| Material Capability | Carbon steel, stainless steel, tool steel, nickel-based alloys, cobalt alloys, aluminum alloys and copper alloys | High | Confirm that the foundry routinely melts the required alloy, follows the applicable material specification and can provide heat-lot traceability and chemical-analysis reports. |
| Dimensional Accuracy | Common investment-casting tolerance grades are approximately ISO 8062 CT4 to CT7, depending on geometry, alloy and casting size | High | Request capability data from comparable parts rather than relying only on a general tolerance statement. Verify datum strategy, inspection methods and allowances for machining or finishing. |
| Surface Finish | As-cast surface roughness is often approximately 3.2–6.3 µm Ra, with results affected by shell material, geometry and finishing operations | High | Ask for sample inspection records and define whether the requirement applies before or after blasting, tumbling, grinding, polishing or machining. |
| Part Size and Weight Range | Investment casting is generally suited to small and medium components, from very small precision parts to castings weighing several tens of kilograms | High | Check the foundry’s actual furnace capacity, flask dimensions, handling limits and proven experience with the part’s minimum wall thickness, length and weight. |
| Complex Geometry | Suitable for thin walls, curved passages, integrated features, undercuts and near-net-shape components that may require fewer machining operations | High | Review wax-tooling design rules, ceramic-shell capability, core-making methods and the foundry’s approach to vents, feeders, shrinkage and difficult-to-fill sections. |
| Prototype and Tooling Support | Options may include machined tooling, modular tooling, silicone or polymer tooling for development, and production tooling for repeat volumes | Medium | Compare tooling ownership, revision policy, expected tool life, maintenance responsibility, design-for-casting support and the ability to transition from prototype to production. |
| Production Volume Fit | Well suited to prototypes, low-to-medium production runs and repeat production where near-net shape offsets tooling and process costs | High | Evaluate batch size, furnace utilization, wax-tree efficiency, mold-reuse limitations and the supplier’s ability to maintain consistent quality across repeated lots. |
| Quality Management | A robust system commonly includes documented process control, nonconformance management, calibration and full batch traceability | High | Request the quality manual or relevant certification evidence, control plans, first-article procedures, corrective-action records and sample inspection reports. |
| Inspection and Testing | Possible controls include dimensional inspection, visual inspection, chemical analysis, hardness testing, dye-penetrant testing, radiography and metallography | High | Match inspection scope to the application’s risk level. Confirm whether testing is performed in-house or by qualified external laboratories and define acceptance criteria in advance. |
| Porosity and Internal Integrity | Soundness depends on alloy, gating, feeding, shell design, melt control and solidification conditions; critical parts may require radiographic or other volumetric inspection | High | Discuss known defect risks, process simulation where appropriate, repair restrictions, inspection levels and documentation for internal discontinuities. |
| Lead-Time Planning | A typical sequence includes design review, tooling, wax injection, shell building, dewaxing, casting, finishing, inspection and shipping | Medium | Obtain a stage-by-stage schedule with tooling lead time, sample approval milestones, production capacity, contingency planning and realistic dates for repeat orders. |
| Total Cost | Cost is influenced by alloy price, part weight, tooling, wax-tree yield, shell cycles, labor, inspection, machining, finishing and order volume | High | Compare total delivered cost rather than piece price alone. Request separate quotations for tooling, casting, secondary operations, inspection, packaging and transportation. |
| Secondary Operations | Available services may include heat treatment, shot blasting, tumbling, grinding, CNC machining, passivation and surface coating | Variable | A consolidated supply chain can reduce handling and logistics, but verify process qualifications, subcontractor controls, dimensional responsibility and final inspection ownership. |
| Application and Compliance | Requirements vary for aerospace, medical, energy, automotive, food-processing and general industrial applications | High | Confirm that the foundry understands the applicable regulatory, documentation, cleanliness, material, marking and record-retention requirements for the intended end use. |
| Communication and Engineering Support | Effective projects typically use early design-for-manufacturing review, clear drawings, revision control and documented technical approvals | Medium | Assess response time, technical depth, escalation procedures, language compatibility, drawing-review discipline and the ability to communicate risks before production begins. |