Help, Cutting problems

[Desertboy]

Hi, I finally dug my machine out and got it running, have a DDCSV 2.1 on the machine now

What's going wrong?

Mechanical or software?

It's meant to look like this
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I cut it once, let the cut finish. Turned the power off and on again to machine and then repeated the same cut again next to it to see if I was losing steps.

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2 cuts look identical to me.

I used Fusion 360 to generate the Gcode.

I have AM882's which have fault protection and if you drive them too fast they do fault but running the cut very slow 1m/min not getting any faults
Adaptive clearing and contour for finishing pass.

[Desertboy]

Things I have already done

Replaced the couplings they were crappy Flexible ones with semi crappy ones
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Replaced one of my motors with a new 3nm one for the gantry as that was 2nd hand and underpowered, I also have 2 4nm cnc4you ones to drop on the bottom axis which has 2*1.8nm on it at the moment and I will swap one of the motors from my bottom axis onto the Z which has a 1.2nm 2nd hand motor.

Which won't help but at least it'll cut wrong a bit quicker.

Made sure the wiring is grounded from the spindle and the Nema's to the GX20 plugs and grounded the wiring from spindle to GX20 socket. The GX20 sockets are mounted on a metal plate that's grounded.

Checked the soldering and continuity from stepper driver to Nema motors.

[cropwell]

What cutter are you using and what is the stepover?

[Nealieboyee]

Your passes look flat-bottomed as if you were using a square end mill instead of ball nose.

[Desertboy]

What cutter are you using and what is the stepover?

https://www.amazon.co.uk/gp/product/B073RKDLDR/

This is the cutter I set it up as a 6mm D 25mm cut length, 2 flute end mill in Fusion

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Run speed full speed, not set up speed control I only intend to do wood and maybe a one off make myself new aluminum plates if I make ever another machine.

[Nealieboyee]

That's a roughing operation. You've set it to leave 0.5mm so you can come back with a finish pass using a ball nose bit or something else.

[cropwell]

OK, it looks as though you are getting steps because the stepover (not stepdown) is too big for a flat bottomed end mill. Try a round nose cutter with a final pass stepover of 10% or less. I don't use Fusion so I don't know the setup parameter screens.

It looks a bit like you are not getting past the roughing cuts.

[Desertboy]

That's a roughing operation. You've set it to leave 0.5mm so you can come back with a finish pass using a ball nose bit or something else.

I also have a contour operation next27414

[Desertboy]

Your passes look flat-bottomed as if you were using a square end mill instead of ball nose.

I am but it's setup up as
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[Nealieboyee]

What is your step over amount?

[Desertboy]

I think I've solved it but won't know until tomorrow.

Will update because it's a doozy if I'm right lol.

[JAZZCNC]

Looks like a roughing pass to me. I don't use F360 so not much help with it but I'd look to see if it's only spitting out the roughing pass and missing the finish pass.?

[Desertboy]

The tool was damaged Jazz, brand new as well I bought 3 of them other 2 perfect.

Was causing that line effect.

The real issues I was having is the Z axis was bottoming out causing it to lose a step with certain tools (Short ones) as it hit the ballscrew mount. Why my 2d engraving was fine was never bottoming the axis.

My AM882's on my X&Y fire fault protects if they hit the ballscrew mounts only happened when my dodgy home switch soldering came a cropper lol.

But the Z can bounce off the mounts all day long guessing my motor isn't powerful enough to trigger it only a puny 1.2nm, it's getting swapped for 1.8nm ones just because I'll have a couple of spare and I bought them new, the 1.2nm one is 2nd hand and well worked.

My solution add another sheet of MDF to the bed to raise it another 18mm I might add 2 to raise it 36mm. Tomorrow I shall test my theory but well it was bottoming out on the mount and I was losing steps on the Z so I think it's a no brainer.

I have 9cm of travel so can afford to lose some.

[Neale]

You are using adaptive clearing which is great for rough-cutting large amounts of material but definitely ain't no finishing cut! The "optimal load" is also set to 2.4mm, which translates as a large stepover for something like this. All this is ok to remove the bulk of the waste but you need to finish with an appropriate cutting strategy. Possibly one of the 3D strategies but I'm not in front of a screen at the moment. You will also do better with a ball-end mill rather than flat, although if you make your cuts at 90deg to what you did for roughing and with a small stepover you would get better results especially with those relatively flat curves. Good luck - this business is a continuous voyage of discovery!

[Desertboy]

You are using adaptive clearing which is great for rough-cutting large amounts of material but definitely ain't no finishing cut! The "optimal load" is also set to 2.4mm, which translates as a large stepover for something like this. All this is ok to remove the bulk of the waste but you need to finish with an appropriate cutting strategy. Possibly one of the 3D strategies but I'm not in front of a screen at the moment. You will also do better with a ball-end mill rather than flat, although if you make your cuts at 90deg to what you did for roughing and with a small stepover you would get better results especially with those relatively flat curves. Good luck - this business is a continuous voyage of discovery!

I do a finishing pass as well, it's still not working properly.

Going to change the bed today and try with some another cut with new milling bits.

[Desertboy]

Just a little update if anyone else with a DDCSV comes across this post.

You have to set the post processor to fanuc in Fusion 360
You need to turn helical moves off for it to work properly.

I had a dodgy coupling which made things much worse, once I replaced the bad couplings and changed the post processor in Fusion everything started working better.

Now I need to program my ball nose mills into Fusion I think and play with the stepover to dial it in.

From what I read set it to 1/8th the diameter should be fine.