C - DTU Nanotech - Danmarks Tekniske Universitet

A
B
5.1 Materials and Methods 29
40 mm
26 mm
Vessel: with a laser machined bottom
Vessel: created as hole
Bores for screws
Figure 5.2: WinMarkPro drawings of the freezing chambers: (A) shows the drawing from
design I and II, where the bottom of the vessel was fabricated with the laser. In
the drawing from design III and IV (B) the vessel was fabricated as a hole, since
the vessel bottom consisted of aluminium or PMMA foil
the CO2–laser models of the freezing chambers were drawn with WinMarkPro. The laser
settings were shown in Tab. 5.1, whereas the settings were based on experience values, such
as the laser velocity, and on the reiteration of the machining process. The dimension of the
laser machined PMMA plates were 20x40x2 mm 3 . Additionally the plates had two bores for
screws, 26 mm apart from each other, and the edges were also cut (Fig. 5.2).
A PMMA plate with an area of 20x40 mm 2 and cut edges represented the standard shape
for thermal bonding which was used throughout this thesis. This shape was used, because
the steel blocks, needed for thermal bonding, had an alignment apparatus for this shape.
Design I and II
The vessel, only machined with the laser (laser settings and WinMarkPro drawing are shown
in Tab. 5.1 and Fig. 5.2), had in design I a depth of 1.5 mm (resulting bottom thickness:
0.5 mm) and in II of 1.75 mm (resulting bottom thickness: 0.25 mm). The depth of the
Shape
20 mm