What are the Cost Drivers of Investment Casting?
At Aero Metals, we will work with you to provide a proven, cost-effective design strategy that takes into consideration all the key factors within your project. Depending on your specifications, we can design your project with cost-reduction in mind allowing for a better understanding of the overall project cost estimates. Additionally, our high volume production requirements can be met with fully automated multiple cavity molds that provide the capabilities to further reduce costs.
How are Investment Casting Costs Calculated?
→ Design Complexity and Tooling are Key Factors
The following considerations should be examined before deciding on what type of investment casting option is best for your project. While we like to think that anything is possible, it always comes down to what it costs to produce it.
Wax Injection Tooling
Tooling type in order of least tooling cost but highest piece price are as follows:
- Manual (may require some tool modifications)
- Fully automatic
Wax Injection Tooling Treatment Methods
The greater the number of cavities per mold, the higher the tooling cost, but the lower the piece price. Configurations that do not allow metal cores to be drawn must be treated in one of the following manners:
- Collapsible Cores - Where possible will yield the lowest piece price but a higher tool cost.
- Loose Inserts - Only for low volume parts, but not recommend.
- Soluble Cores - Additional wax injection mold and injection labor required. Higher piece price but maintains tolerance control.
- Pre-formed Ceramic Cores - Expensive for specialized shapes and only used as a last resort.
Multi-piece Wax Assemblies
An acceptable method to use on selected configurations. Tolerance control suffers and piece price goes up.
Effect of Pieces per Tree
Within certain constraints, the more pieces per tree the lower the cost. When possible, a part should be designed so that a single gate can feed it. This will generally allow more pieces per tree and reduce the pour weight.
Where possible parts should be designed so that gates can be placed on flat surfaces rather than curved surfaces. Gate grinding tolerances in order of increasing cost are as follows:
- .015 inch gate witness
- Flush to cast surface
- Grind to a dimension
- Radial gate removal
- Shot blast (the least cost method)
- Automatic sand blast (tumbling)
- Hand Sand blast (the highest cost method)
Straightening sometimes cannot be avoided and does add to cost. Try not to specify tighter tolerances for flatness, straightness, roundness, etc., than are required. Straightening costs are directly related to the tolerance specified.
Fixed gages such as “go/no-go” are less expensive than gauges with dial indicators. Whenever gauges are used there should be identical gauges for both Aero Metals and the customer.
- Magnetic particle inspection
- Liquid penetrant inspection
- Radiographic inspection
Certification includes chemical and mechanical test reports as well as marking each casting with Heat Codes for tractability.
With top notch metal casting quality, testing and inspection standards, Aero Metals is a trusted source for premium grade precision investment casting services for a variety of industries.
What Materials are Used in Investment Casting?
Investment casting requires the use of a metal die (usually aluminum), wax, ceramic slurry, furnace, molten metal, and any machines needed for sandblasting, vibratory tumbling (with or without a grinding or polishing media), cutting, and grinding.
Investment Casting Alloy Material Options
Precision investment castings can be created from an almost limitless variety of investment casting alloys. The metals we work with include but are not limited to the following materials.
- Stainless Steel
- Ductile Iron
- Beryllium Cooper
- Nickel-Based Alloys
- Cobalt-Based Alloys
- Copper-Based Alloys