Fusion 360 - 3D Surfacing Contact Point Boundary

[Music] hi guys Kevin from Kangol managed comm I wanted to take a second to talk about 3d toolpath containment and how to easily and quickly get the exact results that you're looking for when you're doing 3d operations so here I have a simple example file that we're gonna use to demonstrate this and let's edit this set up and go ahead and you can see the work coordinate system where it's set to and go to the stock you can see I'm using a relative size box with no additional stock that means that the size of the stock and this the bounding box of the part are the exact same size go ahead and hit cancel here and if we click on the set up I've got a 3d adaptive that roughs out this part and then we come back with a 2d contour just clean up the end so if I go to the set up and I simulate this with just the tail toolpath will turn the stock on hit play and maybe speed this up a little bit so we can see what's going on so there's our 3d adaptive that's gonna go and rough that face it's gonna go back to the bottom and finish those edges and then a 2d contour is gonna go around and just clean up the radius on the end so that leaves us this terrorists face that we can come back with the ball mill and clean up on our serpentine operations the operation that I'm going to use to do that is going to be a 3d parallel so from the 3d menu I'm gonna select parallel and I'm gonna grab a tool now I already have this tool set up in this document but if you want to use the same one for you for a simple example for yourself the tool I grabbed us from the tutorial inch and it's tool number 11 for the half-inch ball I'm gonna select that same tool but out of my document and I'm gonna go ahead and hit OK now when we get to the geometry we have different machining boundaries we can work with there's three types of machining boundaries bounding boxes silhouettes and selections and one of the great parts about the fusion cam is if we just hover over something oftentimes we get a nice tooltip with a graphic flyout that kind of explains what these things are so you can clearly see what a bounding box a silhouette and a selection are what we want to use for this example is going to be a selection and now we have to specify a machining boundary so I'm gonna go over here and grab this edge it's gonna select the entire perimeter of the part which isn't what I want but we have an easy way to get around that so I'm going to click on this once it's gonna turn that pro for that region green when I put my mouse over that it's gonna turn red when I see that turn red I can left-click on that region and brings up that pop-up UI now and now I can just move my mouse around and reselect the path where I want that boundary to be so I'm going to click over this line and a very important step is to make sure you hit the green plus to lock in that selection when I do it gives me that selection and flattens it to the lowest point of the boundary that I selected for our tool containment we have three options again nice tooltip here we can keep the tool inside the boundary we can Center the tool on the boundary or we can do the tool outside the boundary tool outside the boundary means that the tool is allowed to go outside of the boundary by one diameter of the tool tool Center is what it sounds like the tool goes to the center and can't go any farther and tool inside the manner II just means that the tool cannot no edge of the tool can break outside that boundary that we've selected so we're gonna use tool Center on boundary for this particular example and we're gonna come back and talk about some of the other options in a minute oftentimes with 3d adaptive or I'm sorry 3d operations the Heights tab is not important it's going to use the region that we specified tool Center on that from the stock top to the model bottom and since they can get outside of that the area that we specified that's gonna be exactly what we want we'll move over to the passes tab now on the passes tab we have a passed direction anytime a tool path is asking for a passed direction the axes always I'm sorry the zero degrees is always lined up with X so the tools I was gonna go the long way when or I should say along the x-axis when 0 degrees is specified so I know exactly which way this tool path is gonna go I don't have to hit ok to see what's gonna happen as long as I can see where my x axis is here I want to enter a step-over of point zero to twenty thousand seven inches what we're gonna do first step over and let's just go ahead and choose ok and see what our tool path looks like so at first glance things look pretty good I recommend that you always simulate 3d toolpaths especially when you're starting out to make sure what's what's what do you think is happening is actually happening so let's click on this parallel and simulate it I want to turn on all tool path and I'm just going to come over here down here I'm going to place my mouse over one of these points and click now let's look at this from the side when I look at this from the side you can see the tool is stopping short of giving the ball middle all the way down there so it's leaving a chunk of material and this is a big source of frustration for new users or people who aren't familiar with the 3d machining operations it may seem like fusions not doing what we've asked it to but it's doing exactly what we've asked it to and to demonstrate that let's go look at this from the top when I look at this from the top you can see the center of the tool is on the boundary that we specified it just can't get all the way down to the bottom because to do that the tangent of the tool would have to go farther out and that would get the tool Center farther than outside of that boundary so that's what's happening there's another thing that's going on with this tool path if I come and click on that point right there and look at it from front view again now what we'll see is that the tools riding up over the surface and going up on the top of the part I've either probably faced this or I don't really want the tool to go up on the top maybe leave it in a tool mark or something up there so I don't want the tip of the tool to break the tangent the tool I should say to break contact with a surface right there and if I left click and hold you can see what's happening that tool is riding over the top and coming back down and writing back over the top and coming back down as it makes its passes so let's go see if we can fix a couple of these issues switches back to a home view I'm gonna go to my parallel and edit that operation and on the geometry we're gonna turn on an option called contact point boundary I'm going to enable that I'm gonna let my mouse hover for a minute again wait for that tool tip to come own and when it does you can see in the top graphic what's happening when it's disabled when the tip when the centerline of the tool gets to the center of the boundary it can't go any farther and you can see that exact example that we just saw where it's not machining the entire surface when we enabled the contact plane boundary it lets the tangent of the tool maintain contact with any part of that surface even if the centerline of the tool has to go outside of the boundary we specified tool Center on boundary but with this enable it allows the tool Center to go outside the boundary but it doesn't allow the tangent of the tool to break contact with that surface so the tangent the tool has to stay in contact with a surface that we're talking about and then the bottom graphic pop that back up again you can see when it's disabled the tool rides over the top and machines on top of the part when we enable it again doesn't let the tangent of the tool break contact with the surface that we specified with our boundary so we will turn that on and now let's go ahead and click OK and if we look at this the tool path is certainly going farther down so let's go ahead and simulate this and go find the spot to put that on there look at that from the front view and you can see that clearly the tool is going past that but we're really getting a fairly noisy and ugly tool path and in fact in some points it's it's going way outside of that you know kind of the boundary that I wanted to do so let's talk about why that's happening I'm gonna edit this parallel and I'm gonna go to the passes tab you can see that there's a tolerance listed here there's a tolerance of 4/10 for this particular operation and what happens when we generate this 3d tool path Fusion takes our perfectly B rep surface or boundary representation surface that's mathematically calculated and turns it into something called an STL file if you've ever seen STL files we commonly use these in 3d printing it takes all the surfaces and turns them into triangular faces so all these surfaces are gonna represented by flat triangular faces but these triangles can never deviate more than 4/10 of an inch from the original surface that we're looking at so to demonstrate what's happening here I have another file I've taken this model and I've exported it out as an STL file and I've reopened an STL file back into fusion so this is what the STL file would look like that Fusion is is using to generate the toolpath you can see the top surface is made of two angles the side surfaces made about two triangles the left right and bottom are both made out of two triangles and then as we look at this radius edge we see lots of triangles around there and then this angled surface is also made up of Vlad triangles so instead of this being a nice curved edge we're getting a bunch a little tiny line segments and I have one more thing we can look at to kind of demonstrate this again a little bit more I want to go to this AutoCAD file and I have a representation here of kind of what's happening so you can see I have a cyan color representing the perfect mathematical geometry of the model and I have this magenta line representing the STL file tolerance now obviously I have this way over exaggerated just so you guys can kind of see what's going on and you can see there's certain points where the boundaries overlap and there's a spot where the tool can kind of poke its head through there and then poke down now won't violate the model but it will kind of give us an ugly-looking tool path luckily there's an easy way we can go ahead and cure that problem so we're gonna switch back over to fusion and go back to our original file I'm gonna edit this tool path one more time and go to the passes tab on the passes tab we see that we have a tolerance and if I hold my shift button down before I get to that field and I mouse over that a pop-up is going to come and let me know some of the parameters that are being used for this tolerance field so first of all this this menu option is called tolerance and a couple things you can see that the value is set to four tenths and it has a parameter name of tolerance with a small letter T so let's go back to the geometry tab now that we keep this tolerance value in mind what I can do in this additional offset is I can type in a negative tolerance that's equal to what I have in the passes tab so I could come in here and type in - point zero zero zero four and type that static value in although there's an easier way to get around doing that because if I ever go back and update that tolerance I have to remember to go change it in the additional offset field instead when I'm going to do is I'm going to put my negative sign and then I'm going to type in the parameter name which was small letters tolerance and now you can see it under fusion understands that value is because the the the text is black if I were to do a capital T you can see everything turns red because fusion doesn't understand what the value tolerance is because that's not a parameter name it knows about so we'll do with the small letter T now I have that small small negative tolerance is what I have listed and when I click OK you're gonna see that tool path that now looks pretty nice everything is pretty clean on there so let's simulate it and make sure we get the results we want so we'll come over and grab it at the top now let's look at it from the side you can see the tangent of the tool is staying in contact with that surface but it's not writing over the edge so that looks great and let's come and grab a different point down here put our mouse there look at it from the side again you can see the tangent the tool again is going all the way down to the bottom even though the tool is going off the centerline of the part of the boundary that we specified but that's okay because we use that contact point boundary option to do that so that's the quick and easy way generally to fix these tool paths so that it covers the entire surface that you want to and you don't have any additional tool path noise or anything like that now that we've shown you the right way to do this one of the common answers I see most in the forum's a lot is to just add an additional positive offset so if I go to the geometry tab I could add an additional positive offset let's use half the dime of the tool so we'll go point to five and we'll choose okay and this is the reason why I don't like to do this because now you can see the tools machining a bunch of stuff I don't want it to in order to fix this problem I have to edit it and go to the geometry tab and use the avoid services option and click on all the surfaces that I don't want this tool path to touch and hit OK and now we're back to the exact same result we got when we use contact point boundary so the right way to do this is to use the contact plane boundary option with a negative tolerance value set and you should get a nice clean and quick tool path to create to do surfaces like this I hope that helped to understand what's happening in the background as we calculate 3d toolpaths in fusion if you found this video useful it would be great if you subscribe and if you have any questions leave them in the comments below and we'll see if we can get them addressed so thanks for watching and have a great day

Channel: Mechanical Advantage

Views: 21,600

Keywords: Fusion 360, Contact Point Boundary, Containment, CAM

Id: 93oCFMCqQZg

Length: 13min 30sec (810 seconds)

Published: Sun Jan 07 2018