Screen Printing - October/November 2017 - 33
device will have the same function. What may be normal
print tolerance for texture, deposit, edge resolution, or
porosity within your plant may lead to failure with a new
design. In other words, the materials and form of the job may
fit the existing production, but will that process change the
function of the part? Only an experienced process engineer
From the viewpoint of the material and sub-component
form factor, many printed electronic devices may seem almost
the same. They may all have traces, use the same conductive
inks, and be printed on the same substrate type. However,
end-use functions can drive considerations that make them
different to manufacture on the same equipment.
For example, for a membrane switch, the key considerations may be trace resistance, width, pitch, and lifespan.
In an industrial control product, the important issues may
be vibration resistance, weather sealing, and flexibility. In a
printed medical device, the most critical functions may be
telemetry signal frequency or the ability to interface with
other liquids or chemicals. Whatever the most important
considerations, the design engineer should keep them frontof-mind when crafting the PoC part to demonstrate these
functions. The "R" part of R&D will then find out what the
production process will do to this functionality.
A variant of this risk can happen when production staff
produces parts at the sample and qualifying print-run stages
without knowing that the finished component has abnormal
sensitivities to characteristics they would consider normal for
similar parts. Often, they won't know this because a design
engineer did not test for it; the process went straight into
When these types of unknown requirements cause the test
batch devices to fail, that's when the label of "excessive cost
for R&D" is usually applied. The device then gets kicked back
to the designer for revision, which is too far backwards in the
process. Had the right questions been asked and answered
early on, the problems could've been addressed through
simple process revisions to improve production efficiency or
reduce printed defects in an otherwise good design.
Instead, these revisions push the product out of development and back into design, when it should be in research.
Time and money is spent on redesigning the devices and specifying different raw materials, which are big changes - ones of
sufficient magnitude that will alter the production equation
circles back to whether or not the company should be taking
the job in the first place. These three questions must be asked
(and the answers should already be known):
1. If the PoC printing/construction stage indicates a process
or material that is not compatible with your existing
printing and downstream equipment, or is unknown to
you, then why are you taking this job?
2. Do you know what your exact imaging capabilities
(resolution, speed, and size) are? At a finer level, can you
establish what chemical, curing, pre- and post-treatment,
and other capabilities you have (and don't have)? If you
answered "yes," is that based on real production data or
on the theory that your design and production team will
innovate under pressure (the philosophy that they will
always get it done, somehow)? If you answered "no," is
that based on data from your facility establishing your
production capabilities, or was it taken from the equipment manufacturer's datasheets? Can a new technique,
accessory, or chemistry augment those capabilities to
expand what you are capable of doing?
3. Has a cost-benefit analysis been done to assess whether you
actually need to retool physically versus simply developing
a new technique (different screens, substrate handling/prep,
etc.) or outsourcing segments of the process?
ExcEssivE cost of REtooling Existing
The reason that many companies have difficulty answering
these questions in the short space of time allowed for quotation and acceptance of a project is that they haven't gathered
enough data on their own capabilities. They may know what
they can do with materials and devices from their past and
present, but that may not help them when a job involves new
raw materials or unfamiliar device functionality.
There is a good business case for what might be called
"speculative R&D" to help quantify these unknowns. Budgeting the time to do testing and trial designs for new product
types and materials can give you information that will pay
off down the road. It's the foundation of continuous process
improvement that can expand your future capabilities.
Finally, as the process flowcharts in this article suggest,
you can also prevent "death by R&D" by getting the right
members of your team involved at the right time. When
an RFQ for a new project comes in, your designer may be
involved as the contact point, but don't wait until the project has already been accepted to get your process engineer
into the decision. Those assets must be interlinked. Lack of
collaboration between them predetermine a project's failure
before the job ever gets to production, and after a lot of
money has been spent on R&D.
This label is sometimes expressed as excessive cost per unit
or unfeasibility, and it involves much of the same missing
data that causes jobs to be rejected as having excessive R&D
expense. Many of the same fundamental issues need to be
addressed, though this time at an administrative level. It all
Ray Greenwood is a printing process and manufacturing consultant in
the printed electronics, industrial, transportation, and medical device
industries. His 28-year career blends a graphic/product design education
with manufacturing experience in screen printing, flexography, offset
lithography, and industrial dispensing.