Joining+i.e+welds,+permanent+joining+techniques,+adhesives

Type in =Joining=

11.1.1 Describe friction welding.
//Friction welding is a completely mechanical solid-phase process in which heat generated by friction is used to create the ideal conditions for a high-integrity welded joint between similar or dissimilar metals.//

11.1.2 Explain how two metal parts are welded using friction.
//Diagrams should include two parts, one revolving, and the other fixed.//
 * [[image:http://www.weldguru.com/images/fig10-79.gif height="400" link="@http://www.weldguru.com/images/fig10-79.gif"]] ||  ||

11.1.3 Describe plastic welding.
//Consider hot air and friction welding techniques.//
 * Wikipaedia reference.
 * Below video on hot air welding

11.1.4 Explain how two plastic parts are welded together.
//Only thermoplastics that do not burn or decompose when heated to their softening temperature can be welded.//

11.1.5 Define permanent joining techniques.
Permanent joining techniques //A permanent join is a type of fastening that is not supposed to be removed. It is only possible to remove such joins by drilling, cutting or grinding the join away.//

11.1.6 List a range of permanent joining techniques.
//Consider pop-rivets, brazing, welding and adhesives.//
 * [[image:http://www.aeroassemblies.com/images/pop/rivets.jpg height="200" link="@http://www.aeroassemblies.com/images/pop/rivets.jpg"]] || [[image:http://www2.roguecc.edu/welding/images/welder1.jpg width="250" link="@http://www2.roguecc.edu/welding/images/welder1.jpg"]] ||
 * Pop-rivets || Welding ||
 * [[image:http://www.artinsteel.co.uk/USERIMAGES/brazing2.jpg height="200" link="@http://www.artinsteel.co.uk/USERIMAGES/brazing2.jpg"]] || [[image:http://www.apexfastenings.com/images/adhesives_2.jpg width="250" link="@http://www.apexfastenings.com/images/adhesives_2.jpg"]] ||
 * Brazing || Adhesives ||

11.1.7 Discuss how permanent joining techniques lead to planned obsolescence and environmental issues.
//Permanent joins do not allow for the disassembly and easy maintenance of products.//

11.1.8 Define adhesive.
Adhesive //An adhesive is a substance that is applied between two surfaces in order to bond them together.//

11.1.9 Identify a range of adhesives suitable for joining metals, woods and plastics.
//PVA (polyvinyl acetate), epoxy resin, contact adhesive, cascamite, tensol cement and superglue (cyanoacrylate).//

11.1.10 Discuss the advantages and disadvantages of using adhesive bonding in products.
//Consider preparation of surfaces, clamping, bonding time, type of material, and health and safety.// Adhesives present several distinct advantages over conventional methods of bonding:

However, there are also disadvantages which may make adhesive bonding impractical:
 * 1) Provide large stress-bearing area
 * 2) Provide excellent fatigue strength
 * 3) Dampen vibration and absorb shock
 * 4) Minimize or prevent galvanic corrosion between dissimilar metals
 * 5) Join all shapes and thicknesses
 * 6) Provide smooth contours
 * 7) Seal joints
 * 8) Join any combination of similar or dissimilar materials
 * 9) Often less expensive and faster than mechanical fastening (can be automated)
 * 10) Heat, if required, is too low to affect metals parts
 * 11) Provide attractive strength-to-weight ratio.

Quoted from @http://www.bostik.com/products-services/products-services.php?id=1023&idtype=257 the content of your page here.
 * 1) Surface must be carefully cleaned
 * 2) Long cure times may be needed
 * 3) Limitation on upper continuous operating temperature
 * 4) Heat and pressure may be required
 * 5) Jigs and fixtures may be needed
 * 6) Rigid process control usually necessary
 * 7) Inspection of finished joint difficult - Non distinctive testing not always possible
 * 8) Useful life depends on environment
 * 9) Special training is often required.