Reducing the thickness of tinplate cans from 0.22mm to 0.16mm involves more than just simply making the plate thinner and reducing the purchasing cost. The real challenges after thinning down are threefold: preventing cracking during stamping, maintaining shape during stacking, and preventing pitting corrosion during acid and salt filling. Many projects encounter issues such as soft cans, wrinkled welds, bulging bottoms, and rusting after printing once the thickness reaches 0.16mm. The fundamental issue is not that "thinner is not better", but rather that the material, can shape, mold, coating, and inspection have not been redesigned together.
Since the transition from hot-dip tin to electroplated tin for tinplate in the last century, the long-term trend has been towards "thinner substrates and more efficient tin usage". In the industry, 0.15mm-thick materials are already used for making lids, and some deep-drawn/stretched can bodies can achieve a wall thickness of 0.1-0.15mm after multiple thinning processes. However, this is the result of process thinning, and not all three-piece cans can be directly replaced with 0.16mm plates instead of 0.22mm ones.
Roughly delineate the boundaries:
For three-piece welded cans and straight-body food and miscellaneous cans: changing the thickness from 0.22mm to 0.16mm requires re-leveling, re-straightening, and re-welding, otherwise they may become soft during manual handling and stacking; for light internal pressure miscellaneous cans such as tea cans, biscuit cans, and candy cans, remedies can be made through high-strength secondary cold-rolled plates and can body reinforcement ribs.
Deep drawing/drawing with ironing two-piece cans (DRD/DWI): 0.16mm is more feasible, but it depends on the drawing ratio, cup depth, bottom thickness retention, and mold clearance; such cans are inherently made thinner by multiple drawing processes on the side walls, without the bottom being reduced accordingly.
For beverages with internal pressure, carbonated drinks, and beer soda, it is necessary to exercise extreme caution when using 0.16mm overall can bodies. Typically, dedicated high-strength tinplate, strict conditioning, and internal pressure design are required, and it is not advisable to substitute with ordinary miscellaneous can plates.
High acidity, high salt content, seafood, marinated, and tomato products: While reducing thickness, it is important not to blindly decrease the tin coating amount and inner coating grade, otherwise it may save on sheet material but increase returns.
When handling lightweight projects, the first step for Iron Hammer is not to specify the thickness, but to inquire about the contents, filling method, stacking layers, and transportation vibration, and then deduce the minimum wall thickness that can be used.
