Broaching Tools

Harnessing The Power of Broaching Tools: A Versatile Machining Process


Broaching tools are cutting tools used in the broaching process to cut or shape metal and other materials by linear relative motion. The broaching tool is pushed or pulled through the workpiece to remove metal by shearing. There are different types based on their design and broaching operation:

– Single-line Tools: These are the most common type of tools used for simple shapes with straight or slightly curved sides. Single-line tools cut in a straight line motion.

– Multi-line Tools: For complex shapes that require angles or contours, multi-line broaching tools are used. They have staggered teeth that cut in different directions allowing for shapes beyond straight lines.

– Insert Broaching Tools: These use replaceable cutting inserts much like turning or milling tools. The insert broaches have removable tips that can be replaced when worn out extending the life of the tool.

– Pull Broaching Tools: As the name suggests, they are pulled through the workpiece from one end to the other during broaching. They are usually used for internal broaching operations.

– Push Broaching Tools: They are pushed through the workpiece from one end to the other. They are commonly used for external broaching operations and places where pulling a broach is not feasible.

Applications of Broaching

Broaching is used in a variety of industries for machining linear slots, keyways, splines, and other shapes in metal parts. Some common applications of broaching include:

– Gear Tooth Forming: Broaching is the primary machining method used for shaping gear teeth on internal and external gears. It produces gears with high accuracy and finish.

– Keyway Cutting: Keyways arecut in metal shafts and hubs using Broaching Tools.Keyways produced by broaching provide a tight, precise fit for keys.

– Splines: Splines are machined features that mate two parts like a transmission. Broaching produces high-quality, tight-fitting splines.

– Internal Keyways and Slots: Broaching is well-suited for producing internal keyways, slots and undercuts in closed-geometry parts.

– Surface Finishing: Broaching can provide an extremely smooth finish to metal parts. It is often used for the final finishing pass on gears, splines and other precision metal components.

Advantages of Broaching

There are several advantages that make broaching a useful machining process compared to other subtractive operations:

– Accuracy and Precision: Broaching produces parts with very high dimensional accuracy, often within a few millionths of an inch. The cutting action yields an extremely precise fit.

– Surface Finish: Broaching provides outstanding surface finishes, usually 16-32 microinches Ra or better depending on the tool design.

– Productivity: Once setup is complete, they can quickly remove metal in production runs. Cycle times per part are usually short compared to machining individual teeth.

– Repeatability: Broaching results in highly repeatable dimensions from part to part. Complex shapes can be duplicated successfully.

– Material Removal Rate: Broaching removes material at a relatively high rate given the cutting action. Production throughput is maximized.

– Applicability: Broaching can produce internal and external features on a variety of metals including low-carbon and alloy steels, aluminum, copper, and more.

Disadvantages of Broaching

While broaching offers many machining advantages, it also has some drawbacks to consider:

– Setup and Tooling Cost: Broaching tooling is complex and expensive to design and build. Setup and prove-out also requires skilled labor and time.

– Tool Life: They have a finite lifespan and tooth cuts wear over time, reducing accuracy. Tools must be replaced or reshaped.

– Complex Shapes: Very complex three-dimensional shapes may not be suitable for broaching depending on access angles required.

– Machine Requirement: Broaching requires a specialized broaching machine with rigid components for precise linear control over long strokes.

– Non-Traditional Shapes: Unusual non-linear profiles may be difficult or impossible to produce through broaching alone.

Broaching tools can efficiently and accurately cut a wide variety of straight-sided features and profiles in metal parts. Though the upfront costs are higher, broaching delivers repeatability, precision and efficiency ideally suited for high-production machining applications. With the right process design, broaching remains a valuable subtractive manufacturing technology.

1.  Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it