Precision machined castings integrate silica sol investment casting with tight-tolerance secondary CNC machining to deliver net-shape components for demanding fluid-handling, hydraulic, structural, and mechanical applications. By consolidating liquid metal casting and high-precision subtractive machining under a single manufacturing framework, this process eliminates non-conformance risks associated with multi-vendor supply chains, reduces raw material waste, and guarantees high dimensional accuracy on functional surfaces.
Components are manufactured using high-purity silica sol binder systems, achieving detail resolution, internal sound integrity, and smooth as-cast surfaces. Critical geometry-including bearing bores, flange faces, threaded ports, and dynamic sealing grooves-is finished on multi-axis CNC machine tools.
Key Dimensional & Surface Capability Matrix
|
Parameter |
As-Cast Capability (Silica Sol) |
Finish-Machined Capability |
|
Dimensional Tolerance |
ISO 8062-3 DCTG 4–6 / VDGW P690 Grade D1 |
ISO 2768-m/f | Up to ±0.005 mm (±0.0002 in) |
|
Surface Roughness (Ra) |
Ra 3.2 µm – 6.3 µm (125 – 250 µin) |
Ra 0.4 µm – 1.6 µm (16 – 63 µin) |
|
Weight Range |
0.005 kg to 30.0 kg (0.01 lbs to 66.0 lbs) |
Finished to customer drawing envelope |
|
Max Footprint Size |
500 mm × 500 mm × 400 mm |
500 mm × 500 mm × 400 mm |
|
Minimum Wall Thickness |
1.5 mm (0.060 in) localized |
0.8 mm (0.031 in) feature-dependent |
Manufacturing Process
Our integrated production line executes end-to-end control from pattern design to final dimensional sign-off:
Tooling Design & Pattern Injection: Aluminum tooling is cut on 3-axis CNC centers. High-purity wax is injected into temperature-controlled dies to yield stable pattern dimensions. Wax patterns are assembled onto tree gates designed via casting simulation to prevent micro-shrinkage.
Silica Sol Ceramic Shell Construction: Pattern assemblies are dipped in high-purity silica sol slurry and stucco-coated with refractory zircon sand. The process takes place under controlled ambient humidity (55% ± 5% RH) and temperature (22°C ± 2°C), producing a non-reactive shell that eliminates surface carbon contamination.
Autoclave Dewaxing & Shell Firing: Pressurized steam autoclaves (8–10 bar) remove wax without shell cracking. Ceramic molds are fired in gas kilns at 1,000°C–1,150°C to burn off organic residue and sinter ceramic bonds.
Induction Melting & Pouring: Alloy charges are melted in medium-frequency induction furnaces. Melt chemistry is verified via Optical Emission Spectrometry (OES) before tapping. Molten metal is gravity-poured directly into preheated molds.
Shell Removal & Heat Treatment: Mechanical knock-out and stainless steel shot blasting remove ceramic residue. Castings undergo batch heat treatment (Solution Annealing, Normalizing, Quenching & Tempering) to restore grain structure and achieve required hardness.
Precision CNC Machining: Castings are located on custom pneumatic or hydraulic fixtures for CNC turning, 4-axis milling, boring, and tapping on internal functional areas.
Materials and Technical Specifications
We melt and process over 100 industrial metal alloys matching international standard designations.
Material Selection & Property Reference
|
Material Category |
Standard Grades (ASTM / DIN / EN) |
Key Mechanical & Physical Properties |
|
Austenitic Stainless Steel |
CF8 (304), CF8M (316), CF3M (316L), 304L, 317L |
Tensile: ≥ 485 MPa | Yield: ≥ 205 MPa | Elongation: ≥ 35% | High corrosion resistance |
|
Martensitic & Ferritic Stainless |
CA15 (410), CA40 (420), 430, 440C |
Tensile: ≥ 655 MPa | Hardness: up to 58 HRC after Q&T | Wear resistant |
|
Precipitation Hardening Stainless |
17-4PH (CB7Cu-1), 15-5PH |
Tensile: ≥ 930–1170 MPa | Yield: ≥ 795–1000 MPa | High strength + corrosion resistance |
|
Duplex & Super Duplex |
2205 (UNS J92205 / CD3MN), 2507 (CE3MN) |
PREN ≥ 34–42 | Yield: ≥ 450 MPa | Superior pitting and chloride SCC resistance |
|
Carbon Steel |
WCB (ASTM A216), WCC, LCB, 1020, 1045 |
Tensile: 485–655 MPa | Yield: ≥ 250 MPa | Structural weldability and strength |
|
Low Alloy & Tool Steel |
4130, 4140, 8620, 4340, D2, H13 |
Tensile: up to 1200 MPa | High fatigue strength, core toughness, heat treatable |
|
Aluminum & Copper Alloys |
A356, A380, C95400 (Al Bronze), Brass |
Low density, high thermal conductivity, non-sparking, wear-resistant options |
Key Product Features
Single-Source Single-Point Responsibility:
Eliminates non-conformance disputes between separate casting foundries and machine shops by managing tolerances under one quality envelope.
Pure Silica Sol Binder Shells:
Uses 100% silica sol binder, avoiding surface carbon pickup, orange peel surface flaws, and inclusions common in water-glass casting processes.
Complex Internal Cavity Execution:
Casts undercut channels, internal impellers, and weight-reduction cavities that are physically impossible or cost-prohibitive to machine from solid billet stock.
Material Utilization Savings:
Reduces raw material waste by 30%–50% compared to full CNC subtractive machining, lowering per-unit costs on high-alloy metals like 316L and 17-4PH.
Integrated Part Consolidation:
Converts multi-piece welded assemblies into single-piece castings, eliminating assembly labor, weld inspection costs, and potential structural fatigue joints.
Typical Applications
|
Industry Sector |
Key Components Manufactured |
Operating Environment / Performance Demands |
|
Fluid Handling & Valves |
Pump housings, closed impellers, valve bodies, ball valve spheres, butterfly discs |
High pressure rating (Class 150–600), zero leakage, cavitational erosion resistance |
|
Hydraulics & Heavy Equipment |
Hydraulic manifold blocks, valve spools, swivel joints, clevis brackets |
High working pressure (>350 bar), zero internal cross-port leakage, fatigue strength |
|
Chemical & Petrochemical |
Filter housings, strainers, mixer agitators, pipe fittings, flowmeter bodies |
Aggressive chemical exposure, elevated temperature, NACE MR0175 compliance |
|
Food & Pharmaceutical Processing |
Sanitary valve bodies, pump rotors, homogenizer heads, tri-clamp fittings |
Ra ≤ 0.5 µm polished surfaces, crevice-free geometries, CIP/SIP compatibility |
|
Automotive & Commercial Vehicles |
Turbocharger housings, exhaust brackets, shift forks, engine mount brackets |
Thermal fatigue resistance, high vibration loads, stringent dimensional repeatability |
Machining and Secondary Operations
In-house secondary processing facilities ensure components arrive site-ready for final assembly:
CNC Turning & Milling:
Dedicated 3-, 4-, and 5-axis machining centers outfitted with custom pneumatic holding fixtures for casting geometries.
Precision Threading & Boring:
Cut and form tapping for NPT, BSPP, Metric threads; high-precision boring down to ISO H7 tolerance limits.
Heat Treatment Operations:
Solution annealing (1050°C–1150°C water quench), Quenching & Tempering (Q&T), Stress Relieving, and Surface Nitriding.
Surface Treatments:
Automatic stainless shot blasting, chemical passivation per ASTM A967, electropolishing, electro-galvanizing, and custom powder coatings.
Quality Control and Inspection
Quality validation protocols follow certified ISO 9001:2015 management procedures. Every heat number is fully traceable.
|
Inspection Phase |
Equipment / Method Used |
Control Parameters & Standard Compliance |
|
Chemical Verification |
Optical Emission Spectrometer (OES) |
Heat-by-heat chemical analysis; raw melt melt-ticket verification |
|
Dimensional Metrology |
Coordinate Measuring Machine (CMM), Optical Profilometer |
GD&T position, profile, runout, flatnesses; 100% critical dim checks |
|
Nondestructive Testing (NDT) |
Radiographic Testing (RT), Dye Penetrant (PT), Magnetic Particle (MT) |
Internal porosity & crack inspection per ASTM E446 / ASTM E1427 |
|
Mechanical Testing |
Universal Tensile Tester, Rockwell/Brinell Hardness, Impact Tester |
Yield strength, tensile strength, elongation %, Charpy V-notch impact test |
|
Pressure Integrity |
Hydrostatic Testing & Pneumatic Air-Under-Water Testing |
Pressure rating testing up to 200 bar; 100% leak check for valve/pump parts |
OEM and Custom Manufacturing
We partner with international OEM engineering teams to facilitate full product lifecycle development:
Rapid Prototyping: Direct 3D-printed wax or PMMA patterns deliver physical prototype castings in 10–14 days without hard aluminum tooling.
Tooling Engineering: In-house CAD/CAM team utilizes SOLIDWORKS and MAGMASOFT flow and solidification simulation to eliminate shrink porosity and cold shuts prior to mold machining.
Flexible Batch Sizes: Adaptable manufacturing cells support low-volume high-mix orders (50–500 units/year) through continuous high-volume production series (50,000+ units/year).
Supply Chain Integration: Laser engraving for heat-number tracking, customized protective packaging, and Vendor Managed Inventory (VMI) buffer stock arrangements.
What Buyers Should Provide for an RFQ
To receive an engineering DFM feedback report and commercial proposal within 24 to 48 hours, please submit:
Engineering Drawings: 2D PDF specifying linear tolerances, GD&T callouts, and finish surface requirements, accompanied by a 3D CAD file (STEP, IGES, or X_T).
Material Specifications: Exact alloy designation (e.g., ASTM A351 CF8M, DIN 1.4408, AISI 4140) and desired heat treatment state.
Volume Requirements: Estimated Annual Volume (EAV) and target batch release quantities.
Inspection & Testing Requirements: Required NDT scope (PT, RT), hydrostatic test pressures, and mandatory material certification level (EN 10204 3.1).
Secondary Operations & Packaging: Machining boundaries, surface finish specs (Ra), protective oils, or export packaging requirements.
Frequently Asked Questions
Q: What linear tolerances can be achieved for as-cast vs. finish-machined features?
A: As-cast features conform to ISO 8062-3 DCTG 4–6 standards (typically ±0.15 mm to ±0.30 mm depending on feature scale). Finish-machined surfaces achieve tolerances down to ±0.005 mm (±0.0002 in) per ISO 2768-m/f standards.
Q: Why select silica sol investment casting over water-glass casting?
A: Silica sol binder systems yield superior surface finish (Ra 3.2 µm vs. Ra 12.5 µm), tighter dimensional accuracy, and zero carbon pickup. Water-glass processes risk silica inclusions and carbon contamination on stainless steel surfaces.
Q: Are material certificates provided with each delivery shipment?
A: Yes. Every shipment includes EN 10204 3.1 Material Test Reports (MTRs) detailing heat-specific chemical composition via spectral analysis and mechanical property test results.
Q: What are standard lead times for tooling, sample submission, and serial production?
A: Tooling fabrication and first-article samples are delivered in 21–28 days. Mass production orders require 3–5 weeks depending on machining complexity and batch volume.
