The Recording and Analysis of Downtime in Processing Enterprises

The paper discusses the importance of recording and analyzing downtime in processing enterprises, and takes Shanghai Mila Brew Company Limited as the example to analyze the problems in recording and analyzing downtime. Finally, suggestions of improvement are given out.

Evidence for self-organized criticality in unscheduled downtime data of equipment

How to reduce downtime and improve availability of the complex equipment is very important. Although the unscheduled downtime（USDT） issues of the equipment are very complex, the self-organized criticality（SOC） is the right theory to study complex systems evolution and opens up a new window to the investigation of disasters, such as the sudden failure of the equipment. Firstly,SOC theory and its validation method are introduced. Then an SOC validation method for USDT of the equipment is proposed based on the above theory. Case study is done on bottleneck equipment in a factory and corresponding data pre-process work is done. The rescaled-range（R/S） analysis method is used to calculate the Hurst exponent of USDT time-series data in order to determine the long-range correlation of USDT data on time scale;at the same time the spatial power-law characteristic of USDT time series data is studied. The result shows that the characteristics of SOC are revealed in USDT data of the equipment according to the criterion of SOC. In addition, based on the characteristics of SOC,the overall framework of the prediction method for major sudden failure of the equipment is proposed based on SOC.

Influence rule of downtime on heat transfer in converters

The models for calculating the heat transfer in converters allow the accurate control of heat dissipation caused by downtime,and thus help in crease scrap ratio and reduce energy consumptio n.ANSYS 17 was used to establish such a model to analyse the coupling law between the downtime and heat dissipation of the converter and the temperature drop of molten iron.Temperature was measured by infrared detection,and model accuracy was verified by comparative analysis.The variation law of the amount of cold charge added for different downtimes under different process conditions was studied.The results show that the range of the variation of heat dissipation caused by downtime is 8.9-78.5 GJ.If the downtime increases by 30 min,heat dissipation of dephosphorisation(deP)and decarburisation(deC)converters increases by about 23.4 and 41.3 GJ,respectively.In a certain smelting cycle,the temperature drop of the molten iron for deP,deC and conventional converters increases by about 12.5,15.0 and 17.0 K,respectively;and the amount of scrap added in the double-linking and conventional smelting processes decreases by 0.93 and 0.75%,respectively.

Some Reliability Problems Arising in the M^x/G(M/G)/1 Repairable Queueing System with Single Delay Vacation

On the basis of Ref.\, the M x/G(M/G)/1 repairable queueing system with single delay vacation is discussed again. The following reliability problems of the service station are studied: (a) The probability that it fails at time t , i.e. its unavailability; (b) The expected failure number during the time interval (0,t\];; (c) The expected failure number during the ″server busy period″; (d) The expected downtime during the time interval (0,t\]. Some reliability results of the service station are obtained. These results would be interest to reliability analysts.

Dynamic trip point categorisation using manufacturing process for polycrystalline diamond compact bits as case study

Disruptions in the manufacturing process cast substantial impacts on the consumer’s centric values,cost,and overall efficiency.The ripple effect of these disruptions is observed in the whole assembly line.The proper analysis and mitigation of disruptions is the key to the proficiency of the plant and resource utilisation.The research focuses on the quantitative analysis of the impact of disruptions of the manufacturing process,which is performed by analysing the disruptive workstation dynamically.The disruptive workstations have a significant impact on succeeding and preceding workstations,which have been analysed dynamically,and accordingly,the preset alarm trip points are elevated.The results show that lowering the number of starts and stops decreases the number of rejections of valuable process batches that finally improve efficiency.Finally,the developed model is implemented on a polycrystalline diamond compact drill bit manufacturing plant.The results are compared with the research work of other researchers,showing a 60%reduction in the number of start/stop events,60%reduction in downtime,while a 75%reduction in the number of rejections is noted.