Factory Maintenance Problem: A Reliability Centred Maintenance Strategy

Problem background

Part of a factory that manufactures extruded building products is shown bellow.

Dust that is processed in another factory is loaded by a wheeled shovel into a hopper and is raised via an inclined conveyor and bucket elevator to the top of the system. The dust is then distributed to storage hoppers by a large scraper chain conveyor.

Each hopper is equipped with an extract conveyor which load dust onto a collection conveyor & then onto the machine feed conveyor.

The machine hopper acts as a surge hopper, allowing an even controllable feed of dust to be added to the mixer of the main extrusion machine. Much ancillary equipment has been excluded for clarity.

The large making machine consists of a single shaft mixer where water and dust are combined and then fed through a de-airing chamber into the extruder. None of the forming or handling equipment is shown.

Product from the extrusion machine is loaded onto refractory lined bogies and processed through a dryer and kiln, which is a continuous process. If the firing process is slowed or stopped, large scrap rates and a kiln fall could follow.

The main extrusion process has to run 16 hours per day but this can fluctuate with demand. Because this is only part of a larger factory, if staff are not working on this system, they are employed elsewhere.

Two fitters and an electrician are always on duty within the factory as a whole.

The immediate task is to suggest a maintenance strategy for the equipment. The strategy should contribute to a factory wide Reliability Centred Maintenance strategy. This includes mobile and electrical equipment. Full explanations must be given and related to this equipment.

Please note any suitable condition monitoring techniques that may be appropriate, which pieces of equipment they relate to and why.

FMEA would not be appropriate as it is not expected students have a full understanding of the equipment. Suggest and justify any modifications which would increase reliability of the plant. This may include changes to layout or maintenance policies.

This report paper is about the maintenance strategy of an equipment is a factory that manufactures building products. The dust processed by another factory is loaded by the use of shovel that is wheeled into a hopper and is raised through a bucket elevator and inclined conveyor to the system’s top. From this point, the dust is dispersed to the hoppers for storage by a huge conveyor of scraper chain. Water is then mixed with dust in the single shaft mixer and fed via chamber for de-airing into the machine of the extruder. The resultant product from the machine for extrusion is loaded onto bogies and processed through kiln and dryer.

This report paper requires an evaluation of the maintenance strategy for this equipment which will contribute to a factory wide reliability centred maintenance strategy. The reliability centred maintenance is a method meant to develop preventive maintenance since it depends on the prevention of potential failure which may pose negative results on the performance of the equipment such as an increase in the cost of maintenance (Darling, 2015). The reliability centred maintenance that can be implemented in this dust equipment is as shown in the figure below:

Reliability centred maintenance strategy (Karwowski, 2013) 

This strategy of maintenance involves automatically replacement of the sections of the machine which are known to be experiencing degradation as a result of continuous usage or age. The replacement of these parts will ensure that the unexpected failures are prevented and maximum duration of production realised. This technique is normally performed as an overhaul where the entire equipment is eliminated from functioning during the shutdown and taken to the workshop for disengagement of its components and then constructed afresh. The use of the strategy of reactive maintenance is aimed at making sure that the production process of the equipment is not interrupted for a given duration (Kelly, 2012).

Some of the sections of the equipment that can be overhauled include the making machine extruder, making machine mixer, extract conveyor, scraper chain conveyor, bucket elevator, and large wheeled loading shovel. Through the process of renewal of the equipment on a regular basis, the stoppages as a result of wear-out are greatly eliminated. After the equipment have been overhauled to the standards of the manufacturer, a new performance is expected by the factory. Nevertheless, there is expected exposure to infant mortality dangers because of improper control of the quality, introduced damage, selection of the material incorrectly selecting a material, and mistakes during assembly. The reactive maintenance we used as a robust and sound quality control and assurance strategy with a perfect checking and rebuild procedures (North, 2010).

The strategy of preventive maintenance is one of the very first and efficient technique. This method can be done by the use of two ways; namely intervention and replacement and observation and inspection. The initial form of preventive maintenance is normally the response used for parts of the equipment which portrays signs of wear-out and age. This technique entails noting and inspecting the equipment’s condition and servicing it on a frequent basis. Some of the parts of this equipment that requires constant inspection include the rotating parts such as high chrome steel blades, belt conveyor, wheel gearbox, shaft mounted gearbox, and scraper chain conveyor (Peters, 2013).

The Task

Some of the servicing that can be done on the parts of the equipment and inspection include oiling, replacement of conveyor belts, lubrication, and replacement of ball bearings. During the process of servicing, it is important to observe the critically impending failures and the working sections. The strategy of preventive maintenance prevents failures with the very initial use. The amount of maintenance can greatly be reduced by the use of preventive strategy and also this technique stops the occurrence of failures by 90% (Safety), 2013).

This form of maintenance is a very critical strategy of maintenance. This technique involves the process of monitoring the evidence of changes in the conditions of the equipment. The rate and amount of change are tracked and utilized in predicting the duration of any failure. The predictive maintenance is based on recognizing that failures take some time before worsening. Usually there is a starting point, then worsening gradually, and finally, a point when the equipment breaks and fails totally. The changes in the working conditions in the equipment of part of the equipment can be observed in the large wheeled loading shovel when it can no longer press the dust into the system properly (Safety, 2012).

This may be caused by the failure of mechanical parts of the shovel. The failure of the rotating parts of the equipment such as wheel gearbox, shaft mounted gearbox, and belt conveyor should be continuously be monitored by qualified staff who will ensure proper functioning of the machine parts. Some of the techniques that can be used in the process of predictive maintenance include ultrasonic thickness testing, vibration monitoring, oil debris analysis, and thermography. These techniques tend to detect a change and enable determination of the rate of change so that prediction can be done on the continuing performance of the equipment (Sharma, 2014).

This the technique of proactive maintenance, the planning begin on the drawing board. Once the first product from the extrusion machine is loaded onto bogies of refractory lines and processed via kiln and dryer, the company is stack with it. Every section of the machine requires a maintenance it to maintain its workability. The design of a part of the equipment determines the requirements of the maintenance. In case the company requires less maintenance, then there is need to use appropriate choices of design which minimizes the maintenance cost.  The technique used in highlighting opportunities to minimize the maintenance are grounded on the mode of failure and analysis effect (Peters, 2013).

The equipment which can undergo changes in its design so as to reduce its maintenance is making machine mixer which is involved in mixing water and lime. This equipment is very difficult to maintain and also very complex. The new design should be easier to maintain and less complex since the work that it will be doing will just be mixing dust and water. The recommendation of the new design should be similar to that of the cement and sand mixer used in the construction industry (North, 2010). The simplest way of understanding this technique is to consider numerous responses to ‘what if’ questions when referring to every section of the equipment. Such questions include what if the rotating belts fail to rotate? What is the gearbox fails to operate?

The strategies for proactive maintenance are the best since they are the cheapest way of reducing maintenance. Its wonder and beauty are that it is an equipment lifetime strategy that results in a recurrent improved functionality for the entire life of operation of the equipment. The outcome of using proactive elimination and detection strategy for maintenance will flow through instantly, however, not be observed for a couple of years (Karwowski, 2013).

Conclusion

This report paper is about the maintenance strategy of an equipment is a factory that manufactures building products. The dust processed by another factory is loaded by the use of shovel that is wheeled into a hopper and is raised through a bucket elevator and inclined conveyor to the system’s top. This report paper requires an evaluation of the maintenance strategy for this equipment which will contribute to a factory wide reliability centred maintenance strategy. Some of the reliability centred maintenance strategies include proactive maintenance, predictive maintenance, preventive maintenance, and reactive maintenance.

References

Darling, P. (2015). SME Mining Engineering Handbook, Third Edition. New York: Society for Mining, Metallurgy, and Exploration (U.S.).

Karwowski, W. (2013). Advances in Human Factors, Ergonomics, and Safety in Manufacturing and Service Industries. Melbourne: CRC Press.

Kelly, A. (2012). Maintenance Strategy. London: Elsevier.

North, K. (2010). Environmental Business Management. Chicago: International Labour Organization.

Peters, R. (2013). Reliable Maintenance Planning, Estimating, and Scheduling. Perth: Gulf Professional Publishing.

Safety, C. (. (2013). Guidelines for Chemical Process Quantitative Risk Analysis. Colorado: John Wiley & Sons.

Safety, A. I. (2012). Guidelines for chemical process quantitative risk analysis. Michigan: The Institute.

Sharma, G. (2014). Handbook Of Management Terms. Michigan: ICFAI Books.