This area will cover physical repair. The number of technologies available for repair of mechanical systems has increased 4 fold in the last 10 years.

As the cost of raw materials and replacement arts and systems continues to increase and repair parts become less available due to the age and multiplicity of products in the field knowledge of and use of the most cost effective technology becomes more necessary.

With the advent of epoxies and lasers the options for repair that are available has increased and in many cases the cost of repairs has decreased significantly.

The second area of repair that has been impacted by new technology is the ability to have in place repairs without the total disassembly of the equipment requiring the repair.

Finally, with the advent of new technologies the application of material and alloys that can positively improve both performance and longevity of the equipment are available.

What are these technologies? They start with the development of brush plating into a process that can provide interstitial bonding of the coatings to the substrate (the only process that fuses the electron fields of the coating to the substrate at temperatures below 150 deg. F/97 deg. C). The use of filled epoxies can go to 300 deg. F/ 180 deg. C. The fill allows for the epoxy to expand and contract at the same rate as the substrate minimizing the shear stress at the adhesion surface. It is also very effective in filling holes. A new type of filled epoxy* is available that allows for plating on the surface. This allows for a hard metal wear surface on the repair which will allow for the use of the epoxies in motion wear areas.

Coatings can be applied by metal spray; flame, plasma spray brazing, detonation coating, and laser. Pits can be repaired by dot welding, arc welding, torch welding, brush plating and filled epoxies.

Damaged bores can be repaired by boring with sleeve replacement. In general, the problem lies in the concentricity of the bore to the supporting structure. Damaged shafts can be rebuilt with sleeves or coatings. In general, the problem of concentricity occurs here also. In both cases four jaw chucks are used. There is available now a three jaw chuck with adjustable jaw faces* which significantly reduces the time required for finishing.

Cracked castings and metal enclosures can be repaired by a process, while not new, has not been discussed in repair. The process is called “Metal Stitching”. It was developed by General Electric and involves the use of high strength steel placed at right angles across the cracks inserted I pre-drilled slots. Crack stoppers are drilled at the end of the cracks. *patents by WR Associates Inc.