Glass flow in the annulus of plunger cells or feeder heads during gob formation process for the forming of hollow or pressed ware is considered in this article. Gob formation process can be divided into two phases: a) forcing out the gob with desired mass and length, cutting; and b) raising the plunger for preparing the next ejection phase. As long as an existing plant manufactures the same assortment, existing know-how about plunger stroke, cycle time and orifice ring may be applied. These experiences often will not suffice if the assortment or the viscosity curve of the glass is altered considerably. In this case, calculations for orientation are helpful to limit the necessary trials in the production plant. A calculation method is presented in this paper.
