SHAREBOT Next Generation, User Manual, Page: 43 / 66

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Chapter 7
Materials and printing plate
One of the most critical elements in current 3D printers is the superficial treatment of the printing
plate. When you extrude the filament, the first layer is crushed by the brass tip on the surface of the
plate; If the contact surface is able to create a good bond with the molten plastic can continue print-
ing with solid bases. If cooling the plastic loses adhesion, it is very likely that the press can be dam-
aged due to the departure from the printing plate before the object is completed. There is no single
solution for all types of printed filament. For this we mainly see how act the two materials mostly
used: PLA and ABS, to which we may link and compare the behavior of other materials.
How ABS entails
It is a thermoplastic with characteristics that can be varied by changing the relationship between the
three main components (acrylonitrile, Butadiene and styrene) to obtain a material with more flex-
ibility or strength, melting point higher or lower and even other physical parameters such as the per-
centage of thermal retraction. With ABS are manufactured by injection moulding and several parts of
common objects and also the first RepRap 3D printers are printing smart engineering parts and ABS
gears. Resists high temperatures before soften and then losing its mechanical resistance and dimen-
sional stability, but as defect has a temperature higher, printing of 230 or more degrees Celsius and
during cooling is reduced appreciably, leading often to deformation of the first printed layers and the
consequent detachment from the printing plate. To avoid this phenomenon, there are two ways to
use so combined. The first way is to have a plate covered with a material that has strong adhesion
with the ABS, while the second is to keep the heat (between 60 and 90 degrees) to allow the printer
to build the entire piece without thermal retraction occurs so pronounced.
A piece kept in shape with these two steps throughout the press, will be far more dimensionally
conforming to 3D model of departure. Often, however, it happens that there is a partial detachment
on thin parts and elongated, with significant coverage. In these cases, the printing is completed, but
deformed in part to the arching wider print plate in the opposite direction.
The material which at the moment is very handy for keeping the ABS attached to the printing plate
is the hairspray: its water-soluble components allow you to create a veil that adheres well to glass
dish and at the same time blends and binds with the ABS, keeping it firmly stuck to the glass. To print
over, if with the blade of the utility knife or spatula you can’t remove the piece (a demonstration of
good grip of ABS on lacquer), you can remove the glass tray from the printer and put it under water
to soften the lacquer until the piece will come off with ease.