Shenzhen Alu Rapid Prototype Precision Co., Ltd.

CNC machines, particularly milling machines, don't have a single "speed"—performance is measured across several metrics: spindle speed (how fast the cutting tool rotates), feed rate (how fast the tool advances through the material during cutting), and rapid traverse rate (how fast the machine moves without cutting). These vary widely based on the machine, material, tool, and operation. Below, I'll break it down with typical ranges for a standard 3-axis CNC mill.

1. Spindle Speed (RPM)

This is the rotation speed of the tool in the spindle, measured in revolutions per minute (RPM). It determines the cutting speed at the tool's edge (surface feet per minute, or SFM).Typical Range: 5,000–30,000 RPM, with many hobbyist or mid-range machines operating at 10,000–20,000 RPM. High-speed spindles can exceed 40,000 RPM for precision work.

Material Examples (based on recommended SFM for high-speed steel end mills):Aluminum: 250 SFM → ~16,000–22,000 RPM for a 1/4-inch tool.

2. Feed Rate (IPM during Cutting)

This is how fast the tool or workpiece moves linearly into the material, in inches per minute (IPM) or mm/min. It's tied to "chip load" (material removed per tool tooth) for efficient cutting without breaking tools.Typical Range: 10–200 IPM for cutting operations. Roughing cuts are faster (50–150 IPM), while finishing is slower (20–60 IPM) for better surface quality.

Material Examples (using a 1/2-inch, 4-flute end mill):Aluminum: 100–300 IPM at 0.004–0.006 inch chip load per tooth.

Mild Steel: 20–80 IPM at 0.003–0.004 inch chip load.

Hardened Steel: 10–40 IPM to avoid excessive wear.

3. Rapid Traverse Rate (Non-Cutting Movement)

This is the machine's unloaded speed for positioning, in IPM. It's much faster than cutting to minimize cycle time.

Typical Range: 300–1,500 IPM for X/Y axes on mid-range machines; Z-axis is often slower (200–1,000 IPM). High-end models reach 2,000+ IPM.

Factors Affecting Overall Speed

Material Hardness: Softer materials (e.g., wood, plastic) allow 2–3x faster feeds than metals.

Tool and Machine: Carbide tools handle higher speeds than HSS; 5-axis machines enable faster complex cuts.

Operation Type: Pocketing or roughing is quicker than contouring.

Software Optimization: CAM programs calculate optimal paths to reduce air time (non-cutting moves).

Trade-offs: Pushing speeds shortens cycle times but risks tool breakage or poor finish—start conservative and test.