| COMMON
BROACHING PROBLEMS: |
| Broaching Problems |
Possible Causes |
Corrective Action |
| Workpiece
Stuck On Broach |
1. Insufficient machine capacity. |
1. Check broaching machine to see if it is delivering rated
power. |
| |
2. Dull cutting edges. |
2. Check broach design, perhaps back-off clearance is insufficient
or step per tooth is too great. |
| 3. Clogged tooth gullets. |
3. Sharpen broach if required. Check tooth design. |
| 4. Failure of power during cutting stroke. |
4. Each tooth gullet should be cleared of chips between passes. |
| 5. Misalignment of the broach puller with workpiece. |
5. Check alignment of fixture for holding workpiece with centerline
of broach puller. |
| 6. Hole in workpiece not square with face which contacts fixture. |
6. Be sure that the hole in the workpiece is square with the
face that contacts the fixture. |
| Galling Or Pickup |
1. Too low or variations in hardness of workpiece. |
1. For the broaching of steel, best results are obtained at
a Rockwell 14 to 30 R.C. |
| |
2. Insufficient flow or wrong type of coolant. |
2. All major oil companies have qualified cutting
oil consultants. |
| 3. Poor broach design. |
3. Inspect the broach closely and sharpen if
necessary. |
| Broach Breakage |
Check 1 to 6 in "Workpiece Stuck on
Broach"
7. Interrupt cutting stroke.
|
7. Stroke of machine should be adjusted so that
broach never leaves guides. |
| Chatter |
1. Too few teeth in contact with workpiece simultaneously. |
1 Check pitch of broach with "Pitch formula." |
| |
2. Excessive hardness of workpiece. |
2. It is sometimes possible to eliminate chatter
by changing the rate of travel, coolant, face |
| Broaching Drifting In Cut |
1. Poor sharpening. |
1. Check broach carefully and resharpen if necessary. |
| |
2. Broach not properly supported especially
in a horizontal machine. |
2. If internal broaching on a horizontal machine
rear support may be required. |
| 3. Variations in hardness workpiece. |
3. In broaching steel, best results are obtained
at a Rockwell hardness of 14 to 30 RC |
| 4. Not enough broach teeth in action simultaneously. |
4. Check pitch of teeth using "Pitch formula." |
| 5. Body diameter too small. |
|
| Scores On Broached Surface |
1. Poorly ground chipbreakers. |
1. Change design of chipbreakers on last few
roughing teeth or semi-finish teeth. |
| |
2. Metal pickup. |
2. Remove any pickup. Check tooth profile design. |
| 3. Burrs left on cutting edges from sharpening. |
3. Grinding burrs must be removed after sharpening. |
| Rings In The Broached Holes
Or On The Surface Of The Workpiece |
1. Uniform pitch of teeth may cause surging. |
1. Sometimes the use of staggered pitches eliminates
this condition. |
| |
2. Back-off clearance may be excessive. |
2. Sheer cutting teeth on surface broaches help
prevent surging. |
| 3. Burrs left on cutting edges after
sharpening. |
3. After sharpening burrs must be removed from
cutting edges. |
