Microorganism 3D Brass Carving Using Industrial Amana Tool® CNC Router Bits
Part 1 of 2: Tool Path Simulation

Hi folks, let's machine this microorganism piece. The folks over at ToolsToday that we've done some videos for before, wanted to know if we could machine it. It was an STL file that has 600,000 faces or facets to it and it's definitely something I don't normally do, both the file type, but also just the general machining strategy and the outcome. I'm going to talk through some of the things we learned, the cam strategies, how we set this part up, how you can make it. So we relied too much on 3D adaptive strategies.

I really fell in love with this strategy when I started using HSMWorks and now Fusion 360 because it does such a good job of maintaining constant chip load, which is really, really helpful and a very powerful tool path strategy, obviously it can prevent you from breaking tools, it can give you a better service finish, it can really help you dial in your machine whether it's a really small bench top machine or a huge factory machine. The problem is, it's incredibly computing powerful, or takes a lot of computing power to do it and I learned why when I was talking to some of the folks at AutoDesk University and I may botch some of the exact specifics or lingo here, but basically it creates a solid model in the background for every pass or every so often and then it does a comparison, like a before and after. So it creates a little bit of tool path, erodes that away, creates a solid model, does more and then it compares how much was removed versus how much it thought it removed. So it's sort of like iterative, it's like a brute force method, which is really cool and you know computers nowadays can do a lot of that stuff really quickly, but the model here I was doing a 3D adaptive tool path with a one millimeter, that's about 40 thousandths ball end mill for the final pass and I had to let my computer do the cam rendering overnight, it was like 12 hours. And hey, if you need to do that, that's okay, there's nothing necessarily wrong with that, but you're going to see here you can generate a morphed spiral tool path in literally seconds and that's what's also really cool.

So, how do we make this part? We've got a chunk of 360 brass free machining, should be really nice. We're definitely using the 440 because we've got the 10,000 rpm spindle. To start out, we'll use tool number 51402 from ToolsToday, it's a single flute quarter inch end mill. We use that to just rough out the stock around the piece of brass we've got, and then we'll use RC3400, it's a four flute about two and a half inch face mill. It'll give us a really nice finish over the top of the part and then we're going to come in, three sixteenth inch ball end mill and here you can see we can really hog out a lot of material.

Now I'm doing adaptive roughings here and I like to do them in two different passes, it's the same operation. In the first pass I'm going a little slower, 20 inches a minute, and I'm taking a little bit more of a step over here, about 75 thou in a more generous depth of cut. I kind of want to use it as a roughing, hogging out operation. And then I'm duplicating that, same tool, we're going a little faster and we're taking a much finer step over, we're still leaving two thou of radial and axial, because remember, the adaptive roughing strategies aren't finishing strategies. And sometimes they can actually, I don't want to say cut corners, but they're not meant to hug the exact perfect end contour, so you do want to do a finishing type pass.

We're switching here to a tapered one sixteenth inch carbide end mill, we'll use that to come in and again, we're just trying to remove that material out as we get to progressively smaller bits. Now here's a really good question is, I like the adaptive roughing strategy because I feel like it helps me ensure I'm not going to plunge that tool into a bunch of uncut material and potentially chip load it or break it, or just impact a negative surface finish because again we had some deflection because we pushed it in too far. So that's the attractive thing. This one though is taking a few minutes to calculate, so I'm okay with that, but it's starting to get to that point where it's inefficient. Ten thousand rpms, 21 inches a minute, and we're going to do 30 thou step over and just up to no more than .1 inch step down if I can, but the fine step down will be .01 inches here.

And you can see, pretty cool tool path when you look at it. You can now see all those little triangles around the part, right? We'll come back and look at a simulation here in a second. And here you can see the .01 inch step downs that I was referring to, so it'll go down as far as .1 inch, I'll pull this back up here, if it can, but if it starts to see taper it'll say, "Okay, well the operator doesn't want me to go more than .01," so that I can make those stair steps as small as again I want to here, .01 inches. But it's obviously not going to create stair steps or go down .01 if it's a straight wall up and down. And then finally we'll do a morphed spiral, I love this tool path.

Now, how did I pick morphed spiral? Well, I wish I had done this whole thing in Fusion 360. Apparently Fusion 360 can't quite handle the STL file yet, but it definitely can handle the cam side, so I'm hoping that they'll get the STL side sort of up. But I actually used Fusion 360 because they have the great hover over pop-ups and if you just go down through the various cam operations, you'll see morphed spiral. This strategy generally provides a much smoother tool path than scalping.

It's very useful when machining free form or organic surfaces. I can't think of a better example of an organic surface. This literally, somehow the folks at ToolsToday had this made from a microorganism, like some biological thing, it kind of looks to me like moon craters. Kind of cool part though. So, morphed spiral it is.

We're going to do the first one with that same one sixteenth inch end mill, and god it's just beautiful the way it hugs it and goes over that and it generates very quickly. And then the last strategy we'll do is the same morphed spiral, but with this one millimeter or about forty thousandths ball end mill from ToolsToday, part number 46471. All this info is in the video description below, and holy cow, folks, look at this tool path, isn't this beautiful? And what's cool, is we can use stock simulation as a really helpful tool, but let's look at just the regular simulation and we can see...hopefully it'll work okay with the graphics card. So I'll slow it down and let's change the tool path to just show a tail, and if you slow it down a little more, you can really see, we zoom in, I mean it's crazy you can just watch it going over and you can see just how fine a detail this part is.

If we take a look at our stock simulation, again it's a bummer that the screen recording software really makes it difficult to run smooth. What I wanted to emphasize though is you see the colors here and they correspond to the operation, so you can actually watch the part be formed and you can see what operation took material away and you can see at the end, for instance, the cleanup end mill didn't have to go where the bigger end mills earlier could cut everything sufficiently. So here you're starting to see the purple, I wish you could see more easily...they'll describe it here on the left I guess the...yeah you can see the morphed spiral, so here's the second to last operation, this is the one sixteenth end mill in that sort of ugly pea soup color and then the last one will be a green color, which is the morph on the one millimeter ball mill. So you can see here, it doesn't have to cut everywhere, it just has to cut where...or it's not cutting additional material away I guess you should say, because again, some of the bigger areas the whole tool could get to. So, with that folks I hope you learned something. So sit back, relax and enjoy some footage of cutting this brass part here on the Tormach 440.

Watch Part 2 of 2 Here.

Watch as master mechanic John from NYC CNC demonstrate the benefits of using different types of 3D Tool Path Operations when setting up art files for his CNC milling machine.

We provided John the artwork in .STL file format of a Microorganism magnified with a microscope. This file was created by Pierre-Luc Arseneau from CNCcraze.com and has over 600,000 facets!

In this real-world demonstration, John speaks about the pros and cons between 3D Adaptive, Rough Adaptive and Morphed Spiral Tool Paths Operations.

Step 1.
Amana's Solid Carbide Spiral 'O' Flute 1/4" Dia. Aluminum Cutting CNC Router Bit #51402 cuts the top 1/4" of the brass round to a 1" square.

Step 2.
Amana's Insert Solid Carbide Face Milling Aluminum End Mill 2-31/64" Dia. CNC Router Bit #RC-3400 Face Mills the top of the brass for a even surface.

Step 3. (Roughing Pass)
Solid Carbide ZrN Coated Spiral 2D/3D Carving Tapered Ball Nose 3/16" Dia. CNC Router Bit #46298 for a roughing pass.

Step 4. (Finishing Pass)
Solid Carbide ZrN Coated Spiral 2D/3D Carving Tapered Ball Nose 3/16" Dia. CNC Router Bit #46298 for a finishing pass.

Step 5.
Solid Carbide ZrN Coated Spiral 2D/3D Carving Tapered Ball Nose 1/16" Dia. CNC Router Bit #46282 carves out the fine details.

Step 6.
Spiral 2D/3D Carving Tapered Ball Nose 1mm Dia. CNC Router Bit #46471 carves out the extremely fine details.

Feed, Speed & Step Down Technical Information:

Solid Carbide Mirror-Finish Spiral 'O' Flute 1/4" Dia. Aluminum Cutting CNC Router Bit #51402

Feed Rate (IPM): 20"
Speed (RPM): 10,000
Chip Load Per Tooth: 0.001"
Step Down (Per Pass): 0.3"
Width of Cut (Per Pass): 0.1"

Insert Solid Carbide Face Milling Aluminum End Mill 2-31/64" Dia. CNC Router Bit #RC-3400

Feed Rate (IPM): 11"
Speed (RPM): 1,400
Chip Load (Per Tooth): 0.002"
Step Down (Per Pass): 0.01"

Solid Carbide ZrN Coated Spiral 2D/3D Carving Tapered Ball Nose 3/16" Dia. CNC Router Bit #46298 (Roughing Pass)

Feed Rate (IPM): 20"
Speed (RPM): 10,000
Chip Load Per Tooth: 0.001"
Step Down (Per Pass): 0.12"

Solid Carbide ZrN Coated Spiral 2D/3D Carving Tapered Ball Nose 3/16" Dia. CNC Router Bit #46298 (Finishing Pass)

Feed Rate (IPM): 30"
Speed (RPM): 10,000
Chip Load Per Tooth: 0.001"
Step Down (Per Pass): 0.02"

Solid Carbide ZrN Coated Spiral 2D/3D Carving Tapered Ball Nose 1/16" Dia. CNC Router Bit #46282

Feed Rate (IPM): 21"
Speed (RPM): 10,000
Chip Load Per Tooth: 0.001"
Step Down (Per Pass): 0.0625"
Width of Cut (Per Pass): 0.03"

Spiral 2D/3D Carving Tapered Ball Nose 1mm Dia. CNC Router Bit #46471

Feed Rate (IPM): 25"
Speed (RPM): 10,000
Chip Load Per Tooth: 0.001"
Step Down (Per Pass): 0.001"

Watch Part 2 to see the amazingly small Microorganism carved from a 2" wide x 5" heigh piece of brass round into a 1" wide x 1/8" heigh work of art Here.

Microorganism designed by Pierre-Luc Arseneau, visit Pierre's websites http://www.pla3d.com and http://www.CNCcraze.com

Purchase your very own Microorganism plans Here.

Microorganism Built with Amana Tool® CNC Router Bits, by ToolsToday.