Wool Exporters and processors are required by purchasers to provide test certificates that show that a consignment of wool meet the requirements specified in a contract. These documents are also used to authorise payments by banks issuing letters of credit. Consignments often consist of numerous sale lots purchased according to the contract specifications. As it is not cost effective for the individual sale lots to be resampled and measured again as a single test, AWTA provides a service where the tests results of individual sale lots can be arithmetically combined to show the overall average measurements on a single IWTO Combined Certificate. These IWTO Combined Certificates are widely recognised and trusted throughout the wool supply chain. Similarly, the same process can be used to produce Objectively Matched Lots, however the combination of lots is restricted by minimum and maximum measurement ranges.
组合计算
说明 IWTO-31 中定义的平均纤维直径、CVD 和纤维直径分布组合程序的概况介绍可供下载。IWTO-31 标准规定了所有可认证参数和其他供参考参数的组合程序。
其中包括
- 羊毛底座 (WB)
- 植物基质（VMB）
- 硬头（HH）
- 平均纤维直径 (MFD)
- 直径变化系数 (CVD)
- 光纤直径分布（FDD）
- 订书钉长度 (SL)
- 钉强度 (SS)
- 中断位置 (POB)
- 颜色（X、Y、Z）
- 商业收益率
有关创建 "客观配对批次"（OML）的其他规则和计算方法，请参阅下面的概况介绍。
了解更多信息：
电子表格样本
下面提供的电子表格显示了所有组合计算以及减法组合的程序。减法组合 "电子表格用于从交货中去除一小部分（重量小于 5%）的情况。被剔除的成分要重新检测，并从原来的组合中减去。