Trouble Shooting
New Developments
Tips of better Use
Shaving Cutters
Shaper Cutters
Master Gears
Spline Gauges
Spline Mandrels
Broach Sharpening Machines

   Contact Us
Trouble Shooting
Broach abrasion :
Any condition, which creates marks, scratches or nicks on the broach comes in this category. These causes excessive wear of the teeth and thus, considerably reduces the overall service life of the broach. The causes of abrasion are as below: Hard scale on cast or forged work piece, Improper use or insufficient cutting fluid, Cold worked surfaces (Work hardened).
Chatter :

This is one of the easily detectable troubles as this can be noticed by, the vibration of the
broaching machine, The chatter normally leaves a distinctive mark on the broached surface.
The common causes of the chatter are as below:
Too few cutting teeth in contact with work piece at any time
Excessive hardness of the work piece.
Lack of rigidity of the work holder or the broach holder (only in surface broaches)
Vibrations in the broach ram because of load variation.
If the chatter occurs with surface broaching the use of shear teeth usually overcomes the
problem. However, if chatter occurs on a internal broach, a correction in broach design may
be needed and for that broach supplier may be consulted,

Drifting :

When the axial or radial alignment of a broach changes with respect to the work piece or the
broaching machine, the condition is known as drifting. Drifting produces out of round or
oval round holes and can cause damage to the cutting teeth This is mainly caused by
Mis-alignment of the broach sharpening machine centers or the dirt in the broach centers
during sharpening.
Inadequate support for the broach or work piece when used on a horizontal broaching
Broach body dia. too small.
Non-symmetrical cuts producing variable cutting load inside the diameter of the hole.
Hardness variations inside surface of a hole.
Too few teeth in contact with work piece.

Streaks :

The definition of a streak in broaching is, a surface or imperfection, which runs parallel to
the direction of broach travel. These defects may be short or long and not so serious as
tearing but they are still undesirable. The usual causes are as below:
Lands on the broach teeth are too wide.
Grinding burrs created on cutting edges while carrying out sharpening.
Material pick up on cutting edges.
Residual abrasive materials on the broach surfaces.
Scales of forging or casting or some cases caused by the heat treatment of work piece.

Rings in broached holes :

This is normally caused by the clearance in ram during the cutting stroke. The reason for
this that if the pitch of the broach teeth is uniform, the ram may have some vibration when
one tooth leaves the work piece until the next tooth enters. The usual remedy is to provide
staggered pitches or if a surface broach is used then provide shear teeth.

Too less life per sharpening :

Following reasons may cause this:
Higher hardness of the component than the broach is designed for.
Unsuitable broach material to the work piece material.
Improper structure of component material.
Improper hardness on the cutting teeth.
Improper sharpening of the broach.
Excessive cutting load on the cutting teeth.
Improper coolant or cutting fluid

Under size/Oversize components :

Following are the general reasons for this:
Smaller wall thickness of the component.
Burrs produced during resharpening.
Improper rack angle or back-off angle.
Improper broach sizes.
Excessive rise per tooth due to poor sharpening.
Abrupt change in broaching length may be due to recesses or changed chamfer values.

Poor concentricity and face run out :

This may be mainly due to following:
Component butting face not rectangular to the prebored hole.
Limitation of the broach design selected.
More clearance between bore and the broach pilot.

Optimised For 1024 x 768 and above resolution. Copyright © MATS. All Rights Reserved.