7-8 CHAPTER 7: OPERATION
QUICK LOAD SERVO III MI
3.2. Lathe mechanical setup
3.2.1. Clamping method
Collets
There are different kinds of collets that are more or less effective:
a) Simple cone collet
The bar is held over about 350 degrees, over a
length from 0.5 to 7 times the diameter.
Efficiency : good to very good
b) Bi-conical collet
Clamping over 1 or 2 x 350 degrees, over an
approximate length of 1.2 times the diameter.
Efficiency : very good to excellent
c) Double cone collet
The double cone clamp has the great advantage
of holding the bar at two points separated by
about 1.5 the diameter, with a clamping 2 times
350 degrees over about 0.5 times the diameter.
Efficiency : excellent
3-jaws chuck
With this type of clamping, one should be very careful given that in many cases the bar is held only at
three points, thereby greatly increasing the risk of vibration.
Frequent errors and possibilities for improving the effectiveness of the clamping grip.
a) Hard grips
Wrong :
The radius of the grip is greater than the radius of
the bar.
The jaws press against only 3 points at 120
degrees.
Correct :
Modify the centres of the jaws to obtain 2 times 6
support clamping points at 60 degrees.
To Next Page
Loading...
