Steel, particularly stainless steel, is another common material for producing PET moulds. The use of steel allows for a more durable mould that can withstand the rigors of high-volume production. Additionally, steel is less likely to warp or deform over time, ensuring that the mould maintains its shape, which is essential for producing consistent containers. This consistency is particularly critical when packaging perishable pet foods, as even slight variations can affect seal integrity and cause spoilage. However, the production process for steel PET moulds typically requires more time and investment due to the material's strength.