The stack-lock lid design meets the reliability, ease of use, and unique appearance required by the product. By incorporating a precisely designed locking mechanism into a custom metal tin, a seal that is both secure and convenient to use can be created. In addition, the stack-lock lid does not require a separate lid or tape, which enhances the convenience and user experience. Implementing this design in a custom metal tin requires close cooperation with the tin can manufacturer. For us, this process involves determining the lid geometry, selecting compatible materials, developing molds, conducting quality testing, and finally, implementing the design in custom metal tins through post-production.

Geometry and Locking Mechanism of Custom Metal Tins Lids

To implement the stack-lock lid design in a custom metal tin, we first need to determine the precise geometry of the lid. Interlocking beads or flanges around the can mouth and lid typically form the locking mechanism, snapping together when pressed. When designing, we need to determine the bead height, flange angle, and tolerance range. During manufacturing, stamping or rolling dies form the lid’s flange, while stretching and trimming processes shape the can body to create a matching flange. By determining these dimensions, we can ensure that the lid and the can body lock with a constant force, yet the force is gentle enough for customers to open without the need for tools.

In the design process, our engineers typically create prototypes of multiple flange shapes and test the insertion force and holding strength of each flange. To ensure that your custom metal tins have a perfect balance between ease of use and security.

Material Selection for Stacking Lock Caps

When using stacking lock caps in custom metal tins, we use tinplate as the primary material. Due to their excellent formability and strong locking performance, they are ideal for larger tins or products that require enhanced sealing integrity. During the manufacturing process, the hardness of the metal affects the performance of the locking bead. The softer hardness makes the flange easier to bend and snap into place, while the harder temper provides greater holding force but requires more precise locking bead geometry. Therefore, choosing equal hardness tempers for your custom tins can achieve the best balance between manufacturability and locking strength.

Tooling and Production of Custom Metal Tins

For custom tin cans with overlapping lock lids, we use specialized stamping dies, one for the can body flange and one for the lid edge. During production, we perform a draw-draw-trim process on the can body, followed by a separate lid stamping operation. After stamping, the lid and can body enter a ball rolling machine to form the final radius on the flange edge, ensuring a smooth joint. For consistency, statistics are implemented to track the size of the trackball and the insertion force from batch to batch. By monitoring these indicators, deviations can be detected and press settings adjusted promptly. Ensure that your custom cans have a consistent locking performance from the first production run to the last.

Quality Control and Seal Performance Testing

First, technicians perform a pull-off test to measure the force needed to remove the lid, verifying it meets the target retention strength. Next, they drop a whole can from different heights to simulate shipping shocks. Environmental testing reveals how extreme temperatures affect lid retention and metal expansion. Using pressure decay testing in sealed cavities to detect micro leaks is especially important when packaging powdered or moisture-sensitive products. Additionally, we document these test results in our quality management system to ensure traceability and accountability. By integrating rigorous testing protocols, we provide the reliability of displaying custom tins.

About surface treatment and branding design

We often use powder coating, offset printing, or UV full-color lithography to display logos and product information in the surface design of custom metal tins. When planning these surface treatments, we ensure that the coating thickness does not change the bead size. Additionally, we select the corresponding primer and topcoat chemistries based on the product’s storage conditions. For example, food-grade coatings prevent oil migration when packaging mixed spices, while anti-scratch coatings protect high-flow cosmetic tins. At the same time, you can also add local UV or embossing to the edge of the lid to create tactile feedback, coordinating functional design with visual appeal.

Achieving the perfect stack lock lid design

Achieving the stack lock lid design in custom metal tins will require precise engineering design, high-quality materials, and thoughtful branding. During the production process, the appropriate metal alloy and tempering temperature are selected to lay the foundation for reliable locking performance. We use professional molds and strict quality tests to ensure each tin can snaps securely and stays sealed under all conditions.