CAM expressions and default settings

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In this video, we're going to discuss cam expressions and default settings.

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After completing this step, you'll be able to create a cam expression and set an expression as a default value.

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In fusion 360, We want to carry on with our coupler for CNC male example.

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We've talked about cam expressions briefly in a previous video but we want to explore them a little bit more.

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We're going to take a look at op one and specifically at the Contour one operation.

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We're going to right click and edit this operation and take a look at the past this section.

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When we're talking about the past this section,

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we created a maximum step down value that was pretty small in order to machine a taper.

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I'm going to expand the models and I'm going to hide my generic vice and rotate this around so we can better see what geometry we're working with.

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When we're talking about a maximum step down value.

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Just randomly entering a value is generally not a good idea.

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You want to have some sort of logic built into your tool path that can be based on the geometry.

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So we're going to right click and we're going to edit the expression which currently is just set 2.01 inch.

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We're going to delete that and we're going to begin to create an expression that we can use to determine this value.

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I'm going to start with the parentheses and begin to enter T for tool.

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I'm going to use underscore and I want the tool diameter.

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As soon as I get the tool diameter I'm going to hit enter and I'm going to divide that by two.

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This is going to give me the radius value.

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Then I want to take this entire value and I'm going to divide it by eight.

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When I say okay, what I've done is I've created an expression that gives me that 0.1 step down.

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But now it's based on the tool.

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What this means is that if I decide to change from a quarter inch ball in mill to an eighth inch ball in mill, the value is going to update.

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So right now it's based on 0.156 for the tool that we're using a quarter inch ball.

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But if I go back in here and I select an eighth inch ball for example.

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And I take a look at the passes, you can see that maximum step down value has been reset.

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If I want to use the expression that I created as a default,

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I need to type in this tool value which is going to be my tool diameter.

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Divided by two to give me my radius and divided by

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Once I create that parameter I can right click and I can use that as a default.

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So notice that the edit expression can be saved as a user default or we can always go back and reset it to a system default.

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If I save it as a user default and I go back and I modify the tool,

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and decide that the quarter inch ball in mill was really the best tool to use,

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go back to aluminum finishing and go back to my passes.

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You can see here that the maximum stepped down has reset itself.

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If I want to use that expression, I can reset it to my user default.

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What this means is that I can use those values anytime I'm creating new operations,

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and they're based on the tool parameters and not just a value that I enter.

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This is important because we can also take this tool path,

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we can right click on it and we can use it for derived operations which will bring in those parameters or we can save the parameters as a default.

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If I save the parameters as a default in the operation it'll be used for all future 3D contours of this type.

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Notice, that it says I won't be able to revert any previously set default parameters for this operation.

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So if you take the time to update these values and you're constantly basing them off the specific tool.

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It's a good idea to come up with a base parameter that you like to use and set it as your default.

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Another thing that we can do is we can begin to build templates.

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When we begin to build templates we can store this entire tool path as a template,

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I'm going to call this one 3D contour and I'm going to call it on taper and we can add a description and we can determine its location.

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So once I save that I can always go into my manage and I can take a look at my template library.

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This template library will allow me to see all the operations that I've saved and then any time I'm creating a new tool path.

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For example, if I begin to create a new 3D contour,

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I can create a 3D contour with my template rather than doing it this way where I manually select my geometry.

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When I do that I can go in and I can right click,

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and I can create a new operation based on that parameter from my template library by using create from template.

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I can say 3D contour on taper and then I can edit this operation.

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Keep in mind when we're using these operations as templates, certain types of operations will work better than others.

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For example a 3D adaptive which is using the stock contour and no selection will update very easily to new parts.

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However, something that does require a selection for example my 3D contour template,

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required me to select a certain area of this and then we also had avoid touch surfaces and slopes.

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In this case we need to remake all those selections.

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Even the bottom height where I selected this edge.

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I need to go back and I need to select those before it can generate that contour tool path.

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So keep in mind when you're making your templates,

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and when you're deciding on what your cam expressions might be,

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there is an amount of re use that is helpful,

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but in some cases it might be easier for you to simply remake certain parameters or certain operations.

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There's no defined value or there's no defined work flow that works for everybody.

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Everyone will have to make adjustments to the process.

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That makes sense for their types of parts and their system.

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But understanding the options that you have for cam expressions, defaults and templates can oftentimes make the process a bit easier.

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At this point, let's make sure that we save this design before moving on.