Im stuck please help!!!!

Hi I am an event prop builder.

Im new to the CNC and I’m building something new with it.

My issue: my files look good in fusion 360 but in Mach 3 the first line is moving right on top of my stock. In other words. I zero the machine out and press cycle. The tool goes up starts spinning, lowers again and moves accross my material and damages the wood or break the bit. The procedure I want (which I would believe is normal) is that the tool goes up and across a few inches off the material and then lowers or ramps into the wood. Anyone?!?? Help?!?!?

raise your feed plane in fusion

Can you just raise the bit above the surface before starting the run? The first couple of months I ran my CNC I added a line in the code to do that automatically and then realized all I have to do is raise it with jog. It moves over to where it's supposed to start and then does what it should.

I guess it could depend, too, on which post processor you're using...

David

It’s not that... it’s currently 2 inch away from stock top. It’s really only the first movement and the last when returning to home.

Quote:

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Originally Posted by difalkner

Can you just raise the bit above the surface before starting the run? The first couple of months I ran my CNC I added a line in the code to do that automatically and then realized all I have to do is raise it with jog. It moves over to where it's supposed to start and then does what it should.

I guess it could depend, too, on which post processor you're using...

David

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Im using fusion 360.

I called Industrial CNC, Where I bought my machine and they are saying to check my traverse or safe z. Anyone know where that is? or is it that.

Post a little bit of the g-code.

(1001)
(T12 D=0.25 CR=0. - ZMIN=-0.5 - FLAT END MILL)
G90 G94 G91.1 G40 G49 G17
G20
G28 G91 Z0.
G90

(2D CONTOUR2)
M5
M9
T12 M6
S20000 M3
G54
M8
G0 X0. Y-0.125
G43 Z4. H12
G1 Z3. F125.
Z-0.1 F40.
G2 X-0.125 Y0. I0. J0.125 F125.
G1 Y4.
G2 X0. Y4.125 I0.125 J0.
G1 X4.
G2 X4.125 Y4. I0. J-0.125
G1 Y0.
G2 X4. Y-0.125 I-0.125 J0.
G1 X0.
Z-0.2 F40.
G2 X-0.125 Y0. I0. J0.125 F125.
G1 Y4.
G2 X0. Y4.125 I0.125 J0.
G1 X4.
G2 X4.125 Y4. I0. J-0.125
G1 Y0.
G2 X4. Y-0.125 I-0.125 J0.
G1 X0.

Quote:

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Originally Posted by FantasyDesigners

It’s not that... it’s currently 2 inch away from stock top. It’s really only the first movement and the last when returning to home.

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That seems to rule out a bad tool length offset

Quote:

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G28 G91 Z0.

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and this probably repeats at the end of the program.
That line is telling the machine to return to a Z reference position. Logically that would be Z HOME but that reference may not be HOME.
This could happen due to a setting in machine parameters or the way the builder configured the machine.

Try deleting that G28 line. Make sure to start in a safe position and starting in single block mode would not be a bad idea.

edit/ I've usually seen that line as G91 G28 Z0 but I don't think it should matter

Quote:

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Originally Posted by FantasyDesigners

Im using fusion 360.

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Yes, I know. Fusion 360 is the CAD/CAM program and it includes a post processor. But you have a choice as to which post processor you use. I'm using CNC Router Parts and the file generated doesn't do what yours is doing.

Attachment 407646

David

I tried running your code on a simulator, it seems like your Z axis travels too high and reaching the Z UP limit offsetting the Z position then goes back to the wood stock on an offset distance lower than the usual then over feeds the tool bit on the wood stock then it snaps the tool bit or sometimes if the offset is too big it will scrape the table.

https://www.cnczone.com/forums/attac...d=407648&stc=1

Try adjusting the clearance plane in 360, not too high, you can also loop it back to zero in 360 (but I dont know what setting it is in 360 because I honestly never used the software yet)

This thread came to mind while using fusion this evening. When posting code in Fusion there's an area in the window to change some
of the post processor behaviour. For my post (not Mach3) G28 can be disabled, it's replaced by G53 which is a simpler code. It works
fine as long as the machine doesn't have something weird like machine zero at the bottom of the Z travel.

If the machine has an auto tool changer there could be more to consider. It's been years since I was lucky enough to have one.

Simulators are good but unless it's part of the machine control it could be mistaken about where G28 has been set.
And it is settable or at least it is on my machine.

I could be wrong altogether about the problem but G28 is confusing and Fusion is pretty good at spotting collisions.
That's all. Sorry for rattling on.

It Started doing it again Today!!!



(NAME34)
(T1 D=0.125 CR=0. - ZMIN=-0.25 - FLAT END MILL)
G90 G94 G91.1 G40 G49 G17
G20
G28 G91 Z0.
G90

(2D CONTOUR2)
M5
M9
T1 M6
S18000 M3
G54
M8
G0 X39.8969 Y55.3677
G43 Z4. H1
G1 Z2. F125.
Z1.5 F41.7
Z-0.2406
G2 X39.915 Y55.3704 I0.0181 J-0.0598 F125.
G1 X40.1815
G2 X40.2383 Y55.334 I0. J-0.0625
G1 X40.9287 Y53.8337
Z-0.1506
X41.0332 Y53.6066
Z-0.2406 F41.7
X42.4142 Y50.6058 F125.
Z-0.1506
X42.5188 Y50.3787
Z-0.2406 F41.7
X43.2091 Y48.8785 F125.
G2 X43.1524 Y48.7899 I-0.0568 J-0.0261
G1 X42.0717

You need to run your machine in single block and dry run mode.
In dry run mode you can control how fast axis will move.

That way you can troubleshoot and find exact line in your code that is creating problem.

Only when you verify that everything is working as intended then you can push that green btn and walk away.

I think that there's an option in Mach3 to use MPG to slowly cycle through program and verify your tool approach and clearance.


If you type in MDI Mode G28 G91 Z0
Does your machine moves UP toward home position or down toward a table?

If it goes down, then your reference point is not set properly.


Sent from my LG-H872 using Tapatalk

I think I know this. Go to post Process in Fusion 360 CAM , under Program Setting there is a list of stuff, scroll down to G28 and set to no. Every time I do a new part I have to set again.

Quote:

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Originally Posted by crocnc

run your machine in single block and dry run mode.

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Yes or single block and rapid override.

Quote:

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G90 G94 G91.1 G40 G49 G17
G20
this-->G28 G91 Z0. --> press once it does nothing, press again goes to machine Z home?
G90
(2D CONTOUR2)
M5
M9
this--> T12 M6 --> does the machine have a tool changer ? If this was answered sorry for missing it.
S20000 M3
G54
M8
this--> G0 X0. Y-0.125 --> the gouge happens in this move ? If your clear of the part this shouldn't happen.
G43 Z4. H12
G1 Z3. F125.
Z-0.1 F40.

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Quote:

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Originally Posted by FantasyDesigners

It Started doing it again Today!!!



(NAME34)
(T1 D=0.125 CR=0. - ZMIN=-0.25 - FLAT END MILL)
G90 G94 G91.1 G40 G49 G17
G20
G28 G91 Z0.
G90

(2D CONTOUR2)
M5
M9
T1 M6
S18000 M3
G54
M8
G0 X39.8969 Y55.3677
G43 Z4. H1
G1 Z2. F125.
Z1.5 F41.7
Z-0.2406
G2 X39.915 Y55.3704 I0.0181 J-0.0598 F125.
G1 X40.1815
G2 X40.2383 Y55.334 I0. J-0.0625
G1 X40.9287 Y53.8337
Z-0.1506
X41.0332 Y53.6066
Z-0.2406 F41.7
X42.4142 Y50.6058 F125.
Z-0.1506
X42.5188 Y50.3787
Z-0.2406 F41.7
X43.2091 Y48.8785 F125.
G2 X43.1524 Y48.7899 I-0.0568 J-0.0261
G1 X42.0717

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You are using metric or inch system ?

Do you setup your tool lenght correctly ?

Does your machine show G54-G59 work offset and machine offset ?

When you home your spindle to machine Z0 ( G53 Z0 or G28 G91 Z0 and dont forget G90 in next line!! ) whats the height between top of the table and end of your spindle ? What's the height of your stock which is ready to be machined ? What's the tool lenght along with toolholder (from end of the spindle to the tooltip ?)

How do you setup your machining Zero in fusion 360 ? Do you set it, in the same position on the machine ? ( on stock )

Can you share your project for further advice ?

Cheers

G28 G91 Z0.
G28 will send the machine home (up) then Z will come back down to 0.
If the machine home has gone out a bit for any reason it will crash

I always delete this line now and replace it with a simple G0 Z0. Never had an issue since.
Also I always set my Z0 height at 1mm above my stock.

I find it good practice to G28 at the end of every day before switching off too.