Selecting the correct mold steel is the foundational engineering choice that dictates tool life, thermal cycle times, surface polishability, and corrosion resistance during plastic injection molding. Tool steel choices range from pre-hardened P20 and 718H for cost-effective medium-volume production to fully hardened S136 stainless steel and H13 tool steel (52+ HRC) for 1,000,000+ shot Class 101 molds. At Jucheng Precision, a certified ISO 9001 and IATF 16949 contract manufacturer, we specialize in high-hardness steel mold building. Utilizing 25+ in-house 5-axis CNC machining centers, vacuum heat treatment, and SPI A-1 diamond mirror polishing, we machine steel cavities to ±0.005mm tolerances verified by Zeiss CMM inspection.
中量産ラン用の経済的な金型ソリューションを確保しながら、機械加工後の熱処理歪みを排除するには、設計された予硬鋼が必要であり、AISI P20（DIN 1.2311）金型鋼がそれを提供します。均一な28～34 HRCに予硬されたP20鋼は、優れた被削性、均一な芯部硬度、およびSPI B-2仕上げまでの良好な研磨性を提供します。ISO 9001およびIATF 16949認定の受託製造業者であるJucheng Precisionでは、P20鋼金型キャビティインサートの5軸CNC加工を専門としています。最大500,000サイクルの金型寿命を提供し、当社のP20射出成形金型は、汎用およびエンジニアリング熱可塑性プラスチックを処理し、Zeiss CMM検査で検証されています。.
抵抗纖維增強化合物引起的嚴重磨料工具磨損，並在無熱裂紋的情況下承受快速熱循環，需要高硬度熱作合金，而AISI H13（DIN 1.2344）工具鋼正是如此。經真空淬火並三次回火至50–54 HRC，H13鉻鉬釩鋼提供卓越的抗熱衝擊性、高抗壓強度和不屈不撓的澆口耐磨性。在巨城精密，一家通過ISO 9001和IATF 16949認證的合約製造商，我們專注於H13鋼模具型腔的5軸CNC加工。我們的H13模具提供超過1,000,000次循環的101級工具壽命，可靠地加工高溫超級聚合物和磨料填充樹脂，並經由Zeiss CMM檢測驗證。.
高純度の医療用および光学用成形において、微細な表面ピッティングを排除し、金型キャビティ壁を酸性のアウトガスから保護するには、エレクトロスラグ再溶解ステンレス合金が必要であり、S136金型鋼がそれを提供します。48〜52 HRCに真空焼入れされたESR S136ステンレス工具鋼は、13.6%のクロムを含み、冷却ラインの錆や腐食性ポリマー分解に対する卓越した耐性を提供します。ISO 9001およびISO 13485認証の受託製造業者であるJucheng Precisionでは、S136鋼製金型インサートの5軸CNC加工とダイヤモンド鏡面研磨に特化しています。SPI A-1光学表面仕上げを達成し、当社のS136量産金型は、Zeiss CMM検査で検証された100万ショット以上の耐久性を保証します。.
大型金型ブロックの熱処理焼き入れ歪みを排除しつつ、標準的なP20を超える優れたコア硬度の均一性を確保するには、高度なニッケル合金プリハードン鋼が必要であり、718H（DIN 1.2738）金型鋼がそれを実現します。均一な32～38 HRCにプリハードンされた718H鋼は、ニッケル添加物を含み、厚さ400mmまでの厚い工具断面全体で一貫した硬度を保証し、微細なSPI B-1研磨と鮮明なフォトエッチングテクスチャを実現します。ISO 9001およびIATF 16949認定の受託製造業者であるJucheng Precisionでは、大型718鋼金型キャビティの5軸CNC加工を専門としています。最大500,000サイクル以上の工具寿命を提供し、当社の718金型は自動車パネルや家電製品の筐体を確実に加工し、Zeiss CMM検査で検証されています。.
Achieving an optimal balance between pre-hardened core steel strength, pinhole-free EDM spark-eroded finishes, and mirror-level surface polishability without post-machining heat treatment distortion requires a precipitation-hardened alloy, which NAK80 mold steel delivers. Age-hardened at the mill to a uniform 37–43 HRC, NAK80 (Cu-Al-Ni alloyed steel) provides exceptional machinability, uniform grain structure, and high weldability. At Jucheng Precision, a certified ISO 9001 and IATF 16949 contract manufacturer, we specialize in 5-axis CNC machining and precision EDM eroding of NAK80 steel mold inserts. Delivering tool shot lives exceeding 500,000 cycles, our NAK80 molds produce high-gloss cosmetic enclosures and clear optical lenses verified by Zeiss CMM inspection.
Selecting the correct mold steel is the single most critical engineering decision in カスタム金型製作. From pre-hardened steels for cost-effective pilot runs to fully hardened stainless steels for 1,000,000+ cycle production tools, choosing the right alloy dictates part surface finish, tool longevity, and thermal cycle efficiency.
We machine and heat-treat premium tool steel alloys from certified European and Asian steel mills to match your production volume and resin chemistry:
| Tool Steel Grade | Hardness (HRC) | Corrosion & Wear Resistance | 保証金型ショット寿命 |
|---|---|---|---|
| S136 Stainless Steel | 48 – 52 HRC (Hardened) | High chromium stainless steel. Exceptional corrosion resistance against acidic outgassing; takes an SPI A-1 diamond mirror polish. | 1,000,000+ Shots |
| H13工具鋼 | 50 – 54 HRC (Hardened) | Hot-work steel with extreme thermal shock resistance and high compressive strength. Resists abrasive glass-fiber wear. | 1,000,000+ Shots |
| P20 / 718H Steel | 28 – 34 HRC (Pre-hardened) | Versatile pre-hardened steel offering excellent machinability and uniform core hardness without post-heat treatment distortion. | 250,000 – 500,000 Shots |
| NAK80 Steel | 37 – 43 HRC (Pre-hardened) | Pre-hardened age-hardened steel providing superior EDM spark finish capability, high polishability, and excellent weldability. | 500,000+ Shots |
Different polymer chemistries exert distinct physical demands on tool cavity surfaces during プラスチック射出成形:
| Resin Chemistry Class | Recommended Tool Steel | Engineering Tooling Rationale |
|---|---|---|
| Optical Clear & Medical Resins (ポリカーボネート（PC）, PMMA（アクリル）, 生体適合性・医療グレード樹脂) | S136 Stainless Steel (50 HRC) | High-purity stainless structure takes a diamond mirror polish (表面仕上げ SPI A-1) without micro-pitting or rust inclusions. |
| Abrasive Fiber Compounds (ガラス繊維（GF）, カーボンファイバー (CF)) | H13 Tool Steel (52-54 HRC) | High surface hardness prevents gate erosion and cavity pitting caused by high-velocity glass or carbon fiber shear. |
| Corrosive & Flame Retardant Resins (難燃性（FR）, PVC（ポリ塩化ビニル）) | High-Chromium S136 / M340 Stainless | Resists acidic outgassing generated when flame retardants or vinyl compounds break down at high melt processing temperatures. |
| Standard Commodity Resins (ポリプロピレン（PP）, ポリエチレン（PE）, ABS, ポリスチレン（PS）) | P20 / 718H / NAK80 Steel | Optimizes tooling cost and delivery lead times while providing reliable 250k–500k shot lives for 高容量射出成形. |
Executing precision mold building demands strict metallurgical heat-treatment control and 5-axis CNC machining:
Vacuum Heat Treatment & Stress Relieving
Hardened steels (S136, H13) undergo computer-controlled vacuum heat treatment followed by triple tempering to achieve uniform 50–54 HRC core hardness. This eliminates internal residual stress and prevents tool warpage during high-speed CNC milling.
5-Axis CNC Precision Cavity Machining
Utilizing 25+ in-house 5-axis CNC machining centers, we cut hardened steel inserts to ±0.005 mm tolerances. This ensures micro-gap shut-offs at parting lines, preventing flash even when running low-viscosity super-polymers like ポリエーテルエーテルケトン（PEEK） および ポリフェニレンサルファイド（PPS）.
Mirror Polishing & Surface Texturing
S136 cavities are hand-polished by master mold makers using diamond paste compounds to achieve SPI A-1 mirror clarity, while P20 and 718 steels support acid etching for Mold-Tech textures or VDI 3400 EDM spark finishes.
Preventive Maintenance & Lifetime Tool Warranty
Molds running at Jucheng undergo scheduled Mold Repair & Maintenance, including ultrasonic cavity cleaning and core alignment checks, ensuring long-term repeatability on 量産射出成形金型 tools.
| Density (Tool Steel) | 7.75 - 7.85 g/cm³ |
| Hardness Range (Fully Hardened S136 / H13) | 48 - 54 HRC |
| Hardness Range (Pre-Hardened P20 / NAK80) | 28 - 40 HRC |
| Tensile Strength (Hardened H13 / S136) | 1,500 - 1,950 MPa |
| Yield Strength (Hardened H13 / S136) | 1,200 - 1,600 MPa |
| Thermal Conductivity (23°C) | 24 - 30 W/(m·K) |
| 熱膨張係数（20-100°C） | 11.5 - 12.8 10⁻⁶/K |
| Compressive Strength (52 HRC) | 1,800 - 2,200 MPa |
| Impact Toughness (Charpy V-Notch) | 20 - 35 J |
| SPI研磨表面能力 | SPI A-1 (Diamond Mirror Polish) - |
| Guaranteed Tool Shot Life (Class 101 Hardened) | 1,000,000+ Cycles |
| Maximum Mold Plate Size | 2500 x 1800 mm |
| 最小加工公差 | +/- 0.005 mm |
