Objectives of Planned Maintenance

The correct kind of maintenance for plastic moulds is one which certainly involves much more than is embraced in the all-too-customary practice of a merely perfunctory examination of the tool upon its removal from the production stage, with the almost complete absence of any organized methods of periodical inspections, tests, and correction of the mould.Usually too,such examinations that are afforded the mould are conducted by some unskilled person .those person are not fully conversant with the principles and practice of mould construction and manufacture.If the mould appears to be in reasonably sound condition, and does not give any serious trouble during operation.it is just given a hasty clean-up, and then placed on one side, not always in a proper storage place,there to await the receipt of the next order for production.

As already explained,suitable storage locations or equipment are often unprovided, which renders it still more difficult for the maintenance engineer to keep effective checks upon the condition of moulds when not in actual use. It should be remembered that unless care is exercised in the storage of moulds, serious deterioration may occur from such features .Those features include

  • damp atmospheric conditions,
  • failure to eliminate all moisture from the mechanism of the mould when ceasing production
  • indiscriminate contact with other metallic articles on the moulding shop floor,or in bins, or shelves,careless handling and so on.

Properly organized and applied maintenance service necessarily involves frequent oversight of all moulds, when in use or in the stores, to cover such normal requirements which arise from time to time.Those maintenances include replacement of worn, broken, or damaged mould parts; rectification of errors due to distortion or wear; adjustments and restoration of alignments; modifications to the construction and design of the mould mechanism; cleaning; lubrication and general overhaul.

Yet all these essential activities are almost exclusively concerned with, and made available for, the correction of some ascertained fault in the operation of a mould. After this has reached a certain stage of seriousness.it generally coincides with noticeable detraction from the quality of the moulded article, or with the inability to operate the mould with efficiency.

However, the prime object behind any scheme of planned maintenance should be not merely to provide an efficient service for the expeditious carrying out of the repairs, etc., but also to secure elimination of such faults requiring correction, as far as ever possible.

Any plan, therefore, should be characterized prominently by efforts combining regularly spaced inspections and tests of the mould,to discover the smallest deviations from smooth working or deleterious effects upon the moulded parts. So the requisite adjustments may be made whilst the fault is still in the trifling stage, of,on the other hand, allowing the introduction of safeguarding measures designed to prevent the fault developing into more serious proportions.

Coupled with this important line of activity there should be cultivated a high degree of intelligent anticipation or skilled foresight of developing troubles before these have had the chance to reach sub¬stantial dimensions likely to result in eventual mould failure.

Such a scheme will also entail some simple clerical methods whereby all maintenance work, repairs and the like, the results of the routine inspections, etc, can all be recorded and carefully filed.So a correct apportionment o£ costs can be made,together with the building up of a body of reliable information concerning the working details and experience surrounding every mould.