Understanding the Extrusion Press as the Conversion Point,
Part 3: Case Study – Billet Taper Quench
如何理解挤压后的废料导致更高的成本（III）
案例分析：柱锭梯度水冷
David Jenista, Granco Clark, Inc
David Jenista
INTRODUCTION 引言
In our 2010 paper to the Guangdong Extruder Conference, we discussed the extrusion press as the conversion point of the extrusion process. The value added is converting billet to profile at the press. In 2012 we used the Hot Log Saw as a case study. In this paper we use the Billet Taper Quench as a case study of this concept, showing the benefit of longer billets and how to optimize production with long billets.
在2010年广东挤压技术研讨会上，我们发表了一篇论文讨论了挤压机是挤压流程的转折点。挤压机把铝锭转变成型材就是给型材赋予了价值。2012年我们用热锯做研究对象。本文中，我们将以“柱锭梯度水冷”作为例，研究在挤压中短锭将能带来什么效益，如何使用短锭优化生产。
REVIEW回顾
In 2010 paper, we provided the following summary of the financial considerations associated with the extrusion plant:
1.There is a large cost associated with owning a press line. This cost falls on the PROFILE because the profile has the added value.
2.There is an operating cost for the extrusion department that also falls on the profile, because the profile is the only source of revenue. So the profile yield is very important to maximize the economic result.
3.The cost of the other departments and the company profit is also covered by the profile selling price. This cost may be more than the entire cost of the extrusion department (#1 and #2 above).
4.Decisions must be focused on the maximum shippable Kg/Hr to spread all of the cost over the most products.
在2010间的论文中，我们提出了运营铝型材挤压厂所要考虑的一些经济因素，总结如下：
1.拥有一条挤压生产线要投入巨大的成本，投入成本需要靠型材的售出来平衡，因为型材自身具有了价值。
2.挤压部门的运营成本也需要靠型材的售出来平衡，因为型材是收入的唯一来源。所以，型材的收益对于经济效益的最大化至关重要。
3.公司其他部门的运营成本和公司的利润同样依赖于型材的售价，这项开支可能多于整个挤压部门的所需成本（上述1、2两点）。
4.做决策时必须以单位时间可供发货产品量Kg/Hr最大化作为核心目标，尽可能地做到最多的产品的成本比。
CASE STUDY 案例分析
For direct extrusion presses, temperature tapering of the billet can provide significant increase in press speed without reducing profile quality and in some cases improving profile quality.
对于正向挤压机来说，短锭温度递减却能使挤压速度明显提高，不会影响型材的质量，一些时候还会提高型材质量。
Taper heating of the billet with an electric induction billet heater is a common practice, but the equipment is not easily and accurately adjustable for different profiles and billet lengths. import suppliers of electric induction heaters can provide a precision gradient but these units are very expensive to purchase.
用工频炉对短锭梯度加热是常见的做法，可是对于使用它们不是一件容易的事，尤其是要针对不同的型材和对于不同的长度的短锭需要做精细的调整。尽管进口工频炉的供应商可提供一个精确的温度梯度，但是要购买这些设备十分昂贵。
Electric cost causes many extruders to choose gas heating. The benefits of gas heating can be combined with the Billet Taper Quench to provide billets with a precise temperature taper.
电耗成本高也引发很多挤压机选择使用天然气加热。天然气加热的好处即结合使用柱锭梯度水冷装置可向短锭提供精确的温度梯度。
The Granco Clark Billet Taper Quench provides accurate temperature tapering with adjustment from the operator console.
格兰克克拉克梯度水冷装置可通过设备操作台提供精确的调整温度梯度。
Figure 1.Taper Quench processing a billet
图1 梯度水冷处理短锭
TECHNICAL CONSIDERATIONS技术考量因素
The direct extrusion press design is the most popular design because it is simple to produce, operate and maintain. The continuous extrusion model with welding dies functions well with puller systems and other automated handling equipment.
正向挤压机是普遍采用的设计，因为它易于生产加工、控制使用和维护保养。它可拥有一个连续挤压的模式，因为有柱锭焊接技术，还有牵引系统和其它自动化的挤压配套设备。
But the direct extrusion press has a thermodynamic problem. At the beginning of the cycle, the aluminum in the press container is too cold and at the end of the cycle the aluminum is too hot. The temperature change is caused by the friction in the container and the flow stress of the aluminum. The result is the aluminum is difficult to push through the die at the beginning of the cycle and the extrusion speed must be reduced at the back of the billet to prevent defects.
但是正向挤压机也存在一个热力学的问题。在挤压循环开始时铝锭在压缸内太冷，在循环末尾时铝锭又变为太热。在压缸内的摩擦力和铝锭的流变应力引起温度变化。其结果是，在挤压周期开始时铝锭难以被挤压通过模具，铝锭后部的挤压速度必须被降低，以防止挤压出废品。
Extruders are always seeking ways to improve production capacity. One method that extrusion press suppliers can offer is a press with a longer container. The longer container increases the ratio of live-cycle-time to dead-cycle-time, increasing the production capacity of the press. Twenty years ago the standard for maximum billet length from most extrusion press manufacturers was 400% of the billet diameter. For example, a press designed to process a 178mm billet would have a container that was 710mm long. Now imported extrusion presses will have containerswith billet lengths that are 500% or greater. It is common to see a specification for a 950–1000mm long container for 178mm billet.
挤压机一直在寻求方法来提高产能。挤压机供应商提供的一种方法就是提供一种长压缸挤压机。长压缸增大了挤压时间和非挤压时间的比率，提高了挤压机的产能。二十年前绝大多数铝挤压制造商的标准是最大的短锭长度是短锭直径的400％，例如，设计一挤压机挤压178毫米的短锭需要一个710毫米的压缸，现在进口的挤压机的压缸长是短锭长度的500%或更长一些，对于178毫米的短锭一般采用的是950－1000毫米规格的压缸，已普遍可见。
This change is good for increasing the productive time of the press but it increases the natural thermodynamic problem with the direct extrusion press. The longer billet results in more container friction and increased heating of the back of the billet. So the benefit of tapered billets is even greater with a modern imported extrusion press.
增加了挤压的生产时间这一变化是好的，但也增加了正向挤压的热力学问题。短锭越长导致压缸产生更大的摩擦，使得短锭后部的热度提升，使用现代的进口挤压机可得到更好的短锭梯度降温的好处。
With an imported extrusion press, the extrusion speed increase will be 20% to 30% for many profiles. In our testing we found that the most difficult profiles will give the largest increase in speed.Many profiles with thin walls using industrial alloys will have speed increases much greater than 30%.
对于很多型材使用进口的挤压机可提高挤压速度20－30%。在我们的测试中，我们发现绝大多数难以挤压的型材在挤压速度上都有极大的提高。很多采用工业铝合金薄壁的铝型材的挤压速度已提高了30%。
When combined with a Granco Clark “Hot Jet” gas furnace, this taper quench solution is less expensive to purchase and lower cost to operate than an imported electric induction heater with precision taper heating.
当与格兰克克拉克热喷射燃气加热炉一起使用时，其梯度水冷解决方案要比具有精确梯度加热的进口工频炉的购买价格便宜，运营成本更低。
The Granco Clark Taper Quench has the following features and specifications:
The Taper Quench is located after the billet furnace and before the press loader.
The unit provides temperature gradients of up to 140C0.
The variation of the taper is less than 10C0.
The operator can select which portion of the billet will be tapered.
Quench does not limit the throughput of the system.
格兰克克拉克梯度水冷具有特点规格如下：
梯度水冷装置安装在柱锭加热炉之后和短锭输送台之前。
梯度水冷可提供了高达140 C0的温度梯度。
梯度变化范围在10 C0之内。
操作员可选择对某部分的短锭进行温度梯度递减。
淬火没有对系统的生产能力有任何限制。
FINANCIAL CONSIDERATIONS经济考量因素
The most important economic issue is the higher production rate. The added benefits of reduced profile defects and protecting the extrusion die from overheating are not calculated in this financial analysis.
最重要经济的问题就是更高的生产率。减少型材次品和保护过热的挤压模具的效益并没有计算在本财务分析中。
This is an example of the calculation for the costs of profile production:
Profile cost per ton:
The cost of profile productionis from the 2010 Conference paper. The profile cost is dependent on production rate, so our assumptionwill be 1.2 ton/hr and 6000 hr/yr production time.In the 2010 conference paper, our sample showed the cost of ownership was RMB 1200/hr, the cost of overhead was RMB 660/hr, the cost of operation was RMB 1000/hr.
1.Cost of ownership: RMB 1200/hr÷ 1.2 ton/hr = RMB 1000/ton
2.Cost of overhead: RMB 660/hr÷ 1.2 ton/hr= RMB 550/ton
3.Cost of operation: RMB 1000hr÷1.2 ton/hr = RMB 833/ton
Total Cost: RMB 2383/ton
下面是有关型材成本的计算：
每吨型材成本：
我们2010年研讨会的论文中有提到型材的成本问题。型材成本是根据生产率来定，生产率我们假设为1.2吨/小时和6000小时/年生产时间。2010年研讨会的论文中我们例题显示的是生产线投资成本1200元/小时，间接成本是660元/小时，运营成本是1000元/小时。
1.生产线投资成本： 1200 元/ 小时÷1.2吨/小时 = 1000元/吨
2.间接成本： 660元/ 小时÷1.2吨/小时= 550元/吨
3.运营成本： 1000元/ 小时 ÷ 1.2吨/小时= 833元/吨
总计：2383元/ 吨
Please note that this cost is the cost if the factory has excess capacity. If the factory production is full then the cost must also include the cost of lost sales. Studies have shown that this cost will be 2 to 3times greater because the entire gross margin of the value added in all departments is lost when the order is lost.
需要注意的是，我们这里提到的成本投入前提是工厂有超额生产能力。如果工厂生产能力是满负荷的，那成本投入还必须包括销售机会丧失的成本。研究表明该成本会增大2到3倍，因为整个公司的毛利润将会因为订单的丢失而损失。
In this example, if the Taper Quenchimprovesthe net press throughput by 15% then the resulting cost per ton would be:
1.Cost of ownership: RMB 1200/hr ÷ 1.38ton/hr = RMB 870/ton
2.Cost of overhead: RMB 660/hr ÷ 1.38 ton/hr= RMB 478/ton
3.Cost of operation: RMB 1000/hr ÷ 1.38ton/hr = RMB 725/ton
Total Cost: RMB 2073/ton
此例中，如果梯度水冷将提高纯挤压产量15%，那么每吨成本结果将是：
1.生产线投资成本：1200 元/ 小时 ÷ 1.38吨/小时 = 870 元/吨
2.间接成本：660 元/ 小时 ÷ 1.38吨/小时 = 478元/吨
3.运营成本： 1000 元/ 小时 ÷ 1.38吨/小时 = 725元/吨
总计：2073 元/ 吨
The example result is a RMB 310/ton (RMB 2383/ton – RMB 2073/ton) cost reduction. If the three year production is 24,840 tons (6000hr/yr╳1.38 ton/hr╳ 3yr) then the payback for the taper quench is RMB 7,700,000.
例题的结果是每吨型材可降低成本310元（2383元/ 吨－2073元/ 吨）。如果3年的生产是24,840吨（6000小时/年╳1.38吨/小时╳3年），那么梯度水冷的投资回收将是770万元。
The calculation for each company and each factory will be different, but the example above can be used as the template to make the calculation for the individual situation.
每个公司和工厂的计算方式可能会不一样，但是上述例证可以作为一个模板，结合个体具体情况来加以计算。
SUMMARY 结语
The extrusion press is a valuable resource and highshippable kg/hr is required to achieve financial success. This must be considered in all equipment and process decisions.
挤压机是宝贵的资源，高交货量公斤/小时是实现财务上的成功所必需的。在做有关设备和工艺的决策时，这是必须都要考虑在内的。
