Common Used Rapid CNC Prototyping Terms and Defini

Rapid CNC Machining

The use of CNC milling and turning processes, optimized for maximum speed, to produce prototypes, tooling, and low-volume parts with very short lead times.

Lead Time

The total time from order placement to part delivery. Minimizing this is the primary goal of rapid CNC.

Digital Manufacturing

An overarching term for manufacturing processes driven directly by digital CAD data, with minimal human intervention. Rapid CNC is a key part of this.

Design for Manufacturability (DFM)

The practice of designing parts to simplify the machining process, reduce costs, and decrease production time. Critical for rapid turnaround.

Design for Machining (DFM)

A subset of DFM focused specifically on optimizing part design for CNC machining (e.g., avoiding deep pockets, using standard radii).

Agile Manufacturing

A methodology that emphasizes flexibility and rapid response to change. Rapid CNC is a key enabler.

CAD (Computer-Aided Design)

Software used to create the 3D model of the part (e.g., SolidWorks, Fusion 360, CATIA). The process starts here.

CAM (Computer-Aided Manufacturing)

Software that converts the 3D CAD model into a set of instructions (G-code) that the CNC machine can execute.

G-code

The programming language that controls the CNC machine. It dictates tool movement, spindle speed, feed rate, and other functions.

Post-Processor

A software translator within the CAM system that converts the generic toolpaths into specific G-code for a particular brand and model of CNC machine.

Toolpath

The calculated path that a cutting tool will follow to machine the part. Efficient toolpath strategies are crucial for speed.

CNC Programmer

The engineer who operates CAM software to create efficient, error-free toolpaths and G-code for the machine.

3-Axis Machining

The most common type, where the cutting tool can move in three linear directions (X, Y, Z). Ideal for parts without complex undercuts.

5-Axis Machining

A method where the tool can move in three linear axes and the workpiece can rotate on two additional axes (A and B). This allows for complex parts to be completed in a single setup, drastically reducing lead time.

Simultaneous 5-Axis

The tool can move along all five axes at the same time, enabling the machining of highly complex, organic shapes.

High-Speed Machining (HSM)

A strategy using high spindle speeds, fast feed rates, and shallow depths of cut to maintain a constant tool load, remove material quickly, and achieve a better surface finish.

High-Efficiency Machining (HEM)

Also known as Adaptive Clearingor Dynamic Milling, this is a roughing strategy that uses a toolpath that maintains a constant chip load and radial engagement, allowing for much higher feed rates and deeper axial cuts to remove material rapidly.

Rest Machining

A CAM feature that identifies areas where material remains from a previous operation (e.g., after a large tool roughs out an area), allowing a smaller tool to machine only the remaining stock.

Roughing

The initial machining step aimed at removing the bulk of the material as quickly as possible, without regard for final surface finish.

Finishing

The final machining step that cuts the part to its exact dimensions and achieves the desired surface finish.

Contouring

A toolpath that follows the contours of the part geometry.

CNC Mill / Machining Center

The machine tool itself, typically classified by the number of axes (3-axis, 5-axis).

CNC Lathe / Turning Center

A machine for producing cylindrical parts by rotating the workpiece against a stationary cutting tool.

Mill-Turn Center

A hybrid machine that combines milling and turning capabilities, allowing complete machining of complex parts in a single setup.

Spindle

The part of the machine that rotates the cutting tool. Spindle Speed is measured in RPM (Revolutions Per Minute).

Workholding

The method of securing the workpiece to the machine table. Rapid setups use quick-change systems.

Vise

A common workholding device that uses jaws to clamp the part.

Fixture

A custom workholding device designed for a specific part to hold it in a precise orientation.

Chuck

The workholding device on a lathe that grips the rotating workpiece.

Tool Holder

The device that connects the cutting tool to the machine spindle (e.g., Collet Chuck, End Mill Holder).

Automatic Tool Changer (ATC)

A magazine of tools that allows the machine to automatically change cutting tools during a program, enabling uninterrupted machining.

Pallet Changer

A system with two or more pallets (tables). While the machine is machining a part on one pallet, the operator can set up the next part on another, eliminating machine downtime.

Probe

A touch-trigger sensor used to automatically find the exact position of the workpiece (workpiece probing) or to measure tool length (tool probe), automating setup and in-process inspection.

End Mill

The most common cutting tool for milling, available in many types (flat, ball-nose, corner-radius).

Face Mill

A large-diameter tool used for quickly creating a flat surface.

Insert

A removable, indexable cutting tip, usually made of carbide, that is held in a tool holder. When one edge dulls, it can be rotated to a fresh edge.

Feed Rate

The speed at the cutting tool moves through the material, measured in inches per minute (IPM) or millimeters per minute (mm/min).

Spindle Speed (RPM)

The rotational speed of the spindle and cutting tool.

Cutting Speed (SFM / m/min)

The surface speed of the tool at the cutting edge, measured in Surface Feet per Minute (SFM) or meters per minute. It is a key factor in determining RPM.

Depth of Cut

The amount of material removed in a single pass, either axially (stepdown) or radially (stepover).

Chip Load

The thickness of the material removed by each cutting edge of the tool per revolution. Optimizing chip load is critical for tool life and efficiency.

Coolant / Lubricant

A fluid used to cool the tool and workpiece and to flush away chips. Flood coolant is common, while Minimum Quantity Lubrication (MQL) is used for a near-dry process.

First Article Inspection (FAI)

The comprehensive verification of the first part produced to ensure it meets all design specifications.

In-Process Inspection

Quality checks performed during the machining process to catch errors early.

Coordinate Measuring Machine (CMM)

A precision instrument that uses a probe to measure the geometry of a physical part and compare it to the CAD model.

Digital Calipers / Micrometers

Handheld measuring tools for quick dimensional checks.

Surface Finish

The texture of the machined surface, measured by roughness (Ra, Rz).

Tolerance

The permissible limit of variation in a physical dimension. Tight tolerances increase machining time and cost.

Geometric Dimensioning & Tolerancing (GD&T)

A symbolic language used on engineering drawings to define the allowable variation in form, orientation, and location of part features.