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Taking on Tough Internal and External Shape Making

Tough materials such as hardened steel and high-temperature alloys pose challenges for machining applications of all types. This is also true for rotary broaching, a rapid manufacturing technique that creates ID and OD shapes in one pass and in seconds on any CNC lathe or machining center. Due to its ease and speed, rotary broaching is generally the preferred method used to cut shapes in metal, however hardened steels and excessive cutting depths can limit feasibility. Where rotary broaching leaves off, indexable punch broaching picks up.

Punch broaching is a manufacturing process of material removal in which a partial form broach creates a shape in a part by punching or shaping the material. Similar to the shaping process, the broach tool reciprocates in the stationary workpiece using the peck mode on the machine to rapidly remove material. This method of broaching is most beneficial for applications requiring no witness (pre-drill) marks, little room for chips, tougher materials, excessive material removal, or where timing the form to a feature on the part is required. Slater Tools’ indexable punch broaches meet the challenges posed by these types of applications to effectively machine keyways, hexagons, Torx-style sixlobes, serrations, splines and squares. Manufacturers utilizing punch broaches can expect high repeatability on lathes, milling machines and presses.

Key to the punch broaching application is the punch broach and indexable punch tool holder. Unlike rotary broaching where the machine spindle is rotating, with punch broaching the part and broach are held stationary. Punch broaching produces ID or OD shapes by moving a single point or dual point broach cutting tool in a reciprocating motion using the peck mode on the machine and indexing, which greatly reduces cutting pressure. By using partial form broach tools and indexing either the tool or the workpiece, Slater’s punch broach holders provide the rigidity necessary to make this type of machining successful and prevents the broach or holder from backing up from pressure. The punch broach holder is precision ground and has multiple flats for easier indicating of the tool and increased repeatability. This is especially helpful in applications that need to have the form timed to another feature in the workpiece.

Punch broaching is gaining favor in several industries in particular, such as aerospace and medical where creating full forms without witness marks in difficult materials has become a common practice. Punch broaching can also offer an economic advantage over alternative methods of shape making. Punch broaches can produce shapes that are otherwise only achievable through EDM or pull broaching-both very costly methods of manufacturing, especially for smaller quantity productions. Punch broach tools are offered at a fraction of the cost with same day turn around.

Slater Tools offers same day quotes for all custom punch broaches. Give us a call at (586) 465-5000 or send us at email at to speak with one of our machining specialists about your next order. For more machining tips, visit or follow us on Facebook.