensions and shapes. In this process, all metal alloys are available, we can customize investment castings according to your material specifications,and even material compositions is feasible for production. To ensure the best quality, we will do quality control in each investment casting process. Below is the steps of a whole investment casting process in our foundry:
Step 1. Tooling Making
To achieve precision products, making tooling is the first step to start investment castings. Such tooling or pattern will be precision machined by CNC center. So tooling cost will be charged from our customers when sample order of a new product is placed. But it is just one-off paid, and we will not ask for this fee for further orders.
Step 2. Wax Injection and Pattern Assembly
After a pair of casting patterns is completed, we will first make wax pattern, such wax pattern is obtained by injecting wax into the pattern. And you will see a model with the same dimensions of desired products. Again, we will repeat the injection job for more wax patterns. Then assemble these wax patterns onto the sprue. Finally hang these pattern assemblies in the room temperature for drying.
Step 3. Shell Building
In this step, the pattern assembly will be dipped into a ceramic slurry, and coated with a refractory material. This process needs to be repeated several times until reaching a certain thickness and strength. Thus, the cetamic shell is built and then dried in an atmospherically-controlled environment.
Step 4. Dewaxing
Placing the shell in a steam autocalve and rapidly heated, so that the wax will be melt and run out through the gate and pouring up under high temperature.The ceramic shell molds must be fired to burn out the last traces of pattern material and to preheat the mold in preparation for casting, usually in the range of 1,600-2,000 degrees Fahrenheit. So investment casting also named as “lost wax casting”.
Step 5. Casting
Casting is the key step in the whole investment casting process. After dewax, we will first melt the steel ingots into liquid status, and pour the liquid metal into the sprue, then cool it under room temperature for a while.
Step 6. Knock out
Break the ceramic shell, and cut the individual investment castings from the sprue. Finally remove the excess metal from casting body by grinding.
Step 7. Heat Treatment
To improve the mechanical properties of casting blanks, heat treatment is usually done after finishing castings. Main heat treatment processes are: Normalizing, tempering, annealing, hardening and tempering, carburizing, ect. Pls note, heat treatment is operated only when customers have such requirements, and extra cost will be counted.
Step 8. Shot Blasting/Sand Blasting
To remove scales and achieve better surface finish, investment castings will be shot blasted or sand blasted by small steel balls.So all the foundries must be equipped with shot blasting machines.
Step 9. Surface Treatments
To protect products from rusting, castings will be dipped into anti-rust water or oil. Of course, other surface treatments can also be performed in this step like paint spraying, galvanizing, etc.
Step 10. Inspection
Inspection is also a necessary step for quality investment castings. Our engineer will do dimensional inspection, 100% surface inspection, inner defects inspection and other inspection jobs according to requirements of products. Only ensure all the products are qualified, can we arrange delivery to our customers.
Step 11. Package
As all the products are exported to overseas market, so, normally we will pack investment castings with ploybags, and then put them into standard wooden cases. Of course, all the package must be carried out on the basis of free from damage. We can also supply custom package service according to customers’ special requirements.
Advantages of Investment Casting Process
1. Excellent Detail and Accuracy:
Investment casting is a process that makes parts with incredible detail and precision. This procedure enables complicated geometries, undercuts, and complex forms that can not be achieved with other casting methods. Secondly, it can also provide parts with high dimensional accuracy that reduces the secondary machining.
2. Superior Surface Finish:
Investment casting includes the production of a smooth surface finish, typically better than other castings. Superior surface finishes minimize the requirement for further treatment or finishing processes thus ensuring savings and quick production runs.
3. Material Versatility:
Investment casting works for entirely different types of metals and alloys including steel, stainless steel, aluminum alloys, bronze and many others. The malleability of materials enables you to pick the best one that will meet all needs for specific qualities in your finished product including strength, heat resistance or corrosion corrosion.
4. Suitable for Complex and Intricate Designs:
Rather than relying on other manufacturing processes, the investment casting process is a perfect choice if one wants to manufacture that complicated and complex part. This is achievable since the entire process employs a wax pattern and ceramic mold which allows it to attain a high level of detail while stipulating specific complexity.
5. Cost-Effective for Small to Medium Production Runs:
Indeed, investment casting is especially budget-friendly when applied in small to medium runs. Fewer steps and less waste are required in this process when compared to other procedures. Although the initial tooling cost can be high, it is usually compensated for by lower per-piece costs in production.
6. Produces Near-Net-Shape Parts:
The investment casting technology also has a reputation for developing near-net shape parts. This indicates that a component requires significant or little additional machining or finishing after the casting process, which eliminates time and money costs. The technology proves even more beneficial for complex-shaped elements or components made of hard materials that turn out troublesome to machines.
In conclusion, the investment casting method offers a number of advantages that make it an effective substitution in many industrial scenarios. Investment casting is a highly accurate manufacturing process and has a large range of variations as far material options are concerned along with the ability to generate finest details in components.
Tips on Selecting Investment Casting Process
Investment casting is a very efficient manufacturing method that may deliver even impressive results. However, it is essential to implement the method critically in order to ensure that the process conforms with your project’s needs. Here are some tips on selecting the investment casting process, specifically considering CFS Foundry as your manufacturing partner:
1. Evaluate Your Design Needs:
The first step is to evaluate your part’s design. Investment casting is particularly suitable for complex and intricate designs that other methods struggle with. Look at the complexity, details, and features of your design to determine if investment casting is the best choice.
2. Consider the Material:
CFS Foundry is able to work with different types of metals and alloys, which gives the advantage that you could choose for your project a material that best meets its needs. When choosing the material, take into factors like strength, heat resistance and corrosive materials into consideration.
3. Assess Production Volume:
Investment casting thereby is cost effective when it comes to production run whether the product can be considered as small or large in quantity. Conversely, the outlays for mold making may be also high and this is more effective way to create an efficient wax pattern. Check the volume of production and share it with CFS Foundry’s team to see if what was done corresponds with your budget.
4. Consider Lead Time:
Although CFS Foundry is renowned for its efficiency, the investment casting process involves several stages which would have to be completed over a period of time. Ensure that you talk to the foundry about your project’s timeline and make sure they can meet it.
5. Review Post-Processing Needs:
While investment casting ensures high surface quality and dimensional accuracy of the products, some projects may need post-processing techniques like machining, heat treatment or special types of coatings. These services are provided by CFS Foundry – make sure to consult us regarding your post-processing requirements in order that we will be able to satisfy such demands.
6. Partner with an Experienced Foundry:
CFS Foundry is very professional and has a solid background in investment casting. We know how to guide you through it, providing advice on design optimization and material choice. In addition to providing quality results, partnering with a reliable foundry such as CFS will ease project management.
Considering these factors combine you can effectively make a decision whether to use investment casting process and partner with CFS Foundry or not. Our focus on quality, customer support and technology ensures us that we are the best choice for your investment casting requirement.