When specifying aluminum composite panels (ACP) for a façade, signage system, or interior fit-out, one of the most common questions architects, contractors, and procurement teams ask is whether a 3mm or 4mm panel is the better choice. The answer depends less on a fixed rule and more on project requirements, aluminum skin thickness, finish, and the application environment. JIASHUNCAI, the international brand of Foshan Jiashuncai Building Materials Co., Ltd., manufactures both thicknesses as part of its standard ACP/ACM product range, giving buyers a clear basis for comparison before placing an order.
Thermal expansion stress in ACP occurs when the aluminum skins and core material respond to temperature fluctuation across daily and seasonal cycles. Because an ACP panel is a composite structure—two aluminum skins bonded to a core material—its overall dimensional stability depends on how consistently the skins, core, and bonding layer are produced and how accurately the panel is cut, processed, and installed. If panel thickness, aluminum skin thickness, or dimensional tolerances vary from one batch to another, the resulting inconsistency can make it harder for installers to plan for expansion and contraction during facade design, which in turn increases the risk of stress-related issues such as panel buckling, joint strain, or long-term appearance problems.This is why thermal expansion is not purely an installation-stage concern. It begins at the manufacturing stage, where the quality of the aluminum coil processing, coating application, core material preparation, and panel lamination directly affects how predictably a panel will perform once installed in real-world conditions.