Metal Finishing Guide Book

2012 Organic Finishing Guidebook Issue

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Page 175 of 331

tim with a greater appreciation for using protective eyewear. UVB lamps are used for tanning beds and booths as well as for the treatment of dermatitis. UVB can irritate eyes, but to a lesser degree than UVC. The UV component of natural sunlight spans the entire UVA band and en- croaches into the UVB range. Generally, UVA and B are used for UV processing of UV-curable coatings. It is important to note that most materials absorb UV light, rather than reflect it. As UV light is invisible to the naked human eye, transparent materials may ap- pear to be transparent but in fact may be only allowing visible light to pass through. The only way to determine UV opaqueness is to use a UV radiometer to measure how much UV the material allows through. It should never be presumed that a material would block or pass UV light simply from observing the amount of visible light that passes through material. Where special UV-transparent quartz passes most UV light, common glass is almost opaque to natural UV. For this reason, tanning through common glass is not possible. This is also the reason why UV light hazards are trivial to manage. Generally, the same safety precautions used for arc welding light are applicable to managing UV processing equipment. UV equipment vendors provide ample literature and guidance regarding UV light safety. Properly designed, installed, and used UV equipment should not pose a serious UV light hazard in the workplace. UV-CURABLE COATINGS: "LIQUID POWDER" UV-curable coatings are polymeric coatings that are applied as a liquid at room temperature; solidified nearly instantaneously on exposure to UV light into a pro- tective coatings; and capable of "lock-and-key" engineering of their physical properties. Having the benefits of both liquid and powder coating systems UV-curable coat- ings also have the ability to be engineered to a lock-and-key fit to specific ap- plications. Multifunctional systems, such as oil-laden phosphate coatings and E-coat systems, have an advantage over single-coat, single-function protective films. The advantage is their ability to effectively protect the metal surface by acting as a barrier to oxygen and water. In the case of phosphate coatings, deposited phos- phate crystals act as a reservoir of oil-borne corrosion inhibitors, which displace water and passivate metal with the inhibitors. E-coat forms an effective barrier by being deposited as a near-perfect barrier film. The ability to engineer coatings with specific lock-and-key properties creates an extraordinary coating system for a wide range of metal coating and finishing applications. UV technology is such a competitive advantage that its utilization is a close- ly guarded secret by manufacturers using it in their production. As such, case stud- ies or photographs of operational UV production lines are rarely if ever released by manufacturers. In addition to remarkable processing advantages and physi- cal properties, UV processing offers the following competitive advantages to manufacturing operations: • UV eliminates the need for third-party coating due to Title V EPA emission limitations • In-house coating operations eliminate costs of third-party processing • In-house coating eliminates freight costs on parts to/from third-party 174

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