What is 2.5D?

[zrrigid]

I have been looking at CAM software and was curious what the difference between 2.5D and 3D is. I was looking at onecnc and I am looking for suggestions. I am already using Solidworks for CAD and I have Tree 3100 with a Anilam 1100 control.

[One of Many]

Several descriptions exist. Some say that 2.5D is where the Z is powered but is not directly controlled as an axis. Others say the Z is displayed as a DRO without motor control. In any effect, the Z axis is not capable of interpolated moves.

DC

[ghynes]

2.5D is used to describe a 3D object that can be machined with a 3axis milling machine or router. The produced object has 3 dimemnsions as far as width length and height HOWEVER, as the machine that produced it had only 3axis there are no undercut or overhanging features. To produce most complex 3D machined objects requires more than 3 Axis. So 2.5D 3 axis machines can produce some simple objects with 3 Dimensions but not more complex 3D objects. A minimum of 4axis but 5 or 6 is better to produce complex 3D objects.

Hope that helps.

Gerald

[Ciaran]

Hi,I am using a 2.5D Gibbs Cam package for the last 8 years and have found it excellent.Basically you draw up in 2d in the gibbs or import in a dxf cad drawing in 2d into the gibbs and use this drawing to do your cnc program by just selecting cutter type etc and set your depth for machining and it will do it.Very basic but here is where it gets good,If you have a rectangular hole that you want to mill with a draft angle on the inside you can using a standard endmill to contour(take small cuts) and create the desired shape.The problem with this program is that if one wall of the rectangular hole needs to be a different angle it will NOT do it.Also if you want to cut a curved shape into the wall you can do this by also drawing somewhere seperate on the screen a "drive curve" so you select your rectangle and instead of giving it a zdepth and angle you select what is called a swept shape and it will cut the rectangular pocket with a drivecurved wall.I think Gibbs do a direct input version for solidworks models that is very reasonable.Remember to ask whoever is supplying your software do they have a postproccesor to suit your machine and its controller.Hope this helps.Regards.

[Usama Handal]

Hi, I think that in 2.5D you can control the Z axis to move down in deferent distance, which means that for example red lines move 1 cm while blue moves for 1.5 cm and so on. While in 3D you can let Z axiz move curves , to make 3D projects.
Good luck

Usama

[Usama Handal]

Originally Posted by zrrigid I have been looking at CAM software and was curious what the difference between 2.5D and 3D is. I was looking at onecnc and I am looking for suggestions. I am already using Solidworks for CAD and I have Tree 3100 with a Anilam 1100 control.

Hi , I have and I use 2.5D to move the z axis to different depth which means red color for example moves Z axis 1cm while blue moves Z 1.5cm and so on.

3D you can make curves movement which means you can make 3D modeling.

Good luck .

Usama

[Malafarina]

Originally Posted by zrrigid I have been looking at CAM software and was curious what the difference between 2.5D and 3D is. I was looking at onecnc and I am looking for suggestions. I am already using Solidworks for CAD and I have Tree 3100 with a Anilam 1100 control.

Generally 2.5" refers to X, Y and Z motion with the ability to have B axis rotation programmed as well. 3D generally refers to full three dimensional machining such as you would find in a 5 axis mill. Packages such as Pro/NC and Master Cam that support solid modeling will provide full 3D machining.

[ataxy]

weird from what i heard .5 axis machine like 2.5 i machine where only two of the axis can work at ounce the third only position it self

[DareBee]

I agree with Ataxy and Usama.
Plain and simple
- a 3 axis machine can move ALL 3 AXIS SIMULTANEOUSLY.

- a 2.5 axis machine has a z axis that is CNC controlled to be used for drilling and positioning to desired depth of cut. A carefully programmed 2.5D process will make parts as good as doing it in 3D. Lets call this "CONSTANT Z LEVEL CUTTING". You can make undercuts perfectly fine with 2.5D as well.

- a 2 axis machine has NO CNC CONTROL over the z axis and must be manually positioned. IMO this type of machine is a waste of good money

[johnatl@mac.com]

http://en.wikipedia.org/wiki/2.5D#Machining

[cadman]

2.5, 3, 4, 5 axis refers to the number of axis a machine can interplolate simultaneously. 2.5 axis machines can generally only interplolate X&Y before doing a Z movement. These machines cannot do helical interploation motion like thread milling, helical entries, etc...

Some 3D toolpaths are 2.5 axis movements, so you still have some ability to do 3D machining on these machines.

Basically what Darebee said above.

[cncwhiz]

I run "pro nc" and do threadmills all the time? I have not run into anything with 2.5 in pro that it will not do using "X, Y and Z"? I also program "4 axis" machines with one axis being an indexing axis?

Cncwhiz