A SUMMARY OF MILL-TURN TECHNOLOGY
MILL-TURN MACHINES: WHAT ARE They?
The different types of mill-turn machines range from the more basic 3-axis lathes (XZ&C), where the spindle is turned into a separate axis that can be rotated for milling operations, to the more sophisticated 6-axis machines, which also have a secondary programmable sub-spindle or counter-spindle and a linear Y-axis. The W-axis is used to position the secondary spindle for machining on machines that have one.
The Y-axis is really mounted using a narrowly angled "wedge" design, as seen in the image above, although even on machines with this kind of layout, the Y-axis always moves perpendicular to the X-axis.
Knowing when a Y-axis is required and when a particular feature may be produced on a simpler 3-axis machine using only the C-axis is a common question surrounding mill-turn technology. Basically, a Y-axis is only required when the tool must be withdrawn from the part's centerline, and even then, it is frequently only required for features being machined into the part's circumference. Typically, only the C-axis needs to be used to complete features on the part's face.
The portions shown below are excellent illustrations of features that can be added simply by include the C-axis. The C-axis can position itself so that the X-axis can move into place and machine the feature even when the holes shown in the blueprint are not on the centerline of the part.
The components shown below have features that call for a Y-axis. Again, the Y-axis, which is parallel to the X-axis and may be used to move the tool above or below center, can be used to move the tool up or down. Although the flats on the brass part might potentially be machined using only the C-axis, a Y-axis would be more appropriate for this feature due to its location in the middle of the part. The Y-axis would unquestionably be required to profile the part's rounded yoke edges on the end.
The flats on the second section would have to be milled with the part oriented as in the top image. therefore it is clear that in order to cut this specific profile, the tool would need to be lifted above center.
