What am I doing wrong?

Assembly questions and answers for the Shapeoko 3 CNC Mill
Post Reply
my07ultra
Posts: 3
Joined: Fri Feb 24, 2017 1:38 pm

What am I doing wrong?

Post by my07ultra » Thu Mar 09, 2017 8:37 am

I'm using a S3 XXL when I try to cut a circle it doesn't come out concentric. Any suggestions? I've tightened belts, rollers and calibrated my servos... I'm at a loss for what else it can be. Cut it at 70% federate too, but nothing seems to help. Thanks in advance.



Image



Sent from my iPhone using Tapatalk

my07ultra
Posts: 3
Joined: Fri Feb 24, 2017 1:38 pm

Re: What am I doing wrong?

Post by my07ultra » Thu Mar 09, 2017 12:18 pm

my07ultra wrote:I'm using a S3 XXL when I try to cut a circle it doesn't come out concentric. Any suggestions? I've tightened belts, rollers and calibrated my servos... I'm at a loss for what else it can be. Cut it at 70% federate too, but nothing seems to help. Thanks in advance.



Image



Sent from my iPhone using Tapatalk
Image

Here's another picture, a little closer



Sent from my iPhone using Tapatalk

WillAdams
Posts: 8618
Joined: Mon Apr 09, 2012 6:11 pm
Location: Pennsylvania --- south of the Turnpike, East of US-15
Contact:

Re: What am I doing wrong?

Post by WillAdams » Thu Mar 09, 2017 1:04 pm

When cutting, there are a number of things which influence how the machine cuts:

- belt tension --- this is tricky to get right at first: https://www.shapeoko.com/wiki/index.php ... ko_3#Belts
- pulley set screws --- http://docs.carbide3d.com/article/169-s ... set-screws
- speeds and feeds --- http://carbide3d.com/shapeoko/feedandspeed/ (and esp. plunge rate and depth of cut)
- climb vs. conventional cutting --- https://www.shapeoko.com/wiki/index.php ... al_Milling (esp. in combination w/ a roughing clearance and finishing pass)
The perfect cutting is not too slow, not too fast, not too shallow and not too deep. http://www.shapeoko.com/forum/memberlis ... file&u=760
https://www.shapeoko.com/wiki/index.php/Materials
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets

HPGreyling
Posts: 123
Joined: Sat Nov 15, 2014 11:37 am
Location: South Africa

Re: What am I doing wrong?

Post by HPGreyling » Thu Mar 09, 2017 6:02 pm

I think runout and feedspeed has a role to play here. When the bit enters the material it is at the spot as programmed but due to maybe high feed and slack belt tension the bit get " deflected" and pulls away from the original path. When the end meets the start the photos are the result.

my07ultra
Posts: 3
Joined: Fri Feb 24, 2017 1:38 pm

Re: What am I doing wrong?

Post by my07ultra » Fri Mar 10, 2017 1:54 pm

WillAdams wrote:When cutting, there are a number of things which influence how the machine cuts:

- belt tension --- this is tricky to get right at first: https://www.shapeoko.com/wiki/index.php ... ko_3#Belts
- pulley set screws --- http://docs.carbide3d.com/article/169-s ... set-screws
- speeds and feeds --- http://carbide3d.com/shapeoko/feedandspeed/ (and esp. plunge rate and depth of cut)
- climb vs. conventional cutting --- https://www.shapeoko.com/wiki/index.php ... al_Milling (esp. in combination w/ a roughing clearance and finishing pass)
The perfect cutting is not too slow, not too fast, not too shallow and not too deep. http://www.shapeoko.com/forum/memberlis ... file&u=760
https://www.shapeoko.com/wiki/index.php/Materials
I found both Y axis pulleys loose, also getting some chatter from one of the Y axis drive units... not sure what it's from, but I'm sure it's not helping anything.


Sent from my iPhone using Tapatalk

WillAdams
Posts: 8618
Joined: Mon Apr 09, 2012 6:11 pm
Location: Pennsylvania --- south of the Turnpike, East of US-15
Contact:

Re: What am I doing wrong?

Post by WillAdams » Fri Mar 10, 2017 3:10 pm

The motors will sometimes shudder if one moves them manually 'cause of generated current generating a pulse.

Sometimes when jogging by holding down a button in CM3 and earlier w/ Grbl 0.9 there will be a pause or hesitation --- hopefully this is fixed in the new CM4 and Grbl 1.1 (the former is in open beta testing now).
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets

Post Reply