在制造瓦楞纸板的过程中，有几个步骤需要精确地在辊之间施加压力，或在辊之间保持一致的间隙，以便测量凹槽上的粘合剂的精确量。为了满足这些要求，辊必须相互平行，并且必须尽可能接近完美的圆形。 如果压辊不是完全圆的，那么当压辊在瓦楞辊上转动时，在压辊压点处施加在单面机卷筒上的压力将会减小。如果压力足够小，单面键会受到影响，从而影响电路板质量。调整压力以补偿问题可能会导致另一个问题- 介质的压力辊切割，以及压缩和/或mullen（爆裂）中可能出现的箱体故障。

In the process of making corrugated board, there are several steps in the process that require precise applications of pressure between rolls, or consistent gaps between rolls in order to meter precise amounts of adhesive to the flutes. In order for these requirements to be met, rolls have to be parallel to each other and also must be as close to perfectly round as possible. If a pressure roll is not perfectly round, then as the roll turns against the corrugating roll there will be areas where the pressure applied to the singlefacer web at the rolls' nip point will be lessened. If the pressure is lessened enough, the singlefacer bond can be compromised and, thus, affect board quality. An adjustment to increase pressure to compensate for the problem could lead to another problem-pressure roll cutting of the medium and possibly box failure in compression and/or mullen (burst).