The five-axis milling process continues to expand and evolve as machine tools and tooling become more capable. As an example, I recently learned about a new workholding system introduced to the market by EMUGE-FRANKEN USA in 2025 that features new vises for five-axis milling that are capable of considerably more clamping force than those offered by other companies. Before I fully explain the significance of this increased capability — to me, at least — it would help for you to know the technological advancements I have witnessed throughout my career.

When I went to engineering school in the 1960s, I learned Fortran programming using IBM punch cards to communicate with a computer that had a footprint of 300 square feet. When I started my shop, the first machines I bought were a manual milling machine and lathe. I soon learned about computer numerical control and that CNC milling machines could do linear and circular interpolation of the different axes on a three-axis mill. That simplified my work and increased my income.

At that time five-axis milling was impractical. The computer power and memory were not up to the task. Then the PC revolution changed all that. Now I have a cell phone with orders of magnitude more processing power and data storage than my first computer — an IBM mainframe owned by the University of Massachusetts and housed on the second floor of the engineering lab building.

These days, five-axis milling has become not only practical but attractive.

To be clear, I’m talking about five-axis milling machines that have three linear axes of motion — X, Y and Z — and have a trunnion, rotary table assembly attached to the X and Y drive mechanisms in place of a rectangular T-slot table. The trunnion and rotary table provide two axes of rotary motion, A and B. The A axis of the trunnion is parallel to the X axis, and the rotary table is mounted to the trunnion so that the face of the rotary table is parallel to the X-Y plane when the trunnion is at 0°. The trunnion may rotate 90° or alternately +/-90°. In either case, the face of the rotary table becomes parallel to the X-Z plane. With this degree of motion, a cube held against the face of the rotary table can have its top and four sides positioned by the rotary motion for machining. Then each of the five faces can be machined by the X, Y and Z motion of the mill. Various intermediate angular positions can be indexed — or different axes can be interpolated — so in one setup a part like the one shown in figure 1 can be made.

For the part in figure 1, the workpiece is mounted into the vises, then the start button is pushed. Now the operator is free to work on other tasks until the job is finished. The part is completed by removing the two standoffs that were created in the five-axis machining process. That’s productivity.

Figure 1

Another thing: spiral toolpaths can be generated when an axis of rotary motion is interpolated with an axis of linear motion. That is the correct geometry for mechanical devices that move fluids such as boat propellors, centrifugal pump impellers and turbine blades.

Back to Workholding

EMUGE’s new workholding system, EvoGrip, is specifically designed for five-axis milling. It includes nine different vises, base plates with zero position indexing, riser blocks and a large variety of vise jaws. It is all designed to allow maximum accessibility of a cutting tool to the workpiece.

With five-axis milling it is advantageous to grip the workpiece with a small clamping surface area. If the clamping area of a workpiece has indentations that mate with protrusions on the face of the jaws that clamp the part, more workholding force can be produced per unit of surface area than would be possible on a workpiece with smooth surfaces. For this reason, hydraulic presses are used to indent the surface of a workpiece for gripping before the part is mounted into a vise.

EMUGE’s new vises can produce enough force so that the surface of a workpiece can be indented in the vise on the milling machine. That is a bit of evolution in workholding technology. Even though the part in figure 1 sticks out of the vises a considerable distance in the Z direction, two EvoGrip vises can be used so the part can be made safely, to spec and in a good cycle time.

In next month’s column I’ll get into the nuts and bolts of this new modular workholding system.