压⽚时重量差异的原因！
低碳生活论文
Caus for Weight Variations during Tableting
偏执型人格6大表现特点压⽚时重量差异的原因
Weight variations of the tablets produced is a relatively common problem of the tableting process. But each tableting process aims at producing tablets with a constant weight. The actual cau for this problem is the lack of weighing systems that are sufficiently fast to weigh or do the required weight for each single tablet. Since this is not possible, each tablet press dos a certain amount of powder into the die and this powder is then presd into tablets by the upper and lower punch. This means that a volume is dod, but the quality requirement is the weight. Hence, weight variations in a limited extent are quite normal due to variations in the density of the powder material and to a partially incomplete filling of the dies.
⽚剂重量差异是⼀个压⽚⼯艺中普遍的问题。每个压⽚⼯艺的⽬的都是制出重量恒定的⽚剂。这个问题的实际原因是缺乏称重系统，不能很快地称出每个⽚⼦的所需重量。在压⽚过程中，每个⽚⼦所⽤的粉料被放⼊模具内，然后由上下冲⽚挤压成⽚。这就是说，实际放⼊的量是按体积来计算的，⽽质量要求的却是重量。因此，在⼀定限度内存在重量差异是很正常的，因为粉料的⽐重会有差异，并且
心存感激
在模具填充时可能会不完全。
市电The pharmacopoeias specify the acceptable level of weight variations. If the weight variations are too high the level of active ingredient in each tablet might be too high or too low and then the tablets don't comply with the specifications any more. It must therefore be aimed at tableting a powder that can be dod quickly and consistently in the dies. For this reason very good flow characteristics are extremely important. That is why tableting often is preceded by a granulating process in order to give the feed material better flow characteristics than the physical mixture has. Is the particle size distribution of the powder rather broad a paration of the components of the powder must be prevented that might occur for example becau of vibrations in the feed container. Hence it has to be prevented that the bigger particles are dod first becau they slipped downwards and the smaller particles afterwards. In this ca a mechanical decoupling of the press from the feed container might be helpful. A further rule of thumb is: the biggest particles should not exceed 20 % of the diameter of the die. The upstream granulation should produce no bigger particles; if necessary a further grinding/sieving process must be carried out.
事前控制
药典指定了重量差异的可接受程度。如果重量差异太⾼，则每⽚中的活性成分可能太⾼或太低，这样⽚⼦就不再符合质量标准了。因此，必须要让粉料填充⼜快⼜恒定。为此，粉料具有⾮常好的流动特
性是⾮常重要的。这就是为什么压⽚前通常会进⾏制粒，这是为了使得填充的粉料⽐起物理混合物具有更好的流动特性。粉料中各不同成分的粒径分布不能太宽，因为在将粉料填充⾄容器的过程中可能会由于震动⽽引起不均匀。否则，在填充过程中较⼤的颗粒会因为其更容易滑下去，⽽较⼩的颗粒则停滞在后⾯。这种情况下，可能需要给进料仓配置机械式偶合推动。还有⼀个原则是最⼤的颗粒不应超过模具的直径的20%。上游的制粒不应⽣产出很⼤的颗粒，必要时，应在其后进⼀步磨粉和筛分。十五二十
But sometimes the situation can also be improved by means of a forced filling. Usually the lower punch already is pulled down before the die reaches the area of the filling unit. This means that the material falls into the die only due to gravitation. In the ca of a forced filling however, the lower punch is flush with the die table. The lower punch is pulled down into its target position only below the filling unit. The material is sucked into the die. This often makes it possible to work with a higher pressing speed even if the material doesn't flow optimally.
有时这种情形也可以通过强制填充来改善。通常下位模在模具到达填充单元区域前已放置到位，这就是说，粉料进⼊模具仅是靠重⼒。这时，如果采⽤强制填充，则下位模被拉⾄低于填充单元的⽬标位置，这时粉料填⼊模具，这样即使粉料流动性不够理想，也可以采⽤⾼冲压速度来压⽚。
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长毛怪•东京大学入学条件
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