2.5D vs 3D

[Rhodan]

I want to make sure I understand the difference between these two labels.

A 3 axis machine is only capable of 2.5D. Although there is cutting depth (the .5D) you cannot rotate the workpiece and come in from any angle you want.

A four axis machine can do 3D but, its not really truly 3D. movement is really along and around a tubular shape.

A five axis machine can do true 3D as its movement is spherical. Other than having to remount the workpiece to get around the holder, you can access just about any place at any angle (omitting, of course, places where there is material between the router and the point where you want to work).

How close is that?

[Rekd]

Close. I think the difference between 2.5 and 3 axis is that they both have 3 axis, but only 2 can move at once on a 2.5 and 3 can move at once on 3 axis.

For example, milling in either XY, XZ or YZ simultanious would be 2.5 axis, and milling in XYZ simultanious would be 3 axis.

A 3 axis machine would be a HAAS and a 2.5 might be a Bridgeport with EZTrak or something.

A 3 axis CAD/CAM package could do 3d surfacing (XYZ simultanious) like Mastercam Level 3, and 2.5 would be up to 2 axis simultanious like Mastercam Level 1, (no surfacing)

[turmite]

Hi Rhodan

It might help to understand what the 3d stands for. 3 dimensional. Rekd is correct on the 2.5 and 3d machining but maybe didn't go far enough. You can do 3d machine work with a 3 axis machine that has a controller capable of moving all three axis simultaneously. A 3d capable machine can machine both 2.5d and 3d. The same is true for a 4 axis or 5 axis machine.

Mike

[ger21]

Normally, 2.5D refers to machining at a fixed Z level. The Z can and does move up and down, but the majority of cutting is done with the Z staying at the cutting depth.

And a 3 axis machine can do 3D, but you'll have to manually reposition it.

3D cutting is just moving all 3 axis together. It's not really about where your machine can reach.

Here's a 3D CAM program for 3 axis machines. http://www.vectric.com/WebSite/Vectr.../c3d_index.htm

[belgrado]

Hello,

I have recently finished my gantry router and started out with mach2 and sheetcam .( they work perfect together ) .
Last week I bought cut3d from vectric and this program does a fantastic job in routing 3d shapes .
I'm using it for guitar building and for some tooling I need like a large radius dish and so . Cut3d does a perfect job and is simple to use it also works great with mach 2 .
I'm going to combine both (sheetcam and cut3d ) in part machining .
First do the 3D surfaces (like top carvings )with cut 3d and than the pocketing and so with sheetcam or similar ( v-carve does 2.5d too ).Make a different toolpath for each operation .
You have to draw 2 different versions of the model or work in layers and also keep the same zero reference point .
These programs work amazingly well and their price is really super value , all 3programs about 600usd together . If I had to do the same work with templates I would spend hours or days on it and it wouldn't be as accurate .
Now I'm making virtual templates and I have endless possibilities .
I'm really enjoying cncing with them .

Greetings ,

Paul