When building larger molds, including hot runner molds, some mold makers may choose to build using rails and pillars instead of cutting a manifold pocket out of a single plate. Regardless of what is chosen, enough force distribution is required to keep the two halves of a plastic injection mold closed during injection. The more you reduce in terms of number of pillars, size of pillars and even distribution of pillars, the more you can introduce load imbalance into your mold plates. If the plates are not thick enough, this can also lead to bowing of the plates and flashing of the parting line faces. Put simply, if you do not have mold design best practices at your disposal then it is recommended to consult an experienced mold shop or to use computer-aided simulation software to examine the estimated forces acting on your mold as well as the stresses within your mold. From there, you can determine if more support pillars are needed to better distribute, balance and transmit loads from the injection machine platen to the parting line face of the mold.