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1.1采购成本构成 introduction of the cost breakdown
What is the cost? There are a lot financial books introducing the cost, but through the sourcing view, I define that the cost is all the investment of the manufacturer from the design to the actual product during the whole product life time, including the setup investment, material investment, equipment investment, manpower investment, cutting and tooling investment, etc. in the whole period of the product life time. The supplier will produce many quantities with different orders during the product life time, and they will invest resource along with different quantities of different orders. See the below chart, which can better explain the relationship. 何谓产品成本？有很多介绍关于成本的财务书籍，但是从一个采购角度来看，成本可以理解为从设计到产品生产出来在其整个生命周期内供应商的所有投入，工装投入，材料投入，设备投入，人力资源投入，刀具和模具投入等。在产品的生命周期内，供应商会根据客户不同时期下的订单，投入不同的资源来完成相应的数量。下面这个图表可以显示这种逻辑关系。 PS: Quantity n is the different quantity of different order PS: Quantity n 是相应订单上要求生产的产品数量 And you will get the unit cost if you divide the investment by the quantities which the manufacturer produces. See below chart. 如果我们把供应商为了生产产品而投入的相应资源除以这些资源生产出来的产品数量，就会得到单个产品的成本。见下图。 We can also use a formula to describe this relationship as following: 我们同样可以用下面的数学公式来描述这种逻辑关系： Qn=batch quantity, Pn=piece cost Qn=第n批次所生产的产品数量, Pn=第n批次的单件成本 Assuming that there is no supplier capacity issue, the raw material price does not change along with the part order quantities, so the material cost per piece will not change along with part order quantities, and assuming the production efficiency does not change, so that the process cost per piece will not change along with the part order quantities either. And assuming the overhead and the profit changes little along with part order quantities, then according to the above formula, we will see the piece cost changes only along with the batch quantities. The below chart can easily tell how the piece cost changes with different quantities. The piece cost will decline when the batch quantity increases, and it will be infinitely getting close to A, if the batch quantity is getting infinitely great. 假设供应商没有产能问题，原材料价格不随产品订单的数量的变化而变化，因此单件产品的材料成本不随产品订单的数量的变化而变化，同时还假设生产效率也保持不变，所以单价的加工成本也不随产品订单的数量的变化而变化，还假设管理费和利润也不随产品订单的数量的变化而变化，那么根据上面的数学公式，我们可以看到单件产品的成本只随产品订单的数量的变化而变化。下图可以更直观易懂的告诉我们这种变化关系。当订单数量增加时，单件成本下降；当订单数量无限大时，单件成本趋于数值A。 Once the supplier receives a RFQ, they normally divide the estimated annual usage into twelve months as a batch quantity or minimum order quantity based on the assumption that the customer will order monthly and they will produce once a month. So we always see that the supplier quotes different price with different estimated annual usage, the higher volume of the estimated annual usage, the lower price they will quote normally. This is also what it tells in the below chart. 当供应商收到RFQ时，供应商通常会假设客户的订单会比较稳定，并且按月下单，所以如无特殊说明，他们通常会把年用量按照每年12个月均等分作为批次订单数量或者最小订单量。所以我们经常会看到供应商对于不同的年用量报不同的价格，年用量越高，价格越低。 PS: Assuming supplier has no capacity issue PS: 假设供应商无产能问题 The above formula model are all based on the assumption that the raw material price does not change along with the part order quantities, so the material cost per piece will not change along with part order quantities, and considering the production efficiency does not change, so that the process cost per piece will not change along with the part order quantities either. And assuming the overhead and the profit changes little along with quantity. However, what if the part order quantities is increasing out of the supplier capacity limit? If the supplier is running out of the capacity as the order quantity increasing, the supplier has to purchase additional resources to support and produce additional demand, such as new equipment, new machines, and hire more people, do a lot of training for the new coming labors. So once the demand increases beyond the supplier capacity limit, then the cost per piece starts to ramp up, until the quantity increase to the certain number which can absorb the additional investment, then the cost will start to go down and flat. See below picture. 上述数学模型是基于很多的假设，原材料价格不变化，所以单件材料成本不会随产品的订单数量的变化而变化，生产效率不变，所以单件加工成本不会随产品的订单数量的变化而变化，同时还假设管理费和利润也不会随产品的订单数量的变化而变化。然而，如果订单数量超过了目前的供应商产能极限，单件产品成本又会怎样变化呢？如果订单数量增加了，而且还超过了供应商产能，那么供应商就需要购买额外的资源来生产多出来的订单需求，例如新设备，新机器，雇佣更多的员工，增加对新进员工的培训等。所以一旦需求超过了目前现有的产能极限，那么单件成本就会开始重新向上攀升，直到产品的订单数量增加到某个数值，这个数值可以吸收掉这些额外的资源投入，然后单件成本又会开始向下和走平。见下图。
PS: If the part order quantity is increasing out of the supplier capacity limit PS: 如果产品订单数量的增加超过了供应商现有产能 But if the other assumptions or conditions changes as well, for example, the factors affecting the raw material cost and process cost changes, what will happen on the cost? It will mention below that how the change of two major factors impacts the part cost. 但是如果其他的假设条件也变了，例如影响原材料成本和加工成本的因素变化了，那么单件成本将如何变化？下面将会提到这两个影响单件成本的主要因素是如何产生影响的。 1.2原材料对成本的影响 Impacts from material cost Material cost=gross weight (kg) X raw material price($/kg) 材料成本=毛重 (kg) X 原材料单价($/kg) Gross weight(kg): How many kg of all the raw material is used to make the part. Including the scrap and the part net weight. 毛重(kg)：生产制造这个产品所用的实际材料重量，包括废料和产品净材料 Raw material price($/kg): The price of the material in the market. 原材料价格($/kg):原材料的市场价格 There are two factors that will affect the material cost, one is gross weight of the part and the other is the raw material price. Take the stamping part for example, the gross weight will change if you use different tooling&die and stamping layout of the material strap. If you use the progressive die, the gross weight normally will be greater than the material with single die due to the different stamping layout of the material strap. The below is an example. The width of the material strap for single die is 66mm, and the width of the material strap for the progressive die is 70mm. The extra 4mm of the material strap for the progressive die is used for pulling and lifting the material strap from one station to the next station on the progressive die. 影响材料成本的因素主要是两个，一个是产品毛重，一个是原材料价格。举个冲压件的例子，如果采用不同的模具和排料方式，产品的毛重是不同的。如果用连续模，由于毛重一般会比用单冲模大一些，主要是因为连续模和单冲模的排料方式不同导致的。下面是一个实际例子。单冲模的料带宽度是66mm，而连续模的料带宽度是70mm。连续模多出来的4mm料带宽度是用来拖料的。 part drawing 零件图
单冲模排料图 layout of the material strap of progressive die 连续模排料图 And even using the single die, the gross weight of the material still could be different. Different design of the material strap results in different material gross weight. Below is another example for this condition. Below are two kinds of different design of the material strap for the same part, a triangular shape stamping part. And it can easily tell that the Material Utilization Rate of the pattern of the material strap #1 is lower than that of material strap #2. 有时即使同样是单冲模方式生产，材料的毛重也可能会由于不同的排料方式而不同。下面是此种情况的一个例子。 layout #1 排料 #1 layout #2 排料#2 Take the turning parts or machining parts for example, in order to improve the Material Utilization Rate, the supplier is always trying to use cold roll bar stock or tube to make the turning parts, because they might not need to do the turning process or just do a little turning process on OD due to good tolerance control and good appearance quality on OD of the cold roll bar stock, or use the tube stock which is close to the part shape, so that the supplier will not only save the material cost but also saving the processing cost. Regarding to the parts with complicated shape, the designer or the supplier will use die casting, sand casting, forging etc. to make the blank in order to improve the Material Utilization Rate. 对于机加工零件，为了提高材料的利用率，供应商往往会尝试使用冷轧棒料或者管料来做车削件，冷轧棒料外径精度比较高，表面外观质量好，使用这种材料不仅会节省材料，还会节省加工成本。如果零件是管状形状，可以考虑使用管料来加工，同样可以节省材料和加工。对于形状比较复杂的零件，设计者或者供应商一般会考虑用压铸工艺，砂铸工艺或者锻造工艺等先做毛坯，然后再进行后道加工，同样也会节省材料和加工的。 Generally if the material utilization rate is better, the material cost will be lower. If the raw material price is higher, the material cost will be higher. The material cost is more sensitive to the material utilization rate, if the raw material is nonferrous metal, such as brass, alum, or stainless steel, such as SS316, 304 etc, or the other high value raw material. 总的说来，如果材料利用率高，材料成本会相对降低。如果原材料价格高，材料成本会相对增加。倘若原材料是有色金属的，如铜材，铝合金材料，或者是不锈钢，如SS316，SS304，或者是其他贵金属材料的，材料成本的变动对其利用率会更加敏感。 1.3工艺对成本的影响 Impacts from process cost Process cost=process time(hour) X hourly rate($/hour) 加工成本=加工时间(小时) X设备工时费($/小时) Process time (hour): How many hours/Minutes/Seconds it takes to do the certain process. 加工时间(小时)：完成某道工序所需时间，小时/分钟/秒 Hourly rate($/hour): The cost/hour of the equipment/machine/cutting tool and labor 设备工时费($/小时)：设备/刀具等和人员单位时间的费用 The process time is mainly related to the machine and cutting tool production efficiency, and the process flow design. If the process flow is short, the process time will be shorter. If the machine and cutting tool production efficiency is higher, the process time will be shorter. 加工时间主要是与设备及刀具生产效率和所设计的工艺流程有关。如果工艺流程短，加工时间会短，如果设备及刀具生产效率高，加工时间也相对会短。 The hourly rate is mainly related to the value of the machine/cutting tool that the supplier uses to make the parts. Higher value of the machine/cutting tool, the higher hourly rate. Normally for stamping, if the punch machine is the same type, the larger tonnage, the more value, then the higher hourly rate. For the turning and machining, if the machine function is similar, the higher accuracy, the higher value, then the higher hourly rate. Generally the labor cost will be considered as a part of the hourly rate, so higher labor salary, the higher hourly rate. 设备工时主要与生产产品的设备/刀具本身的价值有关。设备价格高，设备工时费相对高。对于冲压来讲，一般来说相同类型的冲床，吨位越大，价值越高，其设备工时费越高；对于机加工来讲，一般来说如果功能近似的设备，精度越高，价值越高。通常人工成本也会作为设备工时的一部分考虑，所以工资高，设备工时也会相对变高。 1.4对成本影响的其他因素 Other impacts on the cost The main impacts on the part cost is material cost and process cost, and there are still other factors that will slightly affect part cost, such as freight cost, package cost, scrap rate, waste material recycle , plant rent, oil cost, power cost, coolant cost, overhead, profit etc. 对零件成本的影响主要是材料费用和加工费用，其他非主要的因素也会对零件成本产生影响，如运费，包装费用，废品率，废料回收，厂房租金，油耗，能耗，冷却液成本，管理费，利润等。 1.5成本影响矩阵 Matrix of the cost impacts
As the above matrix showing, If the material utilization rate is better, raw material price is cheaper, the material cost will be less. If the process flow is shorter, machine/cutting tool production efficiency is greater, and if the suppliers use the right machine and lower labor cost, the process cost will be less. 如上面的矩阵图所示，如果材料利用率高，原材料价格便宜，材料成本会降低。如果工艺流程短，设备生产效率高，同时如果供应商用恰当的设备，更加便宜的人工，那么加工成本就会更低。 If the material utilization rate is worse, raw material price is more expensive, the material cost will be higher. If the process flow is longer, machine production efficiency is lower, and the suppliers use the wrong machine without right tonnage and higher labor cost, the process cost will be more. 如果材料利用率低，原材料价格贵，材料成本也会相应的变贵。如果工艺流程长，设备生产率低，供应商用了不合适的设备，以及贵的人工，那么加工成本就会变高。 This also can explain that why we always get different quotation of the same part from the different suppliers, sometimes the difference is quite distinct. If the suppliers are all experienced suppliers, the obvious difference of the quotation may result from the different machines they quoted with. Take stamping for example, 300T is the right tonnage to make the part, however, the supplier has no 300T punch machine available but 450T, then the supplier might make two decisions assuming they will not invest 300T punch machine, one option is to break one process into two processes with smaller punch machine, and the other is to use larger machine, such as 450T punch machine, to make the part. The first option might make the process longer, then the cost will higher, the second option will also make the process cost higher, since they are going to use larger machine, which means higher hourly rate. 这同样也可以解释为什么相同的零件不同的供应商报的价格会有区别，甚至有时这种不同还会很明显。假设供应商都是非常有经验的厂商，那么价格中明显的不同可能产生于他们报价是基于不同的生产设备。举例来说，冲压某个产品恰好需要300T的冲床，然而，某个供应商没有300T的冲床，但是有450T的冲床，那么如果假设这个供应商不想投资一个300T的冲床做这个项目，那么我们可以推断他们会做两种决策，一是把一道需要大吨位的工序拆分成两道相对小的工序，这样就可以使用小吨位的冲床来完成生产，或者还可以使用比300T更大的吨位冲床来完成生产，例如450T的冲床。第一种选择会导致工艺流程过长，相应的加工成本也会增加，第二种选择由于供应商使用超过需要的吨位设备生产，导致更高的设备工时费，这也将会直接导致加工成本增加。 Therefore as a sourcing, when send RFQ, it is very important for the cost to send to the right supplier with the right machine. 因此，对于采购来说，当我们发送RFQ给供应商的时候，这个供应商有合适的设备来生产此产品对于产品的成本是非常重要的。
原创作者：Chris Gu |
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