Heat staking

Responds well to joining technologies, such as chemical bonding, ultrasonic welding, vibration welding, and heat staking... 

Ultrasonic equipment can also be used for mechanical fastening operations. Ultrasonic energy can be used to apply threaded inserts to molded plastic parts and to heat stake plastic studs. 

Snap-fits are injection-molded into the two components of the assembly. Two general heat staking methods are low profile and high profile. Methods of the two types include spherical, flush, hollow, and knurled. In addition, there are cements and adhesives, and a mechanical fastening assembly. Whatever assembly method is used, the choice is usually made at the design stage. 

When two pieces of plastic must be joined together in service but must also be suited to simple disassembly, threaded joints are possible. Such joints may be plastic to plastic, as in toothpaste tubes and caps, where male and female threads are molded. If metal screws are to be used, female threads can be molded in a plastic part to accept the metal screw. If such a threaded application does not have to withstand much tension in the screw, a selftapping screw may be turned into a molded hole of appropriate diameter. Self-tapping screws designed for plastics applications are better suited than those for metal appUca-tions. Metal female-threaded inserts may be molded into plastic parts to accept metal screws in a subsequent assembly operation. Metal female-threaded inserts may also be staked into a molded hole of appropriate size, sometimes mechanically, often with heat ( heat staking ) to soften the thermoplastics at the interface so as to achieve more positive bonding (Figs. 9.16 and Fig. 9.17). 

Premium Products. By the late 1970 s two dry process forms, Polish Air Prills and Procor GX granules were emerging as the front runners in the premium product stakes. Although air is the common heat sink in both of these processes the mechanism of... 

Foxgloves enjoy a shady site with rich, moist, well-drained, slightly acidic soil. Plants tolerate full sun, but favor cool weather and need shade in extreme summer heat. Water regularly to maintain soil moisture. Stake tall cultivars to support flower spikes plant in a sheltered site. Remove foxgloves after they have set seed and self-sown next year s crop. Cutting flowers before they set seed promotes second-year blooms, but flowering is reduced the second year. 

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