2026년 CNC 가공 재료 선택 가이드
응용 분야별 CNC 가공 재료 선택을 위한 실용 가이드. 알루미늄, 스테인리스, 티타늄, 황동, 플라스틱 — 절충안 설명.
재료 선택은 보통 CNC 부품의 비용, 무게, 가공성 및 최종 성능에 영향을 미치는 가장 중요한 단일 결정입니다. 이 가이드는 JLYPT가 매일 가공하는 재료와 각 재료가 어디에 속하는지 — 작업장 바닥에서 작성된 — 안내합니다.
How to think about material choice
Most material decisions can be reduced to four questions, in order:
- Mechanical requirements — yield strength, fatigue, stiffness, weight target, operating temperature.
- Environment — corrosion, chemicals, UV, food/medical contact, sterilisation cycles.
- Machinability and cost — how fast it cuts, how much the bar stock costs, what tooling wear to expect.
- Finishing and downstream processes — does it anodise, plate, weld, paint, glue?
Aluminium alloys — the workhorses
Aluminium dominates CNC work because it cuts fast, takes a beautiful surface, anodises in any colour, and weighs a third as much as steel. For most consumer and industrial parts, the question is which aluminium alloy, not whether to use aluminium.
| Alloy | Yield (MPa) | Best for | Trade-off |
|---|---|---|---|
| 6061-T6 | 276 | General-purpose: housings, brackets, fixtures | Moderate strength; most common |
| 6063-T5 | 215 | Extruded profiles, decorative anodised parts | Softer; slightly worse machined finish |
| 7075-T6 | 503 | Aerospace, motorsport, structural | Harder to machine, less corrosion resistant, anodises poorly |
| 2024-T351 | 345 | Aerospace skin, fatigue-loaded parts | Susceptible to stress corrosion; usually clad |
| 5052 | 193 | Marine, sheet-metal-style folded brackets | Lower strength but excellent corrosion resistance |
| MIC-6 / cast tool | 170 | Vacuum chucks, optical bases, tooling plates | Stable but heavy; rarely used for end-use parts |
Carbon and stainless steels
When strength, fatigue resistance or corrosion in aggressive environments matters, steel is the answer. Three families cover almost everything we machine:
Carbon & alloy steels
- 1018, 1045 — cheap, weldable, easy to machine. Good for shafts, jigs, low-stress brackets.
- 4140, 4340 — pre-hardened or heat-treatable to ~50 HRC. Used for gears, drive shafts, tool holders.
- Will rust without coating — plate, paint or oil.
Stainless steels
- 303 — free-machining, but worse corrosion resistance and not weldable.
- 304 — the default food/marine grade.
- 316L — superior corrosion resistance, medical-implant grade.
- 17-4PH — precipitation-hardened, ~40 HRC, aerospace and pumps.
- 15-5PH — similar to 17-4 with better transverse properties.
For surface treatment of steel parts, see our surface finishing services — passivation for stainless, black oxide for tool steel, electroless nickel for carbon steel.
Titanium and superalloys
Titanium and nickel superalloys are the answer when no other material works — typically aerospace, medical implants, downhole oil tools and high-end motorsport.
| Material | Strength | Density (g/cm³) | Typical use |
|---|---|---|---|
| Ti-6Al-4V (Grade 5) | 895 MPa | 4.43 | Aerospace structural, bicycle frames, surgical implants |
| CP Titanium (Grade 2) | 275 MPa | 4.51 | Chemical processing, marine |
| Inconel 718 | 1240 MPa | 8.19 | Jet engine hot section, downhole tools |
| Inconel 625 | 760 MPa | 8.44 | Marine seawater, chemical processing |
| Hastelloy C-276 | 690 MPa | 8.89 | Worst-case chemical environments |
| Monel 400 | 241 MPa | 8.80 | Seawater, hydrofluoric acid |
Brass, bronze and copper
Copper-based alloys are niche but indispensable for electrical, plumbing and decorative work.
- C360 brass (free-machining). Cuts like butter, ideal for valves, fittings, electrical components and decorative hardware.
- C932 bearing bronze. Self-lubricating; bushings, gears, marine fittings.
- C110 (oxygen-free copper). Best electrical and thermal conductivity; bus bars, heat sinks, RF.
- Beryllium copper (C17200). Springs, non-sparking tools, EMI gaskets — but requires careful handling due to dust hazards.
Engineering plastics
CNC-machined plastics fill applications where metal is too heavy, too conductive or too expensive. Sheet stock and extruded rod are routinely turned and milled to ±0.05 mm tolerances.
| Material | Strengths | Watch out for |
|---|---|---|
| Delrin / POM | Low friction, dimensional stability, machines cleanly | Difficult to glue; weak in UV |
| Nylon (PA6, PA66) | Wear resistance, gears, bushings | Absorbs moisture and grows ~2% |
| PTFE (Teflon) | Chemical inert, very low friction, –200 to +260°C | Soft, creeps under load |
| Polycarbonate (PC) | Optical clarity, impact resistance | Scratches easily; chemical sensitive |
| Acrylic (PMMA) | Optical clarity, easy to polish | Brittle, not for impact |
| PEEK | Aerospace/medical, –60 to +250°C, autoclavable | Very expensive (~$300/kg bar stock) |
| UHMW-PE | Wear resistance, chemical inert, food-safe | Difficult to machine to tight tolerance |
For micro-features in plastics — sub-millimetre walls, optical surfaces — see our micro-machining services.
Materials at a glance
A condensed reference for selecting a starting material based on your top requirement:
| Top requirement | Start with | Upgrade path |
|---|---|---|
| Cheap and good enough | 6061 aluminium | 7075 → 17-4PH |
| Strength-to-weight | 7075 aluminium | Ti-6Al-4V |
| Corrosion resistance | 316L stainless | Hastelloy C-276 / Monel |
| Wear resistance, low friction | Hardened 4140 + DLC coat | Tool steel (D2, A2) |
| Heat resistance (>500°C) | Inconel 625 | Inconel 718, Waspaloy |
| Electrical conductivity | C110 copper | Silver-plated copper |
| Thermal conductivity (heat sinks) | 6061 aluminium | C110 copper |
| Optical clarity | Acrylic (PMMA) | Polycarbonate |
| Food contact / sterilisation | 316L stainless | PEEK for plastics |
| Magnetic permeability needed | 1018 carbon steel | 4140 hardened |
| Non-magnetic (MRI rooms) | 316L stainless or Ti | Beryllium copper |
Material × finish compatibility
The chosen surface finish often constrains the material. Always check both before locking the design:
| Finish | Compatible materials | Not compatible |
|---|---|---|
| Type-II anodising (decorative + protection) | 6061, 6063, 5052 | 7075 (poor cosmetic finish) |
| Type-III hard anodising | 6061, 7075, 2024 | 5xxx series (some grades) |
| Bead blasting | Most metals and plastics | Anything that must remain optical |
| Powder coating | Aluminium, steel, stainless | Plastics (heat-sensitive) |
| Electropolishing | Stainless 316L, 304 | Carbon steel |
| Black oxide | Carbon and tool steels | Stainless (only specific grades) |
| PVD coating | Stainless, tool steel, carbide | Aluminium (substrate softens at coating temp) |
Read more about specific finishes in surface finishing and PVD coating.
자주 묻는 질문
- 알루미늄 6061이 큰 차이로. 봉재가 저렴하고 빠르게 절삭되며 모든 표준 마감을 수용합니다. JLYPT 산업 작업의 약 70%가 6061입니다.
- 대부분 예, 그러나 다른 공구로. 티타늄과 니켈 슈퍼합금은 더 느린 절삭 속도와 날카로운 공구가 필요합니다. 마그네슘은 특수 화재 진압이 필요합니다.
- 실용적으로: Ti-6Al-4V는 피로를 포함할 때 7075 알루미늄을 약간 능가합니다. 순수 인장 강도 대 중량비의 경우 현대 탄소 섬유 복합재가 이깁니다.
- 양극 산화 색상은 합금, 욕조 화학, 타이밍에 따라 다릅니다. 동일 배치 = 좋은 일치. 다른 배치 = 약간의 변동. 중요한 작업은 단일 배치로 처리해야 합니다.
- 부품이 지속적으로 습기, 염분 또는 화학물질에 노출된다면 스테인리스로. 건조한 실내 환경의 경우 아연 도금/도장 탄소강이 훨씬 저렴합니다.
- 종종 아닙니다. 3D 프린팅된 Ti-6Al-4V 부품은 CNC 가공된 것과 다른 재료 등급입니다. 인증된 항공우주 또는 의료 작업의 경우 둘은 별도의 자격 없이는 대체할 수 없습니다. CNC vs 3D 프린팅 비교 참조.
- 네 — 일반 합금(6061, 7075, 304, 316L, Ti 5등급, Delrin, PEEK)을 재고로 보유하며 전체 재료 시험 보고서(MTR) 및 적합성 인증서와 함께 특수 재료를 조달할 수 있습니다.
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저자 소개
JLYPT Engineering Team
Senior CNC Application Engineers
Our application engineering team brings 15+ years of combined experience producing precision components for aerospace, medical, robotics and industrial automation customers.
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