Three-Side-Seal Sachets: Choose a Tear Route for the Portion

A small sachet offers little room for a poor opening. Kaida lists three-side-sealing bags among its formats. The buyer should decide where the user will hold the pack, how the tear will start and where the contents should leave it. A neat flat proof says little about that sequence when the sachet is full.

Define the inputs

Specify the product portion, flow behavior and intended use. Is the sachet opened over food, a cup or a hand? Mark the seal widths, tear feature and available print area on a full-size drawing. Ask the filling team for the headspace and top-seal requirements so the opening route does not conflict with a reliable production seal.

Test the proposed pack

Use actual filled trial sachets for a simple opening study. Give a tester one pack without extra instructions and observe hand position, force and spill. Repeat after normal carton handling, since a bent corner may start a tear differently. Keep a record of the sample version and the direction of the tear; a photograph of the opened pack can be more useful than a one-word rating.

Resolve the design question

If the tear runs into the product area or printed instructions, adjust the notch and review the print together. Test any revision on the converting and filling route, not only with a hand-cut mock-up. Ask the filler to inspect the first units after a changeover because a small shift in registration can change the effective opening point.

Release the decision

Release the sachet with a filled reference, tear-position drawing and agreed opening observation. The buyer can then review new artwork or film against a known use case and avoid discovering after delivery that the portion is difficult to dispense cleanly.

For a portion range, keep the same opening test but change the actual fill. A tear that works on the smallest sachet may be less clean on the largest.

Kaida reference: Three packaging and support.