CNC 가공 대 3D 프린팅 대 사출 성형: 올바른 제조 방법을 선택하는 방법

CNC 이는 여러 대안을 비교하고, 한계를 확인하며, 위험이 적은 공정을 선택해야 할 때 유용한 공학적 주제입니다.

This cnc machining vs 3d printing vs injection molding comparison guide explains practical material, design, manufacturing, and sourcing considerations for Nylon Plastic readers.

최종 업데이트: 2026년 4월 17일

Choosing between CNC machining, 3D printing, and injection molding is a critical decision that affects cost, lead time, part quality, and production volume. Here’s a practical framework for making the right choice for your project.

Production Volume: The Primary Decision Factor

Injection Molding: Most cost-effective above 1,000+ units. High upfront tooling cost (USD 3,000-30,000+) but extremely low per-unit cost at scale.

CNC Machining: Ideal for 1-500 units. No tooling cost, fast turnaround, and excellent precision. Per-unit cost is constant regardless of volume.

3D Printing: Most economical for 1-50 units. No tooling required, design freedom is unlimited, but per-unit cost doesn’t decrease significantly with volume.

소재 옵션

CNC Machining: Works with virtually any machinable material — metals, plastics, composites. Full material properties are preserved since parts are machined from solid stock.

3D Printing: Limited to available filament/resin/powder materials. Some material properties are anisotropic (direction-dependent) due to layer-by-layer deposition.

Injection Molding: Thousands of material grades available in pellet form. Can mold engineered polymers, glass fiber composites, and metal injection molding powders.

Precision and Surface Finish

CNC Machining: ±0.01mm tolerance capability, Ra 0.8-3.2µm surface finish as machined. Post-processing (polishing, anodizing) available for superior finishes.

3D Printing: ±0.1-0.3mm typical tolerance. Layer lines visible on most technologies. Some processes (SLA/DLP) offer smoother surfaces.

Injection Molding: ±0.05-0.1mm tolerance. As-molded surface depends on mold quality; high-polish molds produce mirror-finish parts.

Lead Time Comparison

• CNC Machining: 3-7 days for prototypes
• 3D Printing: 1-3 days for most parts
• Injection Molding: 4-8 weeks including tooling (rapid tooling: 2-3 weeks)

Design Complexity

3D 프린팅 offers the greatest design freedom — complex geometries, internal channels, and organic shapes are possible without additional cost. CNC 가공 is limited by tool access and undercut restrictions. 사출 성형 requires draft angles, uniform wall thickness, and consideration of part ejection.

When to Use Each Method

• CNC Machining: Functional prototypes, low-volume production, tight tolerance parts, metal components
• 3D Printing: Concept models, complex geometries, small batch functional parts, jigs and fixtures
• Injection Molding: High-volume production, cosmetic parts, consistent quality across thousands of units

A Combined Approach Is Common

Many manufacturers use a staged approach: 3D printing for initial prototypes, CNC machining for functional testing, and injection molding for final production. At Nylonplastic, we offer all three services in-house with integrated quality control, allowing you to transition seamlessly between manufacturing methods.