Investment Casting Services

Investment casting, also called lost-wax casting, starts with a wax pattern that matches the final part. The pattern is coated in ceramic slurry to build a shell, the wax is melted out, and molten metal is poured into the hollow mold. After solidification, the shell is broken away to release the cast part. The process produces intricate shapes, smooth surfaces, and tight tolerances that are difficult to achieve with other casting methods.

Sand casting suits larger, heavier parts and offers low tooling cost and easy design changes. Investment casting suits smaller, more intricate parts and delivers a significantly better surface finish and tighter dimensional accuracy, though tooling and labor cost are higher. Our engineering team recommends the right process at the feasibility review.

Investment casting costs more to set up than sand casting because the ceramic mold and wax pattern require additional preparation. That cost is offset on parts where complex geometry or surface finish requirements would otherwise demand extensive secondary machining. We will tell you at the quote stage whether investment casting is the most cost-effective process for your part.

We cast stainless steel, alloy steel, carbon steel, aluminum, grey iron, ductile iron, and copper alloys. Stainless steel suits corrosion-resistant applications; aluminum suits lightweight, high-strength parts; carbon and alloy steels suit high-pressure or wear-resistant uses. Our engineering team confirms the best alloy at the feasibility review.

Investment casting is the right choice when parts are small to medium, geometry is intricate, surface finish is critical, and tight dimensional accuracy matters. It produces near-net-shape parts that cut down on secondary machining. For large, simple parts where tooling cost dominates, sand casting is often better, and for very high volumes in non-ferrous metals, die casting can be more economical. Our engineering team helps you weigh the trade-offs at the feasibility review.

Look for a supplier with ISO 9001 certified foundries, in-house inspection and non-destructive testing such as X-ray and magnetic particle inspection, documented material traceability, and experience in your alloy and industry. Redstone gives you one U.S. point of contact from quote through delivery, with no offshore quote desk between you and the foundry.

Consistent wall thickness, generous radii at transitions, and adequate draft help the wax pattern release cleanly and reduce porosity in the finished casting. Designing in machining stock on critical faces lets secondary machining hold the tightest tolerances. Our engineering team reviews every drawing for these factors before tooling is built.

Standard production lead time is 4 to 8 weeks, with tooling and first-article timing confirmed at the quote stage. Rush programs can be reviewed case by case.

Investment casting is most cost effective on medium-volume recurring production where tooling cost amortizes across a run. We will tell you at the quote stage whether your volume is a fit and recommend the most cost-effective process for your part.

Inconsistent wall thickness. Non-uniform walls cause uneven fill and cooling, leading to porosity, sink marks, warpage, and crack propagation. Redstone reviews every drawing for wall-thickness consistency during the DFM stage and runs mold-flow analysis to identify likely high-porosity areas before production.

Porosity control starts at design, not at inspection. Redstone addresses it through wall-thickness review, gating design, and process capability validation. Where leak integrity matters, X-ray inspection or leak testing is built into the control plan. For micro-porosity in sealed applications, vacuum impregnation seals the part without affecting dimensions.

Redstone translates every print into a ballooned inspection template covering all dimensions, notes, material, and title block. A second pass layers in past quality issues, mating-part requirements, and anything the print fails to specify. Methods include CMM measurement, surface finish verification, material analysis, and functional testing with mating parts to confirm fit before shipment.

Investment casting produces a near-net shape with tight tolerances, typically in the range of plus or minus 0.005 inch depending on part geometry, with exact tolerances confirmed against your drawing at the feasibility review. Tighter tolerances on specific features can be achieved through secondary CNC machining after casting.