Cutting 2" material (poplar) issues

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adamluna
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Cutting 2" material (poplar) issues

Post by adamluna » Wed Aug 12, 2015 2:38 am

Hello!

I have a 2" material and trying to cut only 0.125" why does it drop all the way down almost 1/2" down??

What am I doing wrong?

I have a shapeoko3 and 1/4" 4 flute endmill

Thanks

Adam


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Adam
Shapeoko 3 w/DPW 611 #243
WIN7 64bit - Trying to figure it out a Workflow

WillAdams
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Re: Cutting 2

Post by WillAdams » Wed Aug 12, 2015 11:49 am

What sort of endmill are you using?

A down-cutting bit will tend to pull the Z-axis carriage down.

How tight do you have the Z-axis belt tension? What length is the belt and how much adjustment do you have? It took me a while to get the tension right, and the shorter replacement belt helped.
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets
Nomad 883 Pro #596 (bamboo)

adamluna
Posts: 84
Joined: Sun Feb 08, 2015 8:29 pm
Location: Denver, Colorado

Re: Cutting 2

Post by adamluna » Wed Aug 12, 2015 2:48 pm

the bit is 1/4" 4 flute end mill. I checked the tension and it is not bad the carriage stays up even when turned off.

Adam
Adam
Shapeoko 3 w/DPW 611 #243
WIN7 64bit - Trying to figure it out a Workflow

WillAdams
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Re: Cutting 2

Post by WillAdams » Wed Aug 12, 2015 9:53 pm

Up cutting or down-cutting?



Have you tried an air cut as a test?
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets
Nomad 883 Pro #596 (bamboo)

adamluna
Posts: 84
Joined: Sun Feb 08, 2015 8:29 pm
Location: Denver, Colorado

Re: Cutting 2

Post by adamluna » Thu Aug 13, 2015 3:26 pm

uhmmm good question... I will try an air cut...
Adam
Shapeoko 3 w/DPW 611 #243
WIN7 64bit - Trying to figure it out a Workflow

adamluna
Posts: 84
Joined: Sun Feb 08, 2015 8:29 pm
Location: Denver, Colorado

Re: Cutting 2" material (poplar) issues

Post by adamluna » Fri Aug 14, 2015 2:30 am

Ok did what you told me and did an air cut test and set the machine to be Zero in the very top. Stayed there fine. Turned the machine on and still there on top. Then when started the program to cut it went down 3/4" and started cutting from there.. See top mark then second pass was lower mark.

Maybe I need to tweak my GRBL settings?

ImageImageImage


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Adam
Shapeoko 3 w/DPW 611 #243
WIN7 64bit - Trying to figure it out a Workflow

DRobs86
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Re: Cutting 2

Post by DRobs86 » Fri Aug 14, 2015 4:45 am

Post your code and grbl settings bud.

WillAdams
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Re: Cutting 2

Post by WillAdams » Fri Aug 14, 2015 11:21 am

Please source a 1/8" straight end mill and adapter to use it, try to tension the Z-axis belt better, then remake the CAM file w/ new settings, esp. use a slower plunge rate.

Or just re tension the Z-axis belt. If you can’t get it tight enough, see about getting a replacement from support@carbide3d.com.
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets
Nomad 883 Pro #596 (bamboo)

adamluna
Posts: 84
Joined: Sun Feb 08, 2015 8:29 pm
Location: Denver, Colorado

Re: Cutting 2

Post by adamluna » Fri Aug 14, 2015 3:50 pm

I will post the grbl settings tonight. I think my tension is good. Like I Say It does not come down when the machine is off. The machine automatically thinks my Zero is down like it shows in the second picture and then the first mark of pen is the first cut depth and the bottom one is my second cut depth.

Adam
Adam
Shapeoko 3 w/DPW 611 #243
WIN7 64bit - Trying to figure it out a Workflow

edwardrford
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Re: Cutting 2

Post by edwardrford » Sat Aug 15, 2015 3:24 pm

I think the problem is where you are starting the z-carriage?

Look through your job and find the 'safe z-height'. That is the distance your spindle with move in the *positive* direction when the job begins, and every time you move between toolpaths.

If you start your spindle carriage too close to the top, there is no where for the spindle to go UP when it tries to move to the safe height. So, when your machine tries to move up, your Z axis basically looses that much positive distance, so your machine *thinks* it is at one position, when in fact it is lower than that (by the value of your safe z-height). So when it plunges back down, it's going to go to your target depth + how ever much distance you lost when trying to get to your safe height.

You need to make sure you are zeroing it on the top of the work surface, not at the top of the spindle travel. That should give you a couple inches of upward z-travel anyway.

I'll post this again here for posterity - This is how I generally setup a job:

1.) Turn the power off on your machine and make sure your spindle is off.
2.) Get your material secured to your machine at the location of your choice.
3.) With the power still off, move your machine (just drag it with your hands) to where you want 0,0,0 to be (lets just say the bottom left corner of your material), pressing your spindle down until the bit is touching the material.
4.) Holding The spindle down so the bit is pressing against the workpiece (so the springs don't pull it back up) , turn the power on.
5.) Once the power is on, your machine should stay in place and you can let go of the z-axis.
6.) Load carbide motion and connect to your machine
7.) Go to jog and zero everything - so X, Y, and Z all read 0.00
8.) Jog your machine to about +5mm in the z-axis (so your bit is no longer touching the material.
9.) Load your g-code file
10.) Turn on your spindle!
11.) Click Run Job!
12.) Dominate World.

-Edward
Shapeoko 1 #0 - a couple of upgrades.
Shapeoko 2 #0 - a couple of upgrades.
Shapeoko 3 #2 - Stock

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