MechMate CNC Router Forum

Go Back   MechMate CNC Router Forum > Structure & Mechanics > 40. Z-Slide
Register Options Profile Last 1 | 3 | 7 Days Search Today's Posts Mark Forums Read

Reply
 
Thread Tools
  #1  
Old Tue 09 August 2011, 07:32
boblee
Just call me: Bob
 
Fort Fairfield Me.
United States of America
purpose of z axis gas spring

Hi Everyone
I've visited this site from time to time and drooled over the mechmate design .
I'm thinking of building and have a question concerning the z-axis gas spring .
what is it's function or purpose ?
Thanks
Bob
Reply With Quote
  #2  
Old Tue 09 August 2011, 08:41
MetalHead
Just call me: Mike
 
Columbiana AL
United States of America
It acts as the counter weight for the z axis. If it is not there the full weight of the parts would be felt against the motor. Think of a draw bridge balance.
Reply With Quote
  #3  
Old Tue 09 August 2011, 13:41
boblee
Just call me: Bob
 
Fort Fairfield Me.
United States of America
Makes sense
Does it affect backlash in any way?
Reply With Quote
  #4  
Old Tue 09 August 2011, 16:48
MetalHead
Just call me: Mike
 
Columbiana AL
United States of America
No it does not.
Reply With Quote
  #5  
Old Mon 03 October 2011, 07:23
riesvantwisk
Just call me: Ries #46
 
Quito
Ecuador
Send a message via MSN to riesvantwisk Send a message via Skype™ to riesvantwisk
Bob,

the side effect of having such a gas spring is that your hight will be set more accurately and your Z axis will move more smooth.

The reason for this is that a stepper motor uses micro stepping and if a stepper motor is in a micro step, then it will loose strength as well. When the full weight is on the stepper motor, the stepper motor will go back (give or take) in a full step position because it doesn't have enough torque to hold it into a micro step.

You will see that if you have no gas-spring and you move your Z up and down, you will only get full-step accuracy. Top of my head, that was 1/3 of a mm in my case.
Reply With Quote
  #6  
Old Thu 06 October 2011, 10:07
buuk
Just call me: Buuk
 
Netherlands
Netherlands
Hi,

I have one more question about the gas spring. Is the gas spring extended in its normal (free/rest) state? As this would mean that when moving the Z gantry up, you would have to lift both the weigth of the slide, router, etc. + the pressure of the spring...

Thanks in advance,
Luc

Last edited by buuk; Thu 06 October 2011 at 10:34..
Reply With Quote
  #7  
Old Thu 06 October 2011, 10:47
riesvantwisk
Just call me: Ries #46
 
Quito
Ecuador
Send a message via MSN to riesvantwisk Send a message via Skype™ to riesvantwisk
Luc,

the normal position of the gas-spring would be extended so it pushes against gravity.
So it counter balances the wight of your spindle and your Z axis so your Z stepper doesn't have to work so hard.

Also, when you buy your gas-spring, make sure it doesn't counter banker perfectly, but always have so push again or for gravity so your rack+pinion always make good contact

Last edited by riesvantwisk; Thu 06 October 2011 at 10:50..
Reply With Quote
  #8  
Old Thu 06 October 2011, 10:51
Gerald D
Just call me: Gerald (retired)
 
Cape Town
South Africa
When the z-slide is up then the spring is extended....when the z-slide is down then the spring is compressed.

The bottom of the gas spring is fixed to the y-car, the top of the gas spring is fixed to the z-slide.
Reply With Quote
  #9  
Old Thu 06 October 2011, 11:22
buuk
Just call me: Buuk
 
Netherlands
Netherlands
Thanks for your quick replies.

I was thinking correctly about the forces, but made a mistake in which part was moving... stupid of me. But such things happen after a long day at work. Excuse me for this question...

Thanks anyway!
Luc
Reply With Quote
Reply

Register Options Profile Last 1 | 3 | 7 Days Search Today's Posts Mark Forums Read

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Setting A-axis terminal as X2-axis in EMC2 KenC CNC motion control software 2 Wed 27 January 2010 05:40
Rotary axis (4th Axis) or Indexer software smreish Graphics & CAD 0 Tue 28 July 2009 06:02
FreeCAD - will be an open source general purpose 3D CAD modeler isladelobos Graphics & CAD 0 Sat 07 February 2009 04:25
Gas Spring : Compatible automotive gas spring Nikonauts 40. Z-Slide 0 Sat 03 January 2009 09:59
Umbilical Plate Purpose/Role fabrica 10. Base Table 7 Tue 20 February 2007 12:20


All times are GMT -6. The time now is 08:26.


Powered by vBulletin® Version 3.8.3
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.