The invention relates to an arrangement of a furnace and of bulk material of glass particles, said furnace (10) comprising a pressing punch (36), a pressure, distance and/or speed sensor and a control device for controlling a pressing process based on the output signal of the sensor. The sensor detects at least a pressure, position and/or motion parameter of the pressing punch (36). The pressing punch (36) acts on the bulk material of glass particles (32)—possibly via an interposed ram (28)—, said glass particles being guided and crystallizable in a press channel (30). The trigger criterion for the process control is a change of at least a motion parameter of the pressing punch (36) upon softening of the bulk material of glass particles (32) which change is detected by the sensor.