The Benefits of Stainless Steel Investment Casting
Suppose you want to manufacture a robust product. In that case, you sometimes need a specific component—with corrosion resistance, high dimensional accuracy, smooth surface finish, complex geometries, and a high level of detail.
If you don’t find it fast, you’ll struggle with higher maintenance costs, expensive machine downtime, and customer complaints.
Your solution might be stainless steel investment casting. They’re the go-to answer for many manufacturers.
Table of Contents
What is stainless steel investment casting?
Stainless steel investment castings are components manufactured through the investment casting process.
This process begins with a wax pattern created using a 3D CAD model. The wax pattern is then used to create a ceramic mold. This mold is used to produce the stainless steel investment casting. (We’ll explain more in a moment).
What industries use stainless steel investment casting?
Stainless steel investment casting can produce good surface finishes, complicated shapes, a high level of detail, and corrosion resistance. These features are essential for many industries, including:
- Food Processing
- Desalination Plants
- Pump Manufacturers
- Machinery Producers
What are some common parts made of investment castings?
You can use the investment casting process to produce turbine blades, medical equipment, firearm components, jewelry, golf club heads, gears, pulleys, valve components, doorknobs, medical tooling and equipment, auto parts and components, airplane parts, kitchenware, utensils, cookware, gearbox cases, automotive cylinder heads, cylinder boxes, pipes, tubes, assemblies, plus many other machine components — anything with complex geometry benefits from this technology.
Check out this TFG investment cast Chain Sprocket used in the logging industry.
Who profits most from investment castings?
You’ll get the most significant advantage from using investment castings if your part:
- has a complicated shape that would be difficult or impossible to produce with other casting methods
- requires exceptional surface qualities
- needs tight tolerances
- prefers minimal surface finishing or machining after casting.
What are the benefits of stainless steel investment casting?
Stainless steel is a common material for industrial and commercial castings because it offers excellent mechanical properties and corrosion resistance, making it long-lasting in harsh environments.
The Federal Group (TFG) has extensive experience manufacturing stainless steel investment castings from various alloys to get you the corrosion resistance, mechanical properties, and part geometries that perform best in your application. You’ll derive the following benefits:
- Corrosion resistance—for fasteners in demanding environments.
- Heat resistance—outstanding performance at elevated temperatures.
- Precision tolerances—not possible with other manufacturing processes.
- High level of detail—including fine undercuts and threads.
- Superior surface finish—as good as or better than machined parts.
How does the investment casting process work?
Investment casting is thousands of years old. “Investment” refers to the mold being filled or invested with metal. Investment casting was initially used to produce decorations, religious figures, and jewelry. Today, this process makes intricate parts for many industries with brilliant, smooth finishes out of solid and corrosion-resistant metals. Here are the steps:
- Create the pattern. The pattern defines the geometry of the finished part. It’s made of wax. Typically the wax is molded in a metal die created using a 3D CAD model. But, for very short runs, we can machine the wax directly.
- Build the tree. We attach several wax patterns to a wax rod to create a tree structure.
- Make the shell. We dip the tree into a ceramic slurry and allow it to dry. Several dipping and drying cycles are used to build a robust ceramic shell for the rest of the process.
- Remove the wax. The shell is turned upside down and heated. The wax runs out (that’s why it’s sometimes called lost wax casting). Then the shell goes into a high-temperature furnace to burn off any remaining wax and to strengthen the shell.
- Cast the metal. Molten metal is poured into the shell. The tree we built in the second step defines where the metal goes. Now a metal part exists where each pattern used to be.
- Remove the shell. The ceramic shell is broken away, leaving the tree structure—now only of metal
- Finish the parts. Parts are carefully cut from the metal tree structure. These parts are ground, polished, and machined into the final form.
- Inspect the parts. Dimensional inspection and non-destructive testing (NDT) are performed to guarantee conformance to all required specifications.
How does investment casting compare to other forms of casting?
Your goal as a manufacturing professional is to develop a part that produces the desired function, has the desired appearance, conforms to customer requirements, and has the lowest final cost at a given production volume.
Here’s how investment casting compares to three other metal casting processes:
- Investment Casting: excellent (tight) tolerances, excellent surface finish, suited for low to medium volumes. Uses a precision ceramic mold.
- Shell Mold Casting: fair tolerances, good surface finish, suited for medium volumes. Uses heat-bonded sand patterns and cores.
- Greensand Casting: poor tolerances, fair surface finish, suited for low-medium volumes. Uses a clay-like substance to bond sand particles together.
- Permanent Mold Casting: good tolerances, very good surface finish, suited for medium to high volumes. Uses a permanent mold (generally made of steel or cast iron) reused repeatedly.
The information above aims to give you an overview of the process. The complexity of your part and the alloy you need will help you determine your best choice.
Visit our investment casting capabilities page for more information.
Which investment casting manufacturers are best?
Pick a manufacturer not tied to any one metal fabrication technology—one that has a team to guide you through your entire decision-making journey.
Find one that will help you balance out tooling and labor costs against the mechanical and aesthetic requirements of the part—a team of experts to help you understand the lowest final cost of the component at a given production volume.
TFG can help you “do the math.”
Why do they call it “investment” casting?
Investment means to envelop or surround. The ceramic slurry surrounds the wax pattern to produce the casting mold. So that’s how we get the name investment casting.
Why is precision investment casting so expensive?
Tooling and labor costs are moderate and high, mainly due to the time consumed for the dip-and-dry cycles for the ceramic slurry.
But, if you need complex part geometries and excellent surface finishes, investment casting will give you what you need without spending time and money on extensive post-casting finishing operations.
It’s a balancing act, but many manufacturing professionals recognize the benefits of stainless steel investment castings.
Contact TFG to help you understand and weigh all the factors.
How do I find the right investment casting supplier?
Partner with a supplier who has the heart of a teacher—someone who can help you learn the pros and cons of the many metal fabrication technologies—the costs and the benefits. Then you can make your own informed decision and pick a solution that satisfies both your accounting department and your customer.
Leverage our technical abilities by tapping into our contract manufacturing engineering and manufacturing support.
Let The Federal Group be your sounding board so you can make your best decision.
Invest in your future. Learn more…
Whether you’re exploring options for a new product or you have an existing product that you’d like to put into production, The Federal Group USA can help you with your next stainless steel investment casting project. We’ve provided high-quality metal fabrication services to a wide variety of industries for more than 40 years. Contact us today to request a quote.