| axial |
A direction that runs straight along or parallel to the rotational axis of the cutting tool. The bottom of a tool makes axial cuts. |
| ballscrew |
A long, threaded device that rotates to move the worktable or cutting tool of a CNC machine. Ballscrews are powered by a motor. |
| boring |
The process of enlarging an existing hole with a single-point tool. Boring can be performed on a mill or machining center. |
| carbide |
A common cutting tool material that is used to make both indexable inserts and solid cutting tools. Carbide is very hard and wear resistant. |
| CNC mill |
A machine tool that uses computer numerical data to control cutting operations on flat, square, or rectangular workpieces. On a CNC mill, the cutting tool rotates against a workpiece that is fixed to a worktable. |
| column |
The vertical support of a milling machine. The column suspends components and tools over the workpiece. |
| computer numerical control |
CNC. A self-contained system of computers and precision motors that executes program instructions to guide machine tool components and manufacture parts. Mills often operate using computer numerical control. |
| contour |
A curved surface or dimension that is cut into a workpiece. Contours are generally created using an end mill. |
| cutting variable |
A factor that affects how a cutting tool performs its job. Cutting variables include speed, feed, and depth of cut. |
| depth of cut |
The depth that the cutting tool penetrates the surface of the workpiece. On a mill, depth of cut is dictated by the movement of either the spindle or the worktable. |
| drilling |
The use of a multi-point tool to machine a new round hole into the surface of a workpiece. Drilling is a type of holemaking operation. |
| end mill |
A type of milling cutter that performs a mix of peripheral and face milling with its bottom and side cutting edges. End mills can be used to machine grooves, slots, circular slots, pockets, and contours. |
| face mill |
A type of mill cutter that contains multiple teeth surrounding its large body diameter. The face mill uses the bottom as a cutting surface to mill large flat surfaces. |
| face milling |
A milling operation in which the surface of the workpiece is perpendicular to the spindle axis. Face milling primarily cuts with the bottom of the cutting tool. |
| feed |
The rate at which the cutting tool and the workpiece move in relation to one another. Feed is typically a linear movement but can also be angular and circular. |
| fixture |
A custom workholding device that is designed to effectively support, locate, and hold a specific type of workpiece. A workpiece with multiple, complex dimensions often requires a dedicated fixture. |
| fixtures |
A customized workholding device used to position and hold a part during various machining operations. Fixtures are built to hold a specific part design. |
| flange |
A ring or collar surrounding the toolholder. Flanges allow a tool to be grasped by the toolchanger arm. |
| helix |
A spiral shape. An end mill has cutting edges along its sides in a helix. |
| high-speed steel |
HSS. A category of tool steels used for cutting tool applications. HSS is a tough but inexpensive material. |
| holemaking |
The act of machining a hole into the interior surface of a workpiece. Holemaking can be accomplished by drilling, boring, reaming, and tapping. |
| horizontal mill |
A mill with a spindle that is parallel to the worktable. The horizontal mill is less common than the vertical mill. |
| inches per minute |
ipm. A unit of measurement that indicates how far in inches a tool advances in one minute. Inches per minute is used to measure feed. |
| inches per revolution |
ipr. A unit of measurement that indicates how far in inches a tool advances in one rotation. Inches per revolution is used to measure feed. |
| index |
To rotate a cutting head from one fixed position to another fixed position in order to reveal a fresh cutting edge. A cutting tool with multiple cutting edges should be indexed once the original edge has been worn or damaged. |
| inserts |
A replaceable bit that has multiple cutting edges. Inserts can be indexed to a new cutting edge as each edge wears out. |
| intermittent cutting |
A cutting process in which the cutting edge of the tool comes into and out of contact with the workpiece surface. Intermittent cutting is also known as interrupted cutting. |
| interrupted cutting |
A cutting process in which the cutting edge of the tool comes into and out of contact with the workpiece surface. Interrupted cutting is also known as intermittent cutting. |
| machine control unit |
MCU. A computer that controls and operates a CNC machine. Machine control units interpret the numerical data in the part program to guide machine movement. |
| machining center |
A sophisticated CNC mill that can perform multiple machining operations in the same setup. Machining centers can hold a wide variety of cutting tools, including mills and holemaking tools. |
| machining centers |
A sophisticated CNC mill that can perform multiple machining operations in the same setup. Machining centers can hold a wide variety of cutting tools, including mills and holemaking tools. |
| mill |
A multi-point cutting tool that has teeth around its cutting surface. The term "mill" is also used to describe the machine tool that uses this multi-point cutting tool to remove material from the surface of a workpiece. |
| millimeters per minute |
mm/min. A unit of measurement that indicates how far in millimeters a tool advances in one minute. Millimeters per minute is used to measure feed. |
| millimeters per revolution |
mm/rev. A unit of measurement that indicates how far in millimeters a tool advances in one rotation. Millimeters per revolution is used to measure feed. |
| milling machine |
A machine that uses a rotating multi-point tool to remove material from the surface of a workpiece. Milling machines are commonly used to machine slots, grooves, and flat surfaces on rectangular workpieces. |
| multi-point tool |
A cutting tool with more than one cutting edge. Multi-point tools include mills and drills. |
| pallet |
An automatic, moveable table that supports a workpiece and slides or pivots into and out of the CNC mill. Pallets allow an operator to set up a part while another is being machined. |
| parallel |
Two lines that are equidistant from one another and do not intersect. On a CNC mill, a cutting tool can be positioned parallel to the workpiece. |
| part program |
A series of alphanumerical instructions used by a CNC machine to perform the necessary sequence of operations to machine a specific workpiece. Multiple part programs can be stored in a CNC at one time. |
| peripheral milling |
A milling operation in which the cutting edge of the mill is parallel to the axis of rotation. Peripheral milling primarily cuts with the side edges of the cutting tool. |
| perpendicular |
Two lines or axes that intersect to form a right angle. On a CNC mill, a cutting tool can be positioned perpendicular to the workpiece. |
| pocket |
An interior recess that is cut into the surface of a workpiece. Pockets may be round or rectangular and generally are created using an end mill. |
| pots |
One of the numerous slots of the toolchanger that holds a cutting tool in its toolholder. Each pot has a specific location number. |
| radial |
A direction perpendicular to the tool rotational axis commonly called the radius of the tool. The periphery of a tool makes radial cuts. |
| ramped |
A tool movement that gradually engages the cutting tool with the workpiece. A ramped face mill can cut a pocket without the existence of a premachined cavity in the workpiece. |
| reaming |
The process of enlarging or smoothing an existing hole with a multi-point tool. Reaming is a holemaking operation. |
| retention knob |
A knob screwed into the end of the toolholder. Retention knobs lock a tool in place within the spindle. |
| servomotors |
A motor in a CNC machine that powers the movement of the machine tool. Servomotors rotate ballscrews, which cause a machine component to move. |
| slot |
A narrow channel cut into the surface of a workpiece. Slots can be created with either a face or end mill. |
| speed |
The rate at which the machine spindle rotates. The spindle speed affects how fast the cutting tool moves at the point of contact. |
| spindle |
The part of the machine tool that spins or rotates. On the mill, the spindle holds the cutting tool. |
| tapered shank |
The long, narrow portion of a toolholder that is typically shaped like a cone. Tapered shanks are the most common shape for a mill toolholder. |
| tapping |
The process of cutting internal threads in a hole with a rotating multi-point tool. Tapping can be performed on a mill or machining center. |
| toolchanger |
A milling machine device that arranges and positions multiple cutting tools for the spindle to retrieve. The toolchanger also stores the cutting tools between uses. |
| toolholder |
A mechanism used to rigidly hold a cutting tool in place during machining. Toolholders are classified so that they can be paired with the correct style of cutting tool or insert. |
| vertical mill |
A mill with a spindle that is perpendicular to the worktable. Vertical mill worktables are parallel to the ground. |
| vise |
A workholding device with two jaws that grip and hold a workpiece in place. Vises are mostly used to hold rectangular workpieces with fairly simple dimensions. |
| workholding |
The process of securely supporting, locating, and clamping a workpiece for a manufacturing operation. Workholding devices for CNC mills and machining centers hold the workpiece in place on the worktable. |
| workpiece |
A part that is in the process of being manufactured. A workpiece may be a complete product by itself or one component of a product consisting of many parts. |
| worktable |
The component of a milling machine that supports the workpiece and any workholding device during machining. The worktable moves along the X and Y axes. |