How Is a CNC Machining Quotation Calculated? Una guía paso a paso

If you’re sourcing CNC-machined parts for your project, understanding how quotations are calculated is key to avoiding overpaying or misinterpreting costs. A CNC machining quotation isn’t a random number—it’s a detailed sum of tangible factors like material use, tiempo de mecanizado, y trabajo. This guide breaks down the calculation process, core influencing factors, and practical examples to help you verify and optimize quotes.

1. 8 Core Factors That Shape a CNC Machining Quotation

Every line item in a CNC quotation ties back to specific cost drivers. A continuación se muestra un desglose detallado de cada factor, with real numbers to illustrate how they impact the final price:

(1) Costo de material

Material cost forms the base of the quotation and is calculated by the part’s weight or volume. Different materials have vastly different unit prices, directly affecting this component:

Nota: Scrap material (typically 10–20% of the raw material weight) is often included in the quotation to account for cutting waste.

(2) Machining Time Cost

El tiempo de mecanizado es el única variable más grande en la mayoría de las citas, ya que combina equipos y costos de mano de obra. Incluye tres fases clave.:

• Tiempo de programación: 0.5–2 horas para piezas simples (P.EJ., un bloque plano) y de 3 a 8 horas para piezas complejas (P.EJ., piezas con superficies curvas 3D). Los programadores suelen cobrar entre 80 y 150 RMB por hora.
• Tiempo de mecanizado real: Depende de la velocidad de corte, ruta de la herramienta, y tamaño de pieza. Una pequeña pieza de aluminio. (5cm × 5cm) puede tardar entre 1 y 2 horas, mientras que una gran pieza de acero inoxidable (20cm × 20cm) podría tardar de 4 a 8 horas.
• Reprimición & Tiempo de cambio de herramienta: 0.2–1 hora por parte. Mecanizado de múltiples caras (P.EJ., 4-trabajo del eje) puede duplicar esta vez, adding 0.4–2 hours to the total.

Equipment hourly rates vary by type:

• Ordinary 3-axis CNC machines: 50–100 RMB/hour
• High-end 5-axis CNC machines: 150–300 RMB/hour

(3) Equipment Depreciation

CNC machines cost tens of thousands to millions of RMB, so depreciation is spread over their 5–10-year lifespan and included in the quotation. Por ejemplo, a 500,000 RMB 3-axis machine has an annual depreciation of 50,000–100,000 RMB, which translates to 20–40 RMB/hour added to the equipment cost.

(4) Mantenimiento & Desgaste de herramientas

Herramientas (P.EJ., fábricas finales, simulacros) wear out after repeated use and need replacement. A standard carbide end mill costs 50–200 RMB and lasts for 20–50 hours of machining—adding 1–10 RMB/hour to the quotation. Other maintenance costs (lubricating oil, filter changes) add an extra 5–15 RMB/hour.

(5) Labor Cost

Labor covers operators, quality inspectors, and sometimes programmers. Hourly rates vary by region and skill:

• Entry-level operators: 50–80 RMB/hour
• Skilled operators (for 5-axis machines): 100–150 RMB/hour
• Quality inspectors: 80–120 RMB/hour

For a part that takes 3 Horas a la máquina, labor cost typically ranges from 150–450 RMB.

(6) Costo de posprocesamiento

La mayoría de las piezas requieren un posprocesamiento para cumplir con los estándares funcionales o estéticos., y cada paso se suma a la cotización:

(7) Parte complejidad & Precisión

La complejidad y la precisión aumentan directamente el tiempo de mecanizado y los requisitos de habilidades., empujando las cotizaciones más altas:

• Piezas simples (formas de bloques, tolerancias ±0,1 mm): Menor necesidad de tiempo y habilidades: las cotizaciones oscilan entre 50 y 150 RMB por pieza.
• Partes complejas (paredes delgadas <2milímetros, tolerancias ± 0.01 mm): Requiere velocidades de corte más lentas y más programación: las cotizaciones aumentan a 200-1000 RMB/pieza.

Ejemplo: A stainless steel part with ±0.01mm tolerance costs 3x more than the same part with ±0.1mm tolerance.

(8) Volumen de pedido

Batch size unlocks volume discounts, as fixed costs (programación, configuración) are spread across more parts. Here’s how volume affects unit quotes for a simple aluminum part:

2. 3 Common Methods to Calculate CNC Machining Quotations

Los proveedores utilizan diferentes fórmulas para compilar cotizaciones, dependiendo del tipo de pieza y del tamaño del pedido. A continuación se muestran los métodos más comunes, con ejemplos paso a paso:

Método 1: Time-Based Quotation (Most Common for Complex Parts)

Este método se centra en el tiempo total de mecanizado., combinando equipos, mano de obra, y otros costos relacionados con el tiempo.

Fórmula: Cotización total = (Tarifa por hora del equipo + Tarifa por hora de mano de obra) × Tiempo total de mecanizado + Costo de material + Costo de posprocesamiento

Ejemplo:

• Tarifa por hora del equipo: 100 RMB (3-Eje CNC)
• Tarifa laboral por hora: 60 RMB (operador + inspector)
• Tiempo total de mecanizado: 4 horas (1 programación horaria + 2.5 horas de mecanizado + 0.5 horas de sujeción)
• Costo de material: 40 RMB (0.5kg de aleación de aluminio × 80 RMB/kg)
• Costo de posprocesamiento: 80 RMB (Anodizante)

Cotización total = (100 + 60) × 4 + 40 + 80 = 160 × 4 + 120 = 640 + 120 = 760 RMB

Método 2: Material-Based Quotation (Common for Simple Parts)

This method starts with material cost and adds a fixed or variable machining fee.

Fórmula: Cotización total = (Material Precio unitario × Peso de la pieza) + Tarifa de mecanizado + Costo de posprocesamiento

Ejemplo:

• Precio unitario del material: 50 RMB/kg (acero carbono)
• Part weight: 1kg → Material cost: 50 × 1 = 50 RMB
• Machining fee: 200 RMB (includes equipment, mano de obra, and depreciation for a simple block part)
• Costo de posprocesamiento: 50 RMB (perforación 2 agujeros)

Cotización total = 50 + 200 + 50 = 300 RMB

Método 3: Fixed Quotation (For Standardized Parts)

por sencillo, piezas repetibles (P.EJ., spacers, standard fasteners), suppliers often offer a fixed quote that includes all costs. Por ejemplo:

• A standard aluminum spacer (10mm × 5mm) may have a fixed quote of 20–30 RMB/piece for orders of 100+.
• A stainless steel bolt (M10 × 20mm) could have a fixed quote of 15–25 RMB/piece.

3. How to Verify and Optimize a CNC Machining Quotation

Once you receive a quote, you can cross-check its 合理性 (reasonableness) and reduce costs with these steps:

1. Break down the quote: Ask the supplier to itemize costs (material, tiempo de mecanizado, postprocesamiento) to identify overcharges. Por ejemplo, if the material cost for a 0.5kg aluminum part is listed as 80 RMB (well above the 25–50 RMB market range), clarify the reason.
2. Optimize part design: Simplify geometry (P.EJ., replace curved surfaces with straight lines) to cut machining time by 10–30%. Add hollow structures to reduce material weight by 15–25%.
3. Negotiate volume discounts: Even if you need 20 Partes ahora, ask for a “future batch” discount (P.EJ., 15% off if you order 50+ dentro 6 meses).
4. Adjust precision requirements: Use ±0.05mm tolerance instead of ±0.01mm if the part doesn’t need ultra-high precision—this can lower machining time by 20–40%.
5. Choose cost-effective post-processing: Skip unnecessary steps (P.EJ., polishing internal surfaces that won’t be seen) to save 50–150 RMB/part.

Yigu Technology’s Perspective on CNC Machining Quotations

En la tecnología yigu, creemos transparency is the foundation of trust in CNC machining quotations. Many clients struggle with “black-box” quotes that lack itemized costs, leading to confusion. We always break down quotes into material, tiempo de mecanizado, mano de obra, y costos de posprocesamiento, so clients understand exactly where their money goes. We also proactively suggest optimizations: Por ejemplo, if a client requests a stainless steel part with ±0.01mm tolerance for a low-load application, we’ll recommend aluminum alloy with ±0.05mm tolerance—cutting the quote by 30–50% without sacrificing performance. Además, we offer flexible volume discounts, Incluso para lotes pequeños, by aggregating orders from multiple clients. Our goal is to help clients get fair, cost-effective quotes that align with their actual needs.

Preguntas frecuentes

1. Why is scrap material included in the material cost of a CNC quotation?

Scrap material (10–20% of the raw material weight) is included because CNC machining produces waste (P.EJ., esquejes, leftover raw material after shaping). Suppliers factor this in to cover the full cost of the raw material they purchase, even if not all of it ends up in the final part.

2. Can I negotiate the machining time cost in a CNC quotation?

Yes—if you can show that the machining time is overestimated. Por ejemplo, if the quote lists 5 hours for a simple aluminum block (which typically takes 1–2 hours), provide a 3D model or drawing to prove the part’s simplicity. Suppliers may adjust the time to 2–3 hours, lowering the total quote by 40–60%.

3. What’s the difference between a “time-based” and “material-based” quotation?

A time-based quotation focuses on total machining time (combining equipment and labor) and is better for complex parts with variable machining needs. A material-based quotation starts with material cost and adds a fixed machining fee, making it simpler for basic parts (P.EJ., bloques, spacers) where machining time is predictable. Choose the method that matches your part’s complexity for the most accurate quote.