Plastic joining is the method of joining semi-finished products of plastic materials together or to other materials as a fabrication process or damage repair. Joining methods can be classified into three categories:
# Mechanical fastening,
# Adhesive bonding,
# Welding.
Mechanical fastening
Mechanical fastening methods can offer an advantage of disassembly, but have drawbacks arising from stress concentrations,
galvanic corrosion
Galvanic corrosion (also called bimetallic corrosion or dissimilar metal corrosion) is an electrochemical process in which one metal corrodes preferentially when it is in electrical contact with another, in the presence of an electrolyte. A sim ...
, mismatch of
thermal expansion coefficient
Thermal expansion is the tendency of matter to change its shape, area, volume, and density in response to a change in temperature, usually not including phase transitions.
Temperature is a monotonic function of the average molecular kinetic ...
s, etc. which rivets, screws and ropes can introduce (see
fastener
A fastener (US English) or fastening (UK English) is a hardware device that mechanically joins or affixes two or more objects together. In general, fasteners are used to create non-permanent joints; that is, joints that can be removed or disman ...
s).
Adhesive bonding
Adhesive bonding, which involves a chemical process where a substance is used to create a bond between two materials, is problematic because of extensive surface preparation, long curing time, the difficulty of bonding adhesive materials to plastics, etc.
Welding
Welding can eliminate these shortcomings largely, but its applications are restricted to
thermoplastics
A thermoplastic, or thermosoft plastic, is any plastic polymer material that becomes pliable or moldable at a certain elevated temperature and solidifies upon cooling.
Most thermoplastics have a high molecular weight. The polymer chains associate ...
.
See also
*
Adhesive bonding
Adhesive bonding is a joining technique used in the manufacture and repair of a wide range of products. Along with welding and soldering, adhesive bonding is one of the basic joining processes. In this technique, components are bonded together usi ...
* Mechanical
fastener
A fastener (US English) or fastening (UK English) is a hardware device that mechanically joins or affixes two or more objects together. In general, fasteners are used to create non-permanent joints; that is, joints that can be removed or disman ...
s
*
Plastic welding
Plastic welding is welding for semi-finished plastic materials, and is described in ISO 472 as a process of uniting softened surfaces of materials, generally with the aid of heat (except solvent welding). Welding of thermoplastics is accomplishe ...
*
Rheological weldability Rheological weldability (RW) of thermoplastics considers the materials flow characteristics in determining the weldability of the given material. The process of welding thermal plastics requires three general steps, first is surface preparation. T ...
for plastics
*
Weldability The weldability, also known as joinability,. of a material refers to its ability to be welded. Many metals and thermoplastics can be welded, but some are easier to weld than others (see Rheological weldability). A material's weldability is used to ...
*
Welding
Welding is a fabrication (metal), fabrication process that joins materials, usually metals or thermoplastics, by using high heat to melt the parts together and allowing them to cool, causing Fusion welding, fusion. Welding is distinct from lower ...
References
{{Reflist
Plastics