Prakt. Met. Sonderband 38 (2006) 333 
Specimens were taken out of the production process after 10.000, 20.000 parts and at the 
end of service life, which is defined by quality of the produced thread. A new molding tool 
the feed was also investigated to define the initial state. 
je thread 
seconds. 
-5C and 3.1 VISUAL INSPECTION 
the sheet 
e thread The new former showed a regular gold-like surface, free from injuries. After having done 
10.000 parts surface damages were found especially on two teeth (in picture the third and 
fourth teeth, depending on the rotation angle of the former due to the helix). Those 
damages are located on the tip of the tooth and a metallic bright surface become visible. 
The teeth before and after those two damaged teeth revealed noticeable minor indication 
on the TiN-surface. After 20.000 parts those surface damages spread out on greater 
surface areas, but mainly on the third and fourth tooth. At the end of life time the damaged 
area on teeth tree and four had increased furthermore, without any visual observable 
influence of increasing intensity on the other teeth. 
Fig. 4: molding tool after 20.000 parts Fig. 5: detail from Fig. 4 
stadia of 
and gave 
xaled the 
n EDAX- Fig. 6: molding tool at the end of service life 
jus). The 
ormation 
material.