1.1 本试验方法包括使用能够测量质量变化特性的自动测试仪测量高达4000 dtex（3600 denier）的纱线数以及长丝和纺纱的相关变化特性。 1.2 纱线数量变化特性包括密度扩散百分比（%DS）、变化系数（%CV）、密度频率变化。 注1: 关于使用卷轴和天平测定纱线数，请参阅测试方法 D1907 . 关于测量纱线可变性（不均匀度）的另一种方法，请参阅测试方法 D1425 . 1.3 以国际单位制或英寸-磅单位表示的数值应单独视为标准值。每个系统中规定的值不一定是精确的等价物；因此，为了确保符合本标准，每个系统应相互独立使用，并且两个系统的值不得组合。 1.4 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.5 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 5.1 试验方法 D6612 对于纱线数量和纱线数量，可变性可满足商业装运的验收要求，并用于贸易中。 5.1.1 如果两个或多个实验室的报告测试结果之间存在实际意义上的差异，则这些实验室应使用主管统计协助进行比较测试，以确定它们之间是否存在统计偏差。作为最低要求，用于每次比较试验的样品应尽可能均匀，从与初始试验期间产生不同结果的样品相同批次的材料中提取，并随机等份分配给每个实验室。具有既定测试值的其他织物用于此目的。相关实验室的测试结果应进行适当的统计分析，并在测试开始之前由双方选择的概率水平，在测试系列之前选择的概率水平上进行比较。 如果发现偏差，必须找到并纠正其原因，或者考虑到已知偏差调整未来的测试结果。 5.1.2 在开始测试之前，应使用适当的统计分析和双方选择的概率水平对两个实验室的平均结果进行比较。如果发现偏差，必须找到并纠正其原因，或者买方和供应商必须同意在考虑已知偏差的情况下解释未来的测试结果。 5.2 试验方法 D6612 也用于长丝纱的质量控制。 5.3 可变性指数: 5.3.1 变异系数- %CV是一种标准的统计计算方法，是最常见的纱线不匀指数。对于80至330 dtex（70至300旦）范围内的大多数纺织应用，1。 0到1.3%的变异系数足够。%粗于666 dtex（600旦）的纱线的CV不是常规的，通常没有意义。%CV的辨别力不如%DS。 5.3.2 不良/良好测试- %BGT，通常高达20 % 大于%DS值，强调整个测试长度中的最大扩散，（%DS是平均值）。如果该值大于50 % 在%DS中，有一个过程需要研究。 5.3.3 密度扩散- %DS相当于Uster%不均匀度（试验方法 D1425 )是短期可变性的指标。具有极值的纱线更有可能在后续纱线加工中造成麻烦，这可能是最有用的指标。纱线产品可实现的最小和最大公差范围将取决于纱线制造工艺和最终用途。 3到4的排列 % 对于大多数纺织应用，通常在160至550 dtex（150至500旦）范围内。更关键的应用，例如使用更细纱线的应用，可能需要更低的值。 5.3.4 密度频率可变性- DFV是间距可变性的指数，而其他是幅度或不均匀性的指数。频率变化可能在高速加工中引起共振，是织物中条纹、染色条纹或图案不均匀的常见来源。

1.1 This test method covers the measurement of yarn number up to 4000 dtex (3600 denier) and related variability properties of filament and spun yarns using an automated tester with capability for measuring mass variability characteristics. 1.2 Yarn number variability properties include percent density spread (%DS), coefficient of variation (%CV), density frequency variation. Note 1: For determination of yarn number by use of reel and balance, refer to Test Method D1907 . For another method of measuring variability (unevenness) in yarn, refer to Test Method D1425 . 1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore to ensure conformance with this standard, each system shall be used independently of the other, and values from the two systems shall not be combined. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 Test Method D6612 for yarn number and yarn number variability is satisfactory for acceptance of commercial shipments and is used in the trade. 5.1.1 If there are differences of practical significance between the reported test results for two or more laboratories, comparative tests should be performed by those laboratories to determine if there is a statistical bias between them, using competent statistical assistance. As a minimum, samples used for each comparative tests should be as homogeneous as possible, drawn from the same lot of material as the samples that results in disparate results during initial testing, and randomly assigned in equal numbers to each laboratory. Other fabrics with established tests values are used for this purpose. The test results from the laboratories involved should be compared appropriate statistical analysis and a probability level chosen by the two parties before testing begins, at a probability level chosen prior to the testing series. If a bias is found, either its cause must be found and corrected, or future test results adjusted in consideration of the known bias. 5.1.2 The average results from the two laboratories should be compared using appropriate statistical analysis and a probability level chosen by the two parties before the testing is begun. If a bias is found, either its cause must be found and corrected or the purchaser and the supplier must agree to interpret future test results with consideration to the known bias. 5.2 Test Method D6612 also is used for the quality control of filament yarns. 5.3 Indices of Variability: 5.3.1 Coefficient of Variation— %CV is a standard statistical calculation and is the most common index of yarn unevenness. For most textile applications in the 80 to 330 dtex (70 to 300 denier) range, a 1.0 to 1.3 %CV is adequate. %CV of yarns coarser than 666 dtex (600 denier) is not routine and usually not meaningful. %CV is less discriminating that %DS. 5.3.2 Bad/Good Test— %BGT, which will normally be up to 20 % greater than %DS value, emphasizes the greatest spread in the entire length tested, (%DS is an average). If the value is greater than 50 % of the %DS, it suggests that there is a process that needs to be investigated. 5.3.3 Density Spread— %DS is equivalent to the Uster % unevenness (Test Method D1425 ) and is an indication of short-term variability. Yarns with extreme values are more likely to cause trouble in subsequent yarn processes, which makes this perhaps the most useful index. The minimum achievable and maximum tolerance spread for a yarn product will depend on the yarn manufacturing process and end use. A spread of 3 to 4 % generally is, for most textile applications, in the range of 160 to 550 dtex (150 to 500 deniers). More critical applications, such as those using finer yarns, may require lower values. 5.3.4 Density Frequency Variability— DFV is an index of spacing variability, whereas the others are indices of magnitude or unevenness. Frequency variability can induce resonance in high-speed processing and is a common source of barre, dye streaks, or patterned unevenness in fabrics.