<p>Yes, this is normal. Your printer is, at first, probably going downward with some speed. When it hits the end-stop it has some momentum and doesn't stop right away. So once it hits the end-stop, it has to physically stop the print head and move upward again slightly to get to the right position.</p>

CC BY-SA 3.0
2016-04-23T18:04:42.637Z
2016-04-30T15:14:36.317Z
2016-04-30T15:14:36.317Z
Luca van Straaten
<p>Typically a machine will rapid to find its software stop(s), retract and slowly find its mechanical end stop. Please regard the RepRap Wiki for <a href="http://reprap.org/wiki/Endstop" rel="nofollow">general troubleshooting</a> and <a href="http://reprap.org/wiki/Mechanical_Endstop" rel="nofollow">basic technical information</a>.</p>

CC BY-SA 3.0
2016-03-24T18:02:21.090Z
If I'm understanding your post correctly, it seems that this is normal. Are you experiencing any adverse affects in your printing or motion? If not, then I'd assume everything is fine with that part of the machine.
tbm0115
CC BY-SA 3.0
2016-04-23T16:43:40.803Z
The problem with this theory is that a "software stop" can only exist relative to an assumption of mechanical position - which in these systems would come from a previous homing.  So if the issue were as your described, it would only happen once, unless the steppers themselves were losing position in operation.  After a homing to the switch, the software's sense of position would be close to the machine's actual state and the next homing would work correctly.
Chris Stratton
CC BY-SA 3.0
2016-04-24T13:29:53.427Z
What is the difference between software and hardware stops? Aren't both the move up and the move down intended to find the mechanical endstop (where the move up is intended to improve precision and reliability compared to what you'd get from just moving down)?
Tom van der Zanden
CC BY-SA 4.0
2018-08-05T10:00:48.647Z
I have just come across this answer, referring to software endstops. tbm0115 and @TomvanderZanden, would either of you like to comment/answer this question [Anet A6 Z-axis min endstop not triggering](https://3dprinting.stackexchange.com/questions/6495/anet-a6-z-axis-min-endstop-not-triggering) as comments and answers are saying that there is no such thing as software endstops. It might be an idea to clarify the situation. I am also confused as would like to see more opinions. I have added a comment to that question referring back to here.
Greenonline
CC BY-SA 3.0
2016-03-24T14:14:25.567Z
2016-03-24T14:14:25.567Z
tbm0115
<p>I have adjusted my z axis end stop via the paper test. However when I press to home all the axis the z axis hits the print bed moves it down slightly then goes to the postion I describe. Is this how its supose to be if not what do I need to do?</p>

<calibration>
Adjusting the Z end stop?
Dakota Miller
# Adjusting the Z end stop?

(Asked by: username_0 on 2016-03-24)

I have adjusted my z axis end stop via the paper test. However when I press to home all the axis the z axis hits the print bed moves it down slightly then goes to the postion I describe. Is this how its supose to be if not what do I need to do?

**Tags:** calibration

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## 2 answers

### Answer by username_2 on 2016-03-24. Score: 3 | Accepted answer

Typically a machine will rapid to find its software stop(s), retract and slowly find its mechanical end stop. Please regard the RepRap Wiki for [general troubleshooting](http://reprap.org/wiki/Endstop) and [basic technical information](http://reprap.org/wiki/Mechanical_Endstop).

> **Comments:**
> **username_2**: If I'm understanding your post correctly, it seems that this is normal. Are you experiencing any adverse affects in your printing or motion? If not, then I'd assume everything is fine with that part of the machine.  
> **username_3**: The problem with this theory is that a "software stop" can only exist relative to an assumption of mechanical position - which in these systems would come from a previous homing.  So if the issue were as your described, it would only happen once, unless the steppers themselves were losing position in operation.  After a homing to the switch, the software's sense of position would be close to the machine's actual state and the next homing would work correctly.  
> **username_4**: What is the difference between software and hardware stops? Aren't both the move up and the move down intended to find the mechanical endstop (where the move up is intended to improve precision and reliability compared to what you'd get from just moving down)?  
> **username_5**: I have just come across this answer, referring to software endstops. tbm0115 and @TomvanderZanden, would either of you like to comment/answer this question [Anet A6 Z-axis min endstop not triggering](https://3dprinting.stackexchange.com/questions/6495/anet-a6-z-axis-min-endstop-not-triggering) as comments and answers are saying that there is no such thing as software endstops. It might be an idea to clarify the situation. I am also confused as would like to see more opinions. I have added a comment to that question referring back to here.  

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### Answer by username_1 on 2016-04-23. Score: 3

Yes, this is normal. Your printer is, at first, probably going downward with some speed. When it hits the end-stop it has some momentum and doesn't stop right away. So once it hits the end-stop, it has to physically stop the print head and move upward again slightly to get to the right position.


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