Control Panel Functions for the CNC Mill 252

“Control Panel Functions for the CNC Mill” explains how operators use the machine and control panel functions to operate a CNC mill. Operators use the handle and jog mode to move mill axes incrementally or steadily. MDI mode executes isolated lines of programming and memory mode selects and edits existing programs. Before running a program, an operator may choose to execute the program in single block mode to prove it out or select the optional stop or block delete functions. The cycle start button starts the program. Once a program is running, the operator can use the machine control unit to adjust speed and feed with an override.

To use a CNC mill, an operator needs to know how to perform important operations using machine panel functions to move machine components and control panel functions to execute programming codes. After taking this class, users should be able to explain the purpose of frequently used controls on the control panel of a CNC mill.

Class Details

Class Name:
Control Panel Functions for the CNC Mill 252
Version:
2.0
Difficulty:
Intermediate
Number of Lessons:
19
Related 1.0 Class:
CNC Manual Operations 200

Class Outline

  • Operator Responsibilities
  • Machine Operations and CNC Control Panel
  • Machine Controls and Control Display
  • Basic CNC Mill Controls
  • CNC Mill Operational Modes
  • Operational Mode Review
  • Manual Control Modes
  • Manual Control Comparisons
  • MDI and Single Block Mode
  • Control Modes
  • Types of Override
  • Uses of Overrides
  • Coolant Override
  • Optional Stop and Block Delete
  • Automatic Toolchanger
  • Chip Conveyor
  • Proving Out
  • Control Panel Functions
  • CNC Mill Control

Objectives

  • Describe the responsibilities of the CNC mill operator.
  • Distinguish between machine operations and control panel functions on a CNC mill.
  • Describe the function of a CNC mill control display. Distinguish between machine operations and CNC control panel functions on a CNC mill.
  • Describe the function of the basic CNC mill controls.
  • Identify the operational modes on a CNC mill.
  • Describe the manual control modes on a CNC mill.
  • Distinguish between pulse handle and jog modes on a CNC mill.
  • Describe the function of MDI mode on a CNC mill. Describe the function of single block mode on a CNC mill.
  • Identify the types of overrides on a CNC mill.
  • Describe the use of overrides on a CNC mill.
  • Describe manual operations for coolant on a CNC mill.
  • Describe the role of the CNC mill operator in optional stop and block delete.
  • Describe manual operations for loading tools on an ATC.
  • Describe manual operations for the chip conveyor on a CNC mill.
  • Describe proving out on a CNC mill.

Job Roles

Certifications

NIMS
  • CNC Milling Operations
  • CNC Milling Programming, Setup, & Operation

Glossary

Vocabulary Term Definition
auto mode A CNC mode that allows an operator to call up and execute a part program stored in the machine. Auto mode causes the control panel to temporarily take over for the machine panel.
automatic toolchanger ATC. A device on a milling machine that arranges multiple tools in order and positions these cutting tools for replacement. The automatic toolchanger also stores the cutting tools between uses.
axes An imaginary straight line or circle used to describe the location or movement of an object in three-dimensional space. CNC mill components move along their linear and rotational axes.
block A single line of a part program. A block is composed of words and is written in code.
block delete A machine control that provides the option of skipping a predetermined series of program blocks that are denoted with a slash (/). A block delete allows the operator to run two versions of the same program.
cathode-ray tube CRT. A control panel component that uses a tube device to deliver display information to the operator. Cathode-ray tube screens are older technology and have soft keys next to the screen on the control panel.
chip conveyor A moveable belt that helps remove chips from the interior of a machine. Chip conveyors carry chips away from the cutting area.
chip conveyor button A control button on the machine controls that allows the operator to manually stop and start the chip conveyor. The chip conveyor button runs the conveyor while the part program is running.
chips A small fragment of material that is removed from a workpiece during a cutting operation. Chips are the byproduct of machining.
circuit breaker A safety device that detects overcurrent in a circuit. The circuit breaker of a CNC machine must be closed before the machine can be powered on.
CNC Computer numerical control. A self-contained system of computers and precision motors that executes program instructions to guide machine tool components and manufacture parts. Mills and lathes often operate using CNC.
CNC control panel The group of controls on a CNC machine that runs, stores, and edits the commands of a part program and other coordinate information. When the part program runs without operator intervention, it runs in memory mode using the CNC control panel.
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 and lathes often operate using computer numerical control.
contouring A milling operation that machines curved surfaces or dimensions into a workpiece. Contouring can be performed manually using jog mode.
control interface The combination of the machine and control panels on a CNC machine. On a control interface, the machine panel handles manual and automatic operations while the control panel allows for automated control when a part program runs in auto mode.
control modes One of a number of possible settings that determines the way a CNC machine executes manual and automatic commands. The main control modes include pulse handle mode, jog mode, MDI mode, memory mode, single block mode, and edit mode.
control panel The group of controls on a CNC machine that run, store, and edit the commands of a part program and other coordinate information. When the part program runs without operator intervention, it runs in memory mode using the control panel.
coolant A cutting fluid used for lubrication and to decrease the temperature of the tool and workpiece to prolong tool life. Coolant can be controlled in a part program using M codes or manually using a coolant override.
coolant menu key A button on the control panel that calls up the coolant menu on the display screen. The coolant menu key allows the operator to control coolant options manually.
coolant override An override that allows the operator to control how the coolant pump operates. Coolant override allows the operator to turn the coolant on and off manually.
coolant stop key A button on the control panel that allows the operator to manually stop the flow of coolant. The coolant stop key functions as a coolant override.
cutting variables A factor that affects how a cutting tool performs its job. Cutting variables include speed, feed, and depth of cut.
cycle start The control button used to begin a program or continue a program that has been previously stopped. The cycle start button must be pressed after each block of a program when it is run in single block mode.
cycle stop The control button used to pause a program. The cycle stop, or feed hold, button pauses tool feed but not spindle movement.
dry run A preliminary operation to ensure that the part program machines workpieces properly. Dry runs are performed without any parts or coolant.
edit mode The control mode that allows an operator to make changes to a part program. Once edit mode is complete, the changes are stored in the machine.
emergency stop E-stop. The control that automatically shuts down all machine functions. The emergency stop is the safest and preferred means for stopping the machine in an emergency.
feed hold The control button used to pause a program. The feed hold, or cycle stop, button pauses tool feed but not spindle movement.
feedrate override An override that allows the operator to adjust the feed rate of the tool during operation. Feedrate override functions as a percentage of the programmed value.
flat-panel display A control panel component that displays information to the operator. Flat panel displays are thinner than cathode ray tube screens and have soft keys next to the screen on the control panel.
G code programming A method of programming that pairs address letters with numerical values to form words. G code programming is used to write a part program.
handle controls The rotating knob or dial on a CNC control interface that moves the machine components along the axes. The handle controls click in controlled, measured increments that are selected by the operator.
home position The control that automatically locates the spindle in the machine zero position. Home position is also known as zero or reference return.
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.
jog controls Buttons on a CNC control interface that move the machine components along the axes. The jog controls move machine components in steady movement.
jog mode The manual control mode that allows for the manual operation of steady axes movement using the jog buttons. Some machines have a combined handle/jog mode.
M codes A word in a part program used to signal an action from a miscellaneous group of commands. M codes change cutting tools and turn on or turn off coolant, among other actions.
M codes A word in a part program used to signal an action from a miscellaneous group of commands. M codes change cutting tools or turn on or turn off coolant, spindle, or workpiece clamps, among other actions.
M01 A miscellaneous G code programming code that initiates an optional stop. M01 will not cause optional stop to occur if it has been manually turned off.
machine control unit MCU. A small, powerful computer that controls and operates a CNC machine. Machine control units are comprised of a machine operations panel and a control panel.
machine operations panel The group of CNC machine controls that allows operators to manually control the machine. The machine operations panel, or machine panel, directly guides tool movement and the operation of machine components.
manual data input MDI. The mode that allows an operator to manually enter and execute blocks of programming code at the control panel. In manual data input mode, code is entered one block at a time, and each block deletes from the machine as soon as it is executed.
manual load button A key on a CNC mill machine panel that allows the operator to add cutting tools to the automatic toolchanger by hand. Pressing the manual load button stops spindle movement.
master program A part program saved into the memory of a CNC machine. A master program needs to be updated with any changes made to the part program for those changes to affect the master program.
MDI Manual data input. The control mode that allows an operator to manually enter and execute blocks of programming code at the control panel. In MDI mode, code is entered one block at a time and these blocks delete from the machine as soon as they are executed.
MDI Manual data input. The mode that allows an operator to manually enter and execute blocks of programming code at the control panel. In MDI mode, code is entered one block at a time and these blocks delete from the machine as soon as they are executed.
memory mode The control mode that allows an operator to call up and execute a part program stored in the machine. Memory mode does not involve manual input unless overrides are implemented.
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.
milling A cutting operation that uses a multi-point cutting tool to remove material from the surface of a workpiece. Milling can be performed manually using jog mode.
operator A person trained to run a computer numerical control machine on a daily basis. Operators monitor and adjust machining operations.
optional stop A code in a part program that pauses the machining cycle at key moments. Optional stops can be manually turned off so that the program completes without stopping.
override A control that adjusts a programmed element of part machining during operation of the part program. Overrides can control speed, feed, and coolant flow.
overrides A control that adjusts a programmed element of part machining during operation of the part program. Overrides can control speed, feed, and coolant flow.
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.
part programmer The person responsible for the creation of a part program. Part programmers translate a workpiece design into program instructions for the CNC machine control unit.
proving out Performing a series of steps to verify the accuracy of a part program. Operators prove out by using displays, dry runs, and single blocking to check a program for errors.
pulse handle mode The manual control mode that allows for the manual operation of incremental axis movement using the hand controls. Some machines have a combined pulse handle/jog mode.
rapid feedrate override An override that allows the operator to reduce the rate of rapid tool movement during operation. Rapid feedrate override may reduce tool feed to 25% or less of the original rate.
rapid mode A method of manual CNC mill control that allows the operator to manually move machine components at high speeds and feeds. Rapid mode can move components at 600 ipm (15,000 mm/min) or higher.
rapid positioning The quick movement of a machine component to a certain location. Rapid positioning can be done manually using the jog controls.
rapid positioning The quick movement of a machine component to a certain location. The quick movement of a machine component to a certain location. Rapid positioning can be done manually using the jog controls.
reference return The control that automatically locates the spindle in the machine zero position. Reference return is also known as home position or zero return.
single block mode The control mode that allows an operator to execute a part program one block at a time. In single block mode, the operator must push the cycle start button to execute each block.
single block mode The mode that allows an operator to execute a part program one block at a time. In single block mode, the operator must push the cycle start button to execute each block.
soft keys A button located on the control panel that has a different purpose depending on which function key has been chosen. Each soft key's function is visible between brackets on the screen.
spindle The part of the machine tool that spins or rotates. On the mill, the spindle holds the cutting tool.
spindle speed override An override that allows the operator to adjust the speed of the spindle during operation. Spindle speed override functions as a percentage of the programmed value.
stock Raw material that is used to make manufactured parts. Stock is available in standard shapes, such as long bars, plates, or sheets.
tapping The process of cutting internal threads in a hole with a rotating multi-point tool. Tapping operations cancel overrides because tapping requires that spindle speed and feed rate be timed together.
tolerance An acceptable deviation from a given dimension in part specifications. Checking for accurate part tolerances is done after a successful first part run.
tool offsets A numerical value stored in the CNC controls that repositions machine components. Tool offsets are used to adjust for variations in tool geometry, part size, and tool wear.
touch-sensitive display A control panel component that displays information to the operator. Touch-sensitive display screens allow the soft keys to be located and manipulated by the operator on the screen itself.
worktable The component of a CNC mill that supports the workpiece and any workholding devices during machining. Worktables move along the X and Y axes.
zero return The control that automatically locates the spindle in the machine zero position. Zero return is also known as home position or reference return.