ELECTRONICS
Touchstone has earned numerous awards as an industrial problem-solver,
new product developer, and applied research laboratory for hundreds
of manufacturers in a wide range of business sectors. Our unique
capability as an industrial problem-solver is based on the diversity
of our highly experienced technical staff, supported by over $10
million worth of in-house laboratory equipment and testing facilities.
The following examples illustrate some of our contributions to this
business sector:
- Repeated, explosive failures of heating elements in commercial
coffee vending machines led to the evaluation of both new and
failed heating elements. The elements were inconel-sheathed, resistance
elements and after only a short service were seen to burst when
the machine began to heat water. The failures clearly appeared
to be the result of bursting, probably under steam pressure, but
no corrosion was seen which might have allowed water to seep into
the element. Metallographic evaluation found the elements to have
a uniform, fine-grained microstructure with no obvious defect.
Examination of the element exterior did not find any cracks or
obvious manufacturing defects that would explain the failure.
A discussion of the problem with the vending machine manufacturer
found that, as part of their quality control, each new element
was tested by powering it until it became orange hot to assure
the element was operational. Immediately afterward the hot element
was then plunged into cold water. Metallographic examination of
new "untested" elements revealed that the units were
supplied with the sheath in an annealed state. The annealed structure
allowed for normal expansion when the element was used. Quenching
has rendered the sheath hard and relatively inflexible. During
initial heating the sheath would crack and allow water to seep
into the element. During a subsequent heating cycle the element
would burst from steam pressure.
- A computer manufacturer requested that Touchstone help to solve
problems with the surface quality of their galvanized computer
chassis. Touchstone determined the thickness of the zinc plating,
the type of chromate conversion coating and the nature and cause
of the white stains. The coatings were found to meet appropriate
requirements, and the stain was found to be caused by an inorganic
acid coming into contact with the chassis in a post forming operation.
- An analysis was performed on a plated, copper wire sample using
a scanning electron microscope in the EDS mode to determine the
type of plating present.
- A fastener manufacturer wanted a detailed engineering and cost
analysis which compared the laser cutting or turret punch systems
versus the method which incoporates either press blanking or a
wire-edm process. Touchstone performed a comparative evaluation
of the edge quality resulting from several different cutting systems
including: Blanking press, wire EDM, Laser, Turret punch, and
abrasive water jet cutting systems. While the Abrasive Water Jet
produced the best result in terms of the characteristics evaluated,
areas for improvement of this system were identified.
- Repeated failures of screws in computer chassis led the manufacturer
to contact Touchstone. Broken screws were frequently the source
for complaints of "rattling" noises and electrical shorts.
Examination of the fracture surfaces found intergranular, faceted
fracture surfaces typical of hydrogen embrittlement. A production
check found that the screws were plated, but not baked to remove
hydrogen.
- Touchstone performed an evaluation of brass plating on exterior
light fixtures in order to determine the cause of corrosion and
to suggest changes in manufacture which would assure the satisfactory
performance of new units. TRL concluded that the rusting on the
light fixtures was due to very thin plating, which did not provide
adequate protection of the base metal. The rusting on the globe
fastener screw was also due to the same conditions as the fixture.
- Workmen for a telephone company opened a manhole to begin repairs
and noticed a strong odor emanating from the opening. Also, an
orange surface layer was seen covering the floor of the storm
drain. Touchstone was contacted by the Telephone Company. An investigation
found that the odor was due to decomposition of leaves and other
organic debris that washed in during recent rainstorms. Methane
was detected in the atmosphere by GCMS analysis of air samples.
The color (orange) was caused by iron-rich debris sandblasted
from a nearby interstate bridge during repainting operations that
had covered the organic debris.
- Eleven metal samples from guitars were sent to TRL for evaluation.
These included a pole piece and a gap piece from a speaker, 3
round headed wood screws, 3 spacer bars and 3 pieces suspected
of being alnico magnets. The speaker parts were to be examined
to determine what type of metal was used in their manufacture,
how they were manufactured, their density and what type of plating
might be present. The remaining samples were evaluated to determine
what metal alloy was used in their manufacture.
The above examples are only a sample of our work in this area.
We would be pleased to provide any additional information you may
require. We also invite you to review examples on our website of
work that we have performed in support of other business sectors.
Please contact one of our Project
Managers to discuss your manufacturing problem. We would welcome
an opportunity to add you to our rapidly growing list of satisfied
customers.
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