Indexable-insert ballnose endmills for high-speed finishing of molds can be purchased as individual units from a standard endmill catalog, or assembled from components of available modular end-milling systems.

The modular systems offer the advantage of broad application flexibility, based on a wide range of available insert grades and geometries and a large selection of shank types, styles and lengths. The tooling components can be combined to provide the best possible solution for particular moldmaking requirements.

Among the modular endmilling systems now available for moldmaking applications are two-piece, indexable-insert endmills specifically designed for copy-milling operations, which consist of steel shanks in different lengths and screw-in cutting heads in various styles using indexable inserts.

As a whole, the two-piece modular endmilling systems can meet virtually any mold and die copymilling requirements – including high-speed finishing of molds. For example, cutting heads in the traditional 90-degree ballnose style are available in both a standard design for high-speed semifinish and finish contouring, and a helical-flute design for deeper cuts or sidewall milling. The latter design, in which inserts on the periphery of the cutter head are arranged in helical flutes, provides very smooth, vibration-free rough machining of hardened materials.

Another important asset in the two-piece cutter line is a new 120-degree ballnose cutting head that can be used for both full 3-D cutting and high-speed semifinishing of vertical walls. Up to now, vertical walls have been a stumbling block to productive high-speed finishing of molds and dies. The conventional 90-degree ballnose endmills traditionally used to machine these features must be retracted after every downward stroke, interrupting the machining cycle and subjecting the cutter to rubbing and insert wear.

By contrast, the 120-degree cutting head is designed with edges that extend beyond the tool shank and the stem of the cutting blade. This enables the cutter to take cuts on the back as well as the front of its edge, allowing it to remove metal in a consecutive series of downstrokes and upstrokes. The new machining technique not only provides an uninterrupted and faster machining cycle, but also eliminates cutter rubbing and insert wear, resulting in longer tool life and better surface finish.