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Medical Plastics Components Industry
Plastics -
A Material of Choice for Medical Innovations
Plastics
remain at the forefront of medical innovations. We rely on
plastics in every aspect of our lives. The plastics used
in healthcare and medicine support us from birth through
maturity and eventual old age. The dynamic and relentless
pace of medical development has been matched by the
development of specialist plastics.
Injection
Molding of Medical Components
Injection
molding is a manufacturing process for producing parts
from both thermoplastic and thermosetting plastic
materials. Material is fed into a heated barrel, mixed,
and forced into a mold cavity where it cools and hardens
to the configuration of the mold cavity. After a product
is designed, usually by an industrial designer or an
engineer, molds are made by a mold maker from metal,
usually either steel or aluminum, and precision-machined
to form the features of the desired part. Molders can
achieve virtually identical parts by controlling several
key variable of the molding process. Although many
variables affect the molding process, four variables
having the greatest impact on the maintenance of a
systematic injection molding process are: injection
velocity, plastic temperature, plastic pressure, and
cooling temperature and time.
Material
Selection for Injection - Molded Devices
Injection
molding has been employed widely for manufacturing a great
variety of medical device and system components.
Functional performance and quality of a medical device
stems from the integrity of three fundamental elements:
materials, design, and processing. These three elements
have to interact with each other in a synergistic manner
to generate a unique function for a device to meet the
customer's requirements. A typical new product development
cycle starts with customer requirement definition. Only
when customer requirement are fully understood and clearly
and accurately defined from the end user's perspective can
the ultimate product succeed in the marketplace. A design
engineer takes the customer requirements and translates
into product requirement definition in engineering terms.
That will then allow the materials requirements to be
defined by an experienced materials engineer based on the
functional requirements of a device. Materials selection
and optimization process begins with the preliminary
material requirement definition.
Injection
Molding Machine Basics
There are two
basic components to an injection molding machine: an
injection unit that melts and transfers plastic into a
mold, and a clamp unit that opens and closes the mold and
ejects the part.
Injection
Molds for Molding of Medical Components
The
injection mold is a key component in the overall process
of making a finished medical product. The process of
building injection molds to produce components for these
products is best understood if one knows the driving
factors of why plastics are the material of choice in the
first place. It is through an understanding of what the
medical customers are looking for that we can define what
steps are important in the design and construction of
medical injection molds. The process for constructing
injection molds for medical components has become more
complex as the medical industry places higher demands on
plastic products. Medical companies are expecting molders
to provide parts that meet all their requirements of
dimensional stability, low cost, fast turnaround and
particulate free (clean).
Preventing
Failure through the Proper Design of Parts and Molds
MEDICAL
PART QUALITY depends on factors that include part design,
resin selection, the quality and design of the molding
tool, and processing conditions. Design and molding
considerations, in turn, depend on the type of resin to be
molded. By understanding how part design affects injection
molding, tooling, and production costs, part designers and
engineers can significantly reduce mold complexity. By
understanding how tool design affects the process ability
of polyester resins, they can avoid complications during
molding.
Designing premature Failure out of Molded Medical Parts
Part
failure occurs when a part does not perform its expected
function. Premature failure signifies the cessation of
function before the end of expected life. The designed
life of an improperly or inadequately designed part can be
far less than its expected or intended life. Premature
failure of medical parts and applications may cause
irreparable damage to someone's health. When a part
prematurely fails because of lack of proper design, the
designer alone does not take the blame. The major portion
of the blame unjustly goes to the material of
construction. To avoid such failures and the resulting
disappointments, it is essential to put major stress on
proper part design. Functional design is the focal point
of all other aspects of design, which must support it. The
function could include aesthetic appearance, which can be
addressed by industrial design, if the part function
involves load bearing capability, a structural design
would be needed. The part must be produced by a commercial
process and hence must be designed for manufacturing, in
this case, for injection molding.
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