Design for subtractive manufacture

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Designed for subtractive manufacture.

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After completing this video,

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you'll be able to

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identify the various types of subtractive machine tools,

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use fusion inspection tools to validate a model,

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and understand the principles of material removal and tool access.

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In fusion,

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we're going to begin by taking a look at the supplied data set,

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Subtractive samples.

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F3D.

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Now it's important to note we're discussing subtractive manufacture,

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that we're not going to be diving deep into

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the different types of machines that are available.

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We're going to talk a little bit about types of geometry that suit certain machines,

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but it will be important as you prepare for your certification

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to have good general knowledge of different types of

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manufacturing machines that are used for subtractive manufacture.

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Now,

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in general,

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when we talk about subtractive manufacture,

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we're thinking about designs that start as a

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larger piece of material and have material removed,

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and that's how they're produced.

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This is the sort of opposite of 3D

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printing or fabrication based on building material up.

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So to get started,

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the first thing that we're going to take a look at is 2D fabrication.

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This is generally thought to be things like

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water jet machines or laser cutter machines.

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The important aspect here is that the parts are a consistent thickness,

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and all of the

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material that's being removed,

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slots and holes in the external shapes

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all get done in a single normal direction to the part.

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This means that the fabrication is removing material,

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but it's done in two dimensions.

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Now,

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it is important to note that certain machines,

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like laser cutters and water jets do have compensation on different axes.

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They can tilt the head of the tool,

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and that can adjust for things like curve or an angle that gets

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cut on the side of parts when we deal with thicker materials.

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But for the most part,

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we want to understand that 2D machining

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is generally thought of as water jet or laser cut.

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When we look at a part that is set up for CNC milling,

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CNC milling is oftentimes a 2D operation as well,

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but it can also get into 45,

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and even more axis of movement.

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But for our purposes,

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let's focus on CNC machining at the 3 axis level.

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Y,

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and Z directions.

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When we look at parts that are designed for CNC machining,

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we want to make sure we understand tool access.

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As we look down from the top of this part,

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everything that needs to be machined

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can be accessible from the tool.

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This means we don't have any areas that are overhanging or

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getting over into the area where the tool needs access to.

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Now,

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even if we do have some overhangs or undercuts,

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that doesn't necessarily mean that we can't still machine it with a 3 axis machine,

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just simply means it requires special or additional tooling to make that happen.

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But for the most part,

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when we look at CNC machined parts,

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they're not going to be a consistent thickness or height,

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but in general,

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they'll have material removed at various Z heights on the part,

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while the tool is moving around in X and Y.

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In addition to CNC milling,

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there's also CNC turning.

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Now,

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there are various

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applications where turning and milling work together,

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and there are many machines that do both things at the same time.

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They'll be able to turn apart as well as machine or mill apart.

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In this case,

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when we're talking about turning,

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we're generally looking at a revolved or cylindrical part,

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something that can be put on a spindle and spun.

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The main difference when we talk about the

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difference between a CNC mill and a CNC lathe

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is that in a mill,

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in general,

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the tool is spinning,

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and on a lathe,

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the material or stock is spinning and the tool is stationary.

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Now,

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as I mentioned,

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there are many variations to these machines,

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so that's not universally true.

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But for the purposes of at least our introduction into this,

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we can think of a turned part as having stationary

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tooling in the stock or the part itself is spinning.

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And a CNC milled part,

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the stock is stationary and the tool is spinning.

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There are other types of manufacture that get into some

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nuances in the specific geometry that needs to be created.

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One of these examples is EDM or electronic discharge or deposition machines.

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When we think about an EDM machine or geometry suited for EDM machines,

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we generally think of geometry that can't

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be manufactured or milled in another fashion.

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For example,

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if we need to cut the square pocket into our part,

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Because the corners are square,

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there's no spinning tool that could get into that corner and cut this.

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Now I say there is no tool.

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There are some very unique tools on the market,

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but as a general term,

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when we have geometry like this that's squared or

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generally difficult or nearly impossible for other manufacturing methods,

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we need to consider something like an EDM

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type machine as the preferred manufacturing method.

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When we're thinking about manufacturing,

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and we're talking about fusion specifically,

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there are many tools that we can use to help us along the way.

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Let's go ahead and focus just on our milling part for this next example.

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When we go to our inspect tools,

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there are 2 main tools in here that we can use for CNC manufacturing,

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and that's the accessibility analysis,

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as well as the minimum radius analysis.

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The other inspection tools,

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such as measure and taking a look at things like the curvature of our part,

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could come into play for CNC machined parts,

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but in general,

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we want to take a look at the accessibility.

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Generally,

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the accessibility is looking at whether or not a tool has access.

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And the direction is gonna be based on the normal direction of our tool.

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This means,

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in most cases,

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the Z axis.

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So when we take a look at this,

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let's go ahead and toggle off the section for you,

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but take a look at accessibility.

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Everything being green

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means that the tool has access to these areas.

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As we rotate it around,

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you can see the bottom is red,

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and that's because

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from that direction,

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the tool does not have access to these areas.

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If we were to redo our accessibility analysis,

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and we were to change our machining direction

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to this side here,

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let's just assume that we put it in the machine this way.

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We can see very quickly that as soon as we get

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to the outside or the outer edge of this diameter,

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the tool no longer has access to these underside areas.

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Also,

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any of these ribs or walls,

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the tool can't get underneath this area,

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and anything in these counterbores or the holes themselves,

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the tool just doesn't have access to from that direction.

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So when we look at a 3 axis CNC machine part,

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we need to consider the tool access in the direction

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of the machine when we're setting up our parts.

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I'm gonna go ahead and hit cancel and turn off the accessibility analysis.

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Next,

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we want to take a look at the inspect tool for minimum radius analysis.

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We're going to select this body here,

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and then we're going to rotate it around and take a look at the green areas.

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If we look at our dialogue,

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we have the optimal minimum radius as 0.25.

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We can also have it target the sharp edges.

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In most cases,

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our machine tools are going to have a square edge on the bottom.

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If they don't,

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we would need to take a look at using other tools

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like a bold nose mill or a ball end mill.

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When we take a look at our dialogue,

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we have an area for minimum radius,

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and then we have the maximum tool radius value.

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We can play around with these toggles changing the minimum tool radius values.

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For example,

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if we wanted to use a 0.375 inch tool as the smallest available tool,

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As we look at this dialogue here,

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we can see that it's telling us the optimum minimum radius is 0.25,

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and as we rotate this around,

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we can see that we've got areas that our tool just won't fit into

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as denoted by these red colors.

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So when we look at this,

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it'll help us plan out the available tools that we may

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have and which tools will be good for our use case.

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And while this specific course and the certification is not intended

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to teach you how to do CNC machining or manufacturing,

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There are a couple of factors that we should always consider.

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For example,

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if we're machining in this corner,

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we don't want to use a tool that's exactly the value of that radius.

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So for example,

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a 1/4 inch radius tool would mean a 0.5 inch diameter tool.

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If we use the exact same radius,

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oftentimes that leads to imperfections in the

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cut and chatter marks on those surfaces.

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So,

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in general,

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for a finishing tool,

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we would likely want to come back with a smaller radius tool

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to finish off those areas.

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It's not gonna be a real factor in the certification,

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but it's just an important note when we're thinking about manufacturing our parts.

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So once again,

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there are many different types of machines and it will be up to you

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to make sure that you do explore various manufacturing methods.

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For our purposes,

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we're looking mainly at things like 2D parts,

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such as water jet and laser cut machines.

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We're looking at turning machines,

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at least at the basic level.

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We're looking at CNC milling machines.

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Most cases will be 2.5 or 3 axis,

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and we're also looking at EDM machines for some hard to manufacture geometry.

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Make sure that you do explore all these different

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machine types and do some research on your own,

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and when you're ready,

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go ahead and move on to the next step.