Nylons can absorb up to 7% (by weight) water under high humidity or submerged in water. This can result in dimensional changes up to 2% and a corresponding reduction of physical properties. Proper design techniques can frequently compensate for this factor.
In general, acetals do not perform as well in abrasive wear applications as nylons. Compensation for moisture related growth generally allows nylons to be used for wet, abrasive applications. If your application requires dimensional consistency in an abrasive, high humidity or submerged environment, PET-P will often offer improved performance.
Because it is more rigid and offers greater thermal performance than nylon and acetal, Ertalyte machines differently. Ertalyte and other polyesters have less resistance to hot water than Acetron GP POM-C acetal.
Quadrant PC 1000 polycarbonate is machine grade, not optically clear. It can be both mechanically and vapor polished to improve optical clarity. Caution: During machining, never use coolants with an aromatic base.
Polysulfone is not a wear material and may stress craze under high pressures in certain chemical environments.
Quadrant PPSU has been approved for use in a variety of medical devices, it is FDA compliant and is appropriate for food contact applications.
Quadrant PPSU is not a wear material, and its properties degrade when exposed to sunlight.
Since Duratron PEI is an amorphous material, selection of appropriate non-aromatic coolants during machining is important.
Care must also be used in selecting adhesives and designing press fit components to avoid stress cracking.
Duratron PEI is not designed for use in bearing and wear applications.
Due to its PTFE matrix, Fluorosint's physical strength characteristics are not as high as other advanced engineering plastics like Ketron 1000 PEEK or Duratron PAI.
PPS products offer dimensional stability and strength at moderate temperatures. They are rated for continuous service to 425°F (220°C), but strength and stiffness vary based on temperature and grade.
Unreinforced Techtron PPS is generally not recommended for wear applications. Products like Techtron HPV, Duratron PAI or Ketron PEEK are better selections for wear applications.
When designing with Quadrant's compression molded grades, it is important to note its relatively low elongation and impact strength.
The stiffness of all PEEK grades drops off significantly and expansion rate increases above its glass transition temperature (Tg) of 300°F (150°C). A material like Duratron PAI would be better suited for close tolerance bearings or seals operating at temperatures higher than 300°F (150°C).
As Duratron PAI has a relatively high moisture absorption rate parts used in high temperature service or made to tight tolerances should be kept dry prior to installation. Thermal shock resulting in deformation can occur if moisture laden parts are rapidly exposed to temperatures above 400°F (205° C).
Duratron PBI is extremely hard and can be challenging to fabricate. Polycrystalline diamond tools are recommended when fabricating production quantities. Duratron PBI tends to be notch sensitive. All corners should be radiused (0.040" min.) and edges chamfered to maximize part toughness.
High tolerance fabricated components should be stored in sealed containers (usually polybags with desiccant) to avoid dimensional changes due to moisture absorption.
Components rapidly exposed to temperatures above 400°F (205°C) should be "dried" prior to use or kept dry to avoid deformation from thermal shock.
It is important to know how applied voltage affects the resistance of a material. Some materials exhibit high resistance at low voltages, but when subjected to harsher conditions, they can fail. This is due to dielectric breakdown and is irreversible. Since static electricity can be several thousand volts, consistent performance across the voltage range must be considered. Some materials are very inconsistent and vary on the "grain" of machining.
|NOTE: The information contained herein are intended for reference and comparison purposes only. They should NOT be used as a basis for design specifications or quality control. It is given without obligation or liability. Contact us for manufacturers' complete material property datasheets.|