Inside Softgel Production: Dies, Seams, Drying, What Buyers Should Ask

A quotation for a capsule line usually arrives as three numbers: unit price, minimum quantity, lead time. Buyers who want to challenge any of them need to understand how the capsule is actually built. Softgel production is a wet, continuous process, and most commercial terms a factory quotes trace back to one of four stages on the floor.

None of those stages is exotic. What separates factories is how tightly each one is controlled, and how honestly the limits are written into the specification. A short walk through the line makes the commercial conversation far more concrete.

Shell mass is prepared first, either gelatin with a plasticiser or HPMC with water. It is cast into two thin, flexible ribbons that travel over a rotating die. Fill enters through a wedge between the ribbons, the die presses both layers together, and a seam forms as the capsule is cut free. Shell thickness, seam width, and fill weight are all fixed within seconds, which is why the fill wedge and the die alignment receive so much attention during setup. Fill temperature matters here as well, because a warm fill can soften the shell before the seam has fully set.

A die cavity defines the silhouette, the volume, and the wall thickness at once. That single piece of tooling explains much of what a buyer sees in a quote.

• Standard round or oval dies carry no tooling charge, set up quickly, and suit a first order.
• A custom silhouette adds shelf presence but requires a dedicated die, a longer build, and a higher minimum.
• Thin walls suit small fills of 0.2ml to 0.4ml, while thicker walls give more protection to fragile or hygroscopic fills.

Fresh capsules are soft and carry excess moisture. They pass through tumble dryers, then trays in a humidity-controlled room, until the shell reaches its release moisture. Drying too fast hardens the surface while the core stays wet, which produces dents and seam splits weeks later. Drying too slowly invites sticking and deformation. A buyer should ask for moisture at release, not only at fill, because that number predicts how the product behaves in a container on a warm quay.

Most disputes begin with a vague line in a purchase order. Ask for all five in writing before a pilot batch, then confirm them on the sample report:

• Shell material, including plasticiser level for gelatin or polymer grade for HPMC.
• Nominal shell thickness with an agreed tolerance.
• Fill weight window per capsule.
• Moisture content at release.
• Seam integrity test method and acceptance limit.

A supplier who can state all five is running a controlled process rather than a habitual one. That control is what makes the single-dose format dependable in the first place: each capsule is sealed at the seam, shielded from light by an opaque or amber shell, formulated without preservatives because no water enters the system, and dosed precisely enough that the label claim holds across the batch.

CapsulesBiotech runs rotary die lines for facial oil, eye serum, hair oil, body lotion, cream, and mask formats, with either a 100 percent plant-based shell or food-grade gelatin. Share your target market and positioning, and our team will reply with a formula direction, fill specification, and available production slots. We will also flag which die options keep your first order economical.