The first thing to be done on receipt of any machine tool is the initial inspection, i.e., to open the packing immediately and to check for any transport damages and shortages. Generally a packing list is enclosed, according to which all the items are checked.
While unpacking, care must be taken that nothing gets lost especially with the boxes containing accessories. In case of any complaint, it should be immediately conveyed to the nearest manufacturer’s representative quoting the type of machine and serial number and copies sent to the head office, servicing centre, etc.
At the time of packing at the works all bright parts of the machine are coated with rust preventives, which should be carefully removed before moving any of the sliding parts of the machine. Kerosene can be used for this purpose but the solvents that dissolve paints should be avoided. Soft cotton waste is generally used for washing away the preventive coating and dry cloth to wipe the machine dry.
All bright parts should then the immediately oil. All oil nipples should also be cleaned carefully to prevent any dirt from being forced in when lubricating with an oil gun. There are certain moving parts which are generally clamped to the fixed parts and these should be first un-damped; e.g., in the case of lathe the saddle is clamped to the bed guideways and, therefore, before traversing the saddle, it must be un-damped. When moving the machine for erection purpose, such parts should be kept clamped.
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The next step is the preparation of foundation plan. In preparing it, the location of the machine should be selected in such a way that sufficient working space is provided for the operator and floor space for work piece to be machined and the machined workpiece awaiting removal. The foundation is best made up with tamped concrete which is fully cured before the machine is placed on it. The foundation plan of a lathe machine is shown in Fig. 13.1.
After the foundation plan is prepared, the next step is to prepare the machine for slinging. To avoid damages to the working surfaces, hemp rope is recommended for slinging the machine. Chains or wires will have tendency to slip. Even while using hemp rope felt paddings would be required to prevent damage to the paint.
For erection and levelling, the machine is lifted clear off the ground by any type of crane, foundation bolts are introduced from below and the levelling plates are introduced from below so that the levelling screws seat in the blind holes given in each plate.
The machine is levelled provisionally by means of the levelling screws making use of a spirit level with bubble gauge sensitivity of 0.03 to 0.06 mm/m. Final levelling is undertaken only after foundation bolts are set hard in the cement grouting. The four outer levelling screws may be adjusted to obtain suitable transverse levels at three positions near the headstock, near the tailstock and in the middle positions.
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The middle screws are adjusted to achieve the desired convexity. The transverse level is to be rechecked at the three measuring positions. The longitudinal levelling is also to be carried out carefully especially for machine with intermediate supports.
When the level is adjusted correctly as above, the machine is run for about 2 hours at various speeds and the levels rechecked after this period of running. If the same previous accuracy of level is not indicated, then the levelling screws are adjusted again.
After ensuring that correct level is thus obtained by manipulating the levelling screws, the foundation bolts are evenly tightened taking care that previously obtained accuracy of level is being maintained. The machine again runs for an hour on medium speed. The level is again checked and readjusted, if necessary. Now the machine is ready for grouting.
Initial Lubrication of Machine:
Initial lubrication is then carried out as per the schedule, supplied by the manufacturer of machine tool, after thorough cleaning of the machine. All the moving parts like saddle, cross and top slides etc. are traversed along their length for a few times. The tailstock spindle is drawn in and out to spread the oil. All the levers are manipulated to ensure easy movement.
All the machines are generally supplied with complete electrical equipment (main motors, switch-gear and control circuitry) and simply have to be connected to the power mains. The incoming voltage supply (voltage level, permitted voltage variation and frequency variation) should be as per the recommendation of the supplier so that the motors can give guaranteed performance.
For starting the machine, first the main isolating switch is to be switched on and then the spindle starting lever be turned downward and rotation of main spindle checked. If it is clockwise, all right. If direction of rotation is anti-clockwise, simply two phase connections be interchanged. Pressing the lever upwards makes the spindle rotate in anti-clockwise direction. The machine can be stopped by pressing down the brake pedal.
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If the machine is provided with a star-delta starter, the time delay relay should be set to minimum 5 seconds. It should be ensured that the motor is not switched ‘or’ more than 30 times in an hour. For starting the coolant pump, the plug pin of the coolant motor be inserted to the socket and power switched on.
The coolant tank should be cleaned and filled with coolant (having good cooling and lubrication effect, and providing protection against rust or other chemical influence and harmless to the operator). The lowest level should be about 25 mm above the impeller of coolant pump and the level has to be checked periodically. The sump and piping’s should also be cleaned thoroughly every six weeks and coolant renewed.
If no coolant flows through, then direction of rotation of the pump motor should be checked. Overloading of pump motor is indication of dirt accumulation within the pump. All the change gear levers should be in correct positions, otherwise the gear wheels will not move along their full width and may be overloaded. Initially the speed and feed selector levers should be arranged to get the lowest speed and feed.
Speed and feed changing should never be done while the machine is running. The push button ‘inch’ is provided for helping the gear shifting. The machine should be ‘run in’ for 45 minutes. The working of all lubricating system should be checked and if necessary, more oil be filled in to maintain the minimum oil levels in the sight glasses.