Creating metal parts requires a strategic blend of material science, precision engineering, and manufacturing expertise. Whether for automotive components, industrial machinery, or aerospace parts, the process demands strict adherence to tolerance (±0.005mm to ±0.5mm), material properties, and functional requirements. Goldcattle, with 26 years in metal fabrication, outlines the step-by-step process to create high-quality metal parts—from design to production—using technologies like CNC machining, forging, casting, and welding.
How to Create Metal Parts?

Step 1: Define Requirements & Material Selection

The foundation of creating metal parts lies in clarifying performance needs and selecting the right material. This phase ensures the final part meets strength, corrosion resistance, and cost targets.

Key Considerations:

  • Functional requirements: Load capacity (tensile strength ≥300MPa for structural parts), temperature resistance (-40℃ to 500℃), and environmental exposure (saltwater, chemicals). For example, a marine bolt requires 316L stainless steel (515MPa tensile strength, 1,500+ hours salt spray resistance) instead of carbon steel.
  • Material properties: Match metals to application needs:
Metal Material
Tensile Strength
Corrosion Resistance
Primary Applications
Carbon Steel (1045)
620MPa
Low (rusts in moisture)
Structural brackets, machinery parts
Stainless Steel (304)
515MPa
High (1,000+ hours salt spray)
Food processing equipment, marine parts
Aluminum (6061-T6)
310MPa
Moderate (anodizable)
Automotive components, electronics
Titanium (Ti-6Al-4V)
895MPa
Excellent (resists seawater)
Aerospace parts, medical implants
  • Cost vs. performance: Balance material expense with longevity. For example, 304 stainless steel costs 3x more than carbon steel but lasts 10x longer in wet environments.

Step 2: Design & Engineering (DFM)

Design for Manufacturability (DFM) ensures the part can be produced efficiently while meeting specifications. Use CAD software (SolidWorks, AutoCAD) to optimize geometry and avoid production bottlenecks.

Critical Design Elements:

  • Tolerance definition: Specify achievable tolerances based on manufacturing method (e.g., ±0.005mm for CNC machining, ±0.1mm for casting). A precision gear requires ±0.01mm tooth spacing, while a bracket may tolerate ±0.5mm.
  • Feature optimization:
    • Avoid sharp internal corners (use 0.5mm radii) to prevent stress concentration in CNC-machined parts.
    • Design uniform wall thickness (≥2mm for cast parts) to prevent cooling defects in aluminum casting.
    • Include draft angles (1-3°) in injection-molded metal parts for easy removal from molds.
  • FEA simulation: Test virtual prototypes for stress, vibration, and thermal performance. A 4140 steel axle designed with FEA showed a 20% weight reduction by optimizing rib thickness without compromising strength.

Step 3: Choose Manufacturing Process

Select the production method based on part complexity, volume, and material. Goldcattle specializes in four core processes:

1. CNC Machining (Best for Precision, Low-Medium Volume)

  • Process: Removes material from solid blocks using 3-5 axis CNC mills/turning centers, achieving ±0.005mm tolerance.
  • Applications: Complex parts with tight tolerances (e.g., aerospace fittings, medical instruments). A 6061 aluminum valve body with 12 precision holes (0.003mm positional accuracy) is machined in 2 hours per part.
  • Advantages: High precision, Suitable for a variety of materials，no tooling costs for small batches (1-100 units).

2. Forging (Best for High-Strength, Medium-High Volume)

  • Process: Compresses heated metal (700-1,200℃) into dies to shape parts, aligning grain structure for 30% higher strength than machining.
  • Applications: Crankshafts, gears, and structural parts. A 4340 steel forging for a truck axle withstands 100,000+ load cycles without fatigue failure.
  • Advantages: Superior strength, Suitable for mass production (1,000+ units), cost-effective for large parts.

3. Casting (Best for Complex Shapes, High Volume)

  • Process: Pours molten metal into molds (sand, die, or investment casting) to create intricate shapes. Aluminum die casting produces parts with ±0.1mm tolerance at 100+ units/hour.
  • Applications: Engine blocks, pump housings. A 316L stainless steel investment casting for a valve body includes internal channels impossible to machine cost-effectively.
  • Advantages: Complex geometry capability, low per-unit cost for high volumes (10,000+ units).

4. Welding & Assembly (Best for Large/Composite Parts)

  • Process: Joins metal components using MIG/TIG welding (steel/aluminum) or laser welding (titanium), ensuring 99% weld penetration and tensile strength ≥80% of base metal.
  • Applications: Truck frames, industrial machinery. A 6m steel frame welded with robotic MIG welders achieves 0.5mm straightness over its length, critical for alignment.
  • Advantages: Enables large/hybrid parts, reduces material waste vs. solid machining.

Step 4: Prototyping & Testing

Before full production, create prototypes to validate fit, function, and manufacturability.

Prototype Methods:

  • CNC machined prototypes: Produce 1-10 functional parts in 3-5 days for fit testing. A stainless steel bracket prototype undergoes load testing (10,000 cycles at 500N) to verify strength.
  • 3D printed metal prototypes: Uses SLM (Selective Laser Melting) to create titanium or stainless steel parts with 0.1mm layer resolution, ideal for complex geometries (e.g., lattice structures).
  • Validation tests:
    • Dimensional inspection (CMM for ±0.001mm accuracy).
    • Material testing (tensile, hardness, corrosion resistance).
    • Functional testing (e.g., pressure testing for fluid-carrying parts at 150% of rated pressure).

Step 5: Production & Quality Control

Full-scale production requires consistent processes and rigorous quality checks to ensure every part meets standards.

Production Technologies:

  • Automated CNC machining: 5-axis CNC centers with robotic loading produce 500+ parts/day with ±0.005mm tolerance. In-process probing corrects tool wear (≤0.002mm) for uninterrupted accuracy.
  • Die casting automation: High-pressure die casting machines (4,000 tons clamping force) produce 1,000+ aluminum parts/day, with X-ray inspection to detect internal defects (≥0.5mm voids).
  • Welding robotics: 6-axis robots perform MIG welding with 0.1mm torch positioning accuracy, ensuring consistent bead geometry (3-5mm width) across 10,000+ welds.

Quality Assurance:

  • Statistical Process Control (SPC): Monitors critical dimensions (e.g., diameter, thickness) with CPK ≥1.33, ensuring 99.97% of parts meet specifications.
  • Non-destructive testing (NDT): Ultrasonic testing detects subsurface defects in forged parts; dye penetrant testing identifies surface cracks in welded joints.
  • Final inspection: 100% visual inspection for surface finish (Ra ≤0.8μm for critical areas) and functional testing (e.g., torque testing for bolts to 120% of rated torque).

Step 6: Finishing & Surface Treatment

Protect metal parts from corrosion, enhance aesthetics, or improve functionality with tailored finishes:
  • Painting & powder coating: Applies 60-100μm layers (epoxy/polyester) for corrosion resistance (1,000+ hours salt spray) and color customization (ΔE <1).
  • Plating: Chrome plating (0.05mm thickness) for decorative parts; zinc plating for bolts (1,000+ hours corrosion resistance).
  • Anodizing: Creates 5-25μm oxide layers on aluminum (6061-T6) for wear resistance (300HV hardness) and dye acceptance (custom colors).
  • Heat treatment: Hardens steel parts (e.g., 4140 steel quenched to 50-55 HRC) for wear resistance; anneals aluminum to reduce brittleness.

Common Challenges & Solutions in Metal Part Production

  • Warpage in thin parts: Use stress-relief annealing (600℃ for steel) and fixture-based machining to reduce distortion by 80%.
  • Corrosion in high-moisture environments: Select 316L stainless steel or apply duplex coatings (zinc + epoxy) for 2,000+ hours salt spray resistance.
  • Tolerance stack-up in assemblies: Design with GD&T (Geometric Dimensioning and Tolerancing) to control cumulative variation, ensuring ≤0.1mm total assembly gap.

Why Partner with Goldcattle for Metal Part Production?

Goldcattle’s 26-year expertise in metal manufacturing ensures:
  • Material-optimized processes (e.g., CNC machining for precision, forging for strength).
  • Strict quality control (ISO 9001, IATF 16949) with 99.95% part acceptance rate.
  • Scalable production (1-100,000+ units) with lead times as short as 3 days for prototypes.
Upload your part drawings (STEP/IGES) or requirements via our online form to receive a free DFM analysis, material recommendation, and quote within 24 hours. Let’s turn your metal part design into a high-performance reality.
“Goldcattle’s CNC-machined titanium parts for our aerospace project achieved ±0.003mm tolerance—critical for our 8G load requirements. Their attention to material selection and process control eliminated rework entirely.” — Aerospace Component Client

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