An investigation of labor assignment rules in a dual-constrained job shop

One of the management decisions required to operate a dual-constrained job shop is the labor assignment rule. This study examines the effects of various labor assignment rules on the shop's performance. Eleven different labor assignment rules are simulated. A longest-queue rule and the traditional counterparts of the first-in-system, first-served, shortest operation time, job due date, critical ratio and shortest processing time dispatching rules are used to determine to which work center available workers should be transferred. Also tested are five new labor assignment rules that use an average of the priority values of all jobs in queue at a particular work center to determine whether that work center should receive the available worker.A SIMSCRIPT simulation program that models nine work centers provided the mechanism by which these rules were tested. Five dispatching rules, the counterparts of the five “traditional counterpart” labor assignment rules mentioned earlier, provided different shop environments. Also, the level of staffing of the work centers was altered to provide additional ship environments. Staffing levels of 50% and 67% were employed.The results show that none of the eleven labor assignment rules had a significant impact on shop performance. This is an important result because it implies that a manager can make the labor assignment decision based on other criteria such as ease or cost of application of the rules. These results were relatively insensitive to the shop environment, as represented by the dispatching rule and the staffing level.     

Use of the net present value criterion in a random job shop where early shipments are forbidden

Both practitioners and researchers in the field of Operations Management have suggested that shop scheduling should be an integral component in both the strategic and tactical plans for an organization's assets. This paper examines the use of an accepted measure of return on assets, net present value (NPV), in a simulated shop scheduling environment where early shipment of jobs before their due dates is forbidden. In addition, early shipment of raw materials to the shop is also forbidden. This shop environment is consistent with the prevalent practice in industry of accepting orders only on a just-in-time basis to reduce purchased parts inventories. The NPV measure provides a means of balancing a variety of performance criteria that have been treated as separate objectives previously, including work-in-process inventory, finished goods inventory, mean flow time and mean tardiness, while also providing a means of measuring monetarily the value of various shop scheduling approaches.The NPV performance of priority scheduling rules and order release policies is measured in this research through the simulation of a random job shop under a variety of environmental conditions. It is found in a comparison of priority rules that use time-based information with those that use job value information that the Critical Ratio rule provides higher average performance than the three other rules used in the study. However, in some situations that are consistent with JIT practice, value-based priority rules also perform well. The use of a mechanism for delaying the release of jobs to each work center in the shop provided higher average NPV when shop utilization was set at a low level of 80%, while immediate release of work upon its arrival to the shop provided superior performance at a higher shop utilization level of 94%. While JIT materials delivery and costing yields higher NPV, it did not alter the relative ranking of priority rule/release policy combinations. In addition, it was found that environmental factors, including average job length, average number of tasks per job and level of tardiness penalty, resulted in greater variations in NPV performance than the institution of a JIT raw materials delivery policy.     

Irregular workloads with MRP systems: Some causes and consequences

Material Requirements Planning (MRP) systems have been widely applied in industry to better manage multiproduct, multistage production environments. Although many applications have been quite successful, much is still left to the planner's intuition as to how to assure that master schedules, component lot sizes, and priorities realistically conform to the capacity limits at individual work centers. Capacity issues may indeed be the soft spot in MRP logic.This paper explores some possible causes of irregular workload patterns when using an MRP system. Better insight on which factors cause temporary bottlenecks could help managers better assess the vulnerability of their plants to this problem. It might also suggest ways of dampening peaks and valleys. The problem setting is a multistage environment; several products are made from various subassemblies and parts. Each shop order is routed through one or more capacitated work centers. An order is delayed either by temporary capacity shortages or the unavailability of components. Of course, the second delay can be caused by capacity problems previously encountered by the shop orders of its components.Seven experimental factors are tested with a large-scale simulator, and five performance measures are analyzed. The factors are the number of levels in the bill of material, the average load on the shop, the average lot size, the choice of priority rule, demand variability, the use of a gateway department, and the degree of equipment specialization. We have one measure of customer service, two for inventory, and two for workload. The workload measures are unconventional, since our interest is when workload variability occurs and how it affects inventory and customer service.The simulator has been developed over the course of eight years, and since this study has been further enhanced to handle many more factors. The simulator was validated recently with real data at two manufacturing plants. It is quite general, in that the bills of material, shop configuration, routings, worker efficiencies, and operating rules can be changed as desired.An initial screening experiment was performed, whereupon the average load and priority rules were not statistically significant at even the .05 level. A full factorial analysis with two replications was then conducted on the five remaining factors. Multivariate analysis of variance (MANOVA) and analysis of variance (ANOVA) statistical tests have been performed.The results confirm that workload variability can have a detrimental impact on customer service and inventory. The following structural changes to the manufacturing system can be beneficial, but tend to be more difficult to achieve. More BOM levels improve customer service, but increase inventory and capacity bottlenecks. Resource flexibility is a powerful tool to reduce workload variability. Capacity slack averaging much over 10% is wasteful, having no benefits for inventory and customer service. In general, revising the routing patterns only, such as creating more dominant paths, will not give big payoffs. The following procedural changes are easier to implement. Master schedules which smooth aggregate resources are an excellent device to reduce workload variability. Even with a smooth MPS, debilitating workload variability can still occur due to the design of the BOM, lot size, and leadtime offset parameters. Selecting a priority rule does not seem to be of overriding importance compared to master scheduling and component lot sizing. These findings must be considered within the context of the range of plant environments encompassed by this study.     

Tenant assignment policies with time-dependent priorities

Public housing authorities require flexible methods for determining how to allocate scarce housing units. Some tenant assignment policies assign applicants using absolute priority structures (for example, emergency versus regular applicants). Other policies utilize mixing ratios to achieve objectives such as racial or social integration of housing projects. In this paper, we develop a class of policies with time-dependent priorities which incorporates the features of both approaches discussed above. We show that time-dependent priorities repair some of the problems associated with fixed priority systems. In addition, we emphasize the ease with which time-dependent priorities can be implemented.     

Managing product lines that share a common capacity base

This paper examines the difficulties of maintaining competitive delivery times on product lines that share a common capacity base. The analysis is derived from a case study of a manufacturing firm producing finished product and service parts at a single plant. A system dynamics simulation model is used to represent production and ordering policies of the firm and its distribution network. Simulation analysis shows that these policies cause demand volatility for the finished product to be converted into supply volatility of service parts, leading to long parts delivery times and loss of service parts market share. To improve the performance of the service parts business, the production of finished product and parts should be decoupled, so the supply of the two product lines becomes independent. The results are discussed for the general multiproduct-line case. A brief report of implementation results is included.     

Labor relations at the shop floor level

The tenacious myth that a free economy and free society impoverish working people undergirds modern government interference in labor markets and legal privilege for adversarial labor unions. Managers are concerned about harmony and productivity at the shop floor level. The opposite characteristics of conflict, disco-ordination and inefficiency are anathema. Most of the union difficulties managers must cope with at the shop floor level stem from a fundamental source, namely the philosophy of collectivism. This paper analyzes the fable of labor's disadvantage, wage determination under personal and impersonal conditions, public policy toward labor contracts and the role of businessmen in making labor markets operate more efficiently.     

The effect of lot-sizing on workload variability

Lot-sizing models which group demand requirements for one or more consecutive time periods into a single production run have received considerable attention in recent years. Material Requirements Planning (MRP) systems must, for instance, make a lot-size decision for each planned order release. Existing decision models attempt to minimize the sum of setup plus inventory holding costs. However, lot-sizing tends to increase the work center load variability, and, consequently, the costs associated with changing production levels from period to period should be incorporated into the economic analysis. This study is concerned, first of all, with analytically describing the relationship between dynamic lot-sizing models and workload variability. Secondly, in order to account for production level change costs we propose a simple modification to existing heuristic models. Lastly, we employ a simulation model to empirically extend these results to a typical MRP multiechelon production environment. An example is included to show clearly that with cost premiums for overtime and severance or guaranteed minimum costs for undertime the traditional lot-sizing techniques significantly underestimate actual costs and can lead to very costly policies.Mean, variance and coefficient of variation of period work time requirements are derived as a function of several algorithm characteristics. Average cycle time (number of periods covered by a single batch) is found to be the most influential factor in determining workload variability. Variance grows approximately in proportion to this cycle time with the proportionality constant being the square of average period workload. Cycle time and demand variability also contribute to workload variability. Results indicate that for a given average cycle time, the EOQ method will minimize workload variability. When N products utilize the same work center, the coefficient of load variation will be reduced by a factor of N^{?$\text{1}\text{2}$} unless requirements are positively correlated. Positive correlation would result when products have similar seasons or parent items. In this case grouping such products cannot help reduce variability.In order to incorporate production level change costs into existing heuristics we may simply introduce a term consisting of a penalty factor times average cycle time. The penalty factor represents the costs of period by period production level changes. Several popular heuristics are extended in this fashion, and it is found that solutions are still readily obtainable, requiring only modifications to setup or holding cost parameters.The effects of level change costs are examined via simulation for a specific yet typical environment. It is found that when setup costs are significant, traditional lot-sizing heuristics can provide cost savings and service level improvements as compared to lot-for-lot production. However, whereas for our model the obtainable profit improvement from lot-sizing was 25% in the case of freely variable capacity, actual improvements were only one half as large when reasonable hiring and firing practices and overtime and undertime costs were considered. Consequently, management needs to consider carefully labor costs and work center product relationships when determining a production scheduling method.     

Resolving uncertainty in manufacturing systems

This paper examines the effectiveness of three commonly practiced methods used to resolve uncertainty in multi-stage manufacturing systems: safety stock under regenerative material requirements planning (MRP) updates, safety capacity under regenerative MRP updates, and net change MRP updates, i.e., continuous rather than regenerative (periodic) updates. The use of safety stock reflects a decision to permanently store materials and labor capacity in the form of inventory. When unexpected shortages arise between regenerative MRP updates, safety stock may be depleted but it will be replenished in subsequent periods. The second method, safety capacity, overstates the MRP capacity requirements at the individual work centers by a prescribed amount of direct labor. Safety capacity either will be allocated to unanticipated requirements which arise between MRP regenerations or will be spent as idle time. The third method, net change, offers a means of dealing with uncertainty by rescheduling instead of buffering, provided there is sufficient lead time to execute the changes in the material and capacity plans.Much of the inventory management research has addressed the use of safety stock as a buffer against uncertainty for a single product and manufacturing stage. However, there has been no work which evaluates the performance of safety stock relative to other resolution methods such as safety capacity or more frequent planning revisions. In this paper, a simulation model of a multi-stage (fabrication and assembly) process is used to characterize the behavior of the three resolution methods when errors are present in the demand and time standard estimates. Four end products are completed at an assembly center and altogether, the end products require the fabrication of twelve component parts in a job shop which contains eight work centers. In addition to the examination of the three methods under different sources and levels of uncertainty, different levels of bill of material commonality, MRP planned lead times, MRP lot sizes, equipment set-up times and priority dispatching rules are considered in the experimental design.The simulation results indicate that the choice among methods depends upon the source of uncertainty, and costs related to regular time employment, employment changes, equipment set ups and materials investment. For example, the choice between safety stock and safety capacity represents a compromise between materials investment and regular time employment costs. The net change method is not designed to deal effectively with time standard errors, although its use may be preferred over the two buffering alternatives when errors are present in the demand forecasts and when the costs of employment changes and equipment set ups are low. The simulation results also indicate that regardless of the method used, efforts to improve forecasts of demands or processing times may be justified by corresponding improvements in manufacturing performance.     

The effects of workforce strategies on manufacturing operations

This paper tests the effects of three workforce strategies on a multistage, multiproduct manufacturing system under various operating conditions. These three strategies are those that are predominant in today's world economics. One type is a chase strategy, often used by firms that employ low skilled workers and faced with seasonal product demands, where workforce levels fluctuate according to increases and decreases in production requirements. A level-flexible strategy, commonly called the Toyota system, keeps the aggregate workforce at a constant size but by having flexibly trained workers it can allow transfers of workers between various departments and processes as production requirements dictate. The third major type is a level-inflexible strategy, such as that used on mass-assembly lines employed by American automobile manufacturers. Under this strategy, the number of workers remains constant in each department as well as at the aggregate level regardless of short term changes in the production requirements. The manufacturing system is envisioned as a sequential planning process with interrelated decisions made at the levels of aggregate planning, master production scheduling, and departmental planning. This process is modeled as a zero-one mixed integer program. The operating conditions under which the strategies are tested are the variability of demand, the level of service, and the degree of inventory investment. The strategies are statistically tested as to their effects on five criteria: average weekly workforce size, average quarterly inventory investment, average weekly overtime, total setups and the average weekly ratio of departmental load to capacity.Using four different products and an experimental manufacturing environment described within the paper, we tested for any statistical differences between the three strategies. We found that none of the strategies had significantly different workforce sizes. Also, the chase strategy had the smallest average quarterly inventory investment. This implies that the “Japanese” level-inflexible strategy does not have the smallest workforce or lowest inventory as claimed by some.We also tested the effects of the operating conditions on the workforce strategies. The level-flexible strategy was most insulated from the seasonality, inventory restrictions, and service level. Thus again the claims made for the level-inflexible strategy about being insulated from its environment were not substantiated. It was found that the seasonality of demand had the greatest impact on the three workforce strategies. Also, the level of service greatly affected the utilization of labor resources.The major overall conclusion is that the level-flexible strategy which is associated with some Japanese manufacturing firms does not achieve the claims that some of its adherents have made for it. It does not have the smallest workforce or the lowest inventory nor is it best insulated from its environment. Furthermore, the seasonality of demand and the level of service do effect this strategy.     

Optimal inventories for repairable redundant systems with aging components

Complex systems that are required to perform very reliably are often designed to be “fault-tolerant,” so that they can function even though some component parts have failed. Often fault-tolerance is achieved through redundancy, involving the use of extra components. One prevalent redundant component configuration is the m-out-of-n system, where at least m of n identical and independent components must function for the system to function adequately.Often machines containing m-out-of-n systems are scheduled for periodic overhauls, during which all failed components are replaced, in order to renew the machine's reliability. Periodic overhauls are appropriate when repair of component failures as they occur is impossible or very costly. This will often be the case for machines which are sent on “missions” during which they are unavailable for repair. Examples of such machines include computerized control systems on space vehicles, military and commercial aircraft, and submarines.An interesting inventory problem arises when periodic overhauls are scheduled. How many spare parts should be stocked at the maintenance center in order to meet demands? Complex electronic equipment is rarely scrapped when it fails. Instead, it is sent to a repair shop, from which it eventually returns to the maintenance center to be used as a spare. A Markov model of spares availability at such a maintenance center is developed in this article. Steady-state probabilities are used to determine the initial spares inventory that minimizes total shortage cost and inventory holding cost. The optimal initial spares inventory will depend upon many factors, including the values of m and n, component failure rate, repair rate, time between overhauls, and the shortage and holding costs.In a recent paper, Lawrence and Schaefer [4] determined the optimal maintenance center inventories for fault-tolerant repairable systems. They found optimal maintenance center inventories for machines containing several sets of redundant systems under a budget constraint on total inventory investment. This article extends that work in several important ways. First, we relax the assumption that the parts have constant failure rates. In this model, component failure rates increase as the parts age. Second, we determine the optimal preventive maintenance policy, calculating the optimal age at which a part should be replaced even if it has not failed because the probability of subsequent failure has become unacceptably high. Third, we relax the earlier assumption that component repair times are independent, identically distributed random variables. In this article we allow congestion to develop at the repair shop, making repair times longer when there are many items requiring repair. Fourth, we introduce a more efficient solution method, marginal analysis, as an alternative to dynamic programming, which was used in the earlier paper. Fifth, we modify the model in order to deal with an alternative objective of maximizing the job-completion rate.In this article, the notation and assumptions of the earlier model are reviewed. The requisite changes in the model development and solution in order to extend the model are described. Several illustrative examples are included.     

The use of workload information to control job lateness in controlled and uncontrolled release production systems

The performance of a workload dependent scheduling and due date assignment rule is investigated. The rule uses time-phased workload information and time-phased capacity information. Performance comparisons are made with a rule that uses only time-aggregated workload information. The performance for two methods of releasing jobs to the shop is investigated: an uncontrolled method where the jobs are released at random, and a controlled method where jobs are released to maintain a specific workload norm. Computer simulation is used as the research tool. The mean and standard deviation of lateness are used as performance measures.The results indicate that the use of time-phased workload information may decrease the variance of the lateness, as compared with the use of time-aggregated workload information only. However, the magnitude of the effect depends on the type of sequencing rule used. Furthermore, if time-phased information is used, control of the mean lateness requires that the amount of capacity available for loading used in the loading procedure differs from the amount of capacity actually available for production. It is shown that by selecting adequate parameter values, both a constant mean lateness and a small variance of lateness can be obtained with this type of assignment rule.These results are valid for both types of release situations. So even in the case where the workload of the shop is under strict control, and the mean operation flow time does not, therefore, vary, the use of time-phased workload information can decrease the variance of the lateness.     

Order review/release in the absence of adherence to formal scheduling policies

In many plants, the performance of shop floor workers is measured by accounting-based productivity criteria. Such systems encourage workers to maximize their individual performance, often at the expense of total shop performance. One such company, Union Switch & Signal, a manufacturer of railroad equipment, has decided to increase finished goods inventory in an effort to counteract poor due date performance. Management at Union Switch & Signal feel that workers not following priorities contribute significantly to this poor performance. It has been suggested that the controlled release of jobs into the shop, i.e., Order Review/Release (ORR), may provide the operations manager a vehicle for enforcing job priorities when formal dispatching rules are not strictly followed by workers. In this study, two ORR methodologies are studied in regards to their ability to offset the dysfunctional behavior by workers who seek to maximize their own individual productivity. This type of behavior was captured by simulating the phenomenon of `cherry picking'. Cherry picking occurs when a job is selected for processing based not on its formal priority but on the difference in standard allowable processing time and actual processing time. Results suggest that at least one ORR methodology is able to reduce the difference in resulting labor productivity while improving overall shop performance.     

Service levels for priority and nonpriority products with a common component

This paper refers to an article by Baker, recently published in the Journal of Operations Management. We point out an error, and provide correction, in the calculation of service level for a non priority product when a priority product and the nonpriority product share a common component.     

关于船员外派法律关系的分析——兼析《船员条例》和《船员注册管理办法》

金融危机席卷全球,进一步证明了经济的全球化趋势,外派劳务市场也未幸免,船员外派作为外派劳务市场的一个重要组成部分,受到了严重的影响。而目前的《船员条例》和《船员注册管理办法》在起到规范作用的同时,也受到了法律效力过低的限制。文中旨在分析船员外派法律关系,更好地去保障船员的权益,并结合《条例》和《办法》去发现其中存在的问题。     

The cyclicality of effective wages within employer-employee matches in a rigid labor market

This study analyzes real wage cyclicality for male full-time workers within employer-employee matches in Germany over the period 1984-2004. Five different wage measures are compared: the standard hourly wage rate; hourly wage earnings including overtime and bonus pay; the effective wage, which takes into account unpaid overtime; and monthly earnings, with and without additional pay. None of the hourly wage measures exhibits cyclicality except for the group of salaried workers with unpaid overtime. Their effective wages show a strongly procyclical reaction to changes in unemployment. Despite acyclical wage rates, salaried workers without unpaid overtime experienced procyclical earnings movements if they had income from extra pay. Monthly earnings were also procyclical for hourly paid workers with overtime pay. These findings suggest that cyclical earnings movements are generated by variable pay components, such as bonuses and overtime pay, and by flexible working hours. The degree of earnings procyclicality revealed for the German labor market is comparable to the United States.     

A heuristic algorithm for capacity sensitive requirements planning

Available lot sizing rules for use in MRP (Material Requirements Planning) systems ignore capacity limitations at various work centers when sizing future orders. Planned order releases are instead determined by the tradeoff only between the item's set up and inventory holding costs. This limitation can cause unanticipated overloads and underloads at the various work centers, along with higher inventories, poorer customer service, and excessive overtime.This research explores one way to make MRP systems more sensitive to capacity limitations at the time of each regeneration run. A relatively simple heuristic algorithm is designed for this purpose. The procedure is applied to those planned order releases that standard MRP logic identifies as mature for release. The lot sizes for a small percentage of these items are increased or decreased so as to have the greatest impact in smoothing capacity requirements at the various work centers in the system. This algorithm for better integrating material requirements plans and capacity requirements plans is tested with a large scale simulator in a variety of manufacturing environments. This simulator has subsequently undergone extensive tests, including its successful validation with actual data at a large plant of major corporations.Simulation results show that the algorithm's modest extension to MRP logic significantly helps overall performance, particularly with customer service. For a wide range of test environments, past due orders were reduced by more than 30% when the algorithm was used. Inventory levels and capacity problems also improved. Not surprisingly, the algorithm helps the most (compared to not using it at all as an MRP enhancement) in environments in which short-term bottlenecks are most severe. Large lot sizes and tight shop capacities are characteristic of these environments. The algorithm works the best when forecast errors are not excessive and the master schedule is not too “nervous.”This proposed procedure is but one step toward making MRP more capacity sensitive. The widely heralded concept of “closed-loop” MRP means that inventory analysts must change or “fix up” parts of the computer generated material requirements plan. What has been missing is a tool for identifying the unrealistic parts of the plan. Our algorithm helps formalize this identification process and singles out a few planned order releases each week. This information comes to the analyst's attention as part of the usual action notices. These pointers to capacity problems go well beyond capacity requirements planning (CRP) and would be impossible without computer assistance.Our study produced two other findings. First, short-term bottlenecks occur even when the master production schedule is leveled. The culprits are the lot sizing choices for items at lower levels in the bills of material. “Rough-cut” capacity planning, such as resource requirements planning, therefore is not a sufficient tool for leveling capacity requirements. It must be supplemented by a way to smooth bottlenecks otherwise caused by shop orders for intermediate items. Second, the disruptive effect of large lot sizes is apparent, both in terms of higher inventories and worse customer service. Large lot sizes not only inflate inventories, but paradoxically hurt customer service because they create more capacity bottlenecks. The only reason why management should prefer large lot sizes is if set-up times are substantial and cannot be efficiently reduced. This finding is very much in step with the current interest in just-in-time (JIT) systems.     

Assessment Adrift: Review of the Current State of Assessment of Academically Based Leadership Education Programs

Assessment is a growing priority among the academy and also appears to be of increasing interest among academic‐based leadership education programs. This article offers a brief history of assessment within higher education as well as an overview of the current state of assessment in the context of academic‐based leadership education programs. While there are numerous studies reporting on assignment‐ and course‐level assessment activities, comparatively limited literature addresses program‐level assessment. It is the author's assertion that we must raise the level of conversation within our emerging discipline to identify effective best practices.     

The deployment of temporary production workers in assembly operations: a case study of the hidden costs of learning and forgetting

The dynamics of workforce skill levels has a considerable impact on plant-level performance that is commonly overlooked by managers of manufacturing operations. In this study, we present a discrete event simulation model inspired by and validated in an actual manufacturing setting that includes short product life cycles, mid-volume production quantities, and a production environment consisting of assembly, inspection and testing.The effect of worker skill dynamics is analyzed using a factorial experimental design that contrasts the use of temporary versus permanent workers on manufacturing cost performance. The manufacturing costs assessed include labor, inspection and testing. The cost of reworking a defect is captured as an increase in the labor consumption. Materials costs are not assessed. At the core of the analysis, it is assumed that temporary workers have relatively less skill and therefore have higher average production times, higher average defect rates associated with their assembly activity, and lower rates of learning. In addition, the variance of the production time is higher for the temporary workers. Despite these indicators of performance problems, temporary workers may be used because of the considerably lower wage rate compared to permanent employees.Our in-depth case analyses shows that assigning skilled permanent workers to upstream build operations was superior to other policies deploying temporary workers, regardless of lot size or product complexity. Attesting to the importance of the labor mix component of manufacturing strategy, workforce deployment policies tended to dominate product switching frequency (a proxy variable for lot size and product mix) in impacting costs.     

Informality in developing economies: Regulation and fiscal policies

This paper proposes a unified theoretical framework where formal and informal firms coexist and face the same type of product and labor market imperfections: they have monopoly power in the goods market, they are subject to matching frictions in the labor market, and wages are determined by bargaining between large firms and their workers, through either individual or collective bargaining. Our model matches the main stylized facts on informality for developing countries and appears to be a good candidate for policy analysis. In this framework, we study the impact on informality, wages and unemployment of policies that may be used to reduce informality. We consider changes in product market regulation (PMR) and in two types of fiscal policies, labor taxes and formality enforcement. We find that lessening PMR decreases informality and unemployment simultaneously, indicating that there is not necessarily a tradeoff between informality and unemployment. The tradeoff appears when fiscal policies are used, though. Moreover, the impacts of PMR on unemployment and on wages are larger under collective than individual bargaining. With respect to wage inequality, lessening PMR reduces it, while lower taxes tend to increase the formal sector wage premium.     

浅谈在施工现场对工程机械故障的应急维修

在工程机械使用中,机械设备一旦损坏,往往会由于缺少个别零部件而影响机械的使用和施工工期,同时,在工程机械修理过程中,也常常会因为缺少合适的工具、备品备件导致修理工作不能正常进行,因此应该能够在工程机械的使用和维修工作中,灵活处理一些看来比较棘手的问题。文章从零部件故障没有备件的应急办法、几种应急维修技巧、几种能够在工程机械修理中应急代用的日常生活用品三个方面,介绍了工程机械应急维修的方法。