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Lead Free CW724R (CuZn21Si3P) CNC Machined Parts
Lead Free CW724R (CuZn21Si3P) CNC Machined Parts
Electrical Accessories India produces precision Lead Free CW724R (CuZn21Si3P) CNC machined parts on modern multi-axis CNC machining centres, Swiss-type turning centres, and live-tooling CNC lathes for electrical OEMs, EPC contractors, power utilities, and global industrial distributors. CW724R (EN designation CuZn21Si3P) is a silicon-modified, lead-free (<0.09% Pb) Brass alloy under EN 12164 / EN 12167 specifically designed for precision CNC machining of complex components with tight tolerances, superior surface finish, and full compliance with RoHS 2, REACH, NSF/ANSI 61, and ELV Directive. Indicative price: US$ 11.50/kg ex-works India.
Product Overview
CW724R CuZn21Si3P – The Lead-Free CNC Machining Brass Alloy
CW724R (CuZn21Si3P) is a ternary Copper–Zinc–Silicon alloy with trace Phosphorus, developed as the primary lead-free alternative to conventional free-cutting Brass (CW614N / CuZn39Pb3) for CNC precision machining. Silicon (2.7–3.5%) replaces lead as the chip-breaking element through its formation of brittle CuSiZn intermetallic particles in the Brass matrix. These particles promote segmented chip formation without the machining hazard of lead aerosols — a critical consideration for operators and workplace health compliance. CW724R is the most widely specified lead-free Brass alloy in Europe for electrical, plumbing, and instrumentation CNC machined components.
CNC Turned Components and Swiss-Type Machining
Our CW724R CNC turned parts range covers components produced on Swiss-type sliding-head lathes (Citizen L-series, Star SB-series, Tsugami B-series) and CNC turning centres with bar-feed systems. Swiss-type machining excels for high-aspect-ratio parts (L/D >10:1): long contact pins, coaxial connector bodies, slender valve stems, precision guide bushings, threaded standoffs, and instrument thermocouple wells. CNC turning centres (Mazak Quick Turn, DMG MORI NLX) handle shorter, larger-diameter components (Ø10–100 mm): cable gland bodies, terminal blocks, valve body blanks, manifold sections, and connector housings. All CNC programs generated in Mastercam or Esprit CAM with toolpath simulation and post-processing for each machine model.
Multi-Axis CNC Milling and Machining Centres
Complex CW724R lead-free Brass parts requiring multiple machined faces, cross-drilled ports, milled features, angled bores, or splined profiles are produced on 3-axis, 4-axis, and 5-axis CNC machining centres (Haas VF-2, Mazak VCN-530, DMG MORI DMU 50). Five-axis simultaneous machining enables one-setup production of complex valve body internals, hydraulic manifold blocks, multi-port junction blocks, and intricate electrical connector housings that previously required multiple setups and expensive dedicated fixtures. Workholding: vise, ER collet chuck, and custom modular fixturing. Tooling: solid carbide end mills, Sandvik Coromant and Seco Tools catalogued inserts optimised for silicon Brass.
CNC Turned and Milled Electrical Hardware
CW724R CNC machined electrical hardware includes: precision contact pins (single and multi-way), socket contact inserts, PCB terminal pins, earth terminal stud bodies, cable compression lug bodies, earth bus bar sections (custom profiled), DIN rail terminal block bodies, cable gland bodies (Metric, Pg, NPT, BSP thread), conduit fittings, cable marker holders, plug-in busbar connector bodies, and substation compression deadend connector bodies. All components conform to IEC 60999, IEC 60947-1, IEC 61238-1, or customer-specific dimensional drawings.
Precision CNC Machined Fittings and Hydraulic Components
CW724R CNC machined fittings include: BSP/NPT/G-threaded nipples, adaptors, elbows, tees, and crosses; compression olive (ferrule) bodies; push-fit coupling inserts; hydraulic banjo bolts; hydraulic swivel fittings; pneumatic push-in connector bodies; instrumentation tube fittings (Swagelok-type, Parker A-LOK type); thermocouple well bodies; gauge root valve bodies; and pressure test point bodies. All threaded fittings are machined to ISO 228-1 (G), ASME B1.20.1 (NPT), or BS EN ISO 228 dimensional standards with thread-form verified by go/no-go gauge.
CNC Machined Fasteners and Structural Components
CW724R CNC machined fasteners and structural components: hex head bolts and nuts (ISO 4014, ISO 4032), socket head cap screws (ISO 4762), button head screws (ISO 7380), countersunk screws (ISO 10642), barrel nuts, threaded inserts (DIN 7965 style, solid flanged), expansion inserts, rivet nuts, studbolts, jam nuts, pillar bolts, and precision shoulder bolts. CNC machining provides tighter head-to-shank concentricity (TIR <0.05 mm) and sharper hex socket dimensions compared to cold-heading, making CNC Brass fasteners preferred for aerospace-grade and high-precision assembly applications.
Custom OEM CNC Machined Components
Electrical Accessories India’s CNC machining service for CW724R lead-free Brass includes full OEM contract manufacturing: drawing-to-part manufacturing from customer DXF/DWG/STEP/IGES files, prototype machining (1–50 pcs, 1–2 weeks), pilot runs (100–500 pcs with FAI), and production runs (500–500,000 pcs/month). Design for Manufacturability (DFM) review, material selection advisory, and value engineering for cost optimisation are provided as free engineering support services. Parts supplied with full EN 10204 3.1 MTC, RoHS declaration, and dimension report.
CNC Machining of CW724R vs. Other Lead-Free Brass Alloys
CW724R (machinability ~70% vs. CW614N at 100%) is the predominant lead-free Brass alloy in EN (European) standard products. C69300 ECO BRASS (machinability ~80%) offers slightly higher machinability for high-volume screw machine applications. Bismuth Brass (machinability ~85%) approaches leaded Brass performance but has higher material cost. For CNC machining centres and Swiss-type lathes producing complex multi-featured parts, CW724R provides an optimal balance of machinability, corrosion resistance, regulatory compliance, and cost — making it the standard alloy for European-market CNC machined parts.
Key Features
- 5-Axis CNC Capability: Complex single-setup machining of valve bodies, manifold blocks, and multi-port connectors — reduced setups, better geometric accuracy.
- Swiss-Type CNC for Long Slender Parts: L/D >30:1 achievable; precision ±0.005 mm on diameter; ideal for pins, stems, and long connector bodies.
- Lead-Free Compliance: CW724R Pb <0.09% — fully RoHS 2, REACH, NSF/ANSI 61, and ELV compliant; complete documentation supplied.
- Tight Tolerances: IT6 on diameter (±0.008 mm at Ø10 mm); IT5 achievable on critical bearing surfaces.
- Surface Finish: Ra 0.4 μm achievable on CNC turned surfaces; Ra 0.8 μm standard; mirror polishing available.
- Complete Documentation: EN 10204 3.1 MTC, CMM dimensional report, RoHS declaration, FAI available.
- Price: US$ 11.50/kg ex-works India; ISO 9001:2015 certified.
CNC Machining Process Optimisation for CW724R
CW724R Lead Free Brass requires specific CNC machining parameter optimisation compared to conventional leaded Brass. Recommended cutting parameters: cutting speed Vc = 150–250 m/min (carbide inserts), feed rate f = 0.05–0.15 mm/rev (turning), chip load fz = 0.02–0.08 mm/tooth (milling). Tooling: TiAlN-coated carbide inserts with positive rake angle (+20° to +25°), sharp cutting edge (no T-land), and polished rake face to prevent chip adhesion. Coolant: water-soluble emulsion at 8% concentration and 15 bar pressure for Swiss-type machines; flood coolant for turning centres. These parameters achieve tool life within 20% of leaded Brass tooling life with surface finish Ra <0.8 μm.
Dimensional Accuracy and GD&T Compliance
CNC machined CW724R parts are fully GD&T compliant per ASME Y14.5 or ISO 8015. CMM (Mitutoyo Crysta-Apex) measurement capability: position tolerance ±0.003 mm, cylindricity 0.003 mm, perpendicularity 0.005 mm/100 mm. Thread gauging: 100% go/no-go inspection using TESA and Protool calibrated thread gauges traceable to NPL (UK) or NABL (India). Surface roughness: Taylor Hobson Surtronic profilometer on 10% AQL sampling. Roundness: Talyrond measurement on bearing surface components. Full dimensional reports (CMM balloon drawings) available for first-article and production sampling.
Tool Life Management and Alloy Segregation
Dedicated tooling, workholding, and material handling systems for CW724R Lead Free Brass prevent alloy contamination in our multi-alloy CNC facility. Tooling management: individual insert grades and geometries optimised for lead-free Brass; RFID-tagged toolholders; tool life monitoring by CNC controller (part count and cutting time). Material segregation: separate raw material racks, separate bar-feeder magazines, and clearly labelled WIP (work-in-progress) bins by alloy. Operator training: certified lead-free alloy handling procedures; coolant contamination prevention protocols; XRF spot-checks on changeover verification.
Post-Machining Surface Treatments
CW724R CNC machined parts accept all standard industrial surface treatments. Standard offerings: barrel finishing/vibratory finishing (deburring and brightening), ultrasonic cleaning, bright acid dip, bright nickel electroplating (EN/ISO 1456 – 5 to 25 μm), electroless nickel (EN/ISO 4527 – 10 to 50 μm), tin plating (matte/bright, EN/ISO 4520), silver plating (1–50 μm, flash to heavy), gold plating (flash 0.1 μm to 5 μm for electrical contacts), zinc-nickel plating (8–25 μm, ISO 9587), trivalent chromate passivation (RoHS-compliant, iridescent or clear), and phosphating. Laser marking, part numbering, and barcode etching available on machined surfaces.
CNC Programming, Prototyping, and DFM Review
Electrical Accessories India provides full new part development services for CW724R CNC machined components: 3D CAD model creation from 2D drawings (SolidWorks, CATIA), DFM (Design for Manufacturability) review identifying geometric features that increase machining cycle time or risk dimensional inconsistency, CAM programming (Mastercam, Esprit), toolpath simulation and collision check, CNC prove-out on physical prototype parts (3–5 samples), first article inspection (FAI) report, and production process documentation. DFM review typically reduces part cost by 10–25% through feature rationalisation and machining sequence optimisation without changing functional performance.
Technical Specifications
| Parameter | CW724R (CuZn21Si3P) Value |
|---|---|
| EN Designation | CW724R / CuZn21Si3P |
| Copper (Cu) | 75.0 – 77.0% |
| Zinc (Zn) | Balance (~21%) |
| Silicon (Si) | 2.7 – 3.5% |
| Lead (Pb) max | 0.09% |
| Phosphorus (P) | 0.02 – 0.15% |
| UTS (drawn rod) | 490 – 630 MPa |
| 0.2% Proof Stress | 300 – 500 MPa |
| Elongation A5 | ≥ 5% |
| Hardness | 130 – 170 HB |
| Machinability Index | ~70% (vs. CW614N = 100%) |
| Electrical Conductivity | ~14.5% IACS |
| Thermal Conductivity | ~115 W/(m·K) |
| Dezincification Resistance | DZR Class – ISO 6509 compliant |
| Lead Compliance | RoHS 2, REACH, NSF/ANSI 61, ELV, WRAS |
| Price (ex-works India) | US$ 11.50/kg |
CNC Machining Centre Capabilities
| Machine Type | Model / Brand | Capacity | Tolerance | Best For |
|---|---|---|---|---|
| Swiss-type CNC Lathe | Citizen L20-VIII, Star SB-16 | Ø1 – 32 mm | ±0.005 mm | Long slender pins, stems, connectors |
| CNC Turning Centre | Mazak Quick Turn Nexus, DMG MORI NLX | Ø6 – 100 mm | ±0.01 mm | Valve bodies, gland bodies, housings |
| CNC Turning + Milling (Live Tool) | Mazak Integrex, DMG MORI NTX | Ø6 – 150 mm | ±0.01 mm | Complex turn-mill components |
| 3-axis CNC Milling | Haas VF-2, Mazak VCN-430 | 500 × 400 mm | ±0.01 mm | Manifold blocks, flat components |
| 5-axis CNC Milling | DMG MORI DMU 50, Haas UMC-750 | 500 × 500 mm | ±0.005 mm | Complex multi-face parts, valve bodies |
International Equivalent Grades
| Standard | Designation | Country/Region |
|---|---|---|
| EN 12164 / EN 12167 | CW724R / CuZn21Si3P | EU / Europe |
| DIN 17660 | CuZn21Si3 | Germany |
| UNS (ASTM) | C87500 (approximate) | USA |
| ISO 426-1 | CuZn21Si3 | International |
| BS (UK) | CZ132 (approximate) | United Kingdom |
| JIS H 3250 (Japan) | C6782 (approximate) | Japan |
| GOST (Russia/CIS) | ЛМцС 50-1-1 (similar) | Russia / CIS |
| GB/T (China) | HSi80-3 (approximate) | China |
Product Types / Variants
| Product Variant | CNC Process | Diameter/Size | Typical Application |
|---|---|---|---|
| CNC Turned Components | CNC turning centre | Ø6 – 100 mm | Gland bodies, terminal housings |
| Swiss-Type CNC Parts | Swiss-type sliding head lathe | Ø1 – 32 mm | Contact pins, stems, long connectors |
| CNC Milled Parts | 3-axis / 5-axis machining centre | Up to 500 mm | Manifolds, valve bodies, blocks |
| Turn-Milled Components | CNC turn-mill (live tool) | Ø10 – 150 mm | Complex OEM components |
| CNC Machined Fasteners | CNC turning + rolling | M2 – M64, BSP, NPT | Precision Brass bolts, studs, inserts |
| Prototype / Sample Parts | Any CNC process | Per drawing | New product development, FAI |
Applications by Industry
| Industry | CW724R CNC Machined Components |
|---|---|
| Electrical / Switchgear OEM | Contact pins, cable gland bodies, terminal blocks, earth bars, compression connectors |
| Power Utilities / EPC | Substation connectors, compression lugs, earthing clamp bodies, grounding hardware |
| Potable Water (NSF/WRAS) | Ball valve bodies, manifold fittings, meter unions, push-fit inserts |
| Instrumentation | Thermocouple wells, pressure tap connectors, gauge adaptors, impulse line fittings |
| Automotive (ELV) | Fuel system connectors, coolant fittings, sensor housings, brake line adaptors |
| HVAC / Refrigeration | Valve bodies, service ports, flare fittings, refrigerant connector bodies |
| Electronics / RF | Coaxial connector shells, RF adaptors, PCB standoffs, EMI shielding components |
| Renewable Energy | Solar connector hardware, DC junction box fittings, grounding connector bodies |
Manufacturing Process
Raw material: EN 12164 certified CW724R (CuZn21Si3P) bright-drawn Brass rod (h9 tolerance) in diameters 3–65 mm, sourced from European or certified Indian mills with full EN 10204 3.1 MTC and XRF-verified alloy composition. Incoming inspection: 100% XRF spectrometer check for alloy composition and Pb content; hardness verification (Brinell); dimensional check on rod straightness and diameter. CNC machining: CAM programs loaded from engineering server to CNC controllers via DNC link; tool offsets set by pre-setter (Blum TC60); first-off parts fully dimensioned on CMM before production run start (APQP/PPAP compliant). Production monitoring: SPC charts on critical OD/ID dimensions; operator inspection every 25 parts on go/no-go gauges. Post-machining: vibratory deburring (Rösler), ultrasonic cleaning (Elma), bright acid dip (if specified). Quality inspection: AQL sampling per ISO 2859-1 on all outgoing lots; full CMM dimensional report on FAI and first deliveries; certificate of conformity with each shipment. Export packing: polybag with desiccant, bubble wrap for fragile assemblies, corrugated carton with moisture-barrier lining.
Quality Standards and Certifications
| Standard / Certification | Applicability |
|---|---|
| ISO 9001:2015 | Quality Management System – full manufacturing scope |
| EN 12164 / EN 12167 | CW724R rod and bar for CNC machining |
| RoHS 2 (2011/65/EU) | Lead-free compliance – Pb <0.09% |
| REACH (EC 1907/2006) | No SVHC substances at or above 0.1% w/w |
| NSF/ANSI 61 | Potable water contact components |
| WRAS (UK) | Water Regulations Advisory Scheme (upon request) |
| ELV Directive 2000/53/EC | Automotive end-of-life vehicles – lead-free compliance |
| ISO 286-1 | Tolerance system for linear dimensions (IT grades) |
| EN 10204 3.1 | Material test certificates with each production lot |
| ISO 6509 | Dezincification resistance – DZR classification |
Why Choose Electrical Accessories India for CW724R CNC Machined Parts
Electrical Accessories India is a specialist in CW724R Lead Free Brass CNC machining, with dedicated production lines, segregated material handling, and documented lead-free machining procedures. Our investment in Swiss-type CNC lathes, 5-axis machining centres, and CMM inspection equipment enables us to produce complex CW724R components to the tightest dimensional tolerances with full GD&T compliance. We supply to over 40 countries with competitive pricing at US$ 11.50/kg ex-works India, lead times of 3–6 weeks for new parts, and complete regulatory documentation (RoHS, REACH, NSF, WRAS, ELV). ISO 9001:2015 certified. Technical support available for DFM review, alloy selection, tooling advisory, and substitute material recommendations.
Frequently Asked Questions (FAQ)
What is CW724R (CuZn21Si3P) CNC machining Brass?
CW724R (CuZn21Si3P) is a lead-free Silicon Brass alloy designated under EN 12164 / EN 12167. It contains ~76% Copper, ~21% Zinc, 3% Silicon, and trace Phosphorus, with lead limited to 0.09% maximum. Silicon replaces lead as the chip-breaking element for CNC machining without the regulatory and health risks of lead aerosols.
What is the price of CW724R CNC machined parts?
Our ex-works India price is US$ 11.50 per kilogram for standard CNC machined CW724R parts. Complex multi-axis parts with tight tolerances, long cycle times, or special surface treatments may carry a surcharge. Submit your drawing for a specific quotation.
How does CW724R compare to CW614N (free-cutting Brass) for CNC machining?
CW614N (CuZn39Pb3) has a machinability index of 100%; CW724R achieves ~70%. With optimised carbide tooling and cutting parameters, CNC cycle times are 20–35% longer for CW724R. However, CW724R provides full RoHS/REACH/NSF compliance, superior dezincification resistance, and eliminates occupational health risk from lead machining dust — making it mandatory for EU and North American market products.
What tolerances can be achieved on CW724R CNC machined parts?
On our Swiss-type CNC lathes: diameter tolerance ±0.005 mm (IT6); concentricity TIR <0.005 mm; thread tolerance 6H/6g. On CNC machining centres: position tolerance ±0.01 mm (3-axis), ±0.005 mm (5-axis). Surface finish: Ra 0.4 μm on turned bores, Ra 0.8 μm standard machined surfaces.
Can you produce CW724R CNC machined parts to customer drawings?
Yes — we work entirely to customer-supplied 2D drawings (DXF, DWG, PDF) or 3D CAD models (STEP, IGES, SolidWorks, CATIA). We provide DFM review, CAM programming, prototype machining, first article inspection, and production supply in a complete new part development package.
What is the minimum order quantity for CW724R CNC machined parts?
Standard MOQ is 500 pieces for new production parts. Prototype/sample lots (10–100 pcs) are available for new part qualification. High-volume production runs (≥10,000 pcs) qualify for preferential pricing and dedicated machine scheduling.
What surface treatments are available for CW724R CNC machined parts?
As-machined, barrel polished, nickel plated (bright/satin), electroless nickel, tin plated (matte/bright), silver plated (1–50 μm), gold plated (flash or thick), zinc-nickel plated, trivalent chromate passivated, and phosphated. All plating processes are RoHS and REACH compliant (no hexavalent chromium, no lead-tin solder).
Is CW724R suitable for CNC machining of food and pharmaceutical contact parts?
CW724R is not specifically approved for direct food contact. For food contact applications, we recommend Stainless Steel 316L, copper-free aluminium, or PTFE-lined components. For potable water contact, CW724R is approved per NSF/ANSI 61 and EN 15664-1.
Do you offer 5-axis CNC machining of CW724R parts?
Yes. Our 5-axis machining centres (DMG MORI DMU 50, Haas UMC-750) produce complex CW724R components in a single setup, achieving superior geometric accuracy and eliminating multiple-setup alignment errors. Ideal for valve body internals, hydraulic manifold blocks, and multi-port electrical connector housings.
What countries do you export CW724R CNC machined parts to?
We export to Germany, UK, France, Netherlands, Italy, Spain, USA, Canada, UAE, Saudi Arabia, Qatar, South Africa, Australia, Singapore, and 30+ additional countries. Full export documentation: EN 10204 3.1 MTC, RoHS/REACH declaration, certificate of origin, and customs documentation for EU/USA/GCC import clearance.
International Terms and Equivalents
| Language | Equivalent Terms |
|---|---|
| Spanish (Español) | Piezas mecanizadas por CNC de latón CW724R sin plomo, Mecanizado CNC latón CuZn21Si3P, Latón sin plomo CNC |
| Russian (Русский) | Детали с ЧПУ обработкой из безсвинцовой латуни CW724R, CNC обработка латуни CuZn21Si3P, Безсвинцовая латунь ЧПУ |
| French (Français) | Pièces usinées CNC en laiton sans plomb CW724R, Usinage CNC laiton CuZn21Si3P, Laiton sans plomb CNC |
| Portuguese (Português) | Peças usinadas CNC em latão sem chumbo CW724R, Usinagem CNC latão CuZn21Si3P, Latão sem chumbo CNC |
| Italian (Italiano) | Parti lavorate a CNC in ottone senza piombo CW724R, Lavorazione CNC ottone CuZn21Si3P, Ottone senza piombo CNC |
Related Products / Internal Links
- CW724R (CuZn21Si3P) Lead Free Brass Machined Parts
- UNS C69300 ECO BRASS Lead Free Brass Machined Parts
- Lead Free Brass Screw Machine Parts
- Lead Free Brass Forgings
- Brass CNC Machined Parts (Standard)
- CW614N Brass Components and Parts
Request a Quote – Lead Free CW724R CNC Machined Parts
Electrical Accessories India – ISO 9001:2015 certified manufacturer of Lead Free CW724R (CuZn21Si3P) CNC machined parts. Swiss-type, 5-axis, and CNC turning. Price: US$ 11.50/kg ex-works India. Complete RoHS / REACH / NSF / ELV compliance documentation. Export to 40+ countries.
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