Machine Factor for Longmill in Fusion 360

Software Help Fusion 360
24

Thanks for that information, Jeff.

I didn’t do one at 30" x 30". As I said, I didn’t have a clue what it was for, and I looked at the one that was online and saw that it was done on a 4’ x 8’ sheet, so I assumed - wrongly, i now understand - that the ratio should be 1:2.

I just arbitrarily chose landscape 12" x 6". It would be simple to scale it up, but, of course, if the ratio of width to height is changed, it would be distorted.

I did mine in VCarvePro. If you are still interested, I can post the .crv file. If not, no worries.

25

Thanks for offering it. I think I’ll probably use it as a good learning exercise in F360 and mock up something similar. I was thinking doing it in mm scale and making the grooves the right width for a standard tape will make checking it easier. I’d like to have a reference cut for how the machine should perform when dialed in and I figure over time we can detect signatures in variations against this that will become known conditions with known solutions.

-Jeff

26

Now that I know what it is for, I’ll be interested to see what you find out over time, Jeff.

27

@gwilki I’ve only run a few jobs in wood so far but my initial swag at it is a very encouraging 85% (or .85 I think is how it is displayed) seems to yield fairly accurate times. I’m not sure how much that changes with different end mills or materials (if at all). It is very nice to have the simulations fall within <1m of the actual.

Give .85 a try and let us know if you see a similar result.

-Jeff

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@jwoody18 @KimballArms @Lumpy @gwilki

I know the years have passed but since we’ve now posted recommended feeds and speeds for the LM MK2 it seems to me that it’d be doable to compare our suggestions to other common cutting tool manufacturers and create some sort of Machine factor off of that? Jeff what would be you’re thoughts on that, or perhaps I’m missing the mark on your initial idea on this

29

@chrismakesstuff @KimballArms @Lumpy @jwoody18

I realize, Chris, that you posed your question only to Jeff, but since you included me in the targeted list of recipients, I figured that I would throw my 2 cents worth in.

I played for a while with the factor setting in VCarvePro - comparing its time estimates to actuals - and could never come up with a factor that held true for all toolpaths. In particular, 3D carving was really hit and miss, given all the Z movements. As you know, we can set X and Y to run at a given speed, but if the Z movement is slower, all of the movements default to the slowest speed.

For me, VCP was pretty close on toolpaths like simple profiles and pockets, so it seemed pointless to mess with the settings to get them to better reflect real time runs for 3D carves, only to negatively affect the estimates for those simpler toolpaths.

I believe, too, that trying to come up with factors that others could use would be a daunting task. There are so many variables between users. Feed rates, plunge rates, ramp lengths, safe Z heights, and even project size compared to material size will all affect how accurate the VCP estimate is.

I confess that all this is much beyond me, which is why, I guess, I gave up on it. Thankfully, I don’t need take into account any of the factors that Jeff mentions in his previous explanatory post, so the fact that VCP’s estimates are frequently off is not a game changer for me.

I refer here to VCP, but I’m assuming that the challenge will be same regardless of the CAM program.

As an aside, this is also an issue for gSender. I frequently start a job and gS shows it will take many, many hours to complete. However, within a few minutes, those hours and hours disappear in favour of a more realistic time span. Then, it can occur that, after settling down, the estimate goes up again. I am not even close to being competent enough to understand what it going on under gS’s hood, but it can be unnerving on some jobs until it settles down.

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