Mechanical finishing

Mechanical finishing (dry finishing) is a surface treatment of textiles by means of special mechanical processing machines. A multitude of mechanical finishing processes were developed to generate special fabric characteristics. The three most important processes are listed in Table 9.3. 

Shearing Leads to a smooth and even fabric surface (outerwear, especially woolen). 

The fabric runs between shearing cylinder and screw-like shearing blades. The sharp deflection allows the cutoff of projecting fibers. 

Gigging Leads to a rough fabric surface, for example, for loden cloths. 

The fabric runs under slight tension over brush-like rollers. Depending on tension, roller rpm, and surface, the surface effect can vary. 

Drilling Glass is drilled with carbide or bonded diamond drills rmder a suitable coolant such as water or kerosene. Other drilling processes include a metal tube rotating about its axis, an ultrasonic tool in combinarion with abrasive slurry, or an electron beam. 

Grinding Glass is ground with diamond, silicon carbide, garnet and sand. These materials are used loose, as in the grinding process employed for plate glass. They are bonded in grinding wheels or coated on fabric belts. 

Mechanical polishing It is more or less similar to grinding, but the polishing compound (cerium oxide, ferric oxide) is finer. The polishing tool may be plastic, cellulose and pitch. A mixture of hydrofluoric and sulphuric acids is used for acid-polishing. 

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Tannery B. This tannery, also located in New England, employs 80 workers who process about 700 hides per day producing fully tanned and colored leather which are shipped to a separate facility, Tannery E, for surface and mechanical finishes. During the site visit on October 12, 1978, 19 air samples and 4 bulk samples were collected. The air samples were collected at all stages of the tanning operation. The bulk samples consisted of two waste water specimens, one steam system condensate and one floor scraping from the dye room. 

Many of the finishes applied to other types of metal products can also be applied to zinc die castings, although some differences in formulation as well as occasional differences in method of application may be desirable. The types of finishes applicable to zinc die castings include mechanical finishes (buffed, polished, brushed, and tumbled) electrodeposited finishes (copper, nickel, chromium, brass, silver, and black nickel) chemical finishes (chromale, phosphate, molybdate and black nickel) and organic finishes (enamel, lacquer, paint and varnish, and plastic finishes). Electrodeposited coatings of virtually any metal capable of electrodeposition can be applied to zinc die castings. 

Lockett A P, Mechanical finishing - traditional and modem , in Textile Finishing, HeywoodD (ed.), Bradford, Society of Dyers and Colourists, 2003,114—134. 

Because the pharmaceutical industry requires smoother product/solution contact surfaces to achieve a purer product with less danger of bacteria growing in surface defects or cross-contamination of one product with another,in addition to purely mechanical finishes, sanitary tubing and components are also available in highly polished surfaces. 

Only highly dense ceramics with high thermal shock resistance can be utilized for such strongly mechanically and thermally stressed components. These demands are met by hot-pressed silicon carbide produced at pressures of 350 bar and sintering temperatures of 1900 to 2000°C. The necessary, but very expensive, mechanical finishing is disadvantageous for industrial manufacture of hot-pressed silicon carbide. 

Ni(P) is used as an underlayer in high-density metallic memory disk fabrication to improve the mechanical finish of the surface. Thus, hardness, wear resistance, and corrosion resistance have been major properties determining the technological applications of electroless Ni(P) in the electronic, aerospace (stators for jet engines), automotive, machinery, oil and gas production, power generation, printing, and textile industries. 

We said that Chapter 22 marks the point where most of the important ways in which molecules react together have been introduced—most but not all. For the next section of the book we survey a range of rather less common but extremely important alternative mechanisms, finishing with a chapter that tells you how we can find out what mechanism a reaction follows. 

Mechanical finishing processes such as compacting, calendaring, raising, polishing, etc., are performed to alter fabrics appearance or function like fabric luster, smoothness, softness, residual shrinkage, etc., by using mechanical means alone or accompanied by application of heat, steam pressure, etc [96]. 

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