CNC rpm & feed

[Rewound]

yes so 7mm in the z and 2.8mm in its horizontal moves. 2.8mm is hefty , okay in a softwood, you might need to dial that down in anything harder.

what would be typical in a hard hardwood (lest say oak)

 

[Steve Mehrlich]

i normally run with 15 - 20 percent. the drop in material removal can be countered by using the both ways option in the tool path set up page. this will use both both climb and conventional and stops the tool retracting between moves, saves a bit of time.
what is it that youre making? just being nosey.


cheers

steve

 

[Delaney]

I use straight flute cutters (like router cutters) in my cnc when cutting ply or MDF.
They leave an excellent cut that I wasn’t able to achieve with up or down cutters which are primarily for metal cutting.

https://www.wealdentool.com/acatalog/Plywood-Straight.html

The problem with speeds and feeds is you have to know your machine. A chart is not the be all and end all.

 

[Rewound]

i normally run with 15 - 20 percent. the drop in material removal can be countered by using the both ways option in the tool path set up page. this will use both both climb and conventional and stops the tool retracting between moves, saves a bit of time.
what is it that youre making? just being nosey.

Not making anything - simply just trying to work out how to use it (and the fusion software) really struggling to understand the settings

on the one I cut (see above) the "Sock to Leave" was set at 0.5mm (which made the depth 0.5mm out and the diameter 1mm out)
If I remove the 'Stock to Leave' it wants to trim the whole top surface?

it is as if I can't control what path it will follow (it is just going to follow every path)
there must be a way to tell it what path to follow?

 

[Delaney]

lol it’s not called ‘confusion 360’ for no reason.

It took me about 2 years to figure this out so I reluctantly will tell you even though you’ve probably been playing with it for a week.
(This is how bad fusion makes you feel, you will have to suffer greatly)

When you do sketches in ‘design’ you need to bare in mind the CAM. In
‘Machining’ you can use sketch lines as CAM pathways (make sure they’re visible).
So when you now go into CAM, you can select those sketch lines and use them to do exactly what you want. Otherwise the software will take a holistic approach to it’s core mission.
Each CAM strategy has it’s own algorithm and way of thinking abut things.
You would think it was obvious but each one has a lot of overlap with another and this looks like it will do the job you want but when you use it, it will constantly do the opposite of the thing you want it to.
That is because each variation has a totally different way of doing what you think it will do and regardless of what you think you can do to tweak it,
It will never do what you want it to.
Picking the right 2d or 3d stratergy is vital

For example, if you want it to follow a line, use 2D Contour’ not ‘slot’ and make sure you have the line you want it to follow, visible as a sketch. Use that sketch line in contour and the machine will cut that line.

Once you start thinking in ‘sketch lines’ in CAM you can get much more control.

 

[meccarroll]

This explains about chip load
https://www.rennietool.co.uk/blogs/news/solid-carbide-router-bits-speeds-and-feeds

Have you looked at the example calculation they produced?.. Looks wrong to me.

 

[Steve Mehrlich]

When you created the tool path the second tab will allow you to guide where the tool goes.as Mr Delaney said, the circle you drew for the top of your model should be able to be selected and then set the tool to machine inside that circle. It will then ignore that top face.
Fusion is an incredible program but has a fairly steep learning curve.

 

[Rewound]

When you created the tool path the second tab will allow you to guide where the tool goes.as Mr Delaney said, the circle you drew for the top of your model should be able to be selected and then set the tool to machine inside that circle. It will then ignore that top face.
Fusion is an incredible program but has a fairly steep learning curve.

Fusion is a phenomenal product, I just love it, it was a very very steep learning curve, when I started with the 3d printer a few years back, but I did get the jist of it and can design quite complicated things quite quickly now.

I know I will get their with the CAM, but it's doing my head in at the moment, so many settings.

have discovered "Machining boundary" options this morning, so that is helping to limit what is cut (sometimes)

I am just using simulation within fusion, learning the cnc router is still to come (although I did manage to cut that bit out earlier and seemed straightforward)

 

[Delaney]

Fusion is a phenomenal product, I just love it, it was a very very steep learning curve, when I started with the 3d printer a few years back, but I did get the jist of it and can design quite complicated things quite quickly now.

I know I will get their with the CAM, but it's doing my head in at the moment, so many settings.

have discovered "Machining boundary" options this morning, so that is helping to limit what is cut (sometimes)

I am just using simulation within fusion, learning the cnc router is still to come (although I did manage to cut that bit out earlier and seemed straightforward)

The CAM side of F360 is imo far more complicated than the ‘design’ side.

Things that seem so obvious are maddening.
The software is written by techs for techs and until recently, their tech support was terrible, leaving you at the whims lf imo predatory 3rd party’s, offering you massively overpriced generic training.
So you are then left to your own devices.

The reason F360 is popular at all is because it’s free and has CAM.

For example try getting the tool to stay down when cutting out islands for a vacuum bed.

 

[Steve Mehrlich]

For example try getting the tool to stay down when cutting out islands for a vacuum bed

Run that past me again? Like machining a grid?

 

[Delaney]

Run that past me again? Like machining a grid?

Basically yes.

If you make a 3d model in design of a vacuum bed, then try to machine it using a tool down poccket clearing strategy, it’s like trying to pull teeth.
The only way I've gotten it to work is by putting sketch lines as a pattern in design, then in machining, use those lines in 2d contour, and create a pattern of the contour vertically and horizontally and then machine.
Depending on your widths and gaps between islands (is use a fillet on all corners), you then re-run the process with offset (stock to leave) etc.. to widen the channels.

You would think that using a 2D pocket to do all of this and selecting the floor as a surface, would do the trick but instead of looking at the floor, it looks at the islands and treats them all individually. This means is picks the spindle up at every corner.
I had so much trouble with that. Basically the floor is not seen but instead the islands are seen so it does not define the floor even though you can select it and it highlights on selection.

(by floor, I don’t mean stock or model bottom. I mean the surface around the base of the islands in the sketch).

 

[Ollie78]

Have you looked at the example calculation they produced?.. Looks wrong to me.

Can`t say i read it in detail. Just the first one I found when trying to explain it.

This is a calculator thingy which might be better, https://www.cmtorangetools.com/na-en/work-parameters-calculator

When I entered the Rennie 6mm 2 flute example in the cmt calculator it comes out at 1,152 m/ min which is an odd way to write it.
Pretty sure it doesn`t mean one thousand one hundred and fifty two meters a minute, so probably means eleven and a half meters a minute which is what the Rennie example says. The decimal points are important here I think.

This is a chip load calculator with explanation, interestingly it shows chip load per tooth which must be noted. https://www.machiningdoctor.com/calculators/chip-load-calculator/#chip-load-calculator

The CAM side of F360 is imo far more complicated than the ‘design’ side.

Things that seem so obvious are maddening.
The software is written by techs for techs and until recently, their tech support was terrible, leaving you at the whims lf imo predatory 3rd party’s, offering you massively overpriced generic training.
So you are then left to your own devices.

The reason F360 is popular at all is because it’s free and has CAM.

For example try getting the tool to stay down when cutting out islands for a vacuum bed.

I find the cam to be very capable in fusion but it is almost too capable.
It was the first thing I used for cam and can work well. However, now I sometimes design things in Fusion then export the model to vcarve pro to do the gcode. The Vectric cam is very well optimised to woodworking tasks and simpler to understand. But the fusion one is probably better for complex metal machining etc.

 

[Ollie78]

Basically yes.

If you make a 3d model in design of a vacuum bed, then try to machine it using a tool down poccket clearing strategy, it’s like trying to pull teeth.
The only way I've gotten it to work is by putting sketch lines as a pattern in design, then in machining, use those lines in 2d contour, and create a pattern of the contour vertically and horizontally and then machine.
Depending on your widths and gaps between islands (is use a fillet on all corners), you then re-run the process with offset (stock to leave) etc.. to widen the channels.

You would think that using a 2D pocket to do all of this and selecting the floor as a surface, would do the trick but instead of looking at the floor, it looks at the islands and treats them all individually. This means is picks the spindle up at every corner.
I had so much trouble with that. Basically the floor is not seen but instead the islands are seen so it does not define the floor even though you can select it and it highlights on selection.

(by floor, I don’t mean stock or model bottom. I mean the surface around the base of the islands in the sketch).

Is there a mode for "fluting" in Fusion ? I can`t remember if there is or not.
I do remember it being very important in fusion cam to set the Z zero in the correct way, it can be set to top of model, bed/ bottom of model or some other height or plane you can enter. So check this is not causing it to do wierd stuff.

If trying to do this in Vcarve I would use the fluting toolpath option. But as you say 2d pocket should work as well.

 

[meccarroll]

and should I have used climb or conventional (I know what they are but never entirely sure what to use)

Take a look at this:

https://www.bing.com/videos/rivervi...7DC68A8682A4BE8489367DC68A8682A4B&FORM=WRVORC

 

[Steve Mehrlich]

The only way I've gotten it to work is by putting sketch lines as a pattern in design, then in machining, use those lines in 2d contour, and create a pattern of the contour vertically and horizontally and then machine.
Depending on your widths and gaps between islands (is use a fillet on all corners), you then re-run the process with offset (stock to leave) etc.. to widen the channels.

Hmm I see what you mean. How wide is channel? Have you tried trace tool path with an axis offset to get the depth? I would definitely explore using a tool the same width as the channel and turn off lead in and outs.
I solely use fusion , it makes me think I'm better than I actually am.
I'm aware we've hijacked this thread , is Mr rewound sorted?

 

[Rewound]

, is Mr rewound sorted?

good god know - i'm at the stage where the more I learn the more I am becoming confused - still lots and lots to ask

really simple things like - how can I tell it (through fusion) how to take 1 mm off the top surface

 

[Steve Mehrlich]

Okay this is where your model and stock become two different things. Is your current stock too thick and you need to get it to your model height? Use a facing tool path. You could use a pocketing tool path but your machine/ fusion need to know where to pocket to.
Even typing this makes me realise how easy it is to forget what it was like not to know these things and how confusing it can be. Did the above make any sense?

 

[Rewound]

Okay this is where your model and stock become two different things. Is your current stock too thick and you need to get it to your model height? Use a facing tool path. You could use a pocketing tool path but your machine/ fusion need to know where to pocket to.
Even typing this makes me realise how easy it is to forget what it was like not to know these things and how confusing it can be. Did the above make any sense?

that bit wasn't too painful - thankyou
I take it you make the work into sections as I have done below - Face1, Adaptive2, Adaptive3
but how would I pause it to change the tool

think of someone wanting to learn to drive, no good starting off with road positioning and who has right of way, they may be at the point of wanting to know what seat in the car they should sit in, or even - "Do I actually need to be in the car"?

as for CAM in fusion, I may of found the driving seat but wondering what the three pedals are for
(design in fusion - I'm at the boy racer stage, think I know it all)

 

[Delaney]

Doing a facing operation in CAM is easy. Wait till you actually have to do one and realise your machine needs tramming. The fun of CNC machining

The tool will automatically stop between
required tool changes. It’s in the code.
If you din’t require a tool change then it will just move onto the next operation.
If you want it to pause, then you use the pendant or panel, on your machine to do it physically.
Just make sure you stop the spindle during pauses. Easy to forget it’s on and cause yourself a lot of trouble.

 

[Steve Mehrlich]

hat bit wasn't too painful - thankyou
I take it you make the work into sections as I have done below - Face1, Adaptive2, Adaptive3
but how would I pause it to change the tool

somethings not quite right there. face operations should remove all of the top face of your stock. i reckon you have a geometry selected that you shouldnt for that toolpath. leaving it there potentially presents material to your next toolpath that it isnt expecting to be there. if its cutting into the middle of that stock expecting to cut at 7mm deep, with that extra material there that cut may be 8mm or more depending on how flat your stock is to start with.