Fine boring with fine boring heads EWN/EWE
Fine boring methods
There are two different methods of precision boring, machining with the fine boring cycle and machining with the reaming cycle. Both methods have advantages:
Fine boring cycle (G 76) boring – spindle stop – spindle orientation – displacement – retraction This cycle is used for: • deep bores with long tools
Reaming cycle (G 85) Forward – backward boring This cycle is used for: • short bores • small diameters
• low cutting speeds and low rpm • large boring diameter > 200 mm Ø • problems with tool life and surface quality
• high cutting speeds and high rpm • tight form and position tolerances
Extension of the boring range
Insert holder type E, with 87° approach angle For each one of the fine boring heads EWN 20 - EWN 100 and EWE 41 - EWE 100 there are two additional insert holders (size 2 and size 3) available for the extension of the boring range and for back boring. The boring range from Ø20 - 153 mm is covered with insert holder size 1 of each boring head.
E
87˚
ØD1
ØD1
ØD
ØD
ØD
Size 1
Size 2
Size 3
Size 3
Size 2
Insert holder Type C, with 90° approach angle For each of the fine boring heads EWN 25 - EWN 100 and EWE 41 - EWE 100, there are two insert holders with 90° approach angle available.
E
The cutting data given in the tables is valid for the insert holders type E and type C as well as for forward and back boring.
90˚
ØD1
ØD1
ØD
ØD
Size 2
Size 3
Size 3
Size 2
Caution: • Counter clockwise spindle rotation is required for back boring operations. • The cutting edge is at a shorter length than the boring head. Consider total length of tool. Check the space at the back side of the workpiece. Back boring For back boring, it is required to enter into the bore off centre, with a tool adjusted to the back bore diameter. In this respect, the back bore diameter "ØD" as well as the diameters of the entry bore "C" and the tool body "A", are related to each other. These values can be calculated as follows:
Min. entry bore diameter "C"
C
ØD1
ØD + ØD1 2
C =
Max. back bore diameter "ØD"
ØD =
2C - ØD1
Max. tool body diameter "A"
ØD1 =
2C - ØD
ØD
9
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