Aluminum Alloy CNC Hardware Parts Casing Custom Parts Machining Services

I. Material Selection for Coffee Machine Hardware Parts (Classified by Application Scenarios)

1. Core Food-Contact Components (Boilers, Brew Heads, Portafilter Baskets, Water Circuit Joints, Valves)

• Advantages: Compliant with GB 4806.9-2023 national food contact standards, no heavy metal migration; resistant to corrosion from hot water, steam and coffee liquid, rust-proof, no patina formation, high structural strength, deformation resistance, easy cleaning and long service life.
• Application: Boilers, brew heads, portafilter baskets, high-pressure joints, steam pipe connectors, filter screens, etc.
• Grade Selection: 304 offers cost-effectiveness, suitable for both household and commercial coffee machines; 316L provides better resistance to chloride ions (adaptable to poor water quality & cleaning agents), preferred for high-end commercial equipment.

• Advantages: Excellent thermal conductivity & stable temperature control (ideal for boilers/brew heads); superior machinability for precise thread processing and reliable sealing; uniform thermal expansion & contraction to resist stress cracking.
• Risks: Prone to patina and heavy metal precipitation; must be treated with food-grade nickel/chromium plating or passivation, with plating temperature resistance ≥150℃ and anti-peeling durability.
• Application: Small & medium-sized boilers, water circuit joints, valves, handle bases (non-direct coffee liquid contact parts).

2. Structural/Shell/Non-Contact Parts (Brackets, Outer Casings, Handles, Knobs, Bases)

• Advantages: Lightweight, good thermal conductivity, easy die-casting/CNC machining, cost-controllable; anodized surface features wear resistance, corrosion resistance, easy cleaning and premium appearance.
• Application: Outer casings, brackets, handles, knobs, non-pressure-bearing structural parts.

• Advantages: High-end texture, durability and easy cleaning; suitable for outer casings & decorative parts of high-end models.

3. Sealing/Wear-Resistant Auxiliary Parts (Valve Cores, Valve Seats, Gaskets, Bearings)

• PTFE (Teflon): High temperature resistance (-200~260℃), chemical inertness, low friction and odor-free, used for high-temperature sealing & valve cores.
• Ceramics: Wear-resistant, corrosion-resistant and metal-contamination-free, applied for grinding discs and valve cores.
• Food-grade Silicone/EPDM: Used for O-rings and gaskets, featuring temperature resistance, aging resistance and excellent sealing performance.

General Principles of Material Selection

• Direct contact with coffee/hot water/steam: Food-grade 304/316L stainless steel > Food-grade plated brass
• Non-contact structural/shell parts: Anodized aluminum alloy > Stainless steel
• Sealing/wear-resistant parts: PTFE/Ceramics > Food-grade rubber

II. Machining Pitfall Avoidance (Classified by Process, Risks & Solutions)

1. CNC Machining (Stainless Steel/Brass/Aluminum Alloy)

(1) Machining Pitfalls of 304/316 Stainless Steel

• Pitfall 1: Severe work hardening, tool sticking & rapid tool wear

   

  Causes: High toughness & poor thermal conductivity of stainless steel, concentrated cutting heat and hardened layer formation.

   

  Solutions:
   
  • Tools: Cobalt-containing high-speed steel / coated carbide tools (TiCN/AlTiN) for sharpness and wear resistance.
  • Parameters: Low rotating speed, moderate feed rate, large cutting depth, one-time forming to avoid secondary cutting hardening.
  • Cooling: High-pressure sufficient extreme-pressure cutting fluid for forced cooling and chip removal.
   
• Pitfall 2: Deformation of thin-walled/slender parts

   

  Causes: Clamping force, cutting force and internal stress-induced deformation.

   

  Solutions: Special tooling (soft jaws/vacuum fixtures), step-by-step cutting, stress relief annealing (300~400℃ heat preservation) and post-machining aging treatment.
   
• Pitfall 3: Surface scratches & oxidation

   

  Solutions: Special cutting fluid, timely cleaning, passivation/electropolishing to enhance corrosion resistance and surface finish.

(2) Machining Pitfalls of Brass

• Pitfall 1: Surface black spots, oxidation & patina

   

  Causes: Residual cutting fluid, steel particle contamination, overheating during machining and incomplete cleaning.

   

  Solutions:
   
  • Equipment: Dedicated machines/tools for brass, separate from steel part processing.
  • Cooling: Non-corrosive fully synthetic cutting fluid with controlled pH value and regular cleaning.
  • Post-treatment: Thorough cleaning + passivation + food-grade plating to eliminate patina.
   
• Pitfall 2: Poor thread precision & water leakage failure

   

  Solutions: High-precision taps/tools, stable machining parameters, dedicated fixtures and 100% go/no-go gauge inspection.

(3) Machining Pitfalls of Aluminum Alloy

• Pitfall: Tool sticking, surface white spots & oxidation
   
  Solutions: Special aluminum alloy tools & cutting fluid, high rotating speed & large feed rate, timely cleaning and anodizing treatment.

2. Stamping/Deep Drawing (Outer casings, brackets, thin-walled parts)

• Pitfall 1: Dimensional deviation & large springback (especially stainless steel)

   

  Solutions: Die springback compensation, precise clearance (8%~12% of material thickness), additional shaping processes, stable blank holder force and stress relief treatment.
   
• Pitfall 2: Wrinkling, cracking & burrs

   

  Solutions: Reasonable die fillet radius, step-by-step deep drawing, high-quality lubrication, controlled stamping speed and timely deburring (vibratory grinding/polishing).

3. Welding & Assembly (Boilers, pipelines, structural components)

• Pitfall 1: Weld porosity, slag inclusion & corrosion susceptibility

   

  Solutions: Complete degreasing/oxide removal before welding, high-purity shielding gas, standardized welding parameters and post-weld pickling & passivation.
   
• Pitfall 2: Assembly deformation & sealing failure

   

  Solutions: Tooling positioning, step-by-step fastening, food-grade thread sealant application and pressure testing (1.5 times working pressure).

4. Surface Treatment (Core: Food Safety & Corrosion Resistance)

• Pitfall 1: Plating peeling & heavy metal precipitation

   

  Solutions: Food-grade nickel/chromium plating/passivation, strict coating thickness/adhesion/salt spray testing and compliance with food contact standards.
   
• Pitfall 2: Rough surfaces, easy scaling & difficult cleaning

   

  Solutions: Polishing with Ra≤0.8μm, electropolishing and passivation to improve surface finish and corrosion resistance.

Universal Non-Negotiable Machining Rules

1. No mixed materials/production lines for food-contact parts: Separate production lines, tools and cutting fluids for stainless steel, brass and aluminum alloy to avoid cross-contamination.
2. All coffee/water contact surfaces must be burr-free, sharp-edge-free, crack-free and residue-free, with 100% cleaning & inspection.
3. Match materials with corresponding machining processes: Do not use brass machining parameters for stainless steel, or steel tools for brass processing, to prevent mass scrap loss.
4. Full verification is mandatory: Material certificates, food contact safety testing, pressure testing, salt spray testing and service life testing.

     We have introduced advanced equipment and technology from Japan and Germany (CNC 5-axis and 6-axis machines) to better serve our customers' needs.

    Our maximum processing outer diameter is 60, and the minimum control tolerance is 0.001. We have Japanese CNC Tsugami, CNC Citizen, multi-station cold extrusion forming machines, 500T press machines, casting equipment, and various process equipment, which can effectively provide customers with the best technical solutions.

   Our company has a total of 300 employees, including 20 technicians, 10 engineers, and 15 quality control personnel. We have over 300 pieces of equipment.

   Our company implements 8S management and has passed ISO9001 and TS16949 automotive certifications.

   Our customers include Siemens, bo-sch, Foxconn, Panasonic Motors, Husqvarna, Shimano, NVIDIA, DJI Drones, Siegenia, and Cater-pillar.