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12 · Manufacturing Glossary
Manufacturing Engineering Glossary
A quick-reference dictionary of common machining and manufacturing terms. Each entry links to the relevant detailed article or calculator.
A
| Term | Definition |
|---|
| Accuracy | How close a measured value is to the true value. Not the same as precision. See Measurement Fundamentals. |
| Absolute Programming | CNC programming mode (G90) where all coordinates are measured from the program zero, not from the previous position. |
| Axial Depth of Cut (ap) | Depth of cut measured along the tool axis — in milling, how deep the end mill plunges. See Depth & Width of Cut. |
B
| Term | Definition |
|---|
| Backlash | Lost motion in a machine axis due to clearance between the ballscrew and nut. Causes dimensional errors when direction reverses. See Dimensional Error. |
| Boring | Enlarging an existing hole with a single-point boring bar on a lathe or mill. See Drilling & Hole Making. |
| Built-Up Edge (BUE) | Workpiece material welded to the cutting edge. Causes poor finish and dimensional drift. See Tool Wear & Breakage. |
C
| Term | Definition |
|---|
| Chatter | Self-excited vibration during cutting, causing washboard surface marks and tool noise. See Chatter & Vibration. |
| Chip Load (fz) | Amount of material removed per tooth per revolution. Also called feed per tooth. See Chip Load Reference. |
| Climb Milling | Milling where the cutter rotates in the same direction as the feed. Shears cleanly, less tool wear, but requires tight machine backlash. |
| Coolant | Fluid applied to the cut to cool the tool, lubricate the edge, and flush chips. Types: flood, mist, through-spindle, minimum quantity lubrication (MQL). |
| Cp / Cpk | Process capability indices. Cp compares tolerance to process spread; Cpk also accounts for centering. See Process Capability & SPC. |
| Cutting Speed (vc) | Surface speed at the tool edge, in m/min (or SFM). Independent of tool diameter. See Cutting Speed. |
| Cutter Compensation (G41/G42) | CNC feature that offsets the tool path by the tool radius, so the programmed part geometry stays correct regardless of actual tool diameter. |
D
| Term | Definition |
|---|
| Datum | A reference surface, edge, or point from which dimensions are measured. Datums A, B, C establish the reference frame. See Setup & Workholding. |
| Deflection | Elastic bending of tool or workpiece under cutting force. Causes taper and poor finish. See Dimensional Error. |
| Depth of Cut (ap) | How deeply the tool engages the material in one pass. See Depth & Width of Cut. |
| Drill Point Angle | The included angle of the drill tip — 118° for general use, 135° for hard materials, 90° for soft materials. |
F
| Term | Definition |
|---|
| Feed Rate (vf) | How fast the tool advances through the material, in mm/min or IPM. See Feed. |
| Fixture | A custom workholding that locates and holds a part during machining. See Setup & Workholding. |
| Flank Wear | Wear on the relief face of the tool, measured as VB. The normal wear mode. See Tool Wear & Breakage. |
G
| Term | Definition |
|---|
| G-Code | The programming language of CNC machines — G00 (rapid), G01 (linear feed), G02/G03 (arc), G81 (drill cycle), etc. |
| GD&T | Geometric Dimensioning and Tolerancing — a system for specifying form, orientation, location, and runout. See GD&T Symbols. |
H
| Term | Definition |
|---|
| HSS (High-Speed Steel) | A tool material (M2, M35) used for drills, taps, and end mills. Tougher but lower speed than carbide. |
M
| Term | Definition |
|---|
| MRR (Material Removal Rate) | Volume of material removed per minute, in cm³/min or in³/min. See MRR. |
| M-Code | Machine control functions in CNC — M03 (spindle on CW), M05 (spindle stop), M08 (coolant on), M30 (program end). |
| Machinability | How easily a material can be machined — depends on hardness, toughness, thermal conductivity, and work hardening. See Machinability Guide. |
N
| Term | Definition |
|---|
| Notch Wear | Groove wear at the depth-of-cut line, caused by work-hardened surfaces or scale. See Tool Wear. |
R
| Term | Definition |
|---|
| Radial Depth of Cut (ae) | Width of cut in milling — how much of the cutter diameter is engaged. See Depth & Width of Cut. |
| Runout | Variation in rotation of a spindle or tool — measured with a dial indicator. Excess runout causes poor finish and uneven tool wear. |
S
| Term | Definition |
|---|
| SFM (Surface Feet per Minute) | Imperial unit of cutting speed. 1 SFM ≈ 0.3048 m/min. See Cutting Speed. |
| Spindle Speed (RPM) | Rotational speed of the spindle. Calculated from cutting speed and tool diameter. See Spindle Speed Calculator. |
| Surface Finish (Ra) | Average roughness of a machined surface, in µm or µin. See Surface Finish Basics. |
T
| Term | Definition |
|---|
| Tolerance | The allowed variation from nominal size. See Dimensional Tolerances. |
| Tool Offset | A stored correction value in the CNC — tool length (H) and tool radius (D) — that adjusts the actual tool position. |
| Tool Life | The cutting time a tool lasts before it must be changed. Typically measured in minutes of cutting time. |
| Trochodial Milling | A roughing strategy using small radial engagement (ae) and high feed, keeping chips thin and heat low. |
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