Couple toolpath questions! And the helix ramping

[Anonymous]

Hi! I did my first big project on the CNC router with Fusion yesterday. It went great. I have a few questions though!

(Shapeoko 3 XXL, cutting 3/4" MDF)

1. Had a 3d object routed out, it worked great. But my material needed to be cut down, so I tried to get the router to do it for me. I ran into some issues.

I assume I'd need to use a 2d toolpath. I chose 2d contour then used alt to select the 2 sides i needed to cut. (the other 2 were fine where they were.)

I selected a 1/4" bit and it was insisting it wanted to cut it in a single pass. I tried selecting multiple depths but when I would lower that number to like 3mm, it kept spitting out an error and told me to contact someone about it. I forget the exact error. What are the steps to get the router to just cut through on the outside of 2 lines? Other than drawing on an actual narrow pocket on the 3d design, or is that the smart way to do it?

2. My second question is speed. It went very fast, but a lot of what it was doing was wasted time.  For one, any time it would do the little corkscrew helix plunge(adaptive clearing 3d), it'd start like an inch above the project and take like 30 seconds of doing little tight circles to hit the stock. I could lower my retract height but I like a little bit of retract height for safety. I used the rest machining option to remember what stock was already removed, but still the toolpath starts off above the original model even though half an inch of stock is already gone. Is this just a work in progress or am I missing an option?

3.  I notice that while adaptive clearing is used, after doing a rough (but good enough) pass, it goes along each Z axis and does what I assume is 'cleaning' the lines. But it seems to actually appear that the bit is a fraction of a mm away from actually doing anything. Maybe it's an optical illusion because of the flutes, but it looks like its justtttt away from hitting the stock. I thought maybe my bit was slightly undersized. Could be it. But with what I'm doing, I don't need that pinpoint accuracy and it'd be useful to eliminate that step. Is there a way to remove that cleanup step from adaptive clearing?

4. The models I make are tiered with 2mm between each layer in a birthday cake layer style. (I believe adaptive clearing actually looks like this when you run it.) But this is what I need as the finished look. So I've just been running all my toolpaths as adaptive clearing with it not leaving any stock and it's been working fantastically. Is there a smarter option to do this, or am I just lucky that adaptive clearing is exactly what I need?

5. In the very top millimeter of my projects, I need some pretty intricate details. 1/32" bit would probably be good, 1/16" for some of it. What's the best bet for speeds for this? I've tried seeing some pages but they don't really seem to have info on such tiny details on MDF. The bit would likely have to cut a trench for a lot of the skinny details (180 degrees of the bit touching wood) so what would be a good setup for feeds and speeds? Also, how much of the bit should be sticking out of the collet? I could grip it real low so only like 5mm of the bit is sticking out to lower the chances of the bit breaking. (My 1/32" bits are 1/8" shank and the flute length is actually quite long, I know I should get some of those ones where the flutes are only a few mm deep!)

6. With some of those smaller details, it's not necessary that they're actually as thin as they are in the 3d model. By default, a bit won't go into an area that's a smaller diameter than it is, is there a way to override this? It'd be nice to stick a 1/16" bit in and have it just cut out small details even if it goes past the lines a bit. Right now I'm thinking of just leaving a 1/16" bit in when I run my 1/32" detail toolpath.

Thanks to anyone who read this far and I always appreciate all the help!

[Anonymous]

Curious if anyone has any idea on any of these!!

[fr33l0ad3r]

Actual files would make it. Right now it is hard to understand what you facing.

[Anonymous]

Oh I'm not asking anybody to setup the project for me, just asking these general questions about fusion that will apply to all future projects. An example won't help much, these are just basic questions

thanks

[Anonymous]

Here's an example for one question though.

Piece is 14x20"

In setup i have stock as 20mm more on the top and right. Because the piece of material is actually larger than my design and i need the router to cut that 20mm off the 2 sides.

I set 2d contour on multiple paths to cut out those 2 lines in 3 or 4 passes but it throws an error at me. Is there an easier way? I can get the machine to cut out intricate 3d objects but i cant get it to cut 2 straight lines in a few passes

[DarthBane55]

I'll try, but I might deviate from what you are facing, I'll answer just based on what I understand you are doing.

1-If you had "stock contour" selected, it will only do what it needs to to clear it.  So if your tool was to clear it in 1 pass with the stepover you specified, and you had "stock contour" activated, it will only do 1 pass if the tool clears it, even if you say that you want to take 20 passe (I'm talking about radial passes).  Just de-activate that option and you can take as many passes you want.  This option is very useful sometimes, as you can set a different stock than what you have defined in the setup, but need to learn when it's best to use it, and when it's not.

2-The helix has a "ramp clearance height" option in the last tab.  Yours must have been set high.

3-I don't really understand, a picture would be worth a lot here.  But if you have some Z cleanup stuff and don't want them, set the fine step down to be the same value as the stepdown, this will eliminate any extra Z passes.

4-not getting it.  pic needed.

5-Sorry, I've never cut wood.

6-A few ways to do it.  Best way is to modify your model so the tool fits, but I know this can be a pain.  Another way would be to make a sketch in those areas and pick that in your operation.  Another way would be to set a negative finish allowance, but you'd have to split your operation to have the negative finish allowance only in those areas where the tool doesn't fit, otherwise all the features would be overcut.

I hope some of this will help 😲

[Anonymous]

Thanks! I'll need to look into what you wrote for number 6. I was trying to do something similar. I set up a bit in the toolbox that was 1/64" width but I plan to actually stick a 1/32" in there cause I don't have a good 1/64" bit and the lines dont need to be perfectly accurate, i just want a thin detail, i don't care if it overcuts. But those intricite details are only on the top 1mm of the piece, so I set stock bottom up to 1mm under the top but it wanted to go in and clean up all the lines on everything, I was trying to just figure out how to get it to hit the important stuff and not waste time on all that other stuff. Wheres the negative finish allowance option?  And how do i split the operation so it'll only work on part?

(Just imagine the piece is a giant intricate hole thats good enough and on the side, theres a bunch of intricate other shapes. I need detail on those shapes, NOT the hole)

Thanks!

[DarthBane55]

for the negative finish allowance, it's just under the "passes" tab, "stock to leave".  Just put a negative number in there, so instead of leaving material, it will cut extra by that amount.

To split the operation (assuming you are still talking about 2d contour here), just select the stuff you need to be overcut separately than the rest.  So 1 operation for the stuff to be on size, and 1 operation for the overcut stuff.  When you pick your "contour selection" just pick what you want to cut in each operation and nothing else.

For your stock bottom issue... 2d doesn't care about the stock much, you can have a 1mm stock, and still cut 100" below it.  Instead, in your operation, in the "heights" tab, "bottom height", set that to "model top" -1mm.  These heights are extremely useful and critical to set correctly.

Kin toé!

[Anonymous]

Great!! The projects Im doing are on MDF and wood and are artsy. So I don't need insanely precise cuts. I've been doing adaptive 3d clearing with No leave stock. 1 run with a 1/4" bit to clear the big stuff, a pass with a 1/8" to get into the nooks, then I do what you said and set bottom height to model top -1mm for the 1/16" pass.

That bit is super short so I don't want to go deeper than that in fear of the collet holder smashing into the work piece. Plus, all those tiny details are in the very top mm anyways. I never thought to put a negative value in the stock to leave. That's awesome how that works. I should be able to run a pass with a 1/16" bit and tweak that number so itll just barrel through all the finer details. Their accuracy isn't as important as the fact they're there. So that sounds like itll work perfect.

Right now I'm currently only really using 3d adaptive clearing for basically all the steps since the end result is the 'adaptive' layered look anyways. Does 2d contour clear out pockets or just do an outline? Because some of the smaller details I'd like to hit in that selective detail final pass are larger than others and I need the pockets to be cleared, and if the diameter of the hole is too big, if it just does an outline there will be a raised area in the middle.

Here's a screenshot of my project at the bottom of the post! It seems like 3d paths just automatically clear everything out. So I'm assuming theres a good option where I can basically adaptive clear with various bits the whole piece then with a smaller bit and a negative value on the leave stock, I can just deselect the main 'hole' and it should ignore that and just go around and tap out all the little tiny holes and rivers!

[DarthBane55]

Yes, you can clear out a pocket with 2d contour, just add passes under the passes tab, where it says "roughing passes".  But you can also use 2d pocket.

In the last paragraph you mentioned that you could use 3d adaptive to do everything, and you are quite correct, since you dont need to do finish passes.  But, on the small features, I think I would use 3d pocket instead.  It will function the same way as 3d adaptive as far as selection, and rest material goes, but it wont do a trillion little passes when you have very small stuff.  But I know you use a very small tool too, so you can experiment with them.

Little trick: When you have a good adaptive toolpath, and you want to compare what it would do with 3d pocket, right click on the toolpath, and choose "create derived operation", and pick 3d pocket.  You'll see what will happen, most of the stuff will be populated automatically.  Time saver here.  Watch your chip load tho, because 3d pocket is not a constant chip load like adaptive, so I would assume full slot cutting speeds and feeds for that.

You will have to drag that new toolpath above the previous one to see the result, if you activated rest material, because otherwise it won't cut anything, since you are cutting the same stuff with another toolpath... it will see that there is nothing left to cut.  So you'll have to drag them up above another to generate.  You can then "lock" the toolpath by right click on the path and choose "protect".  If you protect both, they will be both active until you regen them, so then you can have them both up at the same time to compare.

[Anonymous]

Awesome!! These are the golden tips! Ill have to check it out because I did notice the 1/8" bit doing some tiny detail passes that didn't seem to be doing much and they were wasting some time but later in the operation it was set to do some important stuff so I couldn't skip it.  So Ill definitely use that trick. I'll probably upgrade my computer soon too cause this one takes a while to calculate the toolpaths, lol.

I'll need to figure out the best way to set a detail toolpath to hit all the tiny little holes, cause right now selecting every single one is a lot of zooming and clicking. Is there a "Select all" button then I could just unselect the main lake? I guess if it selected everything I'd need to unselect the land too just so the tiny sublakes stay selected. I'll need to play with it all a little!