Softgel shells are a combination of gelatin, water, opacifier and a plasticiser such as glycerin or sorbitol.
Two flat ribbons of shell material are manufactured on the machine and brought together on a twin set of rotating dies.
At the same time a pump delivers a precise dose of fill material through a nozzle incorporated into a filling wedge whose tip sits between the two ribbons in between two die pockets at the point of cut out.
The wedge injection causes the two flat ribbons to expand into the die pockets, giving rise to the three-dimensional finished product.
Since the 1990s, manufacturers have been able to replace gelatin in the shell with other polymers based on, for example, starch and carrageenan.