Almost any metal part can be converted to an investment casting. Conversions generally allow for weight reduction opportunities, reduced machining, elimination of draft angles, and increased design flexibility. Castings can be converted into any alloy, allowing for virtually unlimited mechanical properties.
Candidates for casting conversion include metal parts that are otherwise difficult or impossible to machine, castings with highly complex internal geometries, and expensive alloy types that produce extensive waste using other manufacturing methods.
Depending on part complexity and desired production rate, investment casting is not always the best option. The following comparison guide can help you determine if investment casting conversion is right for you.
Investment Casting vs. Machining
- Parts that previously required welding or mechanical fastening can be condensed into one solid investment cast
- Near net-shapes eliminate or reduce secondary operations
- Quicker product turnaround and significant cost savings in labor and tooling with investment casting
Investment Casting vs. Forging
- Investment casting surface finishes eliminate forging parting lines and pitting
- Investment castings offer uniform internal stresses
- Forging process causes directional stresses
- Forging tooling is generally more expensive
Investment Casting vs. Die Casting
- Similar surface finishes
- Similar reduction in machining operations
- Investment casting tooling is considerably less expensive
- Die casting is also quickly worn down, requiring additional maintenance costs and labor
Investment Casting vs. Permanent Mold Casting
- Similar surface finishes
- Permanent mold casting requires draft angles; investment casting does not
- Investment casting requires less machining
- Similar tooling costs
- Permanent mold casting necessitates additional tooling maintenance
- Permanent mold castings are primarily available in non-ferrous alloys; investment castings offer unlimited alloys
Investment Casting vs. Stamping
- Investment casting provides greater design flexibility than stamping
- Decreased tooling and maintenance costs with investment casting
- Repeatability is similar for both processes
- The stamping process does not allow for thickness variations
- Investment casting allows tapering and large variations in wall thicknesses
Investment Casting vs. Powder Metallurgy
- Investment casting generally offers a superior surface finish and tighter tolerances
- Powder metallurgy can sometimes be more cost-effective for simple shapes, unless secondary operations are required
- Powder metallurgy shrinks during sintering, causing larger variations in cast dimensions
Investment Casting vs. Weldments
- Weldments are sometimes cheaper from a tooling perspective, but lack consistency in design
- Investment casting provides significantly tighter tolerances, as well as more complexity in part geometry.
- Weldments are weaker due to stress rises at welding points. Weldments compensate by reinforcing cross sectional areas, resulting in additional costs
Investment Casting vs. Sand Casting
- Pound for pound, sand casting is cheaper, and is a great alternative for large production runs of simple parts
- Parts requiring tight dimensional tolerances or fine surface finishes are cheaper when investment cast
- No need for tapering or draft angles in investment cast part design
- Sand castings suffer from parting lines and general surface defects