I have loaded a 3D topographic model of the White Mountains into Fusion 360

[allanpoole]

I want to cut a 3d model out of wood for a gift. I would like to learn how to reduce or enlarge the model and also reduce or enlarge the z movement independent from the XY scale, if that's possible. I have never done roughing and finishing cuts but thought I would use a 1/4" end mill then a 1/8" angle bit for finishing. would like to work with a Z maximum depth of 2 to 4 inches. I would appreciate help with this. 

[engineguy]

@allanpoole 

Always best if you can upload a file so that best advice can be given 🙂

To upload a file go to :-

File > Export > Select f3d Format > Save to a location on your computer > Then attach to your reply

You can use the "Scale" function in Design Mode which is found under the Modify tab as shown in the image below.

The Z axis movements can be set to different Stepover/Stepdown under the Heights and Passes tabs in the Manufacture mode.

[allanpoole]

Your suggestion for scaling keeping the aspect ratio the same worked for me. Thanks! I have ben able to scale the model( which was originally maybe 25' square) down to 25" square but I don't see how I can down scale the Z span independent of the other 2. From my meager experience, in Manufacturing mode, if I  limit the depth of the z movement  it will not cut all the way to the valleys of the topography. What would you recommend for tools and how do I first do a roughing pass with maybe a 1/4" flat end mill and then a finishing path with some kind of smaller tool? Should I use round tipped tools? Thanks so much for your help.

Allan

[j.mitch97]

Hi @allanpoole,

Could you use the non-uniform scale to adjust your z (height)? 

It's hard to recommend tools and toolpaths without seeing the model or photos. can you upload something? 

if you are able to upload the model @engineguy, I and others might be able to recommend some good toolpaths for you.

[allanpoole]

here is a 19 centimeter almost square 3d model of what I presume is the central White Mountains. I can go back to the original and scale it down to about 24 inches square. At that scale, the wood stock height would be about 6" high. I have only done simple rectilinear wood joints and plaining so far with a 1/4" flat end mill bit. What do you recommend for tools, roughing, steps etc.? My cousin has hiked all of these every month of the year. He would be thrilled to have a model! Can I scale back up from this or do I work from a scaled down model of the original model. I have a home made machine with a 24000 rpm spindle running off Mach 3. Thanks

Allan Poole

[engineguy]

@allanpoole 

I have looked at your file and done a couple of example toolpaths, a 3D Adaptive with a 1/4in End mill to rough it out and a Parallel with a 1/8in Ball End mill to get the shape as close as possible, at 100in/min feedrate your small model takes around 4 Hours to machine so a 24in square is likely to take a lot longer although you should be able to use a larger tool for the Roughing.

However, the closer that you want the finished shape to be to the Model will depend on two things, one is the smallest "valley" that you need to get into and the amount of stepover you need for best finish, the smaller the stepover the better the finish but the longer it will take to machine.

I have no idea how good your machine is so can`t give you any help with Feeds/Speeds etc, when doing this type of 3D machining the Z Axis will be doing a tremendous amount of movement to follow the shape, so if it is Stepper Motors then they may not be up to the task and you may ned to slow everything down if you get problems,the attached file is just an example of how it can be done.

Another thing that can be an issue is the time it takes to generate these large type of toolpaths, all depends on how powerful your computer is 🙂 🙂 🙂

The first image below shows the Roughing and the Finishing shapes, the second image shows the Finishing Parallel toolpath following the Model shape, hope this is of some use to you if only to point to possible types of toolpaths that could be used 🙂 🙂 🙂

For what it`s worth I would go back to the start and scale the Original Model to the size that you want 🙂

Rough is Green-Finish is Blue