Other Welding Methods

When thick-walled hollow molded artieles and molded articles with a shape having thick-walled sections and thin-walled sections are produced, the molded article is produced in two parts. These parts are eventually eon-nected by welding. Alternatively, the two parts are placed in another mold so that they face each other at the parting lines. Then, molten resin is injected about the periphery of the opposed faces to connect the parts. This technique is addressed as insert molding, or overlap molding. Other welding methods include ... 

Ultrasonic welding is the most common thermal assembly process used with polybuty-lene terephthalate parts. However, heated tool welding and other welding methods have proven satisfactory joints when bonding PET and PBT to itself and to dissimilar materials. Solvent cementing is generally not used to assemble PET or PBT parts because of their solvent resistance. 

Spin welding is an old and uncomplicated technique. The equipment required can be as simple as lathes or modified drills. Spin welding has a lower capital cost than other welding methods. The base equipment required is comparatively inexpensive however, auxiliary equipment such as fixtures, part feeders, and unloaders can drive up the cost of the system. Depending on the geometry and size of the part, the fixture that attaches the part to the rotating motor may be complex. A production rate of 300 parts/min is possible on simple circular joints with an automated system containing multiple heads. 

Vibration welding is ideally suited to parts injection molded or extruded in engineering thermoplastics as well as acetal, nylon, polyethylene, ionomer, and acrylic resins. Almost any thermoplastic can be vibration welded. Unlike other welding methods, vibration welding is applicable to crystalline or amorphous or filled. 

Induction welding is less dependent than other welding methods on the properties of the materials being welded. It can be used to weld almost all thermoplastics, crystalline and amorphous. 

A number of other deposition methods have been used for growing diamond, with varying degrees of success. These include oxyacetylene welding torches, arc jets and plasma torches, laser ablation and hquid phase crystallisation, but none of these yet reahstically compete with the hot filament or microwave systems for reliability and reproducibility. 

Record of the heat treatment temperature cycle shall be monitored by attached thermocouple pyrometers or other suitable methods to ensure that the requirements are met. See para. GR-3.4.12 for attachment of thermocouples by the capacitor discharge method of welding. 

Pipeline systems shall be tested after construction to the requirements of this Code except for pretested fabricated assemblies, pretested tie-in sections, and tie-in connections. The circumferential welds of welded tie-in connections not pressure tested after construction shall be examined by radiographic, ultrasonic, or other nondestructive methods in accordance with para. PL-3.19.2. 

In the electrical and electronic equipment market, adhesives compete with other joining methods such as mechanical fasteners, brazing, welding, soldering, and thermocompression bonding. Major uses of adhesives in the electrical and electronic equipment market are shown in Table 1.5. Adhesives are generally the preferred method of joining whenever... 

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