Broaches

Nanodynamic Broach

Features

1. Super-hard coated to maximize the tool life (twice as long as that when TiN coated).
2. The flaking of broached workpieces tooth surface is reduced thanks to the significant improvement of brooches tooth roughness to Ra 0.03 µm.

Surface roughness

Performance

Flaking of workpieces is reduced and the tool life is improved as twice as conventional TIN coated broaches.

Broach size and material	φ25mmｘL1500mm　MAC-A
The tooth measured for wear	#31 finish teeth

Constant Cutting Force Broach

Features

1. Stable broaching with constant cutting force of the roughing teeth
2. Lowering the cutting force setting will give less impact to the existing machine and allow the use of a lower rank compact machine.
3. Increasing the cutting force setting will maximize the performance of existing machine leading to shorter tool length and less machining time.

Samples

Work piece	DP24/48
	PA30°
	NT30
	cutting length 23.5mm
	S48C
Broach	Involute spline broach
	Φ33 x L900
	SKH51

Burr-free Broach

Features

1. The original designed of cutting teeth can minimize occurrence of burr.
2. The original super-hard material with excellent grinding performance can ensure prolonged cutting edge sharpness.

Samples

Work piece	m2.0
	PA20°
	NT30
	cutting length 18.1mm
	SCM420
Broach	Involute spline broach
	Φ65 x L1350mm

Fir Tree Broach

Features

Using technologies and know-how developed through the long year experience of supporting aircraft and turbine manufacturing industries, we can provide high-precision and high-quality products.

1. High precision can be obtained with the original optimized design based on our rich experience and advanced technologies.
2. Long tool life achieved by adopting high-alloy powder high-speed steel for difficult-to-machine materials
3. High reliability ensured by the dedicated line equipped with the advanced NC gear grinding machine and sharpening machine

Processing by broaches

Processing by internal broaches

The internal broach can make up the specific shape of work piece internal surface efficiently and with high precision.
Normally the internal broach is inserted into a pilot hole which is made on the work piece before machining. Various kinds of hole can be created by selecting the optimum cutting edge shape and cutting method (for example, round hole, square hole, polygon hole and various kinds of spline hole and tapered hole)

Samples of machining result

Samples of machining result

Processing by surface broaches

The surface broach can make up the specific shape of work piece outer surface efficiently and with high precision.
Roughing and finishing can be conducted at the same time, which means significantly higher productivity than milling, plaining and grinding.
It can machine many kinds of shape (for example, plane surface, contour surface, various kinds of groove, concave-convex surface, gear, turbine blade root, and turbine disk groove) and their outline can be either simple such as keyway or complex such as fir tree shape.

Examples of machining result

Examples of machining result

Cutting method

Types of Broaches with Round Teeth

Hardness of Work piece

Hardness of work piece suitable for broaching is generally HB200 to 230 (HRC14 to 21).
Also up to HB300 (HRC32) is used popularly. Too soft steel may cause adhesion on the side of tooth or the land resulting in low quality of finishing surface with tear or flake. Harder work piece than HB300 may shorten the life of broach.

Cutting Speed

The cutting speed has an influence in both the accuracy of broaching and the tool life. Use the recommended values for each material shown below as the guide to determine the cutting speed.

Recommended cutting speed by materials

How to Resharpen Broach Teeth

Timing of resharpening

Resharpen the teeth normally when the symptoms as below occurred in the broach, work piece and broaching machine.
In practical ways, use the number of machined work pieces as a standard when the symptoms appear.

Cautions for resharpening

Grinding wheel angle for resharpening internal broach teeth

In contrast to the case of surface broach, internal broach may not be resharpened correctly if the diameter and setting angle of grinding wheel are not appropriate, as the grinding wheel and the tool may interfere with each other.

Explanation of the diagram : If you resharpen the broach of diameter d=30 with the grinding wheel of diameter D=50 and the cutting edge hook angle is α=15°, the appropriate setting angle of grinding wheel is β=41°.

Points to be checked after resharpening

1. Ensure that the wear and crack of the cutting edge are completely removed.
2. No grinding burn.
3. Ensure the roughness of finishing surface is at 3.2s or less.

1. Ensure degaussing was conducted.
2. No remarkable unevenness in gullet that may prevent chip removal (see the below sketch)