Tinplate packaging remains one of the most reliable and economical choices for food manufacturers worldwide. Although the finished cans look simple, the production behind each piece involves a precise sequence of mechanical processes and strict quality controls. This report takes a closer look at how round tinplate food cans are produced on the factory floor.
Corner Cutting (Pre-Forming the Tinplate Sheet)
Technicians begin with flat tinplate sheets and trim their corners to prepare for shaping.
Major and Minor Corner Cuts
Large corner cut: Workers align the printed side upward and press the right corner against the mold fixture before activating the foot switch.
Diagonal cut (two stages): The sheet is positioned at the mold center to trim both diagonal sides.
Small corner cut: After three corners are completed, the last small corner is trimmed following the same alignment and safety rules.
Edge Bending (Routing)
The pre-trimmed sheets undergo directional bending:
Large-corner edges bend inward with the printed surface facing up.
Diagonal-cut edges bend outward with the unprinted side facing up.
This creates the form needed for consistent rolling.
Sheet Rolling
Workers manually insert each prepared sheet into the rolling machine:
The printed face is placed downward to avoid scratches.
The machine automatically rolls the metal into a perfect cylinder.
Finished cylinders must be stacked individually to avoid abrasion.
Side Seaming (Locking the Cylinder Body)
This operation includes:
Neck hooking: Both ends of the cylinder opening are positioned in the mold, ensuring hands remain away from the 50 mm danger zone.
Flattening: After hooking, the seam is pressed flat using the upper mold to finalize the side lock.
Beading (Body Reinforcement)
To strengthen the can body:
The semi-finished cylinder is inserted into the beading mold carefully to prevent paint damage.
The mold is pushed fully inward before activation.
Each can receives a single controlled stroke to avoid deformation.
Finished pieces are checked and removed gently.
Bottom Blanking
Tinplate bottoms are stamped separately:
Sheets are lifted one by one (never dragged) and fed into the blanking machine.
Workers maintain a 60 mm safety distance while operating the clutch pedal.
Stamped bottoms are stacked and recorded for production tracking.
Can Bottom Seaming (Body + Bottom Integration)
The can body and stamped bottom are combined:
The operator positions the can into the upper mold, keeping fingers away from the rim.
The pedal activates the seaming cycle.
When sealed, the mold drops automatically and the worker removes the finished body.
Necking (Shaping the Can Mouth)
The upper opening is narrowed for later lid fitting:
The body is placed gently into the rotating mold without touching the rollers.
The machine spins the can to shape the neck.
After completion, the handle is lifted to release the can.
Lid Blanking
Lids are punched out similarly to bottoms:
Sheets are separated and fed into the blanking die without dragging.
Operators maintain the 60 mm safety distance.
Lid Trimming (Deburring)
This removes sharp edges:
A magnetic plate picks up the lid and positions it inside the cutting mold.
After trimming, defective pieces are removed and qualified lids move to the next stage.
Lid Curling (Final Lid Forming)
The curling die shapes the lid’s edge for seaming:
Using the magnetic plate, workers place each lid into the curling mold.
After one controlled press, the curled lid is removed and placed face-down on the work table.
Lids are counted and stored in designated containers.
Comparison Table: Body vs Lid Production Steps
Process Stage
Can Body (Cylinder)
Lid Components
Material Prep
Corner cutting, routing
Sheet separation
Forming
Rolling + side seam + beading
Blanking
Structural Reinforcement
Beading (body lines)
Curling (lid edge)
Safety Requirements
50–60 mm clearance around molds
Same clearance; magnetic tools required
Final Integration
Bottom seaming
Lid supplied to filling line
Industry Insight: Why Tinplate Packaging Remains Competitive
From a tin packaging manufacturer’s perspective, tinplate cans continue to hold a strong position in food packaging for several reasons. First, tinplate’s durability and barrier performance provide natural protection against moisture, oxygen, and light—qualities that plastic packaging often struggles to match. Second, tinplate supports high-speed molding and printing, which reduces unit cost and enables large-scale production with consistent appearance. Finally, recyclability is a growing advantage: steel remains one of the most recycled materials globally, making tinplate an eco-efficient choice for brands seeking sustainability.
