Maintenance of Machine tools Prepared By Dr.K.Elangovan Nizwa College of Technology

Maintenance of Machine tools Objective : Equipments and machine tools are very important component of production activity Break down of machines resulted in reduced production and it will be great loss It is very important to maintain machine tools to minimize loss and to improve the production

Maintenance Definition Maintenance is the process of keeping the machine and equipment in good working condition so that the efficiency and life of the machine is increased Advantages of good maintenance Increased life of the machine Ensured quality of the product No production loss Machinery is not damaged Disadvantages of bad maintenance Loss of production More wastage of material Reduced life Leads to accidents Cost of production is increased

Lathe maintenance The lathe is a precision machine tool and must be treated with great care. Regular cleaning and maintenance will help to assure that the lathe will maintain its service life and accuracy for many years Lathe maintenance involves maintenance of Drive belts Gib Adjustment( cross slide, Compound slide) Wipers Pads Adjusting the Tailstock Clamp

Drive belts Removal of guard Checking belt Tension

Adjusting belt tension Drive belts come in matched sets and should only be replaced with a matched set of belts. Visually inspect the drive belts for excessive wear and cracking. If you notice that one or more of the drive belts appear to be excessively worn replace it with new one Check the belt tension by applying finger pressure to each belt at a point midway between the two pulleys For correct tension a deflection of about 6-8mm should be evident in each belt. If the amount of deflection is more than 6-8mm in any one or more of the belts adjust it with belt tensioner

Gib Adjustment All lathes employ precision slide ways. The saddle, cross slide, and the compound slide all ride along a box slide way or dovetail slide way After time the parts that ride along the slide ways begin to wear To compensate for this wear, machine tools are equipped with adjustable parts called gibs that allow you to eliminate the space that has been created by the wear between the slide ways

Gib Adjustment Cross slide (Tapered Gib)

Gib Adjustment Procedure The procedure is to first loosen the similar gib screw in the rear face of the tool slide Then re-tighten the front screw to lock or adjust the Gib in its new position After making the adjustment, traverse the compound slide over its entire travel to be sure of smooth, even operation

Cross slide (Tapered Gib) Front gib screw Tapered gib with screws

Compound slide (straight Gib) There are two types of gibs, straight gibs and tapered gibs Straight gibs are adjusted by screws spaced out along the length of the gib. The screws push the gib in to create more contact with the sliding mechanisms

Wipers Pads

Wipers Pads Wipers are designed to keep out small chips and dirt between the slides and the ways. Wipers are saturated with oil to catch the fine particles of dirt or debris before they get between the two sliding surfaces. The wipers should be removed, cleaned, and re-saturated with oil regularly. Never use compressed air for cleaning a lathe Compressed air will push the fine particles trapped in the wiper between the mating surfaces of the slides, causing premature wear on these precision surfaces

Scheduled maintenance Maintenance carried out in accordance with the schedule defined by the manufacturer of the machine Usually carried out in predetermined dates It involves inspection, Cleaning, lubrication, repairing and replacing the parts of the machine as per the recommendations of the manufacturer

Scheduled maintenance- Lathe Daily - Cleaning chips from carriage, cross slide, compound rest and bed - Check the head stock oil level through inspection glass Weekly -Check auto drain on filter regulator -Clean out small chip catch pan in coolant tank Monthly -Lubricate the way covers -Remove pump from coolant tank and clean it -Check the gear box oil level, top up if necessary Six months -Remove the coolant and thoroughly clean the coolant tank -Replace the hydraulic unit oil filter - Check all hoses and lubrication lines for cracking Annually -Replace gear box oil -Check and replace drive belts