How to Save Money When Buying stainless steel investment casting parts

Stainless steel investment casting is an excellent method for producing affordable, high-quality parts suitable for sensitive applications. When considering the need for custom stainless steel parts using the investment casting process, it is crucial to evaluate the information a manufacturer requires, as well as the factors that influence costs and turnaround times. By being informed about these details in advance, you will be better positioned to set your project up for success.

Cencho contains various products and information you may need, so please explore it.

Considerations When Ordering Stainless Steel Investment Castings

Preliminary Design

Maximize the benefits of the stainless steel casting process and reduce costs by including specific details such as:

• Minimum section thickness: A casting's desired rigidity and strength determines its minimum thickness. Typically, a stainless steel investment casting should be no less than 3mm thick.
• Draft: Drafts are the tapers on the vertical faces of a pattern that facilitate the removal of the pattern from a mold without damaging its walls.
• Cores: Cores create hollow spaces within a stainless steel casting and may be additional components placed inside a mold to produce a cavity when the mold alone cannot create it.
• Parting line: A straight parting line simplifies the production of molds and patterns, making them easier and less costly to manufacture.

Patterns

Manufacturers utilize wax patterns to create molds, referred to as investments. A casting's quality, particularly regarding finish and tolerances, largely depends on its pattern. Clear communication about pattern design and production will help avoid misunderstandings and provide a clearer understanding of associated costs.

Quantity

It is essential to specify the quantity of parts needed, as this affects the type of tooling required. It also impacts a stainless steel foundry's capability to fulfill your production volume. Some foundries specialize in short-term, short-run projects, while others focus solely on high-volume production.

Specifications

Specifications represent essential requirements for the stainless steel investment casting process as outlined by ASTM International. Adhering to these standards is advisable to avoid increased costs, potential misunderstandings, and exclusions from suitable foundries.

Foundries may employ heat treatments to standardize and improve the material properties of stainless steel. The solution treatment method commonly optimizes the internal structure of products, benefiting future machining operations.

Soundness

The soundness of a stainless steel component refers to the level of discontinuities or impurities, such as shrinkage or sand inclusions. It is crucial to define acceptance and rejection criteria with the foundry before production.

Testing and Inspection

Post-production, an investment casting manufacturer should test the stainless steel castings to ensure they meet specifications, including surface finish, physical properties, internal soundness, and dimensional accuracy. Establish clear testing and inspection requirements with the manufacturer before production begins. After completing tests, manufacturers may either ship the stainless steel investment castings or subject them to further processing.

Weight

The cost of materials increases with the weight of a stainless steel investment casting. Providing detailed weight-related information will yield a more accurate quote from manufacturers, who are interested in both gross and net weights.

Machining

Machining involves removing excess materials from a stainless steel casting to ensure dimensional accuracy. Allocating material for machining allowance facilitates achieving tight tolerances. Evaluate the casting design initially to determine if the machining specifications are feasible.

Schedules: Production and Delivery

Your required turnaround time for short and long-term needs will narrow down the foundries capable of accommodating your request. When requesting a quote, consider the following aspects that affect turnaround times:

• Commercial considerations
• Pattern construction and modifications
• Tooling production
• Sampling
• Inspections
• Full production setup
• Production
• Post-production processes
• Logistics and shipping

CFS boasts over 20 years of experience in producing ISO-certified stainless steel investment castings. We guide you through every phase of the investment casting process, from design to delivery. Our specialists assist you in achieving the most economical solutions tailored to your needs and oversee your project diligently. Contact us today to discover how CFS can fulfill your stainless steel investment casting requirements.

Related Article: How Stainless Steel Casting Compared to Iron Casting?

Every metal casting is unique, but these nine factors significantly influence casting prices.

1. Material

The type of metal used plays a substantial role in cost. General alloy prices vary from metal to metal, with precise prices fluctuating daily.

Moreover, material weight influences costs when considering labor and transportation.

Aluminum

At Batesville Products, we cast aluminum A356, which serves over 70 industries, is food and medical safe, and can be heat-treated, anodized, and coated for versatility. Additional advantages of aluminum include its lightweight nature, strength, flexibility, corrosion resistance, conductivity, heat transfer, and recyclability.

Zinc

At Batesville Products, we cast ZA5 and ZA12, which are ideal for parts requiring additional weight, such as a dental chair base. For aesthetically demanding parts, zinc can also be mirror buffed or chrome plated.

2. Design for Manufacturing

Designing with the manufacturing process in mind saves time and thus reduces costs. Your design should align with the manufacturing capabilities to maximize manufacturability and eliminate unnecessary operations.

Refer to this design guide to assess if your design is casting-ready.

3. Order Quantity

Each casting method requires a mold (tooling). The tooling type is generally driven by your Estimated Annual Usage (EAU). Aligning your EAU with the casting method optimizes your return on investment by balancing tooling costs and piece prices.

For instance, if you plan to produce ten parts a year, investing in a $50,000 die-cast mold would be impractical. Conversely, producing 100,000 parts annually would yield an excellent return on investment for a die-cast mold.

Permanent mold casting is ideal for moderate-volume production, with tooling costs typically situated between those of sand and die casting. This method often results in lower porosity and superior surface finish.

4. Part Complexity & Size

The complexity and size of a part can escalate tooling costs or incur additional operations and manufacturing expenses.

Pulls, Cores, and Inserts

Incorporating cast-in features like logos or inserts can conserve machining and assembly costs. For example, steel tubing could be integrated during casting rather than added as a secondary operation.

If minimizing secondary machining time is necessary, sand cores or pulls can create hollows, though they may elevate tooling costs.

Multi-Cavity Mold

Setup charges, cycle time, and labor all impact casting prices. Depending on your part's dimensions, you might maximize efficiency by accommodating multiple cavities within a single mold, effectively doubling output. While this increases tooling costs slightly, it enhances efficiency significantly without necessitating two separate molds.

1 Mold Makes 2 Different Parts

Special circumstances might allow you to halve your tooling costs. If you need to manufacture two similar products with minor differences, instead of creating two tools, you could buy one tool that casts a generic version. A secondary machining process could then tailor this generic casting into two distinct parts.

5. Secondary Machining

A secondary machining operation is typical for refining a casting and ensuring all essential specifications are met. Machining from a near-net shape casting is more economical than machining from stock and welding components together.

However, machining costs can escalate if tolerances are extremely tight. If your tolerances exceed what the casting process can accommodate, you may need a more elaborate secondary machining operation, increasing spindle time and costs.

Custom fixtures often add to tooling costs, and complex machining operations may require multiple machining steps, each needing its own fixturing. Ultimately, aim to craft the as-cast part as closely as possible to the final product to minimize secondary operation expenses.

6. Mechanical Properties

You can implement secondary operations to enhance your casting's mechanical properties.

Heat Treat

Heat treatment involves heating already cast parts to high temperatures and systematically cooling them to boost material strength and hardness, decrease stress, enhance stabilization, improve machining capabilities, or alter their properties.

Impregnation

Casting impregnation seals all porosity (including microscopic porosity) in castings, ensuring they are leak-free and pressure-tight.

7. Inspection

When obtaining a quote, inquire about the inspection types included. Clearly highlighting key specifications and establishing expectations between the supplier and customer is vital. At Batesville Products, we provide a First Article Inspection (FAI) at no additional cost and have quality procedures to prevent defective products from reaching customers.

Additional inspection costs could encompass:

• PPAP (varying levels at varying costs)
• Certifications
• Liquid penetration testing
• Pressure testing
• And various lab testing options

8. Surface Finish

If the part is concealed within assembly, you might economize on finishing unless specific enhancements for corrosion resistance, insulation, or conductivity are required. For highly visible, aesthetic products, multiple surface finish options are available:

• As-Cast - Permanent mold castings generally have a high-quality 200-420 RMS finish.
• Grit Belt Polishing - Polishing with varying grit strengths produces finer surfaces.
• Stainless Steel Shot Blast - Shot blasting results in a consistent, textured surface.
• Mirror Buff or Plated - Makes zinc products reflective and shiny.
• Power Coat or Paint - A colorful finish that can also enhance insulation, conductivity, or protection.
• Chromate - Increases conductivity of parts.
• Anodize - Provides additional protection against corrosion.

9. Packaging

When reviewing quotes, take note of packaging and shipping options included. Communicate your expectations for packaging and shipping upfront to avoid unexpected fees, especially if custom packaging is required.

• Will you supply the packaging, or do you expect the supplier to provide it?
• Should each product be individually wrapped?
• Do powder-coated products need extra protection?

Consider reusable and returnable dunnage options, which can significantly reduce costs. Some customers send us crates that we fill with their products and return for repeated use.

Get a Free Quote!

Contact Batesville Products today for a free quote on permanent mold casting. With over 75 years of experience in casting, machining, and polishing aluminum components for various industries, we are ready to assist you.

For more information on stainless steel lost wax cast, feel free to reach out to us.