When sourcing custom flange bases, housings, and precision fittings, combining investment casting with CNC machining delivers the optimal balance of cost efficiency, dimensional accuracy, and production scalability.

Why Choose Investment Casting for Flange Bases?

Investment casting, also known as the lost-wax process, excels at producing complex, near-net-shape components with superior surface finish. For flange bases, this method offers:

• Excellent material utilization – minimal waste compared to machining from solid bar stock

• Thin-walled structures – achievable with silica sol shell casting, reducing weight without sacrificing strength

• Wide material selection – including stainless steel grades such as SUS304, SUS316, and 316L, as well as carbon steel and alloy steel

• Intricate geometry – internal cavities, integrated ribs, and complex flanged features can be cast directly

The Role of Precision CNC Machining

Investment casting produces the near-net shape, but critical mating surfaces require CNC machining to achieve final tolerances. Typical post-casting machining operations include:

• Facing and turning – flange faces, sealing surfaces, and outer diameters

• Boring and drilling – bolt holes, threaded holes, and seal grooves

• Fine finishing – achieving surface roughness down to Ra 1.6 micrometres on critical seating surfaces

For flange base assemblies, industry standards often require bolt hole pitch tolerance within plus or minus 0.2 millimetres and face flatness within 0.05 millimetres, both readily achievable with CNC finishing.

The Combined Process Flow

The production sequence begins with wax pattern production, where CNC-machined aluminium tooling creates wax patterns with precision. This is followed by ceramic shell building through multi-layer silica sol slurry application. The dewaxing and firing step removes the wax and cures the ceramic mould. Pouring is carried out with controlled melt temperature for fine-grained microstructure. Heat treatment, such as solution annealing, is applied for stainless grades. CNC machining then performs turning, boring, drilling, and threading to final dimensions. Surface finishing options include sandblasting, passivation, or electropolishing.

Material Options for Flange Bases

• Stainless Steel 304 / 316L – corrosion-resistant, food-grade, marine, and chemical environments

• Carbon Steel – general industrial and structural applications where cost-effectiveness is key

• Alloy Steel – high-strength, heavy-duty applications in oil and gas or power generation

Quality Assurance

Modern manufacturing facilities combine casting simulation software with full inspection capabilities, including coordinate measuring machines and spectrometer analysis, to ensure consistent quality from prototype through to mass production.

Contact us today to discuss your flange base project. Send your drawings for a free process recommendation and quotation.