Machine tool lubricants

In machine-tool operations, as in all others, the wisest course for the user is to employ reputable lubricants in the manner recommended by the machine-tool manufacturer and the oil company supplying the product. This policy simplifies the selection and application of machine tool lubricants. The user can rest assured that all the considerations outlined above have been taken into account by both authorities. 

This type of filter has found particular application for the continuous cleaning of coolants and other hquids and emulsions, especially where there is a need to separate particles from liquids similar in viscosity to water, such as machine tool lubricants, cold rolhng mill coolants, and some water treatment or effluent control duties. How rates generally run from 20 to 60001/min, and if higher flow rates are required, then units can be connected in parallel. 

This chapter examines the need for lubrication and the types of lubricant available. Various applications are considered, including engines gears, hydraulic equipment, machine tools, metal cutting and working fluids, compressors, turbines and electrical oils. The care of lubricants on-site, application of planned lubrication and inclusion within overall maintenance management are examined. 

Spindles may be the most difficult machine-tool components to design, but slideways are frequently the most troublesome to lubricate. In a slideway, the wedge-type of film lubrication cannot form since, to achieve this, the slideway would need to be tilted. 

Machine-tool gears can be lubricated by oil-spray, mist, splash or cascade. Sealed oil baths are commonly used, or the gears may be lubricated by part of a larger circulatory system. 

The circulatory systems used in association with machine tools are generally conventional in nature, although occasionally their exceptional size creates special problems. The normal installation comprises a storage tank or reservoir, a pump and filter, suitable sprays, jets or other distribution devices, and return piping. The most recent designs tend to eliminate wick feeds and siphon lubrication. 

Note It is essential that lubricants are compatible with the materials used in the construction of machine tools, and particularly with sealing devices. 

Two factors militate against the universal use of water-based fluids. Very severe machining operations call for a lubrication performance that is beyond the capacity of such fluids, and the design of some machine tools means that water cannot be used because of the risk of cross-contamination with machine lubricants. In these instances, neat cutting oil is the only fluid that can provide the required performance. 

It should be made clear to people exposed to lubricants that good standards of personal hygiene are a most effective protection against potential health hazards. However, those individuals with a history of (or thought to be particularly predisposed to) eczema or industrial dermatitis should be excluded from work where, as in machine-tool operation, contact with lubricants is virtually unavoidable. 

Industrial lubrication Machine tools and metal cutting Lubricants for heavy industry Gear lubrication Hydraulic fluids Machine shop lubricants Cutting fluids Compressor lubrication Greases... 

Recently it has been possible to use soluble oils for lubrication of some machine tools as well as for lubrication and cooling the cutting tools and the work. 

Slow moving slides and tables in machine tools are subject to jerky motion due to alternating slipping and sticking of the sliding surfaces. Consequently, specially developed lubricants are required to prevent and/or reduce the stick-slip phenomenon. Slideway oils usually contain polar surface-active compounds, mostly fatty acid derivatives, together with anti-wear additives and oxidation inhibitors. The polar surface-active agents form oriented boundary layers which prevent adhesive friction. 

Inhibited greases were until recently the major and in fact unique material for preserving hardware. Today they tend to be replaced by liquid inhibited lubricants, thin coats and films. Sealing lubricants are used to tighten or to alleviate screwing/unscrewing of threaded joints in engineering, machine-tool construction and the oil and gas industry. 

Grey iron has a good wear-resistance and is used for castings in machine tools containing sUdeways where continuous lubrication is not always possible. The free graphite on the surfaces acts as a temporary lubricant and, when used up, creates minute pockets which then act as small reservoirs for the machine lubricant. 

PI, PTFE lubricated Piston rings, machine tool bearings, pump bearings, valve discs Electric motor bearings ... 

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