What is Machining?

Key Takeaways

• Machining is a high-precision subtractive manufacturing process that uses milling and turning to produce custom metal and plastic parts.

• It is ideal for prototypes and small-batch production, offering fast turnaround, tight tolerances, and compatibility with a wide range of materials.

• Successful machining depends on optimizing cutting conditions, including tool access, cutting speed, heat generation, and material properties to ensure quality and cost efficiency.

Overview

Machining is a core manufacturing process where plastics or metals are shaped into precise components using machine tools. It is a type of subtractive manufacturing, meaning material is removed to form the final part based on a design drawing or CAD model.

Machining is essential for producing high-precision, custom parts used in prototypes, jigs, production equipment, and industrial applications.

How Does Machining Work?

Machining relies on two fundamental movements:

• Cutting motion: removes material from the workpiece.

• Feed motion: shifts the tool or workpiece to enable continuous cutting.

The two main categories of machining are:

• Turning: the workpiece rotates at high speed against a fixed cutting tool. Ideal for round or cylindrical parts.

• Milling: a rotating cutting tool shapes the workpiece. Best for block-shaped or flat-surface parts.

At Yumoto Electric, we specialize in both metal machining and plastic machining, supporting everything from prototypes to custom-built production tools.

Key Features of Machining

Machining is valued for its speed, accuracy, and flexibility. With 3D CAD data, parts can often be manufactured the same day, without the need for molds or expensive tooling. This makes it ideal for small-batch machining and rapid prototyping.

Costs vary depending on:

• Material hardness

• Part geometry and cutting volume

• Required tolerances and surface finish

Advantages of Machining

• High Precision: Capable of extremely tight tolerances (up to ±0.001 mm) and customizable surface finishes. Perfect for high-performance components and test-fit parts.

• Wide Material Compatibility: Supports a broad range of plastics and metals, from lightweight resins to stainless steel and aluminum alloys.

• Prototype & Small-Batch Friendly: No mold costs. Efficient for single-piece production, small lots, or custom tooling.

Limitations of Machining

• Geometric Restrictions: If a cutting tool cannot physically reach a section, that feature cannot be machined.

• Material Waste: Machining starts from larger blocks of material, generating chips. Greater differences between raw stock and final part size increase waste and cost.

Types of Machining

Milling

Milling uses a rotating cutting tool to shape a stationary workpiece. Applications include flat surfaces, grooves, steps, slots, and holes.

Common milling methods:

• Conventional Milling: Manual control by a machinist.

• NC Milling: CAD/CAM-programmed milling for complex shapes with high repeatability.

• Machining Centers (CNC): Multi-axis machines with automatic tool changers, capable of multiple operations in one setup.

Turning

Turning rotates the workpiece against a fixed cutting tool, most often using a lathe.

Types of turning:

• Conventional Lathe: Manually operated by skilled machinists.

• NC Lathe (CNC Turning): Computer-controlled with variable spindle speeds, suitable for drilling, threading, and grooving.

Important Machining Considerations

Cutting Resistance

Friction between the tool and workpiece generates resistance, which varies depending on material, tool type, cutting area, and spindle speed. High resistance shortens tool life, so machining conditions must be carefully optimized.

Cutting Speed

Increasing tool speed improves efficiency, but higher speeds also increase resistance and heat buildup, which may cause thermal deformation. Choosing the right speed depends on both material and machining requirements.

Heat Management

Machining produces significant heat from friction, which can affect accuracy and surface finish. Cutting oils are commonly used to reduce friction, control temperature, and remove chips.

Products Made by Machining

We manufacture a wide range of precision-machined parts:

• Custom jigs and fixtures

• Prototype components

• Industrial equipment parts

• Small to large-scale pieces (from palm-sized components to parts as large as shoulder width)

With short lead times and support for both metals and plastics, machining is one of the most flexible and reliable methods for producing custom parts.

CNC Machining at Yumoto Electric

Yumoto Electric delivers high-quality components fast, worldwide. We provide precision machining for a wide range of metals and engineering plastics. We have experience with over 200 materials including metals such as aluminum alloys, stainless steel, molybdenum, and titanium, and engineering plastics including PEEK, PPS, MC Nylon, and POM.

If you’re unsure about material selection or machining methods, we offer complimentary consultations to help optimize your design and production. For any questions, please feel free to contact us.