Thread: 2d vs 2.5d vs 3d

1. 2d vs 2.5d vs 3d

Ok, I've been reading a lot the last several days trying to understand all this stuff before I go asking about mills and I've gotten a little confused. I think I understand the differences in 2d vs 2.5d and 3d. (2d being one level cut, 2.5d being multilevel cut but not changing z during the pass and 3d being all axis can change during the pass?)

So why aren't all 3 axis mills 3d? Or are they and it's g-code dependent? Sorry, I know this is a very basic question but it seems to be eluding me.

I guess I should've started with this since this is my first post. The name is Jarrett, I am wanting to get a cnc mill to learn with but I'm trying to learn all I can about them before I bug you guys about which mill and what not. I have some (very limited but enough to do the basics) manual mill experience. I'm into speaker building and am wanting to try some custom curved boxes and that's really about all the justification I have right now. I thought it would make a decent excuse to get one to learn with.

Thanks in advance. I have already learned a lot on here in the last week.

Jarrett

2. Some machine controls cannot move 3 axes simultaneously. Some can.

Some CAM software will output code to move 3 axes simultaneously, while some will only move X & Y with Z at a constant value.

3. 2D , 2.5D , 3D
2 axis , 2.5 axis , 3 axis

when ever you see a half axis being referenced it's referring to an axis that is put into a position before the other axis are moved

2 axis , most likely referring to a lathe

2.5 axis, most common , a milling machine where ("Z" the working spindle) is brought to a location before "X" and "Y" are moved

3 axis, most common , a milling machine where all axis can be moved simultaneously

4. Ok so then I guess my next question is, are all 3 axis mills nowadays capable of moving all axis at the same time?

5. 2.5D vs 3D is really more of a CAM software difference, as virtually all machines can do 3 axis machining.

6. I have never seen a 2.5 D machine unless you want to count a Bridgeport conversion that only had servos on X and Y and the machine would pause for Z while the operator physically positioned the quill, either for drilling or milling.

7. Ah ok. thanks guys for the help. Back to reading for a while. I'm sure I'll be back with more questions

8. Originally Posted by holbieone
2D , 2.5D , 3D
2 axis , 2.5 axis , 3 axis

when ever you see a half axis being referenced it's referring to an axis that is put into a position before the other axis are moved

2 axis , most likely referring to a lathe

2.5 axis, most common , a milling machine where ("Z" the working spindle) is brought to a location before "X" and "Y" are moved

3 axis, most common , a milling machine where all axis can be moved simultaneously
Thanks. This is the most understandable, straight forward definition I have seen.

9. Originally Posted by Gt3
Ok so then I guess my next question is, are all 3 axis mills nowadays capable of moving all axis at the same time?

Some of the older toolroom mills (CNC kneemills) had inexpensive controls and/or no control board to interlock Z with XorY. The mechanics were there but computer and control cards werent.

Hence 2.5D ONLY allowed on the machine side.

10. Originally Posted by Gt3
that's really about all the justification I have right now. I thought it would make a decent excuse to get one to learn with.
Jarrett
I feel your pain on the software side of CNC. Trying to figure out all the terms and what is available on the CAD and CAM side.

I went with ViaCad 2D for pure simplicity and figure I would work up from there. I have made couple parts with it and it's extremely easy to use. I may jump up to the 3D version but probably will end up with Alibre for \$199.

Also fumbling my way through CamBam.

I too have no real reason to own a CNC machine other than I have a project that needs 16 identical parts (to my standards)....That was my excuse!
Plus the COOL factor.

11. I may jump up to the 3D version but probably will end up with Aspire for \$199.
Aspire is \$1995.00

12. Originally Posted by ger21
Aspire is \$1995.00
You are right. I knew it started with an A.

I meant Alibre

NO \$1995 for me.
Thanks for the correction also edited my post.

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