Roughing strategies (adaptive, pocket) in CNC Programming - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to select the adaptive roughing strategy.

CNC Programming

strategy = '[1]'

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

Afinishing

Badaptive

Cpocket

Ddrilling

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing 'pocket' which is a different roughing method.

Selecting 'finishing' which is for final passes.

The adaptive roughing strategy is selected by setting strategy to 'adaptive'.

2fill in blank

medium

Complete the code to define the pocket roughing area.

CNC Programming

pocket_area = [1]

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

Atoolpath

B50

Cadaptive

D[(0,0), (50,0), (50,50), (0,50)]

Attempts:

3 left

💡 Hint

Common Mistakes

Using a single number instead of coordinates.

Using strategy names instead of area coordinates.

The pocket area is defined by a list of corner points forming a square.

3fill in blank

hard

Fix the error in the code to set the step-over for adaptive roughing.

CNC Programming

step_over = [1] * tool_diameter

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

A0.5

Bstep_over

Cfeed_rate

Dtool_diameter

Attempts:

3 left

💡 Hint

Common Mistakes

Using tool_diameter twice causing incorrect calculation.

Using feed_rate which is unrelated to step-over.

Step-over is a fraction (like 0.5) of the tool diameter to control material removal.

4fill in blank

hard

Fill both blanks to create a dictionary for pocket roughing parameters.

CNC Programming

pocket_params = {'area': [1], 'step_over': [2]

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

A[(0,0), (40,0), (40,40), (0,40)]

B0.4

C0.5

Dadaptive

Attempts:

3 left

💡 Hint

Common Mistakes

Using strategy names instead of area coordinates.

Using step-over values greater than 1.

The 'area' is a list of coordinates and 'step_over' is a decimal fraction.

5fill in blank

hard

Fill all three blanks to define an adaptive roughing toolpath with feed rate and step-down.

CNC Programming

adaptive_toolpath = {'strategy': [1], 'feed_rate': [2], 'step_down': [3]

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

A'adaptive'

B1500

C2.5

D'pocket'

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'pocket' instead of 'adaptive' for strategy.

Confusing feed rate with step-down values.

The strategy is 'adaptive', feed rate is 1500 mm/min, and step-down is 2.5 mm.

Practice

1. What is the main goal of roughing strategies in CNC programming?

easy

A. Polish the material surface

B. Create the final surface finish directly

C. Remove most material quickly to prepare for finishing

D. Only drill holes in the workpiece

Solution

1. Step 1: Understand roughing purpose

   Roughing removes large amounts of material fast to shape the part roughly.

2. Step 2: Differentiate from finishing

   Finishing is for smooth final surfaces, not roughing.

3. Final Answer:

   Remove most material quickly to prepare for finishing -> Option C

4. Quick Check:

   Roughing = Fast material removal [OK]

Hint: Roughing = fast bulk removal, not fine finishing [OK]

Common Mistakes:

• Confusing roughing with finishing
• Thinking roughing polishes surfaces
• Assuming roughing only drills holes

2. Which of the following is the correct syntax to start an adaptive roughing toolpath in a CNC script?

easy

A. adaptive_roughing(start_point, tool_diameter, step_over)

B. rough_adaptive(tool_diameter, start_point, step_over)

C. start_roughing_adaptive(tool_diameter, step_over, start_point)

D. adaptiveRough(tool_diameter, step_over)

Solution

1. Step 1: Identify correct function name and parameters

   The standard function is named adaptive_roughing with parameters in order: start_point, tool_diameter, step_over.

2. Step 2: Check parameter order and names

   adaptive_roughing(start_point, tool_diameter, step_over) matches the correct syntax and order exactly.

3. Final Answer:

   adaptive_roughing(start_point, tool_diameter, step_over) -> Option A

4. Quick Check:

   Correct function name and parameter order [OK]

Hint: Look for exact function name and parameter order [OK]

Common Mistakes:

• Mixing parameter order
• Using incorrect function names
• Omitting required parameters

3. Given this pseudo-code for pocket roughing:

for depth in range(0, 5, 1):
    clear_pocket_layer(depth, tool_diameter=10)
print('Done')

What will be the output?

medium

A. Done

B. 0 1 2 3 4 Done

C. Error: range parameters incorrect

D. Done 5

Solution

1. Step 1: Analyze the loop behavior

   The loop runs from 0 to 4 (5 excluded), calling clear_pocket_layer but does not print inside the loop.

2. Step 2: Check print statement

   Only print('Done') is outside the loop, so only 'Done' is printed once.

3. Final Answer:

   Done -> Option A

4. Quick Check:

   Loop calls function silently, print after loop = Done [OK]

Hint: Print outside loop means single output after loop ends [OK]

Common Mistakes:

• Assuming loop prints each depth
• Thinking range includes 5
• Confusing function calls with print output

4. This CNC script snippet for adaptive roughing has an error:

adaptive_roughing(8, (0,0), 2)

What is the error?

medium

A. tool_diameter must be last parameter

B. Parameters are in wrong order; start_point should be first

C. step_over cannot be 2

D. No error; syntax is correct

Solution

1. Step 1: Recall correct parameter order

   The function adaptive_roughing expects parameters in order: start_point, tool_diameter, step_over.

2. Step 2: Identify mismatch in call

   Here, tool_diameter is first, which is incorrect order.

3. Final Answer:

   Parameters are in wrong order; start_point should be first -> Option B

4. Quick Check:

   Parameter order matters [OK]

Hint: Check parameter order carefully in function calls [OK]

Common Mistakes:

• Ignoring parameter order
• Assuming parameters can be passed in any order
• Thinking step_over value is invalid

5. You want to rough a pocket with a 12mm tool using adaptive roughing to keep tool load steady. Which approach best achieves this?

hard

A. Use adaptive roughing with constant step-over and variable depth per pass

B. Use pocket roughing with variable step-over and depth per pass

C. Use pocket roughing with fixed depth layers and no step-over control

D. Use adaptive roughing with variable step-over and constant depth per pass

Solution

1. Step 1: Understand adaptive roughing goal

   Adaptive roughing aims to keep tool load steady by adjusting step-over dynamically.

2. Step 2: Match approach to steady tool load

   Variable step-over with constant depth per pass helps maintain steady load during cutting.

3. Step 3: Compare options

   Use adaptive roughing with variable step-over and constant depth per pass matches this approach best; others either fix step-over or use pocket roughing which is less adaptive.

4. Final Answer:

   Use adaptive roughing with variable step-over and constant depth per pass -> Option D

5. Quick Check:

   Adaptive roughing = variable step-over for steady load [OK]

Hint: Adaptive roughing varies step-over, not depth, for steady load [OK]

Common Mistakes:

• Confusing pocket roughing with adaptive roughing
• Fixing step-over instead of varying it
• Changing depth instead of step-over for load control