Investment Casting and CNC Machining Service

YS Precision provides custom investment casting and CNC machining services for metal components that combine complex cast geometry with accurately machined functional features. We coordinate drawing review, wax-pattern tooling, lost-wax casting, secondary machining, finishing, inspection and international shipment as one managed manufacturing route.

Investment casting can form detailed, near-net-shape parts with less material removal than machining the complete shape from solid stock. It does not, however, eliminate machining in every case. Bearing seats, sealing faces, precision bores, threaded holes and assembly datums often require CNC finishing. Planning the casting and machining operations together controls these critical-to-function features without adding unnecessary machining stock elsewhere.

When Investment Casting and CNC Machining Work Together

Investment casting, also known as lost-wax casting or precision investment casting, suits components with curved profiles, ribs, bosses and transitions that would require extensive material removal from billet. Internal passages may also be possible when suitable ceramic cores are incorporated.

CNC machining is applied where the drawing requires tighter dimensional control, a specified surface finish or a controlled relationship between features. This combined process is commonly considered when:

• The part has complex cast geometry
• Machining the complete form from billet would create excessive waste or cycle time
• Bores, faces, threads, bearing seats or sealing areas require finish machining
• One casting can replace welded or assembled components
• Repeat demand supports investment in wax-pattern tooling

Investment casting is not the best route for every part. Simple geometry, very low quantities or designs dominated by machined features may be more economical to machine directly. For larger or simpler brass parts, gravity casting or sand casting may also be considered. We compare the options according to design, alloy, quantity, finish and machining content.

From Wax Pattern to Investment Cast Part

The conventional process begins with wax-pattern tooling, normally a metal die used to produce repeatable wax replicas of the component. The patterns are attached to a central sprue and gating system to form a casting tree.

The tree is repeatedly dipped in ceramic slurry, coated with refractory stucco and dried to build a ceramic shell. The wax is removed from the hardened shell, leaving cavities into which molten alloy is poured. After solidification, the shell is removed, individual castings are cut from the tree, and the gates are ground away.

Pattern design, gating and feeding, process shrinkage compensation, wall transitions, fillets, casting orientation and machining stock all influence manufacturability. Ceramic-core location and removal must also be considered where applicable.

Planning Machining Stock, Datums and Fixtures

Machining should not be added after the casting has already been designed. During the initial review, we identify which dimensions can remain as cast and which features must be machined. Sufficient stock is then added locally so that the cutter can clean up the complete functional surface without increasing material across the entire component.

Normal casting variation must be included. Too little stock may leave an incomplete machined surface, while excessive allowance increases cycle time and tool wear.

An irregular casting also cannot always be located like prepared billet. Stable machining datums and practical fixture points need to be considered early. Where appropriate, cast-on locating or machining pads can be added with foundry approval and removed after machining.

This coordination is particularly important for:

• Concentric bores and bearing seats
• Perpendicular mounting faces and holes
• Sealing faces around cast passages
• Threaded ports relative to internal flow paths
• Mating features shared with other assembly components

CNC Machining for Investment Castings

After the casting has passed the required pre-machining checks, operations are selected according to the geometry, alloy and drawing. CNC machining for investment castings may include:

• CNC milling and multi-side machining
• CNC turning and turn-mill machining
• Drilling, boring, reaming and counterboring
• Tapping and thread milling
• Grinding of selected functional surfaces
• Deburring and controlled edge finishing

Multi-axis positional machining can reduce setups when features are located on several faces. Fixtures and cutting sequences are planned around the as-cast condition and datum-transfer strategy.

Rough and finish machining may be separated when heat treatment or stress relief could affect final dimensions. Machining parameters are also adjusted for the alloy: brass, stainless steel and alloy-steel castings differ significantly in machinability, cutting-tool requirements and heat-treatment planning.

Brass Investment Casting and CNC Machining

Brass investment casting is useful when a component needs the appearance, corrosion resistance or machinability of a copper-zinc alloy together with the geometric flexibility of the lost-wax process. Typical industrial applications include valve and fluid-control parts, fittings, locks, handles, architectural hardware, electrical components and decorative mechanical parts.

The casting can form the main geometry, while CNC machining finishes sealing faces, threads, bores, mounting surfaces and other assembly features. Polishing or plating can then provide the required final appearance.

Not every brass grade supplied as CNC bar stock is suitable as an investment casting alloy. The drawing should identify a cast-alloy designation, applicable standard or required chemical and performance criteria.

Potable-water, marine or regulated applications may require restricted-lead composition, dezincification resistance, RoHS compliance, traceability or chemical verification. These requirements affect alloy sourcing, casting control and testing and must be identified before tooling.

Materials for Custom Investment Cast Parts

Material selection depends on corrosion resistance, strength, service temperature, machinability, appearance and cost.

Casting designations may differ from familiar wrought bar or plate grades. A general instruction such as “brass” or “stainless steel” is not sufficient when chemistry, corrosion performance, mechanical properties or regulatory compliance matter. Material availability is confirmed for each project.

Heat Treatment and Surface Finishing

The processing route depends on the alloy and final application. Brass investment cast parts may receive vibratory finishing, brushing, mechanical polishing, bead blasting, nickel plating, chrome plating, clear coating or another decorative finish. Areas that must remain conductive, dimensionally controlled or suitable for sealing may require masking or finishing after machining.

Stainless and steel castings may require heat treatment, shot blasting, bead blasting, polishing, passivation, plating or painting according to the material specification.

Process sequence matters. Heat treatment can alter hardness and dimensional stability, while blasting, polishing and plating can affect edges and final size. Critical dimensions are therefore completed at the appropriate stage.

Inspection from Casting to Finished Component

Investment cast parts require a control plan that addresses both casting condition and machined features. Depending on the drawing and specification, inspection may include:

• Review of material certificates
• Chemical-composition verification when specified
• Visual examination of the casting
• Checks of as-cast dimensions and machining stock
• Acceptance criteria for surface discontinuities
• Dimensional inspection of machined features
• Verification of threads, inserts and mating areas

A surface discontinuity should be evaluated against the applicable acceptance standard rather than automatically classified as a defect. Required non-destructive testing can be coordinated.

Final inspection focuses on features that affect fit and function, including datums, bores, hole positions, threads, flatness, perpendicularity and relationships between mating features. Reports, material certificates and specified test records can be arranged.

Applications of Cast and Machined Parts

Investment casting with CNC machining is commonly used for:

• Brass valves, fittings and fluid-control parts
• Locks, handles and architectural hardware
• Marine and corrosion-resistant components
• Electrical connectors and equipment hardware
• Pump and valve components
• Industrial machinery parts
• Automation and robotic equipment components
• Automotive and transportation hardware
• Medical, laboratory and general engineering equipment

The combination is most valuable when the near-net-shape casting removes substantial rough machining, while selected CNC operations bring functional features to final specification.

One Managed Route from Drawing to Delivery

YS Precision supports overseas engineering and procurement teams that prefer to receive finished investment cast components rather than manage separate foundry, machine shop, finishing and inspection suppliers.

Based on the customer’s drawings, 3D models, cast-alloy specification and quantities, we review the route before tooling. The review distinguishes as-cast features, machined dimensions, machining stock, locating requirements, process sequence and delivery condition.

By linking investment casting with CNC machining, finishing, inspection and export packaging, we help control the handovers where datum, allowance, material and sequencing problems often arise. The result is a custom cast and machined component prepared for the customer’s next assembly or production stage.