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Control of material flow – The lead screw which pushed the material from the
top of the deposition head at times would not be good enough to maintain a
continuous deposition. To overcome this, the lead screw was rotated at times
with hand to ensure that material was always being deposited when the
Fab@home software was running.
The Fab@home software would refuse to connect to hardware at times for no
reason. Repetitive trials of plug and play would set this right.
When the Fab@home software was paused in the middle of a deposition, and
then restarted back on again it would at times go to the wrong location and
not start from the place it was paused at.
When changing to print between different models / different conditions,
Fab@homeat times would go to print at a wrong location on the machine. To
avoid this, software was closed and started back on again to avoid any wrong
printing.
In spite of all these difficulties, all parts are printed as per the design specifications,
however, with some minor errors in some of the parts. One set of parts printed to the
specifications in Table 4.1 are shown in Fig. 4.1. Some disturbance and discontinuity
of fibres may be evident in a couple of the samples. Otherwise, the specimen parts
have some distortions on the sides due to the spreading of the polymer under its
own weight. For this reason, the samples are polished on the side faces, after
sufficient curing and the finished samples of flat and curved layer specimens are
shown in Fig. 4.2.
4.7 Results and discussion
The specimens are then subjected to 3-point bending tests on the Hounsfield tensile
testing equipment in materials testing lab of AUT University. A typical specimen
under 3-point loading is shown in Fig. 4.3. The maxim compressive force before
fracture of is recorded in the case of each sample, and the final data obtained for all
samples is presented in Table 4.2. All the test samples are cured for about 48 hours
in this case. It was observed that curing time is a critical factor in the case of
fabepoxy, and the more the curing time, the better the part strength.
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