CNC Programming Handbook: A Comprehensive Guide to Practical CNC Programming, Second Edition

Throughout the handbook, there have been dozens of programming examples. They all shared one common feature - they were aimed at the vertical machining centers. There was a reason for this approach. First, there are more vertical machining centers in machines shops overall, and mixing two different types of machines would make all reference material more complex. Second, almost every subject covered so far for the vertical models is equally applicable to the horizontal models. So what are the differences?
The horizontal machining center mainly differs from a vertical machining center in its general functionality. While a vertical machine is mostly used for only one face type of work, a horizontal machine is used for work on many faces of the part during a single setup. This feature alone makes a horizontal machining center a much more versatile machine - and also more expensive. Figure 46-1 shows the comparison of the axis orientation.
From the illustration is clear that all the XY plane is used for the primary plane of work and the Z axis is used to control cutting depth. There is no difference whatsoever between the two machine types in this respect.
Between programming and setup, there are three major differences on a horizontal machining center:
Presence of a fourth axis, typically an indexing B axis
Presence of a pallet changer
Richer variety of setup and offset settings
First, a brief look at the fourth axis of...