Toolpath simulation and verification in CNC Programming - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to start the toolpath simulation.

CNC Programming

start_simulation([1])

Drag options to blanks, or click blank then click option'

Atoolpath_data

Bsimulation_speed

Cerror_log

Dmachine_state

Attempts:

3 left

💡 Hint

Common Mistakes

Passing simulation speed instead of toolpath data.

Using machine state which is not the input for simulation start.

The simulation starts by passing the toolpath data to the start_simulation function.

2fill in blank

medium

Complete the code to check if the simulation detected any collisions.

CNC Programming

if simulation_result.[1]():

Drag options to blanks, or click blank then click option'

Adetect_collision

Bhas_errors

Ccheck_collision

Dcollision_detected

Attempts:

3 left

💡 Hint

Common Mistakes

Using has_errors which checks for general errors, not collisions.

Using detect_collision which is not a method of simulation_result.

The method collision_detected() returns True if any collision was found during simulation.

3fill in blank

hard

Fix the error in the code to correctly retrieve the simulation time.

CNC Programming

total_time = simulation.[1]

Drag options to blanks, or click blank then click option'

Atotal_time()

Bget_total_time()

Csimulation_time

DgetTime()

Attempts:

3 left

💡 Hint

Common Mistakes

Using total_time() which is not defined.

Accessing simulation_time attribute which may not exist.

The method get_total_time() correctly returns the total simulation time as a value.

4fill in blank

hard

Fill both blanks to filter and store only safe toolpath points.

CNC Programming

safe_points = [point for point in toolpath if point.[1]() and not point.[2]()]

Drag options to blanks, or click blank then click option'

Ais_within_bounds

Bis_collision_point

Cis_valid

Dis_error

Attempts:

3 left

💡 Hint

Common Mistakes

Using is_valid which may not check bounds.

Using is_error which is too general.

We keep points that are within bounds and exclude those that are collision points.

5fill in blank

hard

Fill all three blanks to create a dictionary of points with their status if safe.

CNC Programming

point_status = [1]: [2] for [3] in toolpath if [3].is_within_bounds()}}

Drag options to blanks, or click blank then click option'

Ap.id

Bp.status

Cpoint

Dp

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'point' as loop variable but not matching keys and values.

Using point object as key which is not hashable.

We use p.id as key, p.status as value, and 'p' as the loop variable name.

Practice

1. What is the main purpose of toolpath simulation in CNC programming?

easy

A. To clean the CNC machine after use

B. To physically cut the material faster

C. To write the CNC program code automatically

D. To visualize the cutting process before actual machining

Solution

1. Step 1: Understand toolpath simulation

   Toolpath simulation shows a virtual preview of the cutting process on the computer.

2. Step 2: Identify the main benefit

   This helps catch errors and understand the machining steps before actual cutting.

3. Final Answer:

   To visualize the cutting process before actual machining -> Option D

4. Quick Check:

   Simulation = Visual preview [OK]

Hint: Simulation means seeing the cut before it happens [OK]

Common Mistakes:

• Confusing simulation with actual cutting
• Thinking simulation writes code automatically
• Assuming simulation cleans the machine

2. Which of the following is the correct syntax to start a toolpath simulation command in a CNC script?

easy

A. START SIMULATION

B. TOOLPATH_SIM()

C. SIMULATE TOOLPATH START

D. RUN TOOLPATH SIM

Solution

1. Step 1: Identify typical CNC scripting syntax

   Commands often use function-like calls with parentheses in CNC scripting environments.

2. Step 2: Match syntax to options

   Only TOOLPATH_SIM() matches a valid function call style for starting simulation.

3. Final Answer:

   TOOLPATH_SIM() -> Option B

4. Quick Check:

   Function call syntax = TOOLPATH_SIM() [OK]

Hint: Look for function call style with parentheses [OK]

Common Mistakes:

• Choosing commands without parentheses
• Using incomplete or invalid command phrases
• Confusing natural language with code syntax

3. Given this CNC script snippet for toolpath simulation:

TOOLPATH_SIM()
MOVE X10 Y10
CUT Z-5
END_SIM()

What will be the output of the simulation?

medium

A. Syntax error due to missing parameters

B. Simulates moving to X10 Y10 but no cutting

C. Simulates moving to X10 Y10 and cutting 5 units deep

D. Simulates cutting at origin only

Solution

1. Step 1: Analyze the commands inside simulation

   The commands move the tool to X=10, Y=10, then cut down to Z=-5 depth.

2. Step 2: Understand simulation output

   The simulation will show this movement and cutting action as a preview.

3. Final Answer:

   Simulates moving to X10 Y10 and cutting 5 units deep -> Option C

4. Quick Check:

   Move + Cut commands = Simulated cut at X10 Y10 Z-5 [OK]

Hint: Look for MOVE and CUT commands inside simulation [OK]

Common Mistakes:

• Ignoring the CUT command effect
• Assuming syntax error without checking commands
• Thinking simulation cuts at origin only

4. This CNC script for toolpath simulation has an error:

TOOLPATH_SIM()
MOVE X20 Y20
CUT Z-10
END_SIM

What is the error and how to fix it?

medium

A. Missing parentheses in END_SIM; fix to END_SIM()

B. MOVE command missing Z coordinate; add Z0

C. CUT command depth should be positive; change to Z10

D. TOOLPATH_SIM() should be TOOLPATH_SIM_START()

Solution

1. Step 1: Check command syntax

   All commands use parentheses except END_SIM which lacks them.

2. Step 2: Correct the syntax error

   Add parentheses to END_SIM making it END_SIM() to fix the error.

3. Final Answer:

   Missing parentheses in END_SIM; fix to END_SIM() -> Option A

4. Quick Check:

   Function calls need parentheses [OK]

Hint: Check all commands have parentheses if others do [OK]

Common Mistakes:

• Ignoring missing parentheses on END_SIM
• Changing CUT depth sign incorrectly
• Adding unnecessary coordinates to MOVE

5. You want to verify a CNC program that moves the tool in a square path cutting 2mm deep. Which sequence correctly simulates and verifies this toolpath?

hard

A. TOOLPATH_SIM()
MOVE X0 Y0
CUT Z-2
MOVE X10 Y0
MOVE X10 Y10
MOVE X0 Y10
MOVE X0 Y0
END_SIM()
VERIFY_PROGRAM()

B. START_SIM()
CUT Z-2
MOVE X0 Y0
MOVE X10 Y0
MOVE X10 Y10
MOVE X0 Y10
END_SIM()
VERIFY()

C. TOOLPATH_SIM()
MOVE X0 Y0
CUT Z2
MOVE X10 Y0
MOVE X10 Y10
MOVE X0 Y10
MOVE X0 Y0
END_SIM()
VERIFY_PROGRAM()

D. SIMULATE_TOOLPATH()
MOVE X0 Y0
CUT Z-2
MOVE X10 Y0
MOVE X10 Y10
MOVE X0 Y10
MOVE X0 Y0
END_SIM()
VERIFY_PROGRAM()

Solution

1. Step 1: Check simulation command correctness

   TOOLPATH_SIM() MOVE X0 Y0 CUT Z-2 MOVE X10 Y0 MOVE X10 Y10 MOVE X0 Y10 MOVE X0 Y0 END_SIM() VERIFY_PROGRAM() uses TOOLPATH_SIM() and END_SIM() correctly to start and end simulation.

2. Step 2: Verify cutting depth and path

   Cutting depth is negative (-2) which is correct for downward cut; moves form a square path.

3. Step 3: Confirm verification command

   VERIFY_PROGRAM() is the correct command to check the CNC program after simulation.

4. Final Answer:

   The sequence has correct simulation, cutting depth, path, and verification commands -> Option A

5. Quick Check:

   Correct commands + negative cut depth + square path = TOOLPATH_SIM() MOVE X0 Y0 CUT Z-2 MOVE X10 Y0 MOVE X10 Y10 MOVE X0 Y10 MOVE X0 Y0 END_SIM() VERIFY_PROGRAM() [OK]

Hint: Check commands, cut depth sign, and path shape carefully [OK]

Common Mistakes:

• Using positive cut depth instead of negative
• Wrong simulation start/end commands
• Incorrect or missing verification command