PSI - Issue 24

Luca Bonaiti et al. / Procedia Structural Integrity 24 (2019) 764–774 Luca Bonaiti / Structural Integrity Procedia 00 (2019) 000–000

768

5

Table 1: STF gear main data.

Symbol

Value

Description

m n α n

5 mm

Normal module

20°

Normal Pressure angle

0° 24

Pressure angle at normal section

β

z

Number of teeth

b x

10 mm

Facewidth

0 . 2

Profile shift coe ffi cient

h ∗ f P ρ ∗ f P h ∗ aP

1 . 250 0 . 380

Dedendum coe ffi cient of the basic rack profile Root radius factor of the basic rack profile Addendum coe ffi cient of the basic rack profile

1 . 00

Table 2: Process parameter

Machine EOS M280

Laser source fiber Printing direction according to gear axis (see Fig. 4) Gas nitrogen Power 200W Scanning speed 600 mm s − 1

Spot diameter 100 μ m Layer thickness 40 μ m Average particle size 42 . 61 μ m

Table 3: Bending fatigue test results.

Test ID

Gear

Tested teeth

F min

F max

Cycles

Broken tooth

N

N

000001 000002 000003 000004 000005 000006

A A A A A A

1-3 5-7

-15000 -14000 -13000 -12500 -12250 -11000

-1500 -1400 -1300 -1250 -1225 -1100

202550 229575 3581879 481897 581951 631460

1 7

9-11

11 13 17 21

13-15 17-19 21-23

where Y β , Y B and Y DT have unitary value. Y F and Y S have a not unitary value and they are calculated as in Eq.(2) and Eq.(3).

6 h Fe m n s Fn

cos ( α Fen )

(2)

Y F =

m n

cos ( α n )