Extremely Slow CAM on Simple Parts

[angusstevenson123]

Hi,

I am trying to do simple profile cuts - full depth (in 1 pass) on 12 mm plywood. However the calculation of the tool path takes a long time. The shapes are simple and I don't believe I've asked a lot of the program to calculate the tool paths. 

Any help appreciated, thankyou,

Angus

[Anonymous]

You have double lines in imported file, hundreds of segments of small lines, setup issues, tool / operation definition issues ....... 

[angusstevenson123]

Thankyou VicCosta - I'll look closer at the original sketches.

[seth.madore · Accepted solution]

It is true that there are issues in the model, sketch and Setup. However, selecting off of the model and generating a simple 2d toolpath (with no ramp, feed optimization, tabs etc) should NOT take as long as it does. We have received reports from others involving more complex parts performing far far worse. We are investigating the root cause of this. I don't expect to have an answer back this week, as most of the dev team is in the UK and they are on Holiday until next week.

[angusstevenson123]

Thanks for the replies/ input.

[Anonymous]

He did pick top edges of model and yet, it resulted in double tool path only on this one part.

[seth.madore]

Mmhm. And my response was based on clearing out everything the OP did and starting fresh with selections on the bottom edge (with Sketch turned off). Performance is still rubbish

🙂

Heck, it takes 3 minutes to open up the file on my workhorse PC. Creating a Setup almost crashes Fusion. Creating a new toolpath all done up proper gives me a black bar while it churns away:

[fishtruk]

Not just me, misery loves company 😉

[Anonymous]

I think I fixed few things, still awfully slow loading.

[jeff.pek]

I understand from Seth that this came over as an imported DXF. We've had a chance to take a look at things.

Due to the way that the model is created, the contours being selected are made up of many small line segments. When you select a connected chain, each of these segments is tracked. 

For the set of chains that have been selected, this results in more than 3000 separate references to the various model segments. This is a killer for performance, as these need to be reevaluated when you load the model, and then whenever you go to edit the operation.

We are looking into what we might be able to do to handle cases like this. Unfortunately given the way things work I don't have an off-the-top-of-my-head suggestion for how to improve things, unless you have a way to simplify the construction of the model so that it doesn't have so many line segments.

Jeff

[Anonymous · Accepted solution]

Jeff, it's not my file so I  don't know the source of original sketch, but yes it makes perfect sense.

While I was deleting duplicate lines from one of the drawings, I was intrigued by number of segments.

My first thought was, this file came from some cartoon CAD system but my goal was to eliminate main source of error which helped response time somewhat, "simple drawing" is not so simple at all.

[angusstevenson123]

The parts were drawn on AutoCAD - then imported as a DXF in Fusion. I drew the curves in AutoCAD as a spline to reduce the number of nodes on the polylines. I have found a slight improvement in performance by turning all the bodies into components then copying them into a new Fusion 360 file - and hence getting away from the imported DXF's. The CAM performance was then workable - but only just.

Thanks for all the input - appreciated.

[Anonymous]

Well, excuse my "cartoon CAD" comment, but we certainly learned what those short line segments do to the file in Fusion.

[angusstevenson123]

No worries at all - maybe if the DXF's were imported then retraced with lines and splines inside Fusion 360.

[engineguy]

@angusstevenson123 

@Anonymous 

@jeff.pek 

@fishtruk 

@seth.madore 

Well, for what it`s worth I had a look at this and it would appear to be the age old .DXF file "will work with some and not others" issue, pot luck if it works first time, in the case of Fusion 360 always split the shapes up into separate handy small group sketches, this was one very big sketch with geometry problems so it was always going to be a problem generating the toolpaths, poor old Fusion was really up against it, no wonder it was so slow !!

Over the years fighting the .DXF issues I now check the geometry first before I try to use them, in the case of this one there were several breaks in the geometry in the two top right shapes (Bent rectangles) so I sorted those first.

Then I set about splitting the single big sketch into a half a dozen smaller ones and as it is all simple 2D I didn`t bother creating a whole bunch of solids, just something else for Fusion to have to work with and slow it down!

All the above should really be done at the .DXF generation stage, if you are generating the .DXF yourself then do all the checks/repairs (Autocad is famous for these) and splitting into a number of smaller .DXF files at that stage, if the file is from a third party then not doing a full inspection is pretty much guaranteed to have issues, all this is something I have always done from way back, spending some time making sure you have "clean" and manageable files before you start using them in any CadCAM system will save you hours and hours of heartache and $$$ on the Asprin

Anyway, have a look at the attached Fusion file, it generates the toolpaths in about 2~3 seconds here and this is an 8 year old PC that should really have been pensioned off years ago but it is hanging in there for now !!

Enjoy

Regards

Rob

[Anonymous]

So, I understand there was more to geometry then just double lines in one tile. I see that it runs a lot faster even though small line segments are still present in all arcs.

I created bodies from sketches in your file and took new tool paths, although smaller tool needs to be added to finish areas where end mill could not get in.

Loading time increased to just under 30 seconds so it slowed it down significantly compared to your file, editing also takes time before window pops up.

It seems eliminating solids from file does the trick in speeding it up but not having solids lead to error in geometry selection.

So question remains, what will speed up processing of file having all those small line segments and solids generated from such file ?

Tool path is on wrong side of geometry, not confirming to model.

[engineguy]

@Anonymous 

Apologies, I did forget to alter the direction of cut for the cut outs, well spotted, as for the tooling/feeds/speeds/leads/heights etc, etc I left that up to the user(s) as per their preferences.

I have also extruded solids from the geometry so they can be used to verify the cuts, which they do fine, in this case I did each one separatly in order to try and keep the file size down as much as possible, seems to have worked OK as load time from my Fusion online library is about 4~5 seconds and having downloaded it to my PC the load time up to Fusion from the PC is only about a few seconds longer, around the 7~8 seconds mark. (Depending on time of day and how busy my broadband is this might be longer)

The original file size was 4,991Kb, new one is a little smaller at 3,386Kb so quite easily handled IMHO.

Opening the Contour operation to Edit is almost instant and adding the solids here doesn`t seem to have slowed things down at all and I have tried selecting the solids for the toolpath instead of the sketches and it isn`t slowed down at all, so all in all it must be pretty close to being OK now

New file attached with the solids added and used to generate the toolpaths, no issues so far.

Hope that helps a little.

Regards

Rob

[Anonymous]

On my work computer, which has better hardware then my laptop, my file opened in 16.8 seconds and your file opened in 11.7 seconds.

If I open each tool path for editing, your file opens 5 seconds faster then my file, that's heck of an improvement compared to original file.

Only difference I see between two files, without microscope, is that I checked "Preserve order" tab which cuts parts in order they were picked, all things being equal, I guess this is as good as it gets.

In conclusion, it seems we don't need solids in strictly 2D tool paths, except for simulation benefit. 

My note about additional tool is in reference to original file.

I am also not familiar with routers and wonder if X and Y axis layout is same as on mill or not.

Cheers

[seth.madore]

X and Y layout is typically the same. One word of caution though, on the "it seems we don't need solids in strictly 2D tool paths" comment; Fusion has a poor time deciding what side of the part to cut on when dealing with sketches. Further, if you don't have solids, your ability to create a Setup is greatly diminished, as there is nothing for the Setup to recognize and prepare stock for. You are left with a bit more manual process of Setup creation, and also tasked with going through and making sure all your directions of contours are cut on the proper side.

This is all interesting stuff, thanks for churning away on how to make the file more manageable!

[Anonymous]

You'll notice that I swapped X and Y axis in setup when first responded to original post with revised file, I noticed that was not carried over to last version, which is why I wondered what's correct if router is in question.

On subject of solids, I acknowledge the fact that working only with sketch made huge improvement in file loading speed but I am not sold on eliminating it for reasons stated in earlier post.

Key issue causing hangups was apparently in problems with imported DXF file.