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1、,“Lean” Tools,“精益”工具,PQ Analysis,PQ分析,P-Q Analysis,The best way to begin an effort to build a U-shaped “Flow” cell for wide variety small lot production is to study the current production conditions that exist in the factory. This is done through the use of a P-Q analysis. In a P-Q analysis, the P s
2、tands for product and the Q stands for quantify (no consideration to dollar value). Step 1: Obtain at least 6 months of data on products made and production output quantities. (If known, future production quantities would be better.) Step 2: List the products in order of highest quantity output and
3、their associated percentage output of the total and tabulate on a P-Q list (see table 1).,P-Q Analysis List,No.,P/N,Quantity,Total,%,Cumulative %,AB BC CD EF EF FG,15,900 12,500 11,700 9,450 9,400 9,000,15,900 28,400 40,100 49.550 58,950 67,950,17.5 13.7 12.9 10.4 10.3 9.9,17.5 31.5 43.7 54.5 65.2 7
4、4.7,Table 1,PQ分析,-要组建一个多种类小批量生产的U形“流动”工作站,首先要学习工厂内目前的生产条件.整个工作过程由PQ分析来贯穿.在PQ分析中,P代表产品, Q代表质量(不考虑货币价值) -第一步 :收集至少6个月的产品资料和产量数据.如果可以的话,最好可以收集到将来的产量数据. -第二步 :按照产品的产量和占总产量的百分比,由高到低给产品制PQ表.(见表1),P-Q Analysis,Step 3: Create a P-Q Analysis table (see table 2), with the left vertical axis representing the o
5、utput quantity and the horizontal axis representing the product. The graph is a Pareto chart, listing the products and their quantities in descending order, and a cumulative percentage line (right vertical axis). Note: Technically, in a wide variety small lot production shop, 40% of the product acco
6、unts for approximately 60% of the volume (or less). In the above example 40% of 14 total part numbers is approximately. 6. Draw a vertical line through the 6th product until you hit the cumulative % line, and draw a horizontal line over until you intersect the right axis. In this example it intersec
7、ts around 70%, and approximates a true wide variety small lot factory.,PQ分析,-第三步:制出PQ分析表(见图二),左边的纵数标表示产量,横数标表示产品. 此图是一幅排列图表, 产品按照产量由高到低排列,右边的纵数标是积累率. 注意: 从技术上来说, 在多种类小批量生产的车间里, 40%的产品种类应该占60%的生产总量.在上面的例子中,总共有14种零部件, 它的40%约等于6,于是就在第六个产品上面画上一条竖线与积累率线相交,然后在交叉点开始画一条水平线与右边的纵数标交叉. 在这个事例中,他们的交叉点为70%, 接近多种类
8、小批量生产车间的生产实况.,P-Q Analysis,Step 4: Design a line of processes based on the P-Q Analysis list. If the P-Q Analysis shows that 20% of the parts represent 80% of the volume; then each product should be investigated for a single product cell (the relative volume probably already requires dedicated equip
9、ment).,第四步: 根据PQ分析制作图表, 如果PQ分析显示20%的产品占有80%的生产总量, 那么每个产品都应该有单独的生产区(或许相对产量已经要求专门的设备).,PQ分析,P-Q Analysis,In a wide variety small lot factory depicted below (see table 3), Group Technology or families must be identified through the use of a Process-Route (PR) Analysis (described in the next section). I
10、n the diagram below of a wide variety factory, Group A parts typically represent about 70% of the volume and can warrant a specialized single product line. Products falling into groups B&C represent the remaining 30-39%, and will be reviewed for a group or family.,在多种类小批量生产的工厂里(如图3所示),通过对工艺路线的分析, 识别
11、成组技术和产品系列(下部分会讲到). 在下面的图表里, A组部件占了生产总量的70%.这就说明了需要一条单独的生产线. B组和C组的产品占了30%-39%, 我们将把他们作为一组或是一个系列.,PQ分析,PR Analysis,The next step is to analyze the flow of product in group A (as a starting point), to determine if other products follow a similar process path and could be considered a family. When cons
12、idering families via a process-route (PR) analysis, do not consider differences in product shape, size, or material as different varieties of parts, but rather parts that follow the same basic process flow sequence. Most factories have no more than 5 such process families. When grouping several diff
13、erent parts together into a family (Group Technology), the key factor becomes changeover, which must be drastically reduced. Typically Group B & C parts fall into this category, comprising different products that have similar process paths and can therefore use the same line/cell configuration.,下一步就
14、是分析A组产品的流程(作为起点), 然后再决定其他产品的流程是否与它相似以及是否能够归为同一系列. -通过工艺流程分析考虑成组时, 不要认为产品形状,尺寸,或是材料的不同就是产品种类的不同,事实上它们的基本流程顺序都是一样的. 大多数工厂最多有5个不同的工艺系列. 当把几种不同的部件归组为一系列(成组技术)时,主要因素就会发生改变, 我们应该尽量减少变化. - B和C组部件通常归为一组, 其中包括有着类似流程途经和能够使用相同生产线/工作站生产的产品.,PR分析,PR Analysis,To fill out the PR Analysis form, list the operations
15、of the highest volume part from the proposed family across the top of the form. List the operations in sequential order, noting each machine and workstation needed to perform that operation. If there is one piece of equipment that the part must return to several times, show that by drawing a line ba
16、ck to that first location. Process route tables help us to see what machines are needed and the path that the parts take. These tables are key in helping create families for Group Technology lines. Once the machines and flow is established, we can more easily identify other parts that can fit into this line/cell. Note: Efforts should be made to simplify and standardize the flow/sequence of the parts in the family; trying to eliminate any backtrackin
