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3D Printingknowledge~20 mins

Common G-code commands (G0, G1, G28, M104, M106) in 3D Printing - Practice Problems & Coding Challenges

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📋 Factual
intermediate
1:30remaining
What does the G0 command do in G-code?

In 3D printing, the G0 command is used to:

AMove the print head slowly while extruding filament
BHome all axes to their origin positions
CMove the print head quickly to a specified position without extruding filament
DSet the temperature of the print bed
Attempts:
2 left
💡 Hint

Think about which command moves the print head fast without printing.

🧠 Conceptual
intermediate
1:30remaining
What is the main difference between G0 and G1 commands?

Both G0 and G1 move the print head. What key difference affects printing?

AG0 moves without extruding filament; G1 moves while extruding filament
BG0 sets temperature; G1 homes the axes
CG0 homes the axes; G1 moves without extruding filament
DG0 moves slowly; G1 moves quickly
Attempts:
2 left
💡 Hint

One command is for travel moves, the other for printing moves.

🔍 Analysis
advanced
2:00remaining
What happens when the G28 command is executed?

Consider a 3D printer starting a print. What does the G28 command do?

AMoves the print head to the last saved position
BSets the extruder temperature
CTurns on the cooling fan
DHomes all axes to their origin positions
Attempts:
2 left
💡 Hint

Think about the printer's starting position before printing.

❓ Reasoning
advanced
2:00remaining
What is the effect of the M104 command in a print job?

During a print, the M104 command is used to:

ASet the extruder temperature without waiting
BTurn on the cooling fan
CHome the print bed
DMove the print head to a specific coordinate
Attempts:
2 left
💡 Hint

Consider commands that control temperature but do not pause the print.

❓ Comparison
expert
2:30remaining
Which command controls the cooling fan speed during printing?

Among the following G-code commands, which one adjusts the cooling fan speed?

AG1
BM106
CM104
DG28
Attempts:
2 left
💡 Hint

Think about commands starting with M that control hardware like fans.

Practice

(1/5)
1. What does the G-code command G28 do in 3D printing?
easy
A. Sets the extruder temperature
B. Homes all axes to their origin positions
C. Moves the print head quickly without extruding
D. Turns on the cooling fan

Solution

  1. Step 1: Understand the purpose of G28

    The G28 command is used to move the printer's axes to their home or origin positions, ensuring the printer knows where the starting point is.

  2. Step 2: Compare with other commands

    Other commands like G0 move quickly without printing, M104 sets temperature, and M106 controls the fan, so they do not home the axes.

  3. Final Answer:

    Homes all axes to their origin positions -> Option B

  4. Quick Check:

    G28 = Home axes [OK]
Hint: G28 always means 'go home' for all axes [OK]
Common Mistakes:
  • Confusing G28 with G0 or G1 which move the head
  • Thinking M104 or M106 control movement instead of temperature or fan
  • Assuming G28 sets temperature or fan speed
2. Which of the following is the correct syntax to set the extruder temperature to 200°C using G-code?
easy
A. G28 S200
B. M106 S200
C. G1 S200
D. M104 S200

Solution

  1. Step 1: Identify the command for setting extruder temperature

    M104 is the G-code command used to set the extruder temperature to a specified value.

  2. Step 2: Check the syntax

    The correct syntax is M104 followed by S and the temperature value, so M104 S200 sets the extruder to 200°C.

  3. Final Answer:

    M104 S200 -> Option D

  4. Quick Check:

    M104 sets extruder temp = M104 S200 [OK]
Hint: M104 sets extruder temp; M106 controls fan [OK]
Common Mistakes:
  • Using M106 which controls the fan instead of temperature
  • Using G1 or G28 which are for movement, not temperature
  • Omitting the S parameter for temperature value
3. What will happen when the following G-code commands are executed?
G0 X50 Y50
G1 X100 Y100 E10
medium
A. The print head homes all axes, then sets extruder temperature to 10°C
B. The print head moves slowly to (50,50) while extruding, then quickly to (100,100) without extruding
C. The print head moves quickly to (50,50) without extruding, then moves to (100,100) while extruding filament
D. The print head turns on the fan and moves to (100,100)

Solution

  1. Step 1: Understand G0 and G1 commands

    G0 moves the print head quickly without extruding filament. G1 moves the print head while extruding filament as specified by the E parameter.

  2. Step 2: Analyze the commands given

    First, G0 moves the head to X50 Y50 quickly without extrusion. Then, G1 moves the head to X100 Y100 while extruding 10 units of filament.

  3. Final Answer:

    The print head moves quickly to (50,50) without extruding, then moves to (100,100) while extruding filament -> Option C

  4. Quick Check:

    G0 = fast move no extrusion, G1 = move with extrusion [OK]
Hint: G0 = fast move no extrusion; G1 = move with extrusion [OK]
Common Mistakes:
  • Mixing up G0 and G1 commands
  • Assuming extrusion happens during G0
  • Confusing E parameter as fan speed or temperature
4. A user writes the following G-code to turn on the cooling fan at half speed:
M106 S128

But the fan does not turn on. What is the likely error?
medium
A. The printer firmware might require a different command or fan pin setup
B. The S value should be between 0 and 255, 128 is invalid
C. The command should be M104 to control the fan
D. The G28 command is missing before M106

Solution

  1. Step 1: Understand M106 command and S parameter

    M106 controls the cooling fan speed with S value from 0 (off) to 255 (full speed). S128 is a valid half speed.

  2. Step 2: Consider why fan might not turn on

    If the fan does not turn on, it is likely due to printer firmware settings or hardware configuration, such as fan pin assignment or disabled fan control.

  3. Final Answer:

    The printer firmware might require a different command or fan pin setup -> Option A

  4. Quick Check:

    M106 S128 valid but hardware/firmware may block fan [OK]
Hint: Check firmware and hardware if M106 S128 doesn't work [OK]
Common Mistakes:
  • Thinking S128 is out of range (it's valid)
  • Using M104 instead of M106 for fan control
  • Assuming G28 is needed before fan commands
5. You want to start a print by homing all axes, setting the extruder temperature to 210°C, waiting for it to reach temperature, then moving the print head to X10 Y10 quickly without extruding. Which sequence of G-code commands is correct?
hard
A. G28
M104 S210
M109 S210
G0 X10 Y10
B. M104 S210
G28
M109 S210
G1 X10 Y10 E0
C. G28
M109 S210
M104 S210
G0 X10 Y10
D. M106 S210
G28
M109 S210
G0 X10 Y10

Solution

  1. Step 1: Identify commands for each action

    G28 homes all axes. M104 sets extruder temperature without waiting. M109 sets temperature and waits until reached. G0 moves quickly without extruding.

  2. Step 2: Check command order for correct sequence

    First home with G28, then set temp with M104, wait with M109, finally move with G0 to X10 Y10 without extrusion.

  3. Final Answer:

    G28
    M104 S210
    M109 S210
    G0 X10 Y10     -> Option A

  4. Quick Check:

    Home, set temp, wait, then fast move = G28
    M104 S210
    M109 S210
    G0 X10 Y10 [OK]
Hint: Use M109 to wait for temp after M104, then move with G0 [OK]
Common Mistakes:
  • Using M106 instead of temperature commands
  • Moving with G1 and extruding when not needed
  • Setting temperature after moving the head