Due to its excellent machinability, thermal conductivity, electrical conductivity, and adaptability to mechanical processing, brass has become one of the most widely used non-ferrous metal materials in precision CNC machining. Across sectors such as precision machinery, electronics and electrical engineering, sanitary hardware, and automation components, brass parts are extensively utilized in products ranging from structural components, conductive elements, and valves to connectors and housings—a testament to their superior strength, ductility, corrosion resistance, and ease of machining. CNC machining offers distinct advantages, including high precision, exceptional consistency, and the capability to process complex geometries, thereby enabling fully automated production workflows for brass parts—from roughing to final finishing.
Superior Machinability: Brass exhibits low cutting resistance, produces easily broken chips, and resists tool adhesion. It allows for high-speed cutting, resulting in high processing efficiency and minimal tool wear—making it ideally suited for high-volume, precision CNC machining.
Exceptional Precision and Surface Finish: Post-machining, the material demonstrates high dimensional accuracy, excellent surface finish, and minimal thermal deformation, effortlessly meeting the assembly and aesthetic requirements of precision components.
Outstanding Comprehensive Performance:Brass possesses excellent electrical and thermal conductivity, as well as strong corrosion resistance. With a well-balanced combination of strength and ductility, it is highly adaptable for use across a wide range of sectors, including electronics, sanitary ware, machinery, and general hardware.
High Cost-Effectiveness for Mass Production: Characterized by a stable supply chain and moderate pricing, and when combined with efficient machining processes, brass offers significant cost advantages while simultaneously ensuring uncompromised quality.
Features: Free-cutting brass is the most widely used type of brass globally for CNC machining. Its most outstanding characteristics include superior machinability, stable chip formation, and minimal tool wear, enabling high-speed turning, milling, drilling, and tapping operations while yielding high surface finishes and easily controllable dimensional accuracy. Furthermore, it possesses excellent strength, wear resistance, and corrosion resistance, offering exceptional overall value.
Applications: High-precision, high-efficiency CNC machined parts, including precision electronic connectors, hydraulic and pneumatic fittings, valve cores, watch components, miniature shafts, fasteners, gears, bushings, and small instrument parts.
Features: Characterized by a balanced copper-to-zinc ratio and stable mechanical properties, this alloy exhibits strength superior to that of C36000. It features moderate cost, excellent machinability, and outstanding performance under both cold and hot pressure processing. Although its cutting performance is slightly lower than that of free-cutting brass, it remains fully capable of meeting standard CNC machining requirements. Furthermore, this grade demonstrates stable corrosion resistance, performing reliably in atmospheric and freshwater environments, making it well-suited for the fabrication of structural components subject to moderate loads.
Applications: General structural components requiring specific strength and rigidity—such as plumbing valves, pipe fittings, flanges, radiator assemblies, mechanical bases, decorative hardware, locks, and structural brackets.
Features: Characterized primarily by its exceptional plasticity, ductility, and deep-drawing capabilities, this material features a uniform microstructure and an aesthetically pleasing appearance, making it highly suitable for forming processes such as stamping, bending, and deep drawing. This specific grade exhibits excellent dimensional stability and superior surface finish, rendering it ideal for the fabrication of cosmetic components and thin-walled parts.
Applications: Components requiring high standards for formability and surface finish—such as precision thin-walled sleeves, electronic enclosures, shielding parts, elastic elements, instrument exterior components, decorative parts, jewelry hardware, and ultra-thin-walled structural parts.
Features: A typical seawater-resistant brass, this alloy is based on a copper-zinc matrix with the addition of tin, which significantly enhances its resistance to dezincification, seawater corrosion, and salt spray; it is, therefore, known as Naval Brass. This grade features high strength, excellent wear resistance, and superior machinability, making it suitable for long-term use in harsh environments such as marine settings, high-humidity conditions, and high-salt-spray atmospheres.
Applications: Precision components for marine engineering and highly corrosive environments—including shipboard equipment, seawater piping, marine valves, pump bodies, propeller accessories, offshore operational equipment, and corrosion-resistant fittings.
Features: Lead-free eco-friendly brass is characterized primarily by its lead-free composition, environmental compatibility, and safety. By substituting lead with elements such as bismuth, it maintains machining properties comparable to those of C36000 while complying with environmental standards such as RoHS and REACH. Non-toxic and harmless, it is suitable for applications involving contact with drinking water, food, and medical equipment.
Applications: Valves for drinking water systems, sanitary hardware, food machinery components, medical devices, children's products, structural parts for electronics and appliances, as well as precision CNC products—including those exported to markets with stringent environmental standards, such as Europe and the Americas.
The CNC machining process, primarily focused on C37710 and C36000 free-cutting brass, encompasses four core stages—tool selection, cutting parameters, cooling and lubrication, and process routing—and is accompanied by detailed parameter tables.
Tool Selection and Parameter Optimization:
Brass exhibits good plasticity and a tendency to adhere to cutting tools; therefore, the primary requirements for tooling are sharpness, efficient chip evacuation, and wear resistance. The specialized tools and parameters for each machining operation are detailed in the table below:
| Process | Type | Material | Parameters |
| Turning | External/Facing Turning Tools | Carbide (TiN/TiCN Coating) | Rake Angle: 15°–25°; Relief Angle: 8°–12°; Sharp Cutting Edge |
| Milling | 3-Flute End Mill | Ultra-Fine Grain Carbide | Helix Angle: 35°–45° — Suitable for Non-Ferrous Metal Machining |
| Drilling | Internal Coolant Drill | Carbide | Internal coolant channel structure ensures smooth chip evacuation. |
| Threading | Extrusion / Spiral Flute Tap | Carbide / HSS-E | Suitable for Brass: Resists Adhesion and Surface Roughness |
Cutting Parameter Settings:
Brass is well-suited for a "high spindle speed, medium-to-high feed rate" machining mode; roughing operations prioritize efficiency, while finishing operations prioritize precision. The parameters listed below are based on the C37710 alloy; for C28000 and C26800, the cutting speed should be reduced by 15% to 25%, while for C69300, it should be further reduced by 10% to 20%—accompanied by a reduction in feed rate—to prevent tool adhesion and surface tearing.
| Process | Cutting Speed (m/min) | Feed Rate | Cutting Depth (mm) |
| Rough Turning | 100~180 | 0.10~0.20 mm/rev | 1.0~3.0 |
| Finish Turning | 150~220 | 0.05~0.10 mm/rev | 0.1~0.5 |
| Rough Milling | 75~120 | 0.06–0.12 mm/fz | 0.5~1.5 |
| Finish Milling | 90~150 | 0.03~0.08 mm/fz | 0.1~0.3 |
Cooling and Lubrication Requirements:
Cooling and lubrication are critical to finishing operations; while roughing can be performed via dry cutting to control costs, finishing—as well as deep-hole and deep-cavity machining—requires flood cooling. For deep cavities, high-pressure internal cooling is recommended. The specific strategies for each stage are outlined in the table below:
| Machining Stage | Cooling Method | Cutting Fluid Concentration |
| Rough Machining | Dry Cutting / Conventional External Cooling | — |
| Finishing / Deep Hole Drilling / Cavity Machining | External Cooling + High-Pressure Internal Cooling | 5%–8% Emulsion / Semi-Synthetic Cutting Fluid |
Process Control:
Brass machining adheres to the "roughing → semi-finishing → finishing" principle, involving the judicious control of machining allowances and fixturing, as well as the timely inspection of tool wear, to ensure batch consistency. Specific requirements are detailed in the table below:
| Machining Stage | Machining Allowance | Key Control Points |
| Rough Machining | 0.3–0.6 mm | Efficient material removal; relieves internal stress. |
| Semi-finishing | 0.1–0.25 mm | Uniform allowance; shape correction |
| Finishing | Final Dimensions | Guaranteed Tolerance: ±0.01 mm, Ra 0.8–1.6 μm |
| Workholding and Protection | — | Add support for thin-walled parts; use a steady rest for long shafts to prevent deformation. |
Precision Miniature Cylindrical Spur Gear
Worm Gear
Swiss Screw Machining Brass Contact Pin
Brass Hex Nipple
Brass Foot Pad
Threaded Solid Brass Male-Female Hexagonal Standoffs
CNC Machining of Precision Brass Parts
CNC Machining of Precision Brass Parts
A: To resolve issues involving tool adhesion and BUE, it is necessary to adjust cutting speeds and feed rates according to the specific brass grade being processed. Select carbide tools featuring appropriate rake and clearance angles, and utilize a 5%–8% emulsion or semi-synthetic cutting fluid for cooling and lubrication. Furthermore, optimize tool geometry parameters, enhance chip evacuation efficiency, and promptly replace tools with sharp ones to minimize material adhesion and BUE formation, thereby ensuring a smooth machining process.
A: To control dimensional deviations, cutting parameters must be optimized by reducing the depth of cut and appropriately regulating the feed rate. Cooling and lubrication efforts should be intensified to minimize thermal deformation. Additionally, strictly adhere to the principle of separating roughing and finishing operations to relieve internal material stresses, thereby ensuring stable dimensional accuracy and preventing deviations caused by temperature fluctuations or tool wear.
A: To enhance the surface quality of machined brass, select sharp carbide tools and appropriately adjust cutting parameters—specifically, increase the rake angle to reduce cutting resistance. Simultaneously, intensify cooling and lubrication (avoiding dry cutting), promptly replace worn tools, optimize chip evacuation efficiency, and minimize vibrations. These measures will eliminate surface roughness and tool marks, thereby improving the overall surface finish.
A: To resolve issues involving chip entanglement and clogging, select 3-flute milling cutters and internal-coolant drills known for their superior chip evacuation capabilities. Adjust cutting parameters to increase the feed rate, and employ high-pressure internal cooling to promptly flush away chips. Furthermore, optimize the tool's flute geometry and helix angle to promote chip breakage, prevent chips from entangling with the workpiece, and ensure smooth chip evacuation.
A: To ensure the machining precision of brass holes, it is necessary to select internal-coolant drill bits with high centering accuracy; minimize tool overhang to enhance rigidity; carefully control the feed rate to prevent deflection; and simultaneously reinforce clamping stability by adding auxiliary supports. Furthermore, the material hardness should be verified and the cutting speed adjusted to ensure a stable drilling process, thereby avoiding dimensional deviations and alignment errors.
A: To resolve issues involving thread stripping and incomplete thread profiles, one must select specialized taps specifically designed for brass. Key measures include reducing the cutting speed, maintaining a uniform feed rate, enhancing cooling and lubrication through the use of emulsion fluids, and promptly replacing worn taps. Additionally, it is crucial to strictly control the size of the pilot hole and adjust machining parameters according to the specific grade of brass being processed, thereby preventing tap-to-workpiece adhesion and ensuring high-quality thread formation.
