Endstops and homing sequence in 3D Printing - Step-by-Step Execution

Concept Flow - Endstops and homing sequence

Start Homing Command

↓

Move Axis Towards Endstop

↓

Check Endstop Triggered?

No→Keep Moving

Yes↓

Stop Movement

↓

Set Axis Position to Zero

↓

Homing Complete

The printer moves an axis until it hits the endstop switch, then stops and sets that position as zero.

Execution Sample

3D Printing

1. Send homing command
2. Move X axis towards endstop
3. Detect endstop triggered
4. Stop X axis
5. Set X position to zero

This sequence moves the X axis until the endstop switch is hit, then sets the position to zero.

Analysis Table

Step	Action	Endstop Triggered?	Movement	Position Set
1	Send homing command	No	No movement yet	No
2	Move X axis towards endstop	No	Moving towards endstop	No
3	Check endstop	No	Continue moving	No
4	Check endstop	No	Continue moving	No
5	Check endstop	Yes	Stop movement	No
6	Set position	Yes	Stopped	X=0
7	Homing complete	Yes	Stopped	X=0

💡 Endstop triggered at step 5, movement stops and position set to zero

State Tracker

Variable	Start	After Step 2	After Step 4	After Step 5	Final
Endstop Triggered	No	No	No	Yes	Yes
Movement	Stopped	Moving	Moving	Stopped	Stopped
Position X	Unknown	Unknown	Unknown	0	0

Key Insights - 3 Insights

Why does the printer keep moving even if the endstop is not triggered?

Because the homing sequence moves the axis until the endstop switch is triggered, as shown in execution_table steps 2 to 4.

What happens immediately after the endstop is triggered?

The printer stops moving the axis and sets the position to zero, as seen in execution_table steps 5 and 6.

Why is the position set to zero after homing?

Because the endstop defines the physical zero point for the axis, so after hitting it, the printer knows the exact starting position.

Visual Quiz - 3 Questions

Look at the execution_table, at which step does the endstop get triggered?

A Step 3

B Step 2

C Step 5

D Step 6

💡 Hint

Check the 'Endstop Triggered?' column in execution_table rows.

According to variable_tracker, what is the position of X after step 5?

A 0

B Unknown

C 1

D Not set

💡 Hint

Look at the 'Position X' row under 'After Step 5' in variable_tracker.

If the endstop never triggers, what would happen to the movement according to execution_table?

A Movement stops immediately

B Movement continues indefinitely

C Position is set to zero anyway

D Homing completes successfully

💡 Hint

Refer to the 'Endstop Triggered?' and 'Movement' columns in execution_table steps 2 to 4.

Concept Snapshot

Endstops are switches that mark the physical zero position of printer axes.
Homing moves an axis until its endstop triggers.
When triggered, movement stops and position is set to zero.
This ensures the printer knows exact starting points for accurate printing.

Full Transcript

The homing sequence in 3D printing starts when the printer receives a homing command. It moves an axis towards its endstop switch. The printer keeps moving until the endstop is triggered, which means the axis reached its physical limit. Once triggered, the printer stops the movement and sets the axis position to zero. This zero position is used as a reference for all future movements, ensuring accuracy. The execution table shows each step, from sending the command to completing homing. The variable tracker shows how the endstop status, movement, and position change over time. Key moments clarify why the printer moves until the endstop triggers and why the position is set to zero afterward. The visual quiz tests understanding of when the endstop triggers, position setting, and what happens if the endstop never triggers.