In a method of manufacturing a tube of quartz glass by molding a hollow cylinder having a wall thickness of at least 20 mm, the cylinder is continuously fed under rotation about a rotational axis into a heating zone at a relative feed rate V.sub.C, softened and radially expanded under the effect of a gas pressure. A tube strand is continuously formed and is withdrawn at a withdrawal rate V.sub.T. In order to mold thick-walled initial hollow cylinders of quartz glass into tubes with larger diameter, the gas pressure is used as an actuating variable of a diameter regulation for the tube outer diameter or for a geometrical correlated parameter thereof, and in a pressure build-up phase the gas pressure is gradually increased from a lower initial value to a higher final value, and that the following applies to the ratio of V.sub.C and V.sub.T:V.sub.T=V.sub.C0.2.Math.V.sub.C.

In a method of manufacturing a tube of quartz glass by molding a hollow cylinder having a wall thickness of at least 20 mm, the cylinder is continuously fed under rotation about a rotational axis into a heating zone at a relative feed rate V.sub.C, softened and radially expanded under the effect of a gas pressure. A tube strand is continuously formed and is withdrawn at a withdrawal rate V.sub.T. In order to mold thick-walled initial hollow cylinders of quartz glass into tubes with larger diameter, the gas pressure is used as an actuating variable of a diameter regulation for the tube outer diameter or for a geometrical correlated parameter thereof, and in a pressure build-up phase the gas pressure is gradually increased from a lower initial value to a higher final value, and that the following applies to the ratio of V.sub.C and V.sub.T:V.sub.T=V.sub.C0.2.Math.V.sub.C.

A glass manufacturing apparatus configured to manufacture glass through a process of lowering the temperature of a non-contact supported glass material. The glass manufacturing apparatus comprises a heating unit configured to heat the glass material; and a forming unit configured to form the molten glass material while its temperature decreases after the heating by the heating unit has stopped.

A glass manufacturing apparatus configured to manufacture glass through a process of lowering the temperature of a non-contact supported glass material. The glass manufacturing apparatus comprises a heating unit configured to heat the glass material; and a forming unit configured to form the molten glass material while its temperature decreases after the heating by the heating unit has stopped.

The invention relates to a method of manufacturing an primary optical array for a vehicle headlight, wherein the primary optical array comprises a first primary optical element with a light entry face, at least one second primary optical element with a light entry face, and a basic part connecting the first primary optical element mechanically to the second primary optical element, wherein a first mold and a second mold are provided, wherein the first mold comprises at least one first web for molding a side face of the first primary optical element facing the second primary optical element, and for molding a side face of the second primary optical element facing the first primary optical element, wherein the at least one first web has a web edge the width of which amounts to no more than 0.25 mm, wherein a gob is placed between the first mold and the second mold, wherein the gob is press-molded or pressed into the primary optical array by the first mold and the second mold moving towards each other.

A product conveyance apparatus includes an actuator, a movement portion, a first position detection portion, a second position detection portion, and a controller. The controller performs a process of causing the actuator not holding a product to move to a predetermined position, detecting the position of the actuator and storing the position as a first position, a process of causing the actuator to move on a basis of a movement instruction value and hold the product, causing the actuator holding the product to move to the predetermined position, detecting the position of the product held by the actuator, and storing the position as a second position, and a process of correcting and updating the movement instruction value on a basis of difference between the first position and the second position.

A product conveyance apparatus includes an actuator, a movement portion, a first position detection portion, a second position detection portion, and a controller. The controller performs a process of causing the actuator not holding a product to move to a predetermined position, detecting the position of the actuator and storing the position as a first position, a process of causing the actuator to move on a basis of a movement instruction value and hold the product, causing the actuator holding the product to move to the predetermined position, detecting the position of the product held by the actuator, and storing the position as a second position, and a process of correcting and updating the movement instruction value on a basis of difference between the first position and the second position.

A manufacturing apparatus for manufacturing an optical element including two spherical segments and a cylindrical portion by performing press molding using a mold on a molding material that is softened by heat includes: a sensor configured to measure one of a diameter and mass of the molding material; a calculator configured to calculate a target thickness of the optical element based on one of the diameter and the mass of the molding material measured by the sensor; and a controller configured to control an inter-mold distance of the mold at a time of press molding such that a thickness of the optical element becomes the target thickness calculated by the calculator unit.

A manufacturing apparatus for manufacturing an optical element including two spherical segments and a cylindrical portion by performing press molding using a mold on a molding material that is softened by heat includes: a sensor configured to measure one of a diameter and mass of the molding material; a calculator configured to calculate a target thickness of the optical element based on one of the diameter and the mass of the molding material measured by the sensor; and a controller configured to control an inter-mold distance of the mold at a time of press molding such that a thickness of the optical element becomes the target thickness calculated by the calculator unit.

An apparatus and a method of actuating a parison plunger includes transforming linear force applied to a plunger extension into roto-translational motion of the plunger extension via a cam path between the plunger extension and a piston.