Retractable Pen Style in Plastic Pen Case
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Pencil Style
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Only natural diamonds are used in the production of the SPI Supplies brand diamond scribes. Each diamond is cut and shaped to the desired profile,
then polished (with
fine diamond paste) to a mirror finish.
The exact hardness of the diamond is anisotropic, meaning that from a
crystallographic standpoint, the hardness varies by unit call dimensions.
The effective hardness of a particular diamond scribe depends on the
crystallographic relationship of the diamond relative to the writing
direction. Each crystal set with the plane associated with
the highest hardness in the "right" direction". Care must be
taken to ensure that the correct orientation is the one used for the
writing tip. If attention is not made to the orientation (lower cost makers of diamond scribing tools don't track the orientation)
there will be a differences of hardness from tool to tool,
some having harder faces, some having softer faces. This could
result in a substantial population of a new batch of diamond scribes useful lifetime. When the SPI Supplies diamond scribes are
manufactured, great care is taken to ensure that the right orientation of
the diamond is used in order to ensure the longest possible lifetime.
Another important consideration is the degree of polish given to the diamond.
The diamond in the SPI diamond scribes are polished to a mirror finish
and is imperative for the perfect scribing tool. Some lower cost
scribing tools are rough diamonds and not polished at all. Cheaper scribes results in higher
friction and less smooth scribed lines which can, result in breaking of the silicon, glass, quartz or other
substrate materials. An unpolished diamond scribe can also results in more particulates being generated then on average.
With all fine diamond tools, the diamond in our diamond scribes will eventually wear out. Continued
scribing with a worn out diamond results in uneven scribe lines and the
generation of greater and larger debris particles, both of which are undesirable.
Useful lifetime of a diamond scribe is determined by frequency of
use, composition (actually hardness) of the substrate being scribed, and
other factors such as the bending stress placed on the diamond itself. The wear is gradual, and not always obvious, without close inspection.
Regular inspection of the diamond an easy to use inspection tool such as
one of our pocket magnifiers is recommended.
It does not matter which one is used, but the important thing is to be able to
image the diamond. If when using the scribe, the scribe line loses "sharpness" relative
to when it was new, starting all over again with a new scribe will probably bring
back the original sharpness to the scribed line. We recommend keeping a hand
an exemplar scribed substrate made with a brand new scribe. So when trying to make
the decision about replacement, compare the present result with the examples.
The cross-sectional view of the scribed "line"
should have a shape resembling a "V". An old and worn out diamond will
exhibit a cross-sectional profile more like a "U".
Our various diamond scribes are described in terms of their "included angle". The tip of the
diamond is a cone, and the included angle is the angle of the tip of the cone. For many years,
we offered only a 90° included angle. 90° is a compromise between
scribing a finer line with a smaller included angle and longer tip life with a larger included
angle. A smaller included angle also allows one to locate the scribed line more precisely, which
is particularly important in certain types of failure analysis work.
We offer basically two different types:
A) "Retractable pen in plastic case" and
B)
"Pencil". The retractable pen version allows for refill to be used.
The ability to make a more precise line is possible with the "pencil" style. With the pencil style, it is also possible to create
angled styles for catering to the different preferences of different people.
With the retractable pen style, one can only offer straight style designs.
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