Haas NGC: Locating Program Zero on the Lathe 212

“Haas NGC: Locating Program Zero on the Lathe” describes important concepts related to program zero, or part zero, on the Haas Next Generation Control (NGC) lathe. Part zero is the starting point for all machine operations on the lathe. It is most often located at the center of the finished part face. Lathe operators must determine the most effective approach to locating part zero for each workpiece and operations. Methods for locating part zero vary based on the operator’s approach to setting tool length offsets.

After taking this course, operators will be able to distinguish between the different methods for locating part zero and the different factors that determine which approach is best. Operators will also understand the appropriate steps for locating part zero on the Haas NGC lathe with each method. This knowledge will allow them to operate lathes effectively and efficiently.

Class Details

Class Name:
Haas NGC: Locating Program Zero on the Lathe 212
Difficulty:
Intermediate
Number of Lessons:
16

Class Outline

  • Part Zero
  • The Cartesian Coordinate System
  • Machine Zero to Part Zero
  • The Machine Coordinate and Work Coordinate Systems
  • Review: Part Zero and Machine Zero
  • Part Zero Location: the Part Face
  • Part Zero Location: the Chuck
  • Part Zero and Work Offsets
  • Review: Part Zero Locations and Work Offsets
  • Part Zero and Tool Length Offsets
  • Locating Part Zero: Reference Tool
  • Locating Part Zero: Tool Presetter
  • Locating Part Zero: Chuck
  • Accounting for Rough Stock
  • Performing a Manual Facing Cut
  • Review: Locating Part Zero on the Part Face

Objectives

  • Describe part zero.
  • Describe the Cartesian coordinate system.
  • Distinguish between machine zero and part zero.
  • Distinguish between the machine coordinate and work coordinate systems.
  • Describe considerations for locating part zero on the part face.
  • Describe considerations for locating part zero on the chuck.
  • Describe how part zero relates to work offsets.
  • Describe how part zero relates to tool length offsets.
  • Explain how to locate part zero using a reference tool.
  • Explain how to locate part zero after setting tool length offsets with a tool presetter.
  • Explain how to locate part zero after setting Z axis tool length offsets on the chuck.
  • Describe ways to account for rough stock in the Z axis when locating part zero on the part face.
  • Explain how to perform a manual facing cut on the Haas NGC lathe.

Job Roles

Certifications

Glossary

Vocabulary Term Definition
alphanumeric Consisting of or using both letters and numbers. Alphanumeric commands, which make up G code programming, instruct CNC machine operation.
automatic tool presetter An optional device on the Haas NGC lathe used to quickly determine tool length offsets in the X and Z axes. The automatic tool presetter instantly records tool offsets when a tool tip contacts sensors on the tool presetter stylus.
axes An imaginary straight line that is used to describe the location or movement of an object in three-dimensional space. Axes in the Cartesian coordinate system include the X, Y, and Z axes.
Cartesian coordinate system A positioning system that uses three perpendicular linear axes to locate positions in three-dimensional space. The Cartesian coordinate system's axes are the X axis, Y axis, and Z axis.
centerline An imaginary line that divides a shape into two equal halves or that runs through the center of a cylindrical object. The centerline is also the center point of a rotational axis.
chuck A device that holds a workpiece in place as it rotates on a CNC lathe. A chuck commonly has three or four jaws that can be adjusted to fit variously sized parts.
chuck face The surface of the lathe chuck that can be touched off in the Z axis. The chuck face is a possible location for part zero.
CNC Computer numerical control. A combination of software and hardware that directs the operation of a machine. CNC uses mathematical data to direct machine movements.
computer numerical control CNC. A combination of software and hardware that directs the operation of a machine. Computer numerical control uses mathematical data to direct machine movements.
CURRENT COMMANDS A display key that shows various information about the current state of the machine. The CURRENT COMMAND key displays tabbed options for raising or lowering the automatic tool presetter.
CYCLE START The button used to begin a program or continue a program previously stopped. CYCLE START is located on the left side of the NGC control panel.
datum structure A specified point, line, or plane on a part design that acts as a reference for a part feature. The datum structure of a part is often used to establish the work coordinate system.
F2 A function key on the control panel that has different purposes based on which menu is selected. The F2 key raises and lowers the tool presetter arm when setting tool length offsets.
facing cut A cut on the end of a cylindrical workpiece that removes material to leave a flat surface. A facing cut is usually the first step in a part program for a CNC lathe.
facing tool A lathe tool used to perform radial cuts that smooth out the workpiece face. Facing tools typically use triangular or diamond-shaped inserts.
finish To alter the texture or appearance of a part in order to obtain a smooth surface. Lathe operators finish the part face to create an appropriate surface for touching off tools.
G code commands A code in a CNC part program that determines the type of operation performed on the machine. G code commands for work offsets on the lathe are listed in the work offsets menu.
HANDLE JOG A mode key that initiates jog mode. Pressing HANDLE JOG allows operators to move the turret using the jog handle or jog keys and displays various axis positions at the bottom of the control screen.
index To select a tool in the tool turret and move it to the cutting position. Operators must index the appropriate tool when setting offsets.
jaw face The surface of a lathe chuck jaw that can be touched off in the Z axis and that aligns with the back end of the part not held within the chuck jaws. The jaw face is a possible location for part zero.
jog To move the tool turret in the X or Z axis manually in jog mode. Machinists jog the turret by either holding down one of the jog keys or by pressing one of the jog keys to select a machine axis and then turning the jog handle.
jog handle A dial that is turned by hand in order to manually control CNC machine motions. The jog handle on a Next Generation Control is located to the left of the keypad.
jog keys The area of the control keypad that allows an operator to move the tool along a selected axis. Jog keys are located to the left of center on the keypad.
jog mode The operational mode that allows for manual control of steady axis movement. Jog mode can be operated using the jog keys and jog handle.
machine coordinate system A fixed coordinate system with machine zero as its origin. The machine coordinate system encompasses the entire range of movement in the lathe's work area and is the reference for calculating all part zero locations.
machine origin A Cartesian coordinate position at the furthest point of positive travel in the X, Y, and Z axes on the Haas NGC lathe. The machine origin has a value of zero in all three axes.
machine zero The default home position on a CNC machine that is permanently set by the manufacturer. Machine zero is the furthest positive position in the X, Y, and Z axes on the CNC machine.
MDI A mode key that activates MDI mode on the Haas NGC. The MDI key is used to enter and execute commands during part setup.
MDI mode An operation mode that lets an operator enter and execute program data without disturbing stored data. MDI mode is used to activate the spindle and execute other G code commands.
Next Generation Control NGC. The latest Haas Automation®, Inc. CNC control. The Next Generation Control was released in 2016.
NGC Next Generation Control. The latest Haas Automation®, Inc. CNC control. The NGC was released in 2016.
offsets A measurement recorded by the CNC control that re-positions machine components for different tools and parts. Offsets are used to adjust for differences in tool geometry, part size, tool wear, and any other changing variables that may affect the manufacture of the part.
origin A fixed, central point in the Cartesian coordinate system where the three X, Y, and Z axes intersect. The origin has a numerical value of zero.
outer diameter OD. The exterior surface on a cylindrical workpiece. Outer diameter turning cuts decrease the diameter of the workpiece.
parallel Extending in the same direction as another line or plane and equally distant from that line or plane at all points. The Z axis on a CNC lathe is parallel to the spindle centerline.
part face The flat, circular end of a cylindrical part. The part face is used as a reference point to calculate part zero.
part program A series of alphanumeric instructions that guides the movements of a CNC machine. A part program directs a CNC machine to perform the necessary sequence of operations to machine a specific workpiece.
part zero The starting point of X, Y, and Z coordinates for a part program. Part zero, or program zero, acts as a reference point for all part dimensions.
perpendicular Intersecting another line or plane at a right angle. The X axis on a CNC lathe is perpendicular to the spindle centerline.
program zero The starting point of X, Y, and Z coordinates for a part program. Program zero, or part zero, acts as a reference point for all part dimensions.
reference tool A tool to which all other tools in the turret are compared when setting geometry offsets. The reference tool does not require a tool length offset because its exact location is stored as the work offset.
revolutions per minute rpm. A unit of measurement that indicates how many times the spindle rotates in one minute. Revolutions per minute is a measurement of speed.
slant bed lathes A type of lathe with an X axis that is positioned at an angle, typically about 45 degrees. Most Haas NGC lathe models are slant bed lathes.
stock Raw material that is used to make manufactured parts. Stock is available in standard shapes, such as long bars, plates, or sheets.
stylus A measuring instrument with a square tip connected to a tool presetter. The stylus uses sensors to record a tool's position when the tool tip contacts it.
three-dimensional 3D. Having a length, depth, and width. Three-dimensional movements in a Cartesian coordinate system are described as X, Y, and Z axis movements.
tool length offsets An offset used on a CNC lathe to account for variations in tool length along the Z axis and the X axis. Tool length offsets are required for each cutting tool.
tool offsets menu A digital table in the Haas Next Generation Control that displays various tool offsets and settings. The tool offsets menu for the lathe includes X geometry and Z geometry columns for tool length offsets.
tool turret A lathe component that holds a number of cutting tools. The tool turret rotates to index tools in the cutting position.
touching off Determining the exact location of a tool tip by touching it against an object with a known measurement. Touching off various tools allows machinists to set tool length and work offsets.
TURRET FWD A key on the Haas NGC lathe that rotates the tool turret on a CNC lathe. Pressing TURRET FWD replaces the current tool with the next sequential tool in MDI mode.
TURRET REV A key on the Haas NGC lathe that rotates the tool turret on a CNC lathe. Pressing TURRET REV replaces the current tool with the previous sequential tool in MDI mode.
work coordinate system A variable coordinate system that has part zero as its origin. The work coordinate system contains all cutting commands on the lathe.
work offset An automatic adjustment of machine components that moves the lathe tool turret to the part zero location. Work offsets change the position of the turret to adjust the location of every tool when in use.
work offsets menu A digital table in the Haas Next Generation Control that displays programmable work offsets. The work offsets menu for the lathe includes X axis and Z axis values, as well as Y axis values if available.
work origin A Cartesian coordinate position in a work coordinate system on the Haas NGC lathe where the X, Y, and Z axes intersect. The work origin has a value of zero in all three axes.
X axis An imaginary straight line in the Cartesian coordinate system that runs at a 45 degree angle to the spindle centerline on Haas NGC slant bed lathes. X axis movements on a CNC lathe are toward or away from the operator.
Y axis An imaginary straight line in the Cartesian coordinate system that runs perpendicular to the spindle centerline on Y axis Haas NGC lathes. Y axis movements on a CNC lathe are advanced linear movements of the tool turret and are only available on some lathe models.
Z axis An imaginary straight line in the Cartesian coordinate system that is parallel to the lathe spindle centerline. Z axis movements on a CNC lathe are toward or away from the spindle.
Z FACE MEASURE A key on the Haas NGC lathe that automatically stores the Z axis position as a tool length offset for a tool that is properly touched off against the workpiece surface. The Z FACE MEASURE key is also used to set a Z axis work offset.