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

2. 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

3. 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

4. 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

5. Drive belts
Removal of guard
Checking belt Tension

6. 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

7. 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

8. Gib Adjustment
Cross slide (Tapered Gib)

9. 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

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

11. 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

12. Wipers Pads

13. 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

14. 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

15. 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