IPI PLASTICS, INC
1257 BIRCHWOOD DRIVE, SUNNYVALE, CA 94089
PHONE 408-734-4900 FAX 408-734-4995
The selection of a plastic material for a specific application can be a difficult task. After careful
consideration, the possibilities may be narrowed to two or three possibilities and the final selection is
determined by testing.
The first and most important step in selecting a plastic material from the broad range of available
materials (i.e. acrylic, polycarbonate acetal, nylon, polyolefins, etc.) Is to carefully define the
requirements of the application, the physical properties required and the environment in which the
material will need to perform.
The following is a list of questions or considerations that should be used to define the applications
completely as possible. In many cases, the answers to these criteria may be helpful to eliminate a
particular plastic or an entire family of plastics. The more completely the application is defined, the
better the chance of selecting the best material for the job.
Physical & Mechanical Considerations
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What are the overall parts dimensions (diameter, length, width, thickness)?
What load will the parts have to carry?
Will the design carry high loads?
What will be the highest load?
What is the maximum stress on the part?
What kind of stress is it (tensile, flexual, etc.)?
How long will the load be applied?
Will the load be continuous or intermittent?
Does the part have to retain its dimensional shape?
What is the projected life of the part or design?
Thermal Considerations
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What temperature will the part see and for how long?
What is the maximum temperature the material must sustain?
What is the minimum temperature the material will sustain?
How long will the material bat these temperatures?
Will the material have to withstand impact at the low temperature?
What kind of dimensional stability is required (is thermal expansion and contraction an issue)?
Chemical Considerations
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Will the material be exposed to chemicals or moisture?
Will the material be exposed to normal relative humidity?
Will the material be submerged in water? If so at what temperature?
Will the material be exposed to steam?
Will the material be painted? If so what kind of paint?
Will the material be glued? If so what kind of adhesive will be used?
Will the material be exposed to chemical or solvent vapors? If so, which ones?
Will the material be exposed to other materials that can outgas or leach detrimental materials,
such as plasticizers or petroleum based chemicals?
Bearing and Wear Considerations
 Will the material be used as a bearing? Will it need to resist wear?
 Will the material be expected to perform as a bearing? If so, what will be the load, shaft
diameter, shaft material, shaft finish and rpm’s be?
 What wear or abrasion condition will the material used in? Note: Materials filled with friction
reducers (such as PTFE, molybdenum disulfide, or graphite) generally exhibit less wearin rubbing
applications.
Other Miscellaneous Considerations
 Will the part have to meet any regulatory requirements?
o FDA * USDA * CANADA AG * 3A DAIRY * NSF * USP Class VI
 Is UL 94 Flame retardant rating required? What Level
o 5VA * 5VB * V-0 * V-1 * V-2 * HB
 Should the material have a special color and / or appearance
o Natural * White * Black * Other Colors
o Color match to another part or material?
o Window Clear * Transparent * Translucent * Opaque *
o Smooth * Polished * Textured * One side or Both
 Will the part be used outdoors?
 Is UV Resistance required?
 Is static dissipation or conductivity important?
o Insulator * Static Dissipative * Conductive
After you have answered the above list of questions, or determined the suitability of the desired plastic,
you have one more step.
Manufacturing Techniques
 Machining- generally used for short runs or unique parts
o What equipment you have available
o Types of tooling
o What form of material would be best used to make the desired part
Sheet * Rod * Tubing
 Injection Molding used for large quantity of parts
o Size of Injection molding equipment
o How parts per mold
o Life of the mold
o Cost of the mold
 Vacuum Forming
 Blow molding
 Gluing or fastening of components
 Polishing
IPI PLASTICS, INC
1257 BIRCHWOOD DRIVE
SUNNYVALE, CA 94089
408-734-4900 PHONE 408-734-4995 FAX
Regulatory Compliance
& Standards Overviews
Introduction
Plastic materials are often specified in food and drug processing, handling, or packaging
equipment. In order for these materials to be used, federal, state, or association regulatory
requirements may have to be met. Requirements vary from organization to organization, so
standards must be checked for each material, component or equipment configuration.
The following are brief descriptions of regulatory organizations, requirements, and
standards that may apply to stock shape products (sheet, rod, tube and film) or
components made from those materials.
FDA
The Food and Drug Administration (FDA) is the regulatory agency of the United States government
that is responsible for determining how materials may be used in contact with food
products. The FDA participates in publication of The Federal Register, which contains The
Code of Federal Regulations (CFR), a codification of the general rules established by the Executive
departments and agencies of the Federal Government. The Code is divided into 50 titles
which represent a broad subject matter.
Definitions for proper use of food contact materials are found in a series of regulations
published annually under The Code of Federal Regulations (CFR) Title 21. Title 21 - Food and
Drugs is composed of nine volumes, which are subdivided into Parts. Part 177 - Indirect Food
Additives: Polymers lists standards for polymers acceptable for use in components of single and
repeat use food contact surfaces. Part 178 - Indirect Food Additives: Adjuvants, Production Aids, and
Sanitizers includes standards for certain polymer additives. Parts are divided into Sections
identified by chemical family which indicate physical, chemical, and compositional
requirements, as well as acceptable service conditions for food contact. Regulations
generally limit the extractable substance when exposed to selected solvents.
Within the FDA, there is no government-operated process of inspection of plastics produced
for food contact use. Rather, the FDA in their regulations provides certain specifications
regarding composition, additives, and properties. A material which meets these standards
can then be stated as FDA COMPLIANT. End users should note that it is their responsibility
to use the product in a manner compatible with FDA guidelines.
For further information on FDA regulations, contact the U.S. Food & Drug Administration,
Office of Premarket Approval HFS-216, 200 C. Street SW, Washington, DC 20204, by phone
at (202) 418-3080, or visit them at http://www.fda.gov on the Internet.
USDA
The United States Department of Agriculture (USDA) Food and Safety and Inspection Service
regulates manufacturing, packaging and handling practices in the agricultural food industry.
The USDA has jurisdiction over equipment used in meat and poultry processing plants.
Materials used in this equipment are approved on an individual basis.
For a product to be USDA COMPLIANT, components used in direct food contact must be
documented as to their compliance with the Federal Food, Drug and Cosmetic Act ("FDA
compliance") by a written letter of guaranty from the manufacturer to ensure that they are
formulated in compliance with appropriate regulations. Therefore, USDA requirements for
material approval are satisfied by a certification of FDA compliance (see FDA section above).
For further information on USDA regulations, contact U.S. Department of Agriculture,
Compounds and Packaging Branch, Product Assessment Division, Building 306 BARC-East,
Beltsville, MD 20705. By phone; (301) 504-8566. or visit them at http://www.usda.gov on the
Internet.
CANADA AG
Agriculture & Agrifood Canada (Food Production and Inspection Branch) and Health Canada (Health
Protection Branch) are the Canadian government agency equivalents to the United States'
USDA and FDA, respectively. These Canadian counterparts both conduct evaluations on
material formulations, issuing "no objection letter(s)" on an application specific basis. Unlike
current FDA and USDA policies, materials cannot be self-certified by manufacturers without
prior Agency review and approval.
For further information on Agriculture & Agrifood Canada regulations, contact Agriculture
and Agrifood Canada, Food Production & Inspection Branch, Meat & Poultry Products
Division, Plant & Equipment Evaluation, 59 Camelot Dr., Nepean, Ontario, K1A OY9, by
phone at (613) 952-8000, or visit them at http://aceis.agr.ca on the Internet.
For further information on Health Canada regulations, contact Health Canada, Health
Protection Branch, Bureau of Chemical Safety, First Floor East, Sir Frederick Banting
Building, Tunney's Pasture, Postal Locator 2201D, Ottawa, Ontario K1A OL2, by phone at
(613) 952-8000, or visit them at http://www.hc-sc.gc.ca on the Internet.
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3A-DAIRY
3A-Dairy was founded in 1920's by three dairy related associations in the interest of
creating sanitary standards and practices for equipment and systems used to process milk
and milk products, and other perishable foods. Today, the 3-A Sanitary Standards
Committees are composed of representatives from many government agencies and
industry.
Standard Number 20-20, 3-A Sanitary Standards for Multiple-Use Plastic Materials Used as
Product Contact Surfaces for Dairy Equipment has been developed to "_cover the material
requirements of plastics for multiple-use as product contact and/or cleaning solution contact
surfaces in equipment for production, processing and handling of milk and milk product(s)."
Test criteria for approval of plastic materials include cleanability, bacterial treatment, repeat
use conditions, and FDA compliance. Samples are subjected to chemicals representative of
dairy clearing compounds and measured for weight change and changes in surface
appearance.
To display the 3A-Dairy symbol, equipment manufactures must use only 3A Dairy approved
plastic materials. Using unapproved materials while displaying the 3A symbol can result in
the loss of the right to display the symbol. Many states including CA and WI (the two largest
dairy food suppliers) have incorporated the 3A standard into their state inspection
standards.
The 3A-Dairy organization annually publishes a list of approved plastic materials. Important
Note: Materials are approved by product, grade, form, and supplier, and not by generic
material.
For further information regarding 3-A Sanitary Standards, contact IAFIS (International
Association of Food Industry Suppliers), 1451 Dolley Madison Boulevard, McLean, Virginia
USA 22101-3850, by phone at (703) 761-2600, or visit them at http://www.iafis.org on the
Internet.
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NSF
NSF International, formerly known as the National Sanitation Foundation, is an independent,
not-for-profit, neutral agency that sets standards for all direct and indirect drinking water
additives. Manufacturers who provide equipment displaying the NSF symbol have applied to
the NSF for device approval to a specific standard. The approval is issued for the finished
product (device) in a specific use (application). For example, a commercial ice machine
manufacturer will obtain NSF approval for the ice machine (device to Standard application).
To obtain device approval, all components within the device must comply with the Standard.
Establishing compliance of the equipment's components can be accomplished in one of two
ways:
1. The component has been tested to the Standard by the component supplier
and is certified as such.
2. The equipment manufacturer must supply documentation that the component
meets the Standard, If any testing is required, it must be completed by the
equipment manufacturer.
The NSF maintains hundreds of Standards, but three standards which apply to plastic
products are:
# 51 - Plastics in Food Equipment : defines the material requirements for food protection,
considering extractables using FDA guidelines
# 61 - Drinking Water System Components -- Health Effects : covers indirect drinking water
additives and addresses health and toxicity effects of plastic resins.
# 14 - Manufacture of Fittings and for Accessories other than Pipe Fittings : applies to
thermoplastic and thermoset plastics piping system components in contact with potable
water and primarily addresses physical properties of plastic components in piping and
plumbing systems.
For further information on NSF Standards, contact NSF International, 3475 Plymouth Road,
P.O. Box 1301140, Ann Arbor, MI 48113-0140, by phone at (800) 673-7275, or visit them
at http://www.nsf.org on the Internet. Standards can also be ordered on-line.
USP CLASS VI
The United States Pharmacopeia (USP) is a voluntary, not-for-profit organization that promotes the
public health by establishing and disseminating officially recognized standards of quality and
authoritative information for the use of medicines and other health care technologies by
health professionals, patients, and consumers.
USP is responsible for establishing legally recognized product standards for drugs and other
health related articles in the United States. In the 1960's, methodology and requirements
were established for plastic materials used for pharmaceutical containers and closures, and
were subsequently adopted by medical device manufacturers. USP tests measure biological
reactivity of plastics in contact with mammalian cell cultures (in-vitro) and via implantation
and injection of extractables into laboratory animals (in-vivo). Plastics are classified into one
of six classes, each requiring different levels of testing. Class VI requires the most extensive
testing.
USP does not regulate compliance or certification of plastics tested according to their
published methods. The FDA has adopted some the tests specified by USP for regulation of
medical devices.
For further information on USP test methods, Reference USP 23 - NF 18, Chapters 87 - 88
and contact USP at U. S. Pharmacopeia, 12601 Twinbrook Parkway, Rockville, MD 20852,
by phone at (800) 822-8772, or visit them at http://www.usp.org on the Internet.
.
ASTM
The American Society for Testing and Materials (ASTM) is a not-for-profit organization, which
provides a forum for producer, users, and consumers to establish standards for materials,
products, systems, and services. ASTM standards are developed voluntarily and used
voluntarily. Standards become legally binding only when a government body references
them in regulations, or when they are cited in a contract. ASTM standards referenced in this
Guide pertain to characteristics of plastic resins prepared for property testing via injection
molding. Property values listed in these Standards are not always representative of
extruded shapes.
For further information on ASTM Standards, contact ASTM, 100 Barr Harbor Drive, West
Conshohocken, PA 19428-2959, by phone at (610) 832-9500, or visit them at
http://www.astm.org on the Internet.
UL
Underwriters Laboratories (UL) is an independent, not-for-profit organization chartered "to
establish, maintain, and operate laboratories for the investigation of devices, systems, and
materials with respect to hazards affecting life and property." "Listing", the most widely
recognized of UL's services, means that samples of a product have been evaluated, and
they comply with UL Standards. Products tested and recognized by UL are listed in a
Component Directory. Plastic Materials can be evaluated per the following UL Test Methods:
UL746A Polymeric Materials - Short Term Property Evaluations
UL746B Polymeric Materials - Long Term Property Evaluations
UL746C Polymeric Materials - Use in Electrical Equipment Evaluations
UL94 Test for Flammability of Plastic Materials
These tests are described in detail in Plastics Recognized Component Directory - Polymeric
Materials, Processes and Systems, available from UL.
IPI PLASTICS, INC
IPI PLASTICS, 1257 BIRCHWOOD DRIVE, SUNNYVALE, CA 94089
PH 408-734-4900
FAX 408-734-4995
Plastics for Medical Industry Applications
Every day, plastics are involved in critical surgeries, life-saving efforts, and routine medical
procedures. Plastic materials can be sterilized hundreds of times without degradation.
Lightweight plastics are used to form replacement joints, non-surgical supports, and therapy
equipment. Clear plastics provide visibility for transfusions, surgeries, and diagnostic
equipment of all kinds. And plastics can be machined, molded, or formed into almost any
shape imaginable.
The paragraphs below describe specific materials and their uses in this industry . . .
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PEEK (polyetheretherketone)
PEEK offers exceptional chemical resistance combined with heat resistance to 480°F.
It does not degrade with exposure to water or steam, and is flame- and radiationresistant. Because of these properties, PEEK can withstand the chemical and
mechanical stresses present during sterilization and chemical cleaning. This material
is available in sheet, rod and tube forms.
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PEEK-LSG
PEEK-LSG natural / black stock shapes are produced from selected batches of Victrex
®
PEEK PolyEtherEtherKetone resin. This material exhibits a unique combination of
mechanical properties, temperature and chemical resistance. This material is FDA
and USP approved and may be implanted for up to 24 hours. This material is
available in sheet and rod forms in natural (tan) and black colors.
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PEEK-CA30 LSG
PEEK-CA30 LSG PolyEtherEtherKetone stock shapes are produced from genuine
Victrex ® PEEK polymer. This 30% carbon fiber-reinforced grade combines even
higher stiffness, mechanical strength and creep resistance than KETRON ® PEEKGF30 LSG blue with an optimum wear resistance. This material is USP approved and
may be implanted for up to 24 hours. This material is available in sheet and rod
forms and is black in color.
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TecaPEEK ™ Classix
TECAPEEK ™ Classix PolyEtherEtherKetone white stock shapes are produced from
Invibio ® PEEK-CLASSIX ® White resin. This material exhibits a unique combination of
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mechanical properties, temperature and chemical resistance. This material is FDA
and USP approved and may be implanted for up to 30 days. This material is available
in sheet and rod forms and is white in color.
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TecaPEEK ™ MT
TECAPEEK ™ MT PolyEtherEtherKetone USP Class VI compliant PEEK is formulated to
be used in applications that are subject to contact with blood, bone or tissue for less
than 24 hours. Tecapeek MT is an excellent choice of material where high operating
temperatures, good radioactive resistance and extremely low resistance to cracking
make it an ideal material for medical components in medical device applications. This
material is available in sheet and rod forms and is available in standard colors of
Black, Red, Blue, Green and Yellow. Custom colors available upon special order.
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Tecason ™ P XRO
TECASON ™ P XRO PolyPhenylSulfone is a new line of x-ray opaque thermoplastic
shapes. A radio opacifer is added to the standard line of colored PPSU extruded rod
for orthopedic sizing trials and other instrument devices allowing for clear visibility of
the component on fluoroscopy and X-ray. This material is available only in rod form.
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Tecanyl ™ MT (PPE+PS-HI)
TECANYL ™ MT is a new shapes offering from Ensinger Industries and is produced
from GE Plastics’ NORYL ® PPE+PS (Polyphenylene Ether + PS-HI) HNA055 resin. Inhouse specimen testing performed at GE has demonstrated that NORYL ™ HNA055
resin is an excellent material candidate for medical device applications destined for
the repeated exposures of autoclaving cycles. It has good impact properties and is
easily machined. This material is available only in rod form. This material offers FDA
compliance.
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TecaMax ® Self-Reinforcing Polymer
TecaMax SRP has the highest strength-to-weight ratio and stiffness of any
thermoplastic available in the world today. Combined with its remarkable chemical
resistance and dimensional stability, TecaMax SRP is ideal for medical devices and
surgical instrumentation. Developed only recently, this material is available in
molded sheet and rod.
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Topas ® COC (Cyclic Olefin Copolymer)
Topas COCs have a very high moisture barrier, low water absorption, good resistance
to hydrolysis and chemical media, and low density. In addition, they typically offer
high transparency extending into the UV range, low birefringence, adjustable heat
deflection temperature and high rigidity. Examples of applications for Topas COC
plastics include films for pharmaceutical and personal health care blister packs, food
packaging, medical syringes and vials, diagnostic articles, optical lenses, light guides,
and optical sensors. This new material is available in molded sheet and rod.
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Ultem ® Polyetherimide
Because of its superior physical properties and its ability to withstand a wide
spectrum of sterilization methods, Ultem is often specified as the material of choice
in demanding reusable medical device applications. In Ultem's natural unpigmented
form, it meets the requirements of USP Class VI and is FDA compliant. Custom FDA
compliant colors further expand its appeal in a variety of applications such as color
coded orthopaedic provisional trials.
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Acetal Copolymer
Acetal Copolymer is a well-recognized engineering thermoplastic which is widely used
in many medical applications. Acetals may be steam autoclaved, are easily
machined, and are available in seven lot-controlled FDA-compliant colors. Acetals are
an excellent choice for color coded provisional trials. Acetals are also USP Class VI
compliant.
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Polystone ® P MG (Heat Stabilized Polypropylene)
Polystone® P MG Heat Stabilized Polypropylene sheet provides all of the outstanding
properties found in standard polypropylene, but has been subjected to a special
heat-stabilizing process. As a result, Polystone® P MG is able to withstand higher
service temperatures with less water absorption than standard polypropylene.
Recommended sterilization techniques include steam autoclaving and cold
sterilization. This lot-controlled material is available in WHITE & BLACK SHEET ONLY.
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Propylux ® HS (Heat Stabilized Polypropylene)
Propylux® HS Heat Stabilized Polypropylene sheet provides all of the outstanding
properties found in standard polypropylene, but has been subjected to a special
heat-stabilizing process. As a result, Propylux® HS is able to withstand higher service
temperatures with less water absorption than standard polypropylene.
Recommended sterilization techniques include steam autoclaving and cold
sterilization. This lot-controlled material is available in WHITE & BLACK SHEET ONLY.
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Propylux ® HS2 (Heat Stabilized Polypropylene)
Propylux® HS2 Heat Stabilized Polypropylene sheet provides all of the outstanding
properties found in Propylux® HS grade, but has been subjected to an advanced
heat-stabilizing process to offer higher temperature capability and additional
dimensional stability. The lot-controlled HS2 material is available in SEVERAL
COLORS (see datasheet for details).
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TecaPro ® MT (Heat Stabilized Polypropylene)
TecaPro® MT Heat Stabilized Polypropylene sheet provides all of the outstanding
properties found in standard polypropylene, but has been subjected to a special
heat-stabilizing process. As a result, TecaPro® MT is able to withstand higher service
temperatures with less water absorption than standard polypropylene.
Recommended sterilization techniques include steam autoclaving and cold
sterilization. This lot-controlled material is available in WHITE & BLACK SHEET ONLY.
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Radel® A PolyEtherSulfone
Radel® A PolyEtherSUlfone (PESU) is also sometimes called PolyArylSulfone. With
outstanding chemical resistance for an amorphous thermoplastic, Radel® A
withstands cold sterilants, disinfectants, and germicides. A UL 94 V-0 rated material
at .020" thickness, this is the material of choice for electro-mechanical surgical tools.
Dimensional stability and maintenance of physical properties at elevated
temperatures are among its key features. USP Class VI, FDA compliance and
compatibility with all sterilization techniques complete the list of features of this high
performance product.
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Radel® R PolyArylEtherSulfone
Radel® R PolyArylEtherSulfone (PAES) is also commonly referred to as
Polyphenylsulfone (PPSU). Radel® R has virtually unlimited steam sterilizability,
3
making it an excellent choice for medical devices. It also resists common acids and
bases -- including commercial washing solutions -- over a broad temperature range.
Radel® R is available in transparent, natural (bone white), and custom colors. It is
commonly used in sterilization trays, dental and surgical instrument handles,
orthopedic implant trials and in fluid handling coupling and fitting applications.
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Udel ® Polysulfone
One of the first high temperature thermoplastic materials to be sterilizable by all
techniques, polysulfone meets the demanding requirements of FDA and USP. The
availability of a clear grade makes this material the only choice for sterilizable
vacuum-formed medical equipment. Grades may be specified for ASTM F702-81
certification, other FDA specifications, and custom colors to complement this
material's broad offering to the medical industry.
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Noryl ® PPO (Polyphenylene Oxide & Styrene)
Noryl is an important structural material with high strength and excellent
temperature resistance. It may be machined to close tolerances and maintains
dimensional stability even when exposed to moisture. It may be used continuously at
temperatures in excess of 220°F. Some selected Noryl® grades offer FDA compliant.
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Polycarbonate
Some medical instruments or containers require glass-like transparency, FDA
compliance and excellent impact resistance. With these material parameters,
polycarbonate is sometimes the only suitable material, especially, where components
must be machined to close tolerances.
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ABS
ABS is a general purpose amorphous thermoplastic, providing good
impact strength, toughness, stiffness, and good chemical resistance. FDA compliant
grades are available. ABS is easily machined and is cost effective.
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UHMW-PE (Ultra High Molecular Weight Polyethylene)
The diverse uses of lot-controlled UHMW-PE range from standard wear applications
to implantable products. Biocompatibility, self-lubrication, and wear resistance are
among the major requirements of articulating surfaces made from UHMW-PE. The
biological response to UHMW in soft tissue and bone has been well characterized by a
history of clinical use. Traceability from resin through finished product is available to
meet ASTM F648-84 guidelines.
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Polystyrene
Known primarily for its clarity and good electrical properties, polystyrene is
frequently used in dosimetry applications where water is the recommended medium
of choice. The electron composition of polystyrene is almost the same as water, and
several of its physical parameters needed for dose measurement are well
established. Using a polystyrene phantom, one can determine the dosage necessary
to irradiate a tumor in a patient.
4
IPI PLASTICS
1257 BIRCHWOOD DRIVE
SUNNYVALE, CA 94089
PHONE 408-734-4900 FAX 408-734-4995
TYPICAL MECHANICAL PROPERTIES
STRESS - How much load or force will the part be required to carry. Load per unit area is called
“STRESS”
STIFFNESS- Called the “Modulus of Elasticity” the higher the number the stiffer the material
Conversely, the lower the number, the more flexible the material. These numbers can be
affected by temperature. Modulus is given in pounds per square inch.
TYPICAL TENSILE MODULUS VALUES (PSI)
GRAPHITE-EPOXY COMPOSITES
STEEL
ALUMINUM
EPOXY – GLASS LAMINATES
NYLON 30% GLASS REINFORCED
ACRYLICS
POLYCARBONATE
ACETAL
UHMW
40,000,000
30,000,000
10,000,000
5,800,000
1,400,000
500,000
450,000
410,000
100,000
STRAIN –This is the measurement of how much the part will change in dimension
STRAIN is measured by (final length (-) minus the original length / original length
Or
Change in length or deformation / original length
MODULUS =STRESS/STRAIN
THE PERFORMANCE OF A PLASTIC PART IS AFFECTED by
•
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•
•
•
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What kind of load the part will see(tensile, impact, fatigue)
How big the load is
How long or often the load is applied
How high and/or low a temperature the part will see
How long will it be at those temperatures
The kind of environment the part will be used in. Will moisture or other chemicals be
present?
1
IPI PLASTICS
1257 BIRCHWOOD DRIVE
SUNNYVALE, CA 94089
PHONE 408-734-4900 FAX 408-734-4995
YIELD POINT - is when the material is subjected to load, tensile or compression and will no
longer return to its original shape when released. Some materials may break before reaching
their yield point.
TENSILE STRENGTH – The maximum strength of a material being pulled without breaking. Think
of a marshmallow or taffy being pulled. This property is measured in PSI (pounds per square
inch)
TYPICAL TENSILE YIELD STRENGTHS (PSI)
STEEL
ALUMINUM
40% GLASS FILLED PPS
NYLON
ACRYLICS
POLYCARBONATE
ACETAL
POLYPROPYLENE
80,000
24,000
21,000
12,600
10,000
8,000
10,000
4,300
ELONGATION - Is always associated with tensile strength. It is expressed as a percentage of the
increase in its original length. For example a piece of paper 4” long is pulled until it tears. It
would have a 0% elongation as the paper does not stretch prior to tearing. Now do the same
thing with taffy, it will stretch several times its original length before breaking.
COMPRESSIVE STRENGTH – The maximum strength of a material without breaking when the
material is loaded. With materials such Teflon, this measurement is not necessarily meaningful,
as the material will continue to deform without breaking.
SHEAR STRENGTH – When the material is being pulled in opposite directions. An example
would be two piece of material glued together and then pulled in opposite planes until the joint
or the material separated.
2
IPI PLASTICS
1257 BIRCHWOOD DRIVE
SUNNYVALE, CA 94089
PHONE 408-734-4900 FAX 408-734-4995
TENSILE IMPACT STRENGTH – Designed to measure the toughness of a small sample without a
notch when subjected to a sudden tensile stress or load. Other Similar tests are the Gardner
Impact test (dropping of a shaped weight to determine the energy required to break the
sample.) Brittleness Temperature Test – ability of a material to absorb impact as the
temperature drops.
NOTCH SENSITIVITY - Some plastic materials have exceptional impact performance and very
good load bearing capabilities. However the performance of these materials can be greatly
reduced by having sharp corners or notches in the material.
A SHARP CORNER IS A GREAT PLACE FOR A CRACK TO START. MINIMIZING SHARP CORNERS
MAY MAKE THE MACHINING OPERATION MORE DIFFICULT.
The Izod impact strength of a tough material like Polycarbonate is reduced from 20 to 2 as the
radius of the notch is reduced from .020”R to .005” R respectively.
THERMAL PROPERTIES
COEFFICIENT OF EXPANSION – With a change in temperature plastic materials tend to change
size considerably more than other materials, such as steel and ceramics. The measure of how
much a part changes size as the temperature changes is called “THERMAL COEFFICENT OF
EXPANSION”
Typical coefficients of expansion (in/in/F)
Polyethylene
Acrylics
Acetal, Copolymer
Polycarbonate
Aluminum
Polycarbonate
30% Glass Filled
Steel
Glass
3
.000140
.000060
.000047
.000037
.000013
.000009
.000008
.000004
IPI PLASTICS
1257 BIRCHWOOD DRIVE
SUNNYVALE, CA 94089
PHONE 408-734-4900 FAX 408-734-4995
COEFFICIENT OF EXPANSION (cont’d)Assuming a material, how much will a 10 inch dimension change if the temperature changes by
40 degrees Fahrenheit?
The change in length =Original Length x the coefficient of expansion x the change in temperature
Acrylic
=10 x .00006 x 40 = .024 inches
Polycarbonate
=10 x .000037 x 40 = .0148 inches
Glass
=10 x .000004 x 40 = .0016 inches
Assuming you are cutting material for large window lite 100” in one direction you would have to allow
Acrylic .240”
Polycarbonate .150”
Glass.016”
From this you can see replacing existing glass with Acrylic may require alterations to the existing framework
And the type of fastening may also have to be altered or changed.
Coefficient of expansion is also critical to consider when bonding two different substrates with
adhesives.
DEFLECTION TEMPERATURE UNDER LOAD – In addition to changing size, the strength and
modulus of plastic materials tend to decrease as the ambient temperature increases. The
standard test for determining the DEFLECTION TEMPERATURE UNDER LOAD (DTUL) at 66 and
264 psi provides information on the ability of a material to carry a load at higher temperatures.
The 66 psi is for a light load and 264 psi is for a heavy load on a beam. The temperature of the
loaded beam is raised until certain amount of deflection is observed. The temperature when
the deflection is reached is called DTUL. Plastics usually have a higher DTUL at 66 psi than 264
psi because of lower loads.
The DTUL IS SOMETIMES REFERRED TO AS Heat Distortion Temperature
Impact strength is also affected by changes in temperature in most plastics. The changes in
strength can be significant, especially as the temperature is lowered.
THERMAL CONDUCTIVITY –Plastics are good thermal insulators, that is heat does not travel easily
through them. The thermal conductivity of plastics is 300 to 2500 times poorer than with metals. This
property explains why it takes a long time for large plastic cross sections to cool down in the middle.
Internal stress can be set up in a material because of the difference in the cooling rates between the
outside of a part and its core
4
IPI PLASTICS
1257 BIRCHWOOD DRIVE
SUNNYVALE, CA 94089
PHONE 408-734-4900 FAX 408-734-4995
ELECTRICAL PROPERTIES – Plastics are generally very good electrical insulators and offer
freedom of design in electrical products. Electrical properties may also change by
environmental conditions, such as moisture and/ or temperature, or by the additions of various
fillers such as carbon, graphite, or metal fibers to the plastic.
VOLUME RESITIVITY – is defined as the ratio between the voltage supplied from an outside
source and that portion of current that flows through a specific volume of the plastic specimen.
Units are generally ohm per cubic centimeter.
SURFACE RESISTIVITY – IS THE RATIO BETWEEN DIRECT VOLTAGE AND CURRENT ALONG THE
SURFACE PER UNIT OF WIDTH. Units are generally ohms.
DIELECTRIC STRENGTH – is the voltage difference between two electrodes at which electrical
breakdown occurs and is measured as volts per mill of thickness. This is an indication of how
effective an insulator the material is.
ARC RESISTANCE – is the elapsed time in which the surface of the material will resist the
formation of a continuous conductive path when subjected to a high voltage
DISSIPATION FACTOR – is the tangent of the loss angle of the insulating materials. It can also be
described as the ratio of the true in phase power to the reactive power measured with voltage
and current 90 degrees out of phase. This is an indication of the energy lost within the material
trying to realign the molecules every time the current (voltage) changes direction in alternating
current. The property varies with moisture, temperature and frequency.
5
IPI PLASTICS
1257 BIRCHWOOD DRIVE
SUNNYVALE, CA 94089
PHONE 408-734-4900 FAX 408-734-4995
ESD Materials Categories
Materials for protection and prevention of Electrostatic Discharge (ESD) can be
categorized into three distinct groups -- separated by their ranges of conductivity to
electrical charges.
Anti-Static:
Resistivity generally between 109 and 1012 ohms per square.
Initial electrostatic charges are suppressed.
May be surface resistive, surface-coated or filled throughout.
Static Dissipative (SD):
Resistivity generally between 106 and 109 ohms per square.
Low or no initial charges -- prevents discharge to from human contact.
May be either surface-coated or filled throughout.
Conductive (CN):
Resistivity generally between 103 and 106 ohms per square.
No initial charges, provides path for charge to bleed off.
Usually carbon-particle or carbon-fiber filled throughout.
6
IPI PLASTICS
1257 BIRCHWOOD DRIVE
SUNNYVALE, CA 94089
PHONE 408-734-4900 FAX 408-734-4995
WHY USE PLASTICS
1. WEIGHT – generally lighter than metal or glass
2. CORROSION RESISTANCE- Doesn’t rust like metal, or rot like wood
3. IMPACT RESISTANCE – doesn’t shatter like glass, less likely to have
permanent indentations like metal
4. NOISE ABATEMENT
5. ABRASION RESISTANT- Doesn’t wear down as quickly as most other
products in side by side tests
6. LOW FRICTION-Many plastics have low coefficient of friction, or additives
such as silicone, Teflon, graphite and others to increase the plastics internal
lubricity
7. EASE OF MACHINING / FABRICATION – material is easily machined or
formed into other shapes
8. ELECTRICAL RESISTIVITY – most unfilled plastics have natural electrical
insulating properties
9. AESTHETICS – Plastics are available in many shapes and sizes and can be
colored internally or painted.
10.ENVIORMENT-Many plastics resist moisture, and are UV resistant or can
have UV additives put in during the initial processing.
11.TENSILE and LOAD REQUIREMENTS – Plastics can have glass, mineral or
other fibers added to increase the stiffness of the material.
CAUTION
IT IS THE CUSTOMERS RESPONSIBILTY TO TEST IN THE FINAL APPLICATION.
SPECIFICATIONS ARE A BROAD GENERAL APPROACH TO WHAT MIGHT WORK AND LIMIT
THE NUMBER OF MATERIALS TRIED.