Learning & Experience Curves In Manufacturing
Learning & Experience Curves In Manufacturing
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学习
DOI：
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发表时间：
2014
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通讯作者：
Quarterman Lee
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文献类型：
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作者：
Quarterman Lee
学习曲线传统上用于成本估算和培训目的。然而，它们有更广泛的应用，包括制造和营销策略。这就是持续改进的概念。就像复利一样，它们从看似微小的增量变化中产生巨大的利益。学习曲线在第二次世界大战期间变得突出，当时陆军航空队的科学家注意到，根据一个相当可预测的公式，给定飞机模型的成本随着产量的增加而下降。每一次累积产量增加一倍，成本就下降一个固定的百分比。在飞机制造业，当时，这一降幅约为20%。数学是有点复杂，是不必要的制造战略的目的。对于我们的目的来说，重要的是了解典型曲线的一般形式，各种因素如何影响曲线以及由此产生的对制造和营销战略的影响。图1这个线性标度显示了每件直接劳动力作为总产量的函数。这个等式显示了所有单元到第N个单元的总平均成本。然而，每第N个单位的成本相当于20个左右单位后的平均成本。图2双对数标度使数据显示为直线。这条线的斜率反映了发生的“学习”量。图1和图2的示例是许多情况下的典型。在生产启动期间，每个生产单位的直接劳动时间迅速下降。从一个单元到下一个单元的改进变得越来越小，但它确实会持续，通常会持续几十年。当以双对数标度绘制时，数据近似于图2中的直线。这条线的斜率表示“学习”或改进的强度。因此，“陡峭的学习曲线”一词表明改进很快到来的情况。函数的概念和一般形式适用于广泛的行业。它也适用于从执行特定任务的个体工人到中国等国家经济的广泛规模。文献中的大多数例子都说明了学习曲线对直接劳动力的影响。然而，制造业绩效的许多其他方面都遵循相同的模式。例如，质量、交付和（长期）总成本。表1显示了从文献中的各种来源汇编的代表性学习率。百分比是指...
Learning Curves have traditionally been used for cost estimating and training purposes. However, they have a much wider applications, including Manufacturing and Marketing strategy. They underly the concept of Continuous Improvement. Like compound interest, they generate large benefits from seemingly small, incremental change. The learning curve came into prominence during World War II when Army Air Force scientists noticed that the cost for a given aircraft model declined with increased production in accordance with a fairly predictable formula. Each time the cumulative production doubled, cost declined by a fixed percentage. In the aircraft industry, at that time, this reduction was about 20%. The mathematics is a bit complex and is unnecessary for purposes of Manufacturing Strategy. The important thing, for our purposes here, is to understand the general form of the typical curve, how various factors affect the curve and the resulting implications for Manufacturing and Marketing Strategy. Figure 1 This linear scale shows direct labor per piece as a function of total pieces produced. This equation shows the total average cost for all units through the Nth unit. However, the cost of each Nth unit parallels the average cost after 20 or so units. Figure 2 log-log scale makes t he data appear as a straight line. The slope of this line reflects the amount of "learning" that takes place. Key Features The example of figures 1 & 2 is typical of many situations. Direct labor hours for each unit of production drops rapidly during production startup. The improvement from one unit to the next becomes smaller and smaller but it does continue, often for decades. When plotted on a log-log scale, the data approximates a straight line as in figure 2. The slope of this line indicates the intensity of "learning" or improvement. Hence the phrase "steep learning curve" indicates a situation where improvement is coming quickly. The concept and general form of the function applies to a wide range of industries. It also applies on a wide range of scales from the individual worker performing a specific task to national economies such as China. Most examples in the literature illustrate learning curve effects on direct labor. However, many other dimensions of manufacturing performance follow the same pattern. Examples are quality, delivery and (over the long term) total cost. Table 1 shows representative learning rates compiled from various sources in the literature. The percentages are the improvement that …