Ultrasonic welding, vibrational welding, and spin welding have all been used for joining Ryton® PPS parts. However, welds generally have rather low strength compared to the bulk material because the weld is primarily composed of neat polymer with little or no glass fiber reinforcement. The 40% glass filled Ryton® PPS compounds (R-4 Series) are generally easier to weld than the more highly glass and mineral filled Ryton® PPS compounds (R-7, BR111, and R-10 Series). For ultrasonic welding, shear joints are preferred, and butt joints should never be used with glass and mineral filled compounds. Ultrasonic welding should be done using high power with a high amplitude booster, low pressure, and slow horn speed. For more information see our TSM-324 Ultrasonic Welding Ryton® PPS Compounds or contact your nearest Customer Service Center for a copy.
Ryton® PPS parts may be fastened to other components by ultrasonic staking or heat staking. "Low-profile" head-forms that produce a head 1.5 times the diameter and one-quarter the height of the original post may be used, but “standard” head-forms that produce a head having twice the diameter and half the height of the original post generally provide better strength. Heat staking a typical 0.125 in (3.18 mm) diameter post requires a temperature of about 590°F (310°C) for an amorphous part or about 620°F (327°C) for a crystalline part, with a downward force of about 150 pounds (68 kg) applied for about 40 seconds. Due to the abrasive nature of the fillers and reinforcements used in Ryton® PPS compounds, we recommend that staking tips be made of a hardened steel having a Rockwell C-60 hardness or better. For more information see our PTC-393 Heat Staking of Ryton® R-4 and Ryton® R-7 or contact your nearest Customer Service Center for a copy.
In any welding or staking process, the PPS resin is melted and rapidly cooled, so the PPS polymer in the weld or head will be in the amorphous state. Therefore, welded or staked assemblies may need to be annealed if the application requires a thoroughly crystalline part. See Mold Temperature, Crystallinity, and Annealing for further discussion of this issue.
