Page 36 - machining_titanium_05_2019

MILLING TITANIUM Table 23 Indexable Extended Flute Cutter Families: General Data* ●

Design configuration
Insert
Diameter range
Flex.
Endmills with
No. of
tooling
shank**
Cut, edge form
Type
Shell
Cut.
And
Insert
Family
Mm
mills heads
In
Clamping (O/D***) edges Smooth Chipslitted
Cylindrical Tapered
●
●
XQUAD
O
4
radial
50-100 2.0-4.0
HELITANG
●
●
●
●
●
1.0-4.0
tangential
32-80
D
4
T490 LINE
HELITANG
50-80 1.97-3.15
FIN LNK
MILLSHRED 25-100 1.0-4.0 ● ● ● ● ● tangential O 2 2 ● ●
●
radial
O
P290 LINE
* at the time of writing
** The type of the shank is indicated in the columns
*** O-one sided, D-double-sided
Radial or tangential?
Generally, the concept of a tool carrying one-sided radially clamped inserts is more common in
the design of the indexable extended flute cutters for milling titanium. A one-sided radially clamped
(laydown) insert provides more options for varying cutting geometry and ensuring necessary
relief angles. Cutters carrying these inserts usually feature greater chip gullet than tools with
tangential inserts and, therefore, better chip evacuation when milling with high metal removal
rate, especially in machining deep cavities and pockets. Also, they usually have higher ramping
abilities. This explains why the radial concept prevails in extended flute cutters for milling titanium.
ISCAR’s family of HELITANG T490 extended flute cutters, primarily tools with size 13 inserts,
is an exception to this general rule. The principle of tangential clamping contributes to improving
the cutter rigidity and optimal loading of a screw to secure the inserts while usually ensuring
a higher insert density that results in increased feed rate. HELITANG T490 extended flute
cutters show their worth in edging – rough milling the wide edges of titanium workpieces,
where the depth of cut is considerable, but the width of cut is not too large. Under these
conditions there is no problem with chip evacuation, and the extended flute cutter carrying
tangentially clamped inserts wholly meets the requirements of high-efficiency roughing.
 Chip splitting geometry may be a good solution for rough milling in unstable
conditions (high overhang, poor workholding etc.). In many such cases, chip splitting
cutters demonstrates better dynamic behavior that results in better performance.
“Raking by fraze”
Chip chopping is the main principle of the ISCAR
MILLSHRED P290 family. The cutting action
of a shredded P290 mill can be compared with
a fraze or a rotary rake (Fig. 16). If you need to
loosen soil, the fraze will require less effort than
a hoe. In our case, if you overlap the teeth of
your “fraze”, this will reduce the production of
cusps and will improve surface quality. The hand
movements in Fig. 16 illustrate this action.

Fig. 16 A “fraze”

34 ISCAR