1.1 本规程涵盖热固性模塑材料的机械和电气试样转移模塑的一般程序。 注1: 该实践已被证明适用于表现出中等粘度非牛顿流的热固性模塑料的成型。 1.2 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并不总是精确等价的；因此，每个系统应相互独立使用。将两个系统的值结合起来可能会导致不符合此做法。 1.3 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和健康实践，并确定监管限制的适用性。 注2: 没有已知的ISO等效于本标准。 1.4 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====== 4.1 转移模塑特别适用于中等塑性的热固性材料。不能为每种材料指定固定成型参数。根据试验方法测量，同一类型的模塑料具有许多不同的塑性 D3123 和 D3795 . 因此，对于给定的材料类型，生产令人满意的试样所需的成型参数通常会根据特定材料等级的塑性而变化。 4.2 本规程中所示的模具提供了一组五个试样。然而，如果只需要某些试样，则可以通过插入门坯来堵塞其他空腔。 4.3 通常，由于气体可以从模具的通风端自由流动，因此不需要呼吸模具来释放捕获的挥发性物质。这是耐热化合物的一个特别优势，并减少了模制试样在高暴露温度下起泡的趋势。 4.4 模塑件中的流线和编织线通常是机械或电气薄弱部位，在整个模塑件中可以发现一定程度的严重性。通过浇口的半固态模塑化合物受到非牛顿流体的影响，因此，当其沿着模腔向下移动时，会出现褶皱和褶皱。模塑料中的纤维和其他增强材料与流型对齐，因此可以在中心垂直于棒的轴，在棒的表面平行。模具温度、模塑料的热导率和塑性、预热程度和柱塞压力是影响填充模具型腔的时间和编织线形成的参数。 注3: 如果模具温度保持恒定，并且指定热固性模塑料的柱塞压力变化，则可以获得两个极端特征条件。如果压力较低，则空腔的通风端将无法完全填充，材料未完全编织将形成焊缝。如果压力过高，模具型腔将快速填充，当压力仍将材料挤出通风口时，试样外部将硬化，并获得球窝晶粒结构。球窝结构是成型条件的指示，将导致较低的测试数据。 4.5 可以使用含有长纤维填料的热固性化合物，如玻璃粗纱、短切布或刨花，但不建议用于转移模塑。这些填充材料在通过模具浇口时容易破裂、撕裂或成球，因此无法优化其潜在强度。 4.6 含有短纤维的模塑化合物的转移模塑试样的Izod冲击强度通常低于使用压缩模塑方法获得的值。由于成型参数、流型和纤维方向的不同，冲击强度通常会沿棒轴变化。 4.7 含有短纤维的模塑化合物的转移模塑试样的弯曲和拉伸强度通常高于使用压缩模塑方法获得的值。弯曲试验对转移模塑特别敏感，因为在最终填充型腔和压力累积期间，棒材表面形成了薄树脂皮。

1.1 This practice covers a general procedure for the transfer molding of mechanical and electrical test specimens of thermosetting molding materials. Note 1: The utility of this practice has been demonstrated for the molding of thermosetting molding compounds exhibiting intermediate viscosity non-Newtonian flow. 1.2 The values stated in either SI or inch-pound units are to be regarded separately as standard. The values stated in each system are not always exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems can result in nonconformance with this practice. 1.3 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 and health practices and determine the applicability of regulatory limitations prior to use. Note 2: There is no known ISO equivalent to this standard. 1.4 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 ====== 4.1 Transfer molding is particularly suited to thermosetting materials of intermediate plasticity. Fixed molding parameters cannot be specified for each type of material. Molding compounds of the same type come in many different plasticities measured in accordance with Test Methods D3123 and D3795 . Consequently, for a given material type, the molding parameters required to produce satisfactory test specimens will often vary dependent on the plasticity of the specific material grade. 4.2 The mold shown in this practice provides for a set of five specimens. However, if only certain specimens are desired, the other cavities can be blocked by inserting gate blanks. 4.3 Typically, breathing of the mold is not required to release trapped volatile matter as the gas is free to flow from the vent end of the mold. This is a particular advantage for heat-resistant compounds and reduces the tendency for molded specimens to blister at high exposure temperatures. 4.4 Flow and knit lines in a molded piece are often sites of mechanical or electrical weakness and can be found in some degree of severity throughout the molded piece. The semisolid molding compound passing through the gate is subject to non-Newtonian flow and, consequently, wrinkles and folds as it travels down the mold cavity. Fibers and other reinforcements in the molding compound align with the flow pattern and, consequently, can orient perpendicular to the axis of the bar at the center and parallel at the surface of the bar. Mold temperature, thermal conductivity and plasticity of the molding compound, degree of preheat, and plunger pressure are parameters that influence the time to fill the mold cavities and the formation of knit lines. Note 3: If the temperature of the mold is held constant and the plunger pressure varied for a designated thermosetting molding compound, two extreme characteristic conditions can be obtained. If the pressure is low, then the vent end of the cavity will not fully fill, and weld lines will form by incomplete knitting of the material. If the pressure is too high, the mold cavity will fill fast, the outside of the specimen will case harden while the pressure is still forcing material out the vent, and a ball-and-socket grain structure will be obtained. A ball-and-socket structure is an indication of the molding condition, and lower test data will result. 4.5 Thermosetting compounds containing long-fiber fillers such as glass roving, chopped cloth, or shavings can be used but are not recommended for transfer molding. These filler materials tend to break, tear, or ball in passing through the gates of the mold, thereby not optimizing their potential strength. 4.6 The Izod impact strength of transfer molded specimens of molding compounds containing short fibers will generally be lower than the values obtained using compression-molding methods. Quite often the impact strength will vary along the axis of the bar due to molding parameters, flow pattern, and fiber orientation. 4.7 The flexural and tensile strength of transfer molded specimens of molding compounds containing short fibers will generally be higher than the values obtained using compression-molding methods. Flexural tests are particularly sensitive to transfer molding due to the thin resin skin formed at the surface of the bar during the final filling of the cavity and pressure buildup.