Machine Tool Maintenance

Machine Tool Maintenance

Machine Tool Maintenance - A machine tool consists of fixed, rotating and reciprocating elements, using electric, hydraulic and pneumatic systems to achieve the desired movements. It is the relative motion between elements in direct, or indirect, contact which results in the wear or stressing of parts and which leads to machine failure.

Such failure can be a sudden occurrence due to the collapse of one or more of the elements, or can be a gradual deterioration resulting in inefficient performance and eventual failure.Provided a machine is not abused, the sudden failure of an element will generally occur very early in its life due to a material fault, or much later due to wear and metal fatigue.

With present day standards of material testing and machine construction, the former is a relatively rare occurrence, whilst the latter is bound to occur in all machines sooner or later. With modern machine tools, sudden failure is most likely to happen in the control system, not necessarily due to the failure of the system itself, but as a result of shop conditions and a failure to appreciate the changing maintenance needs of advanced control systems.

The direct object of machine tool maintenance is to delay the deterioration which takes place and to avoid disruption to the production programme. A further objective is to achieve this at the most economic cost.

A machine fool is a company asset and, as such, should earn a profit on the capital investment which it represents. Like any other asset, it should be made to provide the maximum return, by:

(i) Adequate training of both operator and supervisor, to ensure that the machine is not abused.

(ii) Regular servicing and inspection to avoid downtime and to maintain efficiency:

(iii) Cutting at the maximum rate for which it was designed.

(iv)Cutting for the maximum number of hours per day, rather than letting the investment lie idle.  In any machine shop, operators as well as the shopsupervisors should be trained on existing machine tools and on the new models as and when they are introduced as regards their maintenance problems.

In particular, the operator should be fully instructed as to the part he must play in carrying out routine servicing and the emergency action to be taken when the machine fails to operate in the normal manner.

Generally speaking, the machine tool makers provide excellent manuals covering the operation of machines; these should be made available not only to the maintenance engineer, but also to the supervisor and operator for detailed study.

Further, when an entirely new model is introduced the supervisor and operator should receive instruction in the operation of the machine from a representative of the maker; most machine tool makers offer this facility.

Similarly, the maintenance engineer should be fully instructed in the installation and maintenance requirements. This can best be done by allowing him to visit the maker's works so that he can see in detail how the machine is built up and tested.

The introduction of sequence control systems, particularly those using electronic devices, means that the maintenance engineer must also be retrained; this retraining must not only take into account the maintenance of such devices, but also the changed installation requirements.