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film coatings of zirconia and alumina.

Knowledge is Base Coat A great deal of care and effort is necessary 		to obtain optimum coating quality. While computer technology makes operating vacuum-coating equipment easier than ever, there is still a required discipline in the area of preventative maintenance and operating procedures.
Paying the toll

Despite the likelihood that in-house tool coating will expand due to the growing availability of less costly coating equipment, hundreds of smaller toolmaking companies will continue to oursource the service.
For the past 20 years, the coating-service industry, particularly PVD, has shown continuous growth in North America. The industry is characterized by a limited number of large, nationwide centers, a few regional coaters and an increasing number of smaller local coaters.
On Jan. 1, 2000 the Surface Engineering Coating Association was formed. SECA includes 16 coating cervices companies (see list). By visiting the association's Web site at www.taol.com/seca, you can obtain information about the organization and its members.
In addition to SECA members, there is a considerable number of additional coating companies throughout the U.S., plus a number of


foreign companies.
It is important to realize that PVD is really a "family" of processes and not just one technology. For example, a TiN coating from one supplier using a certain process technology may have a different coatin structure than a TiN coating from another supplier. This could mean different properties of one vs. the other, leading to varying tool performances.
Therefore, it is critical to determine which coating chemistry and which specific process technology is best suited to your tool in a particular application under specific operating conditions. Granted, this can be a tall order. It requires time and effort to conduct tests and generate and analyze data.
Service and delivery are key factors in the tool-coating business, and the standard service goal of many tool coaters is 3 to 5 days, but often tools can be processed in 24 to 48 hours.
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Purchasers of PVD-coating equipment are given extensive operational and maintenance training by the equipment vendors. It is then up to the purchaser to ensure that is operations understand the requirements of thin-film vacuum coatins and provide a highly disciplined operating procedure. This includes constant monitoring of the process to ensure desired quality is maintained.
To successfully operate an in-house coating center, proper tool cleaning and pretreatment is necessary. This is the area I refer to as "interface engineering," which assures that the tool surface is optimally prepared to provide the best possible adhesion of the thin-film coating to the tool surface.
The preparation of a tool surface prior to the coating operation is significantly more demanding than for an uncoated tool. The thin films range in thickness from, say, 1 to 5 microns, with the average being 2.5 microns, or 0.0001". Thus even minute too-surface imperfections can be fatal to high quality coatings, particularly with regard to adhesion.
Microburrs on the tool surface may have little effect on the performance of an uncoated tool. However, they can have a major impact on the thin-film coating, causing problems in the early stages of the machining operation.
While there is very little downside to operating your own coating equipment from an environmental aspect--the PVD thin-film vacuum-coating process is will-known an "environmentally friendly"--tool precleaning is another matter. Most process water used is in a closed-loop system, but the solid waste generated in the cleaning phase must
For additional information on tool coating equipment and tool coatings, go to "Article Search" at www.ctemag.com and enter the keywords "coating equipment" and "coatings." And while at our site, you can look up suppliers of this equipment and materials in the online Buyers Guide.