Podcast
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?
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?
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 _____?
A boxed dimension is defined as a _____?
basic
S.D.S. (Safety Data Sheet) are sheets that?
S.D.S. (Safety Data Sheet) are sheets that?
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How many 4-7/8 inch long rods can be cut from a rod with a total length of 97-1/2 inches?
How many 4-7/8 inch long rods can be cut from a rod with a total length of 97-1/2 inches?
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What does the code M01 do?
What does the code M01 do?
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Match the code M4 to its description.
Match the code M4 to its description.
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How often should you check waylube and coolant levels?
How often should you check waylube and coolant levels?
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What formula is used to calculate RPM?
What formula is used to calculate RPM?
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Which display screen mode lets the operator enter tooling related data?
Which display screen mode lets the operator enter tooling related data?
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What on/off mode switch works in conjunction with an M01 code in the program?
What on/off mode switch works in conjunction with an M01 code in the program?
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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?
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?
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A boxed letter represents a _____?
A boxed letter represents a _____?
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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?
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?
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Match the G54 code to its description.
Match the G54 code to its description.
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What tool # should be used in the command 'T__ M6 S2000 M3 G43 H12 Z1.0 M8'?
What tool # should be used in the command 'T__ M6 S2000 M3 G43 H12 Z1.0 M8'?
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Which display screen mode lets the operator actually see the distance-to-go in the current CNC command?
Which display screen mode lets the operator actually see the distance-to-go in the current CNC command?
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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?
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?
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What mode switch position allows you to send the machine to its reference position?
What mode switch position allows you to send the machine to its reference position?
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+/-.005 represents a _____?
+/-.005 represents a _____?
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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?
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?
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You need to tool change to Tool #11. How would you do it?
You need to tool change to Tool #11. How would you do it?
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Match the M30 code to its description.
Match the M30 code to its description.
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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?
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?
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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?
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?
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Why do you have to 'home' the machine when you first power up?
Why do you have to 'home' the machine when you first power up?
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You have a dimension that is supposed to be 1.105" +/-.0015". Which of these dimensions is out of your tolerance zone?
You have a dimension that is supposed to be 1.105" +/-.0015". Which of these dimensions is out of your tolerance zone?
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What button will restart the program after a program stop has been read?
What button will restart the program after a program stop has been read?
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What mode switch position allows you to move the machine axes manually?
What mode switch position allows you to move the machine axes manually?
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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?
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?
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What is the code G28?
What is the code G28?
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When should safety glasses be worn?
When should safety glasses be worn?
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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:
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:
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What is the code M00?
What is the code M00?
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What does the G00 code activate?
What does the G00 code activate?
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What does the G94 code activate?
What does the G94 code activate?
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What is the description of a G01 code?
What is the description of a G01 code?
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What on/off mode switch works in conjunction with a '/' (forward slash) in the program to skip over lines of code?
What on/off mode switch works in conjunction with a '/' (forward slash) in the program to skip over lines of code?
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What mode switch position allows programs to be modified?
What mode switch position allows programs to be modified?
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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?
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?
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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.
Display and Navigation
- 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.
Studying That Suits You
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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.
