CNC Specs for the Mill 220
This class identifies common specifications of CNC mills and describes the various features and options available on different machines.
Number of Lessons 17
- Intro to Specs and Features
- Vertical and Horizontal Mills
- Interior Mill Specifications
- Spindle Performance: Spindle Speed
- Spindle Performance: Horsepower and Torque
- Rapid Traverse and Cutting Feed Rate
- Mill Motors
- Tool Specifications
- Positioning and Repeatability
- Machine Dimensions and Power Requirements
- Features: Performance
- Features: Accurate Positioning
- Features: Enhanced Tooling
- Features: Enhanced Workpiece Handling
- Options: Probe and Tool Presetter
- Distinguish among mill specifications, features, and options.
- Distinguish between a vertical and horizontal mill.
- Distinguish among interior mill specifications.
- Describe the importance of spindle speed for a mill.
- Describe the relationship between horsepower and torque.
- Describe the importance of rapid axis travels.
- Distinguish between different mill motors.
- Distinguish among mill tool specifications.
- Describe the relationships among accuracy, positioning, and repeatability.
- Explain machine dimensions.
- Identify mill features that directly affect machining performance.
- Identify mill features that directly affect accuracy.
- Identify mill features that directly improve the use and maintenance of cutting tools.
- Identify mill features that directly improve workpiece handling.
- Identify mill options that directly improve job setup and quality control.
The difference between a measurement reading and the true value of that measurement.
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.
A specification that indicates the length that a spindle or worktable may move in each axis.
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.
A tool taper standard developed in Japan with unequal lands on the outer diameter of the flange.
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.
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.
The time it takes to make one part.
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.
A specification that indicates the amount of floor space a machine occupies.
A device used to measure part dimensions after a part is made.
A unit of frequency equal to one cycle per second. Hertz is abbreviated Hz.
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.
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.
A mill with a spindle that is parallel to the worktable.
A unit of power used to describe machine strength. One horsepower equals 746 watts.
A unit used to describe the power requirements of a machine. Kilovolt amperes is abbreviated kVA.
A flat motor that uses a magnetic field instead of mechanical force to power the motion of machine tool components.
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.
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.
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.
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.
A unit of pressure. One bar is equal to the sea-level pressure of Earth's atmosphere.
Machine components or additions designed to increase machine capability. Options are extra features that are added to the original configuration of a machine.
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.
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.
Two lines or axes that meet at right angles. On a vertical mill, the spindle is perpendicular to the worktable.
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.
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.
A device on the mill used to quickly determine inspection and quality control variables during machining.
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).
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.
A worktable on a mill that provides an additional rotational axis for positioning the workpiece.
The axes that describe turning or spinning movement of machine components.
A mill feature which is capable of holding a workpiece and rotating it in known increments.
A motor used in CNC machines that turns the ballscrew to move machine components with precision.
A description of the essential physical and technical properties of a machine. Specs are the principle indicator of machine capability.
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.
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.
A mill feature that delivers coolant fluid directly to the cutting edge of a tool through the spindle. Through-spindle coolant extends tool life.
A two-sided fixture used to hold workpieces on a mill with a horizontal spindle.
A specification that indicates the maximum number of tools that a mill can hold in its original configuration.
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.
A mill feature that tracks and catalogues all tool usage on the machine in an effort to extend tool life.
The time it takes for an automatic tool changer to replace one tool with another.
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.
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.
A mill with a spindle that is perpendicular to the worktable.
The machine component that supports the workpiece and any workholding devices during machining.
A specification that indicates the dimension of a worktable on a mill.