A broach drill, also known as a rotary broach form drill, is a specialized and innovative tool in the field of machining. It combines the functions of a traditional drill and a broach, designed to streamline the process of creating non - round holes, especially hexagon and square holes, in various materials such as metals and plastics.
Working Principle
The broach drill operates based on a unique principle. First, it drills a pilot hole. The diameter of this pilot hole is a crucial factor. For rotary broaching, the optimal pilot hole diameter is approximately three percent larger than the flat - to - flat dimensions of the intended hexagon or square shape. This oversize pilot hole enables individual chips to curl into the hole, reducing the amount of material that needs to be removed during the subsequent broaching process. As a result, less force is required by the machine to push the broach into the hole.
Moreover, the profile of the broach drill creates a chamfer at the opening of the hole. This chamfer is essential for rotary broaching as it allows the broach to easily start curling a chip at each corner of the non - round shape, such as a hexagon. In traditional machining, creating this chamfer often requires a separate cutting tool, but the broach drill eliminates this additional step, saving both time and the need for an extra tool in the machining operation.
Another feature related to its working principle is the depth of the drill. The depth of the broach drill is predetermined, usually about one and a half times the flat - to - flat dimension of the hexagon or square. Since most non - round holes are broached to a depth of only one time the flat - to - flat dimension, the extra depth provides space for chips to curl up inside the hole without interfering with the broaching operation. This is particularly useful when working with soft materials like aluminum and mild steel, where chips can easily compact.
Applications
1. Aerospace Industry:
In the manufacturing of custom aerospace fasteners, where high - precision and reliable components are crucial. The broach drill can be used to create accurate hexagon or square holes for bolts and other fasteners, ensuring a proper fit and high - strength connection.
2. Medical Device Manufacturing:
For example, in the production of orthopedic bone screws. The ability to create precise non - round holes in the screws using a broach drill helps in achieving better fixation and compatibility with the bone structure.
3. Hydraulic Fittings:
Broach drills are used to create holes in hydraulic fittings, which often require non - round shapes to ensure a tight seal and efficient fluid transfer.
Advantages
1. Lean Manufacturing Benefits:
The broach drill simplifies the manufacturing process by eliminating the need for multiple operations and tools. It reduces the calculations related to pilot hole depth and diameter, cuts down on the requirement for additional chamfering tools, and decreases cutting tool inventory. This not only saves costs but also frees up valuable machine tool positions.
2. High - Precision Results:
By integrating the drilling and broaching functions, it can achieve consistent and accurate non - round hole shapes, meeting the strict tolerances required in industries like aerospace and medical device manufacturing.
3. Time - Saving:
The elimination of multiple steps and tools shortens the overall machining time, making it more efficient for high - volume production scenarios.
Wuxi Geepro Gear Technology Co.,Ltd. was founded in 2016, with the research and development, processing and sales of gears and gear machinery and equipment as the main business direction.
