CNC Specs for the Mill 220

accuracy

The difference between a measurement reading and the true value of that measurement.

additional axes

A feature available on CNC machines that significantly increases the ability of a machine to create complex parts.

automatic pallet changer

A mill feature that reduces cycle times by automatically changing pallets between jobs.

automatic tool changer

A common mill feature that reduces cycle times by automatically changing tools between cuts. Automatic tool changers are differentiated by tool-to-tool time and the number of tools they can hold.

axis motor maximum thrust

A specification that indicates the amount of force, measured in pounds or newtons, a mill motor may exert.

axis motor rating

A specification that indicates the amount of power, measured in horsepower, available to a mill motor.

axis travel

A specification that indicates the length that a spindle or worktable may move in each axis.

ballscrew

A long, threaded device with reciprocating ball bearings that rotates to move components on a CNC machine. Ballscrews are powered by servomotors.

blind pocket milling

A milling operation in a location on the workpiece where the view of the operator is obscured because the tool is contacting a surface behind the part feature. Blind pocket milling is a challenging operation because chip evacuation is difficult and tool clearance is restricted.

BT

A tool taper standard developed in Japan with unequal lands on the outer diameter of the flange.

CAT

A tool taper developed by Caterpillar with equal sized lands on the outer diameter of the flange. Also called V-flange, CAT is an American standard.

column

A four-sided fixture used to hold workpieces on a mill with a horizontal spindle.

cubic feet per minute

A measurement of airflow that indicates how many cubic feet of air pass by a stationary point in one minute. Cubic feet per minute is abbreviated cfm.

cutting feed rate

The rate at which the cutting tool and the workpiece move in relation to one another.

cycle time

The time it takes to make one part.

feature

Machine components designed to increase machine capability. Mills may have features built into the machine or may have them added to the original configuration of the machine as options.

footprint

A specification that indicates the amount of floor space a machine occupies.

gage

A device used to measure part dimensions after a part is made.

hertz

A unit of frequency equal to one cycle per second. Hertz is abbreviated Hz.

high-speed machining

An approach to metal cutting using recent speed technology to allow machining centers to do more work. HSM uses small diameter tools to perform multiple, rapid, light cuts.

high-speed spindle

A spindle that rotates at very high speeds, typically in excess of 8,000 rpm. A high-speed spindle is a feature central to high-speed machining capability.

horizontal mill

A mill with a spindle that is parallel to the worktable.

horsepower

A unit of power used to describe machine strength. One horsepower equals 746 watts.

kilovolt amperes

A unit used to describe the power requirements of a machine. Kilovolt amperes is abbreviated kVA.

linear motor

A flat motor that uses a magnetic field instead of mechanical force to power the motion of machine tool components.

linear scale

A series of fine lines that is located along the axis member of the machine. When read by an encoder, the scale tells the machine control the precise axis coordinates.

liters per minute

A measurement of the flow of a gas or liquid. Liters per minute is abbreviated lpm.

machine weight

A specification that indicates the weight of a machine. Machine weight is critical when load limits exist in a shop.

maximum tool diameter

A specification that indicates the maximum diameter of a tool that a mill is capable of holding.

maximum tool length

A specification that indicates the maximum length of a tool that a mill is capable of holding.

maximum tool weight

A specification that indicates the maximum weight of a tool that a mill is capable of holding.

maximum workload

A specification that indicates the maximum weight of a load, either a workpiece or group of workpieces on a fixture, that a mill is capable of supporting.

maximum workpiece

A specification that indicates the maximum dimensions of a workpiece that a mill is capable of machining.

multiple pallet capability

A mill feature that allows an operator to set up a run of parts while another run is being machined.

one atmosphere

A unit of pressure. One bar is equal to the sea-level pressure of Earth's atmosphere.

option

Machine components or additions designed to increase machine capability. Options are extra features that are added to the original configuration of a machine.

pallet

An automatic moveable table that supports a workpiece and slides or pivots into and out of the mill. Multiple pallets allow an operator to set up a run of parts while another run is being machined.

parallel

Two lines or axes that are equidistant from each other at all points along their length, and thus never intersect. On a horizontal mill, the spindle is parallel to the worktable.

perpendicular

Two lines or axes that meet at right angles. On a vertical mill, the spindle is perpendicular to the worktable.

positioning

The measure of how well a CNC machine can place its tools to a desired location.

pounds per square inch

A measurement of pressure. Pounds per square inch is abbreviated psi.

presetter

A device on the mill used to quickly determine tool length offsets on the Z-axis. The tool tip contacts the stylus of the probe, which instantly records the spindle position in the offset screen.

probe

A device on the mill used to quickly determine inspection and quality control variables during machining.

rapid traverse

The rate at which the mill spindle moves before and after actual machining and in between cuts. Rapid traverse is the fastest possible movement of the machine spindle and is measured in inches per minute (ipm).

repeatability

The measure of how well a CNC machine can sustain its positioning over time.

revolutions per minute

A unit of measurement, abbreviated as rpm, that indicates the number of revolutions a machine component makes in one minute.

rotary table

A worktable on a mill that provides an additional rotational axis for positioning the workpiece.

rotational axes

The axes that describe turning or spinning movement of machine components.

rotational indexer

A mill feature which is capable of holding a workpiece and rotating it in known increments.

servomotor

A motor used in CNC machines that turns the ballscrew to move machine components with precision.

specification

A description of the essential physical and technical properties of a machine. Specs are the principle indicator of machine capability.

spindle orientation

The manner in which the spindle is configured on a mill. Spindles may be oriented vertically or horizontally.

Surface feet per minute

SFM. A measurement of speed describing the distance that the tool tip travels in one minute. Surface feet per minute is dependent upon the spindle's rpm and the cutting tool's diameter.

Surface speed

The rate at which a cutting edge of the tool moves past the workpiece surface at the point of contact. Surface speed depends on the specifications of the mill spindle and the tool diameter.

through-spindle coolant

A mill feature that delivers coolant fluid directly to the cutting edge of a tool through the spindle. Through-spindle coolant extends tool life.

tombstone

A two-sided fixture used to hold workpieces on a mill with a horizontal spindle.

tool capacity

A specification that indicates the maximum number of tools that a mill can hold in its original configuration.

tool taper

The area of a toolholder with a shape that gradually decreases in diameter, similar to the shape of a cone. Different tool tapers are distinguished by their angles and are designed to match the appropriate spindle opening.

tool tracking

A mill feature that tracks and catalogues all tool usage on the machine in an effort to extend tool life.

tool-to-tool time

The time it takes for an automatic tool changer to replace one tool with another.

torque

The ability of a machine to exert a torsional or rotating force at a particular speed. The torque of a machine will vary across its speed range.

trunnion table

A mill option that allows the mill to control the A- and C-axes on a vertical mill, which in turn allows the mill to machine more complex parts.

vertical mill

A mill with a spindle that is perpendicular to the worktable.

worktable

The machine component that supports the workpiece and any workholding devices during machining.

worktable size

A specification that indicates the dimension of a worktable on a mill.