1. Installation & Testing of machine tools
Unit 10
Installation & Testing of machine tools

2. Introduction
Its clear through earlier chapters that the modern industry involves large number of machine tools for producing various components. The quality of these products, apart from the skill of operator, depends largely upon the accuracy of the machine tools. To ensure this, the machine tools are tested at various stages namely
Alignment tests
Performance tests
These are collectively known as acceptance tests.
The pioneer work in this field was initiated by Dr. G. Schlesinger in Germany in and his research in this field is widely used for developing various national standards of different countries.

3. The first step, even before testing a machine tool for acceptance tests, is its installation, which involves:
Deciding a suitable location for the machine tool.
Laying out a proper foundation plan.
Preparing the foundation and curing it.
Slinging the machine tool.
Lifting and erecting the machine tool on the foundation.
Levelling the machine tool.
Connecting the foundation bolts and grouting them.
Second levelling after the foundation bolts are set.
Final levelling check before testing and commissioning.

4. Location:
The decision about the location of a machine tool in a shop includes the selection of a suitable site where
(a)adequate area for the installation, and also the required working area around the machine, will be available without interfering with or endangering other machines or workers around it.
(b)Also, the selected location should ensure a free operation of the installed machine tool without any outside interference.
(c)The space available at the selected location should be sufficiently enough to allow unrestricted working by operator, free movement of all moving parts & machine tools and adequate storage space for the raw material and finished parts.

5. Foundation for machine tool:
The foundation is an important part of the machine tool installation and it needs to be made very carefully because it is required to perform following functions:
To act as the base to the support the entire weight of the machine tool, workpiece, tooling, mounting, accessories etc.
To help in maintenance of the alignment of machine tool, its mechanism and moving parts.
To absorb vibration produced during the operation.
To prevent transmission of vibrations from one machine tool to another.
To provide such height to the machine tool that its operation is convenient to the operator.

6. Different types of machine foundations:
Generally the following four types of machine foundations are in common use:
1. Block type: It is a solid foundation of cement concrete or sometimes brick masonry, in which foundation bolts are grouted and the machine rests over its top surface.

7. 2. Box type: Its is a hollow box type construction of cement concrete
2. Box type: Its is a hollow box type construction of cement concrete. The machine is placed over its top roof. The mass of this foundation is less than block type machine foundation as it is hollow.

8. 3. Wall type: It may be made either in cement concrete or brick masonry. In either case, it consist of strong base over which are erected two parallel vertical walls. The machine is supported over the two walls.

9. 4. Frame type: It is more or less a wall type foundation carrying a fabricated frame at its top. The machine is placed and supported over the framework at the top. This type of foundation is specially favoured for rotating machines and those operating at high speeds.

10. Factors effecting the type and size of foundation:
In general, the following factors effect the choice of a particular type of foundation and its overall size etc.
1.Weight of machine. Heavier machines need stronger foundation and lighter machines will need lighter foundations or no foundations. For example, a 250mm deep concrete foundation or 500mm deep brick foundation can be used for drilling, milling etc upto 4 tons.
2.Type of soil. Different type of soils have different bearing capacities, i.e., the capacity to bear load without settling down or disintegrating. Since the entire weight of the machine tool is ultimately transferred to the soil, its bearing capacity must be taken into consideration, while designing the foundation. For example, a marshy soil which has poor bearing capacity (5000kg per sq. meter) will essentially need a larger foundation of R.C.C.

11. 3.Vibrations. Vibration in the machine tools are caused by unbalanced forces, such as due to shock loads, misaligned parts and similar other reasons. Also, it is reckoned that it is almost impossible to perfectly balance a machine tool. As such, a proper foundation is required to be built, so that it can not only absorb the vibration but also prevent their transmission to other machines.
4.Power of driving motor. The horse power to be transmitted by the driving motor of the machine tool has a direct bearing on the size of the foundation, As a general rule, the higher the horse power of the driving motor the deeper should be the foundation of the machine.
5. Direction of motion. The direction of cutting motion in the machine tool has a significant bearing on the size of foundation. A horizontal machine tool will need a heavier foundation than a vertical machine tool of the same type.

12. Foundation Plan:
Foundation plan is a detailed drawing which contains the following information:
Principal dimension and profile of the machine.
Size and shape of the foundation to be prepared.
Type of foundation and material to be used in its preparation.
Location of mechanism, areas needed for opening of base doors, operator’s position etc.
Location of holes and recesses to accommodate the foundation bolts and projection in machine base, if any.
Weight of the machine.
Location of current supply, power cables, etc.
With the help of these drawings, which are also known as erection drawings, the excavation details can be easily worked out.

13. Preparing the Foundation:
Once the foundation plan is ready, the following operations are to be carried out for preparing the foundations.
Marking the length and breadth of the pit.
Excavating the soil to dig the pit.
Laying the bottom pad in the pit to level its bottom.
Preparing and laying a box type form in the pit, of which the inner dimension will confirm to the overall shape and size of the foundation.
Placing the wooden plugs at the location where holes of foundation bolts are to be made.
Placing steel reinforcement, if specified, at proper places in the pit.
Filling the entire space in the form with concrete.
Removing the inserted plugs after some time of concrete laying.
Allowing few days(usually 3 to 5days) for proper setting and curing of laid foundation.
The foundation is then ready for the erection of machine tool.

14. Transportation & Erection:
Whenever a new machine is received by the buyer its initial inspection is carried out to know about any damages or the shortages in quantity. If this is found ok, the machine tool is ready for erection and the first job is to safely transport the machine tool at the erection site.
There can be two possibilities:
The packed machine tool is received in a suitable mode of transport via truck, and then directly unloaded at site.
The packed machine tool is first received and unloaded at stores and then transported to the site.
In first case, the main job remains is to unload the machine tool and place it correctly over the prepared foundation. For this, machine tool is to be unpacked and lifted clear of the truck so that the latter becomes free to leave back.

15. The common devices used are the different types of pulley blocks
The common devices used are the different types of pulley blocks. Selection of a suitable pulley block mainly depend upon the weight of machine to be lifted.
Rope block: For light loads.
Weston pulley block: For light and medium loads.
Worm block: It’s a chain pulley block, can be used upto 5 tons.

16. In the second case, the machine tool is relifted from the stores and transported to the erection site, the best means indeed will be a mobile crane. Alternatively, it can be reloaded in the another truck and transported internally to the site.
In either case, the operation of lifting and placing the machine tool correctly over the prepared foundation is a common one.
Slinging a machine block over foundation

17. Levelling and Aligning:
As already described earlier, the upper surface of the foundation is properly leveled after concreting work is over. After placing the machine tool in its position, the next step is to level the machine tool. The operation of levelling of the machine is performed very carefully because the accuracy of the machine tool largely depends on its perfect levelling.
For levelling of the machine tools, levelling pads, shoes and wedges are used.
Steel wedges are commonly used for this purpose. These wedges carries one side taper and the other flat, such that thicker end is 3 to 5 mm thick and other end form a wedge. The usual length of these wedges varies from 50mm o 80mm. And width is about 25mm.
A precision spirit level is used to level the machine tool. Deviations from zero readings are corrected by adjusting wedges. After ensuring the machine is properly leveled, the base is properly secured by tightening the loose nuts over the foundation bolts.

18. Machine Tool Testing Site for testing:
After erection, levelling and grouting of the machine tool are over, the next operation before commissioning the machine tool is its proper testing. As already explained, a machine tool is subjected to
Alignment test: To test its manufacturing accuracy.
Performance test: To check its working accuracy.
Site for testing:
The most appropriate site for testing the manufacturing workshop, because the maximum care is exercised there in respect of adjustment and alignment of the machine tool during its assembly.
Another advantage of testing the machine tools at the manufacturing workshop is the availability of skilled worker and necessary equipment for testing. The manufacturer always provides a chart with the machine tool to the user, covering the details of all the necessary test conducted and their results.

19. Degree of accuracy:
Basically, it is the manufacturing accuracy of the machine tool, i.e., the accuracy with which it is assembled, which is tested. This accuracy is tested when the machine tool is idle and run without any load. This accuracy has the direct link with the working accuracy of the machine. It is therefore, necessary, to account for the possible machining errors and suitably adjust them during assembly so that the assemble machine tool is able to produce components within specified limits at the user’s site.
Apart from the manufacturing accuracy of the machine, its working accuracy is also effected by:
Geometry and material of the cutting tool.
Material of the workpiece.
Shape, size and rigidity of the workpiece.
Cutting tool holder.
Cutting speed, feed and depth.
Clamping equipment.
Operator’s skill.

20. Measuring Instruments:
There cannot be any hard and fast rule regarding the choice of a particular instruments to be used for measuring the accuracy of a machine tool. Some commonly used equipments for this purpose includes:
Dial Gauges: They are used for geometrical test. The dial gauge slected should have adequate measuring accuracy. It should be mounted on strong and stiff bases and bars during testing so as to ensure its proper stability.
Straight edges and squares: They should have a strong ribbed construction with wide bearing surfaces.
Spirit levels: Both the horizontal and frame type spirit levels are used. They should have the measuring accuracy of upto 0.05mm per 1000mm for very precision measurements and from 0.1mm to 0.3mm per 1000mm for general measurements. They should have large bearing surfaces.
Test mandrels: They are accurately turned and ground hollow round bars which are properly hardened and stress relieved, They may have either a taper shank for bring fitted in the nose of the machine or round shank for being held between the centers.

21. Thank You……