射出成形金型のコスト内訳：見積もりを左右する要因

If you’ve ever received a mold quote and thought “that’s a lot of money for a chunk of steel,” you’re not wrong—but you’re also not seeing the full picture. Injection mold tooling cost is the single largest upfront investment in any plastic part program, and understanding what drives it is the difference between an informed negotiation and a blind gamble. This article breaks down every cost component with real numbers so you can read your next quote like an engineer, not a gambler. For a broader understanding of the process, start with our complete injection molding guide.

What Makes Up an Injection Mold Tooling Cost Quote?

An injection mold tooling cost quote breaks down into five measurable categories: steel material (15–25%), CNC and EDM 射出成形¹ machining labor (40–50%), design and engineering (10–15%), assembly and bench fitting (10–15%), and tryout/validation (5–10%). These percentages hold across most mold sizes and complexities because machining hours scale with part geometry regardless of mold class. The key insight most buyers miss is that labor, not material, dominates the bill. A mold that requires 300 hours of CNC and EDM work at $30–60/hour will cost $9,000–$18,000 in machining alone before you add steel, design, or testing.

At ZetarMold, our quoting engineers break every project into these categories explicitly. We’ve found that transparency at this stage prevents scope disputes later—a customer who understands why their mold costs $15,000 is far less likely to request mid-project changes that add cost than one who received a single bottom-line number with no explanation.

If you’re new to the process, our injection mold overview covers the basics of mold construction and terminology. The SPI mold classification system provides a useful framework: Class 101 molds (over 1,000,000 cycles) require premium steel and precision finishing, while Class 104 molds (under 100,000 cycles) can use softer steels with less polishing. Your mold class should match your production plan—over-specifying wastes money, and under-specifying risks premature tool failure^[1].

How Does Steel Grade Selection Drive 15–25% of Your Mold Cost?

Steel grade selection determines three cost components simultaneously: raw material price, machining time, and mold longevity. P20² pre-hardened steel (28–36 HRC) is the default for short-to-medium production runs under 500,000 parts. It machines easily, costs $4–8/kg, and delivers adequate life for most consumer product applications. H13 tool steel costs 3–4x more per kilogram but withstands 1,000,000+ cycles in glass-filled and high-temperature resins.

S136 stainless steel adds corrosion resistance for medical and food-contact molds, at 4–5x the P20 price point. The common mistake is selecting steel based on upfront cost alone. A P20 mold for a 1,000,000-part run of 30% glass-filled nylon will fail at 300,000–400,000 cycles, requiring cavity replacement that costs 40–60% of the original mold price. The correct steel for that application is H13 or a hardened grade like 8407. The $3,000–$5,000 premium on steel saves $8,000–$15,000 in repair and replacement cost over the production life.

Steel cost also varies with mold size. A small electronic housing mold might use 50 kg of steel ($200–$400 in P20), while a large automotive fascia mold could require 2,000+ kg ($8,000–$16,000). At larger mold sizes, steel becomes a larger percentage of total cost because material scales volumetrically while machining complexity does not always increase proportionally. For buyers evaluating quotes, ask your mold maker to specify the exact steel grade for cavities, cores, and mold base separately. Many shops quote P20 for the base and H13 for cavities—this hybrid approach balances cost and performance effectively^[2].

Why Does Machining Labor Account for 40–50% of Tooling Cost?

Machining labor dominates injection mold tooling cost because mold making is fundamentally a precision metalworking process. A typical single-cavity mold requires 150–400 hours of combined CNC milling, EDM (electrical discharge machining), and surface finishing. At $30–60/hour for skilled machinists, that translates to $4,500–$24,000 in labor before any other cost is added. Multi-cavity molds and complex geometries push machining hours into the 600–1,200 range. CNC milling handles the bulk of material removal—roughing cavities, cutting parting lines, drilling cooling channels. EDM is used for features that CNC tools cannot reach: sharp internal corners, deep ribs, and complex undercut geometries.

Wire EDM cuts precision profiles through hardened steel with tolerances of ±0.005 mm. Surface finishing—polishing, texturing, plating—adds another 20–60 hours depending on the required surface class. A SPI A-1 mirror finish for optical lenses can require 40+ hours of hand polishing alone. The labor rate difference between regions is the single largest factor in tooling cost variation globally. CNC operators in China earn $8–15/hour, compared to $35–65/hour in the US and $25–55/hour in Western Europe. A 300-hour mold costs $2,400–$4,500 in machining labor in China versus $10,500–$19,500 in the US. The machines, software, and cutting tools are essentially the same globally—Haas, Makino, and GF Machining Solutions equipment appears in competent shops worldwide.

What Do Part Complexity Features Add to Your Tooling Quote?

Part complexity adds cost in discrete, estimable increments. Every undercut, thread, fine detail, and tight tolerance requirement translates into specific mold features that require additional machining, components, and assembly time. Here are the major complexity cost drivers with real dollar ranges: Side actions (external undercuts) cost $800–$2,500 each. These require sliding cam mechanisms that retract during mold opening. Each side action adds 20–40 hours of machining and fitting.

Internal lifters cost $400–$1,200 each. Lifters address internal undercuts using angled pins that pull inward during ejection. They are simpler than side actions but still add precision fitting work. Hot runner systems cost $1,500–$3,000 for a single-drop system; a multi-drop valve-gated system adds $6,000–$12,000. Hot runners eliminate cold runner waste but add temperature-controlled manifold assemblies, nozzles, and controllers^[3].

Unscrewing mechanisms (threaded features) cost $2,000–$5,000 per thread axis. These use hydraulic or servo-driven rotation to unmold internal or external threads without collapsing cores. SPI A-1 mirror polish costs $1,500–$4,000 per cavity face. Optical-quality finishes require progressive hand polishing through diamond compounds. A straightforward single-cavity mold with no undercuts, P20 steel, and a standard polish might cost $5,000–$12,000. Add two side actions, a ホットランナー³, and a textured surface, and you’re at $15,000–$30,000.

The geometry didn’t change the steel or the machine—the complexity added labor hours and specialized components. The design-for-manufacturability (DFM⁴) review is where you control these costs. A skilled DFM engineer can often redesign undercuts into features that strip or collapse during ejection, eliminating side actions entirely. At our facility, DFM reviews catch an average of 3–5 cost-reducing design changes per project, and we encourage every customer to invest in this step before committing to tooling.

When Does a Multi-Cavity Mold Justify the Investment?

A multi-cavity mold makes economic sense when the per-part machine time savings exceed the additional tooling investment over your production run. The math is straightforward: each additional cavity adds 60–90% of the single-cavity tooling cost but doubles output per cycle. The breakeven point depends on three variables: annual volume, machine hourly rate, and cycle time. For volumes under 100,000 parts per year with a 30-second cycle, a single-cavity mold is almost always the lower-cost option. At 500,000+ annual parts, a 4-cavity mold virtually always wins on total cost of ownership. Between 100,000 and 500,000 parts, the answer depends on your specific machine rate and part geometry.

Here’s a practical example: a 20-gram polypropylene part running on a 150T machine at $25/hour. Single cavity, 25-second cycle, produces 144 parts/hour. A 4-cavity mold runs the same part in the same cycle time, producing 576 parts/hour. At 500,000 annual parts, the single-cavity option requires 3,472 machine hours ($86,800 in machine time) versus 868 hours ($21,700) for the 4-cavity mold.

If the 4-cavity mold costs $18,000 more than the single-cavity version, you recover the premium in machine time savings within the first year. The risk with multi-cavity molds is cavity imbalance—uneven fill between cavities causing dimensional variation. A competent mold maker addresses this through balanced runner design and flow analysis (Moldflow simulation), which adds $1,000–$3,000 to engineering cost but prevents production rejects.

How Much Can You Really Save with Chinese Tooling?

Chinese tooling shops deliver dimensionally equivalent molds at 40–60% of Western prices. The cost difference is almost entirely labor rate—CNC operators in China earn $8–15/hour versus $35–65/hour in the US and $25–55/hour in Europe. Equipment, CAD/CAM software, cutting tools, and raw steel costs are globalized and comparable across regions. A 300-hour mold costs $2,400–$4,500 in Chinese machining labor versus $10,500–$19,500 in American machining labor. Same machines, same software, different hourly rate.

The qualification criteria for Chinese toolmakers matter more than the price difference. ISO 9001 certification is the baseline—without it, you’re gambling on process consistency. ISO 13485 (medical) and IATF 16949 (automotive) indicate higher process discipline. English-language documentation capability matters because communication failures cause more project delays than technical failures. A shop with 30+ fluent English speakers on staff can resolve design questions in a single email thread rather than a week of back-and-forth through a translator.

Exchange rate fluctuations of 5–10% can impact tooling costs quoted in USD but settled in RMB. Most Chinese mold makers quote in USD with a 30–90 day validity period to mitigate this risk. Lock your quote early if the RMB is trending against your currency. For guidance on evaluating and selecting Chinese tooling partners, see our injection molding supplier sourcing guide. Shipping and logistics add 3–7% to the landed cost of a Chinese-built mold. A 500 kg mold ships via air freight for $2,000–$4,000 (5–7 days) or sea freight for $400–$800 (25–35 days). Plan for sea freight unless your timeline is critical—the savings are substantial.

What Hidden Costs Should You Budget Beyond the Quote?

The initial tooling quote rarely represents your final cost. Hidden costs fall into three categories: design revisions, mold modifications, and maintenance. Design revisions (customer-requested changes after steel cutting) cost $500–$5,000 per change depending on severity. Weld repair and re-machining of a modified cavity can add 1–3 weeks to delivery. This is why DFM review before tooling starts is the highest-ROI step in any mold project. Mold modifications for production optimization—adding cooling circuits, adjusting gate locations, changing ejector pin positions—typically add 5–15% to the initial tooling cost. These are not failures of the original design; they are normal refinements that experienced molders expect during the first production run. Budget for them.

Maintenance costs run 2–5% of initial mold cost per year for medium-production molds. This includes annual inspection, component replacement (ejector pins, springs, wear plates), and repolishing of cavity surfaces. A $20,000 mold costs $400–$1,000 per year to maintain properly. Skipping maintenance accelerates wear and leads to dimensional drift that produces rejects—always more expensive than the maintenance itself. Sampling and validation costs are often quoted separately. First article inspection (FAI), dimensional reports, and material certifications add $500–$2,000 to the project. If your industry requires PPAP (automotive) or IQ/OQ/PQ (medical), validation documentation can run $2,000–$8,000. Clarify with your tooling supplier whether these costs are included or additional^[4].

Frequently Asked Questions About Injection Mold Tooling Cost

射出成形金型の典型的な費用はいくらですか？

標準的な単一キャビティ射出成形金型は、P20鋼材を使用した単純な形状の場合、$5,000〜$15,000の費用です。ホットランナーやサイドアクションを備えた複雑な多キャビティ金型は、$20,000〜$80,000以上になります。大型の自動車や医療用金型は$100,000を超える場合があります。費用は主に部品の複雑さ、キャビティ数、鋼材グレード、および必要な表面仕上げによって決まります。

射出成形のコスト削減方法 | ZetarMold

金型寿命は鋼材グレード、樹脂の摩耗性、および維持管理に依存します。P20金型は通常300,000〜500,000回の成形サイクルを提供します。H13硬化金型は1,000,000回以上のサイクルを達成します。ガラス充填および難燃性樹脂は摩耗を2〜3倍加速します。金型費用の2〜5％の年間維持管理は、未維持金型と比較して寿命を30〜50％延長します。

品質を損なうことなく射出成形金型のコストを削減できますか？

はい、以下の3つの戦略を通じて可能です：(1)鋼材切削前にDFMレビューに投資して不要な複雑性を排除する、(2)実際の生産量に合わせて鋼材グレードを選択し過剰仕様を避ける、(3)同等の精度を40〜60％低い労務費で提供する認定中国金型工場から調達する。各戦略は独立して10〜30％の節約を実現できます。

プロトタイプ金型と量産金型の違いは何ですか？

プロトタイプ金型（ブリッジツールとも呼ばれる）は、アルミニウムまたは軟鋼を使用し、冷却を簡略化し、手動射出を行い、生産金型費用の30〜50%で100〜10,000個の部品を生産します。耐久性を犠牲にして速度と低投資を実現します。生産金型は硬化鋼を使用し、冷却を最適化し、自動射出を行い、100,000個以上の部品を安定した寸法品質で生産します。

異なるサプライヤーからの射出成形金型の見積もりをどのように比較すればよいですか？

見積書を項目ごとに比較してください：キャビティとベースの鋼材グレード、総加工時間、含まれる表面仕上げ、設計修正回数、含まれる試作成形回数、および保証条件。15,000ドルの2つの見積書は非常に異なる価値提案を表す可能性があります—一方はT1試作と2回の修正回数を含み、もう一方は両方に追加費用を請求します。

射出成形金型の典型的な支払条件はどのようなものですか？

標準的な条件は、注文時に40〜50%のデポジット、T1サンプリング時に30〜40%、最終承認時に10〜20%です。中国の金型工場では、50/30/20または40/40/20の構造が一般的です。100%の事前支払いを要求するサプライヤーは避けましょう—マイルストーンベースの支払いは両者を保護し、適時納品のインセンティブを一致させます。

金型のサイズは複雑さよりもコストに影響を与えますか？

ほとんどの場合、複雑性はサイズよりも費用に影響します。4つの側面動作、ホットランナー、およびSPI A-1仕上げを持つ小型金型は、アンダーカットなしの標準仕上げを持つ大型平面金型よりも費用が高くなります。サイズは鋼材と機械時間費用を直線的に駆動しますが、複雑性は精度適合要件により労務時間を指数関数的に駆動します。

Get an Accurate Tooling Cost Estimate from ZetarMold

射出成形金型費用内訳を理解することは、情報に基づいた調達決定を行うための第一歩です。ZetarMoldでは、鋼材グレード、加工時間、複雑性機能、および検証費用など、資金がどこに使われるかを正確に示す透明な項目別見積書を提供します。驚きや隠れた費用はありません。

20年以上の金型経験、平均10年以上の経験を持つ8人の上級エンジニア、ISO 9001/13485/14001/45001認証により、北米および欧州OEM基準を満たす生産グレード金型を提供します。30人以上の英語を話すスタッフが、DFMレビューから生産試作までの明確なコミュニケーションを確保します。

Request a Quote 3D CADファイルと年間生産量要件を送信してください。エンジニアが48時間以内に詳細な費用内訳を返信します。

1. SPI金型分類： プラスチック産業協会（SPI）は、金型クラスを101（最高、1,000,000+サイクル）から104（最低、100,000サイクル未満）まで定義しています。クラスは鋼材グレード、冷却要件、および表面仕上げ基準を決定します。 ↩

2. 工具鋼費用ベンチマーク： P20プレハード鋼材は世界的に4〜8ドル/kgで取引されます。H13熱間工具鋼は12〜25ドル/kgで取引されます。S136ステンレス工具鋼は18〜35ドル/kgで取引されます。価格はASM International材料仕様および世界的な鋼材ディストリビューター価格（2024〜2025年）から引用。 ↩

3. ホットランナー費用データ： Mastip、Yudo、Synventiveなどの製造業者による単一ドロップホットランナーシステムは、$1,500〜$3,000の範囲です。多ドロップバルブゲートシステムは、ノズル数とコントローラの複雑さによって$6,000〜$12,000の範囲です。 ↩

4. 維持費用のベンチマーク： アメリカ金型製造協会（AMBA）のデータによると、中量生産用金型の年間維持費用は、初期金型費用の2〜5％に相当します。 ↩