Fig 1.
(a): Geometrical limitations of the sputtering machine necessitated modification of the stem: It was shortened, parallel planes were milled and a hole was drilled for anchorage. (b): These modifications allowed fixation in a clamping block.
Table 1.
All three component pairs had similar taper angles.
Fig 2.
Multiple measurements of the same stem region (red rectangle, top) were performed. A 100 μm wide path from distal to proximal was chosen to obtain a mean profile (middle). It is noted that each profile ridge demonstrates a surface roughness of about an order of magnitude smaller amplitude and period (bottom).
Fig 3.
a) The red rectangle on this non-sputtered taper represents the magnified regions in b). b) The first five proximal ridges of stem taper profile #3 are shown. The gold coating is removed from the ridges by shear abrasion during assembly (uncoated silver areas), but remains in the valleys. With increasing assembly force a greater area of the gold coating is removed from the ridges of the threaded surface profile due to increased contact between head and stem.
Fig 4.
Quantification of surface contact.
Black pixels within boxes represent contact areas and contact locations between stem and head component pairs. Profiles are presented for the three tapers under increasing assembly forces.
Fig 5.
With increasing assembly force an increasing number of stem taper surface ridges came into contact with the head taper surface. For an assembly force of 8000 N all stem taper surface ridges were in contact.
Fig 6.
With increasing assembly force a linear increase of the proportion of the surface in contact was observed.
Fig 7.
Permanent radial deformation of the stem taper surface profile.
The height difference of the stem taper profile between assembled and original condition for each ridge is plotted as a black line, with the measurement accuracy (0.6 μm) in grey.
Fig 8.
Permanent deformation of a single surface ridge.
Regions of permanent deformation of the stem surface profile were identified by superimposing the profile of the stem taper interface after disassembly on the initial stem taper profile. The original shape (red transparent surface) was deformed after assembly with 8000 N (green surface). The ridge height was reduced. Note that the axes are not equally scaled, so that the height and curvature of the wave are exaggerated.
Fig 9.
With increasing assembly force the mean ridge deformation increased.