What does a 4-axis CNC machine look like?

[snooper]

Could someone please describe/post pics on the general layout of a typical 4-axis machine? And perhaps the same with 5 and 6 axis? I'm still a noob, so anything above 3 axis still tends to flatten my head...

[ataxy]

the 4, 5 and 6 axis are rotational axis so 1, 2 and 3 move back and forth on the x, y and z axis while 4, 5 and 6 moves around them

[Geof]

Originally Posted by snooper Could someone please describe/post pics on the general layout of a typical 4-axis machine?.....

Four axis is fairly simple; there is a rotary mechanism with an axis (normally) oriented parallel to the X axis of the machine. The 4th axis can be used just for positioning parts so they can be machined in different orientations as the pictures show. The first picture is parts that are slotted in one orientation and then drilled and counterbored in a position 90 degrees to the slot. Using a rotary axis allowed these operations to be done in a single fixturing. The second picture shows lengths of aluminum round bar that just gets machined to length and tapped in each end. Doing it this way on lengths that were cut off on a high speed bandsaw was much quicker than facing and tapping each end in a lathe.

The 4th axis can also be run under full program control so complex shapes can be sculpted. I don't have any examples nor do I have any five axis examples.

[Max]

Snooper,
May I suggest this website ... it has alot of good info along with pics of working DIY 5-axis machines, software and what it is capable of producing.
http://www.rainnea.com/cnc.htm

[snooper]

Geof,

So if I understand correctly, an item can be milled on its top side, then flipped over (or even rotated through 90 degrees) and milled on the other side? (E.g. aircraft model)

[ataxy]

Humm almost the side that sits on the table cannot be machine but all other side can but this image does represent all 6 axis where xyz = 123 and abc =456


actualy that little 5 axis milling in the www.rainnea.com website is quite nice

[Walt@SGS.Inc]

Lets see as I remember.......
Speaking of horzontal machining centers...
X axis travels parallel with the horizon.
Z axis travels perpendicular to X axis and parallel to the centerline of the spindle.
Y axis travels perpendicular to Z axis and perpendicular to the center line of spindle,
as well as perpendicular to the travel of X axis.
Therefore, X axis left and right (looking at the face of the spindle,
Z axis in and out along the center line of the spindle,
Y axis up and down perpendicular to the centerline of the spindle.
In the case of some bigger machines, their is a W Axis. This is when the spindle can
move in and out and the table can move in and out also. One will be W and the other one will be Z axis. Sometimes the column will move in and out and the spindle will move in and out also, then if the table moves in anbd out also, they will designate one axis w and the other one w' as well as the z axis. "w and w prime".

Then you have to talk about the rotary axies.
On a four axis machine, usually the table that rotates with its centerline parallel to the travel of Y axis. would be referred to as B axis.
If the spindle mounted on Y axis is able to rotate from the horizontal position to a vertical position with its centerline parallel to X axis, it would be referred to as A axis.
C axis would be like a rotary table mounted so the centerline of the rotation would be parallel to the centerline of the spindle when it is in the horizontal position.
I think that is what I remember..
Nappy time Regards Walt

PS Post # 6 shows a vertical machining center. Z axis up and down...

[Geof]

Originally Posted by snooper Geof, So if I understand correctly, an item can be milled on its top side, then flipped over (or even rotated through 90 degrees) and milled on the other side? (E.g. aircraft model)

The answer is yes-but.

The BUT is ... but you have to be able to hold it and sometimes this is not easy. Once you have sorted out the holding problem you can do shapes like that either using all four axes simultaneously or you can divide it into halves or quarters and do these with three axes and just use the 4th to rotate it into the new position.

[snooper]

Max,
Thanks for the link, but I seem to have trouble accessing it... Maybe I'm clicking on it with the wrong button! I'd appreciate any similar links that you might offer.

[Switcher]

It looks like the example in Post#6 is straight to the point! Just remember, that the "X,Y,Z-axis" are Linear moves, and the "A,B,C-axis" are in degrees.

I think the most used fourth axis is the "A-axis", which is actually very simple, it can rotate 360 degrees (just like a variable spindle).

.

[Walt@SGS.Inc]

On a horizontal milling machine, I would think the B axis rotary table would be the most used. XYZ and B.
Just my opinion.
Regards Walt.

[Zumba]

Walt, why would a B-axis table be used in that scenario? I think you mean A-axis.

BTW, some machine controllers refer to the spindle as the C-axis. Don't get this confused with a rotary table flat on its back facing up, which is also the C-axis.

A trunnion table (see the Haas website for pics) combines an A-axis and C-axis. Using such a table would effectively give you a 5-axis machine.

However, when people speak of 5-axis machines, they're usually talking about machines with articulating heads. That is, the spindle tilts left/right along the X-axis and forward/backward along the Y-axis. These machines are capable of carving out 3-D objects, such as car body models, without moving the workpiece.