Method and apparatus for sealing medicinal capsules

A capsule welded by a method of sealing parts of a plastic capsule to form a weld seam in an overlapping region of the parts of the capsule, wherein the capsule comprises a capsule cap having an open end and a capsule body having an open end and wherein the capsule cap and capsule body are composed of a material which has a permeation coefficient for steam of less than 10−13 kg/(m·s·Pa), the method comprising:

• (a) holding the capsule cap and the capsule body in a capsule holder comprising a first holding part and a second holding part which can be guided synchronously with one another, wherein the first holding part interlockingly surrounds the capsule cap and the second holding part interlockingly surrounds the capsule body;
• (b) closing the capsule holder holding the capsule cap and the capsule body so that the open end of the capsule cap and the open end of the capsule body form a sealed cavity therebetween and form an overlapping region, wherein the overlapping region is not covered by the capsule holder, to obtain a closed capsule:
• and (c) welding the closed capsule using an energy beam of hot gas or laser light on the overlapping region to form the weld seam thereon, the method resulting in a capsule having:
• in the overlapping region only, a weld seam formed by the energy beam bringing the capsule material to its melting point;
• and, in the rest of the capsule material not in the overlapping region, no effect from being brought to its melting point by the energy beam.