NIMS Milling Quiz: CNC Command & Display Modes

Questions and Answers

If a dimension on a drawing is 4.868" with a tolerance of +/-.003", what is the largest the dimension can check and still be in tolerance?

4.871"

If you are standing in front of a vertical CNC machining center, what direction does the X-axis travel?

left to right

A boxed dimension is defined as a _____?

basic

S.D.S. (Safety Data Sheet) are sheets that?

Describe the chemicals and materials in the shop. Signup and view all the answers

How many 4-7/8 inch long rods can be cut from a rod with a total length of 97-1/2 inches?

20 Signup and view all the answers

What does the code M01 do?

optional stop Signup and view all the answers

Match the code M4 to its description.

spindle on reverse Signup and view all the answers

How often should you check waylube and coolant levels?

every shift Signup and view all the answers

What formula is used to calculate RPM?

SFM times 4 divided by diameter Signup and view all the answers

Which display screen mode lets the operator enter tooling related data?

Offset page Signup and view all the answers

What on/off mode switch works in conjunction with an M01 code in the program?

optional stop Signup and view all the answers

You are running the first workpiece on a proven program. You measure the part, and it checks at 0.4325". What must you do to correct the error?

+input -.0045" to tool 02 height wear offset and re-run the tool Signup and view all the answers

A boxed letter represents a _____?

datum Signup and view all the answers

If you want to use a 1.0" diameter 2-flute end mill running at 3000 RPM, what feed rate should you run at to achieve a 0.003" per tooth chip load?

18 inches per minute Signup and view all the answers

Match the G54 code to its description.

Work offset #1 Signup and view all the answers

What tool # should be used in the command 'T__ M6 S2000 M3 G43 H12 Z1.0 M8'?

T12 Signup and view all the answers

Which display screen mode lets the operator actually see the distance-to-go in the current CNC command?

Program check page Signup and view all the answers

What direction do you turn the manual pulse generator or move the axis to move a tool from right to left on a CNC mill?

The X- direction Signup and view all the answers

What mode switch position allows you to send the machine to its reference position?

Zero Return Signup and view all the answers

+/-.005 represents a _____?

tolerance Signup and view all the answers

While dry running a proven program, the machine goes into an alarm state and shows a message, 'Overcutting will occur during Cutter Compensation.' What is most likely wrong?

You need to change the tool dia. or radius offset value. Signup and view all the answers

You need to tool change to Tool #11. How would you do it?

Use MDI mode to change tools using commands similar to what a program would Signup and view all the answers

Match the M30 code to its description.

program end / rewind Signup and view all the answers

You must cut a part to 10.175 inches long and need to add a total of 1/8 of an inch for finish machining. How long should you saw the block?

10.300" Signup and view all the answers

Using a standard high-speed steel twist drill, you are to drill a hole 0.312" deep (not including the drill point). If the drill point checks at 0.098" long, how deep should the drill be programmed?

Z-.410 Signup and view all the answers

Why do you have to 'home' the machine when you first power up?

so the machine can find the X, Y, and Z axis reference points Signup and view all the answers

You have a dimension that is supposed to be 1.105" +/-.0015". Which of these dimensions is out of your tolerance zone?

1.1033 Signup and view all the answers

What button will restart the program after a program stop has been read?

cycle start Signup and view all the answers

What mode switch position allows you to move the machine axes manually?

Jog Signup and view all the answers

The upper size limit on a pocket is 0.787". You measure the diameter and it checks at 0.7915". How much oversize is the diameter?

0.0045" Signup and view all the answers

What is the code G28?

zero return Signup and view all the answers

When should safety glasses be worn?

as you enter the machining environment Signup and view all the answers

After completing an entire setup and running one tool, you must shut the machine off and go home. When you come in the next day, you must:

power the machine up, home it, and go back through the entire setup process Signup and view all the answers

What is the code M00?

Program Stop Signup and view all the answers

What does the G00 code activate?

rapid motion Signup and view all the answers

What does the G94 code activate?

per minute feed Signup and view all the answers

What is the description of a G01 code?

linear feed Signup and view all the answers

What on/off mode switch works in conjunction with a '/' (forward slash) in the program to skip over lines of code?

block delete Signup and view all the answers

What mode switch position allows programs to be modified?

edit Signup and view all the answers

Before running a program that cuts a pocket 3.0" wide with a +/-.002 tolerance, what should you do to the tool's offset to prevent a scrapped part?

set the diameter wear offset at 0.0100" Signup and view all the answers

Study Notes

Dimensions and Tolerances

A dimension of 4.868" with a tolerance of +/-.003" has a maximum dimension of 4.871".
A tolerance of +/-.005 indicates acceptable variations in measurements.

Axes and Directions

In a vertical CNC machining center, the X-axis moves from left to right.
To move a tool from right to left on a CNC mill, the manual pulse generator should be turned in the X- direction.

CNC Codes and Functions

Code M01 signifies an optional stop during a machining program.
M04 activates spindle rotation in reverse.
G54 denotes Work Offset #1, while M30 indicates program end and rewind.
G00 is used to initiate rapid motion, and G01 corresponds to linear feed operations.
G94 activates feed per minute for cutting processes, ensuring precise control.

Tooling and Setup

The appropriate method for making a tool change is to utilize MDI mode for tool commands.
To avoid errors, parameters like tool height wear offsets must be accurately input and re-adjusted as needed.
Tool #12 should be used based on the specified setup commands T__ M6, S2000 M3, G43 H12 Z1.0 M8.

Safety and Maintenance

Safety Data Sheets (SDS) provide crucial information about chemicals and materials in the workspace.
Regular checks of waylube and coolant levels should be conducted every shift.
Safety glasses must be worn upon entering the machining environment to ensure worker safety.

Program Management

After a program stop, the cycle start button is necessary to restart the program.
Homing the machine upon startup is critical for locating the X, Y, and Z axis reference points.
In edit mode, programs can be modified as needed for adjustments.

Measurements and Calculations

A boxed dimension refers to a basic dimension, serving as a reference point.
When calculating the RPM for a cutting tool, the formula is SFM times 4 divided by diameter.
Feed rates for tools, like an end mill, can be determined based on chip load specifications, e.g., 18 inches per minute for a .003" per tooth chip load.

Common Issues and Solutions

An alarm indicating "Overcutting will occur during Cutter Compensation" suggests a need to adjust tool diameter or radius offset values.
If tools are required for a specific depth, precise measurements must be programmed (e.g., Z-.410 for a drill depth considering drill point length).
If a dimension exceeds tolerance limits, corrective adjustments must be made, such as recalibrating the tool height wear offset.

Dimensional Checks

A rod of 97-1/2 inches can yield 20 pieces of 4-7/8 inches.
When machining, it's essential to saw the block to ensure it incorporates an additional 1/8 inch for finishing if the target length is 10.175 inches.

The Offset page in CNC displays allows users to enter tooling-related data.
The Program check page displays the distance-to-go for current commands, aiding in program verification.
A switch in Jog mode enables manual movement of machine axes, providing control during setup and adjustments.

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Description

Test your knowledge with this NIMS Milling Practice Test #1. This set of flashcards covers key concepts, dimensions, and machine operations relevant to CNC milling. Perfect for those preparing for NIMS certification.

NIMS Milling Practice Test #1