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 candidates and the final selection is then 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, UHMW, Delrin, nylon, 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 list of questions or considerations should be used to define the
application as 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
What are the overall part dimensions (diameter, length, width, thickness)?
What load will the part have to carry?
Will the design carry high loads?
What will the highest load be?
What is the maximum stress on the part?
What kind of stress is it (tensile, flexural, 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
What temperatures 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 be at 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
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 submerged or wiped with solvents or other chemicals?
If so, which ones?
Will the material be exposed to chemical or solvent vapors? If so, which
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
the load, shaft diameter, shaft material, shaft finish, and rpm be?
What wear or abrasion condition will the material see? Note: Materials
filled with friction reducers (such as PTFE, molybdenum disulfide, or
graphite) generally exhibit less wear in rubbing applications.
Other Miscellaneous Considerations
Will the part have to meet any regulatory requirements?
FDA | USDA | Canada AG | 3A-Dairy | NSF | USP Class VI
Is UL94 Flame retardant rating required? What level?
5VA | 5VB | V-0 | V-1 | V-2 | HB
Should the material have a special color and/or appearance?
Natural | White | Black | Other Colors
Color match to another part or material?
Window-Clear | Transparent | Translucent | Opaque
Smooth | Polished | Textured | One-Side or Both
Will the part be used outdoors?
Is UV Resistance needed?
Is static dissipation or conductivity important?
Insulator | Static Dissipative | Conductive
After answers to the above list of questions (or at least some of them) have been
determined, please contact us for further assistance. Our sales or engineering staff
will be happy to help you choose one or more available plastic materials that will
meet your requirements. We stock almost all of the materials we sell, so we can
provide samples or small pieces for your evaluation.
Plastic Material
©
Copyright Boedeker Plastics, Inc.
2008