What is surface broaching?
Surface broaching, also known as external broaching, refers to cutting single grooves, multiple grooves, or special shapes on an object’s surface or edge.
When a groove is in the hole, it is a keyway, as shown in the left picture; when it is at the workpiece’s surface, it is a tooth that can be processed by milling or broaching in the right picture.
Types of surface broaching tools
Here are three kinds of most commonly used surface broaching tools.
The piston broach cuts all teeth on the piston at the same time. The cycle time is fast, the size is well-maintained, and the surface finish is good.
All the teeth are cut at once. The angle of teeth is achieved by fixture design. Axisco takes care of the machine, fixture, and rack broach at the same time to ensure the best and stable quality.
Several surface broaching tools are combined in a seat. It is used for cutting several surfaces at the same time.
How does surface broaching work?
- The motion is linear, and the rise of teeth sizes does the cutting feed. The rough and fine cutting can be done in one surface broaching.
- The cutting force is single-sided. It requires a hydraulic fixture to clamp the workpiece. (While in internal broaching, the cutting force comes all around, so no need for clamping.)
Advantages of surface broaching
Time, output, stability, and low skill requirement are significant benefits when using surface broaching to replace the milling process. All these benefits result in a low per-piece cost.
Cycle time is short
Consider those parts which are suitable for surface broaching. If the milling process takes 3 to 4 minutes, the surface broaching takes only about 30 seconds to make the same part. That means you can produce one piece in one-fifth of the original time.
Output is high
Due to the short processing time and the large output per broaching machine, you don’t need to have a lot of workforce and equipment to achieve the same production capacity. That’s why the application of surface broaching is mostly in mass production.y
Precision is high
Roughing and finishing can be done at once, without the need to complete roughing and finishing several times like a milling machine. The surface broaching machine can be processed directly from the rough surface. The size and surface finish after broaching is similar to fine milling.
Operator requirement is low
The custom-designed broaching tool and fixture are on the broaching machine. The operator does not need to do programming or tool calibration before machining. There is no operator to operator variation as well.
Per-piece cost is low
In terms of the same mass-production requirements, surface broaching requires less equipment, fewer operators, fewer skill requirements, and high stability. The overall impact makes the per piece cost of surface broaching very low. Hooray!
Surface Broaching Examples
brake caliper, door closer piston, linear guide slide, car seat angle adjustment part, nail gun, construction parts, and many applications.