Segmented rounds

[Antoine21130]

Hello everyone,

Have a issue on my Matsuura MC-660-VG (Yasnac j300) when machining 3mm rounds on aluminium using 3mm carbide end mill. My tolerance is set to 0.01 in fusion 360 and everything in the simulation looks great. When machining, the rounds have some visible segments and some of them extend more than the round I need to do (you can see the extension on the round at top left corner of the picture below).
Machining at 600mm/min so I don’t think speed is an issue.
Also have a weird behavior on the chamfering that I don’t have in simulations either.
Thanks in advance !

 

[BajaFire]

Your chamfers look like they have both chatter marks and witness marks. To get rid of the witness line, try adding an overtravel distance in your toolpath so the cutter exits the boss beyond the start point. For the chatter, there could be a zillion things. Lack of rigidity, tool runout, chip load too high.

For profiling the bosses, does Fusion generate actual arc codes (G02/G03) or zillions of little line segments (G01)? If it's fitting lines, a .01 mm tolerance on a 3mm OD boss is going to look huge (Assuming I understand your numbers properly).

 

[Antoine21130]

Thanks for the analysis on chamfer issue !
For profiling, fusion use mainly G02/G03 arc codes. And yes you understood correctly, OD is 3mm.

 

[Vancbiker]

Post the code you are running. That has to be line segments. Why do you not use circular interpolation (G2 and G3)? Is there a finish pass around each post or is this just roughed?
That has got to be the shittiest looking work I've ever seen cut on a Matsuura.

 

[Houdini]

Looks like you have facets in gcode due to tolerance setting in con-Fusion
some software has more than one place to set this also, ie global vs local tolerancing and overrides.
I don't use con-Fusion, but on finish passes I set my tolerances to the minimum .0001"
2 Cents.

 

[Antoine21130]

Hello Vanbicker, here is a portion of the code I’m running. It mainly use G02/G03.
It’s only a roughing pass with finishing pass enabled in pocket settings.
Thanks for the compliment, I’m an electronic engineer normally and just started learning machining so that’s why it’s the shittiest work you’ve ever seen on a Matsuura.

 

[Antoine21130]

Looks like you have facets in gcode due to tolerance setting in con-Fusion
some software has more than one place to set this also, ie global vs local tolerancing and overrides.
I don't use con-Fusion, but on finish passes I set my tolerances to the minimum .0001"
2 Cents.

Thanks for the answer, I will try reducing tolerances and look if there is some hidden parameters haha

 

[Houdini]

Thanks for the answer, I will try reducing tolerances and look if there is some hidden parameters haha

Yeah I use GibbsCAM it has a global tolerance page, with default tolerances for part, fixture, stock...
then in each process you can select to override defaults and set something specific in that operation.
Then when you go to post processing, there you can also override the default globals and set a different posted tolerance,
So yeah depending on software could have a couple places for tolerances.

 

[Antoine21130]

Here is a tool path view, I’ve also tried setting up a finishing pass but that doesn’t change anything to the sides aspect.

 

[Vancbiker]

Hello Vanbicker, here is a portion of the code I’m running. It mainly use G02/G03.
It’s only a roughing pass with finishing pass enabled in pocket settings.
Thanks for the compliment, I’m an electronic engineer normally and just started learning machining so that’s why it’s the shittiest work you’ve ever seen on a Matsuura.

That looks like roughing code only. For a finish pass, I would expect to see only 1-3 G3 lines per boss before a move to the next boss.

Good that you are trying to learn something new. That said, are you just blindly trusting software and some graphic simulation to make a good part? Start with an even more simple part and examine the code. Separate the roughing operation from the finish operation. Examine the result after each operation. Sometimes spraying the part with Dykem or other colorant after roughing but before finishing can be a help in determining if surface defects or gouges are a result of overcutting during roughing or a defect in the finishing cuts.

 

[Houdini]

That looks like roughing code only. For a finish pass, I would expect to see only 1-3 G3 lines per boss before a move to the next boss.

Good that you are trying to learn something new. That said, are you just blindly trusting software and some graphic simulation to make a good part? Start with an even more simple part and examine the code. Separate the roughing operation from the finish operation. Examine the result after each operation. Sometimes spraying the part with Dykem or other colorant after roughing but before finishing can be a help in determining if surface defects or gouges are a result of overcutting during roughing or a defect in the finishing cuts.

You gotta love trying to fix a finish pass flaw to find out the roughing pass is over cutting, and all your efforts were for nothing because the finish pass is in the air. good times.

 

[Antoine21130]

That looks like roughing code only. For a finish pass, I would expect to see only 1-3 G3 lines per boss before a move to the next boss.

Good that you are trying to learn something new. That said, are you just blindly trusting software and some graphic simulation to make a good part? Start with an even more simple part and examine the code. Separate the roughing operation from the finish operation. Examine the result after each operation. Sometimes spraying the part with Dykem or other colorant after roughing but before finishing can be a help in determining if surface defects or gouges are a result of overcutting during roughing or a defect in the finishing cuts.

It’s only the beginning of code (finishing pass is done at the end and yes it’s only composed of few G03 for each boss).
I’m not blindly trusting software, I’ve made simpler parts before without issue so though I could try a more « complex » one.
Thanks for these advices regarding the finishing pass troubleshoot.

 

[Nerdlinger]

Try reducing the tolerance to .001 and see if it looks any better. Make sure you are leaving enough material for a finish pass…like Vancbiker said, the finish pass should be much less code than the roughing. Also, on an old version of MasterCam I use it will not take cutter comp into account on some roughing paths so maybe make sure any diameter offsets you are using for finish pass are appropriate. Good luck!

 

[Antoine21130]

Yeah I will try to reduce tolerance. I can’t leave that much for the finishing pass because I only have 3.1 mm between each boss and my end mill is 3 mm.
I will make some more tests tomorrow !

 

[BajaFire]

Only .004" between each boss once the endmill is in the cut...YIKES. Is your endmill nicking neighboring bosses during entry/exit and roughing passes?

 

[Houdini]

Only .004" between each boss once the endmill is in the cut...YIKES. Is your endmill nicking neighboring bosses during entry/exit and roughing passes?

Yeah , I would move to 7/64" .109" end mill.

 

[Houdini]

Actually looking at the image closer, those facets look like the floor roughing lines up

 

[triumph406]

Hello everyone,

Have a issue on my Matsuura MC-660-VG (Yasnac j300) when machining 3mm rounds on aluminium using 3mm carbide end mill. My tolerance is set to 0.01 in fusion 360 and everything in the simulation looks great. When machining, the rounds have some visible segments and some of them extend more than the round I need to do (you can see the extension on the round at top left corner of the picture below).
Machining at 600mm/min so I don’t think speed is an issue.
Also have a weird behavior on the chamfering that I don’t have in simulations either.
Thanks in advance !

600mm/min is too fast. especially as your running around a 3mm round. Your feedrate at the circumference of the 3mm round is too high.

I typically program .0002-.0003ipt and use 3 flute YG-1 endmills

10000*3*.0003 = 9in/min

but going around those features I would start at 2-3in/min and do 2 finish passes

I assume your running the chamfer tool way to fast as well

 

[Antoine21130]

Only .004" between each boss once the endmill is in the cut...YIKES. Is your endmill nicking neighboring bosses during entry/exit and roughing passes?

No, endmill doesn’t seem to collide with neighboring bosses. I will try to machine only one boss to see if I get any different results.

 

[Donkey Hotey]

Adding something to this about accuracy or precision numbers in Fusion (or any CAM for that matter): those only apply when it's doing conversion of non-arc curves (splines, ellipses) or surfaces into line moves. If your output is G02/G03 moves, accuracy doesn't weigh into the problem.

Arc moves are strictly up to the control to execute them right or wrong. If anything, you should be checking the Yasnac control if it has its own tolerance / accuracy setting for how fine it breaks up circular moves.

As already posted: speed might be a factor. The extremely small amount of clearance between rough and finish cuts probably plays into it. If you're jamming a cutter down there and doing full-depth cuts, that also plays into it. I'd personally do a helical cut around each of those posts and not treat them like pockets.

The artifacts left on the chamfers look like the cutter needs a rough and finish lap around the part. It's probably deflecting at the end and not completing the circle.