Precision moulding for complex shapes
FlexBlow advances mould technology with Extreme Venting solution
FlexBlow has recently introduced a new mould technology, Extreme Venting, designed to address the challenges of stretch blow moulding, particularly with sharp-edged or complex PET container designs.
FlexBlow provides a full in-house mould design, prototyping, and manufacturing capabilities tailored to the most demanding container geometries. Whether it’s stackable containers, lateral handles, deep grips, or heat-set jars, FlexBlow moulds are engineered to give converters more flexibility, better performance, and lower production costs.
The new development Extreme Vent technology is a proprietary venting solution developed to solve one pressing challenge in stretch blow moulding: trapped air and uneven material distribution in sharp-edged or complex PET designs. Traditional mould venting has its limits, especially when forming tight angles or shoulder zones. Air pockets can form during the blowing process, resulting in weak spots, cosmetic flaws, or the need to overcompensate with heavier preforms or higher pressure. The new Extreme Venting system uses electro-discharge machining (EDM) to create precise venting channels in critical areas of the mould. This allows trapped air to escape more efficiently during the moulding process, ensuring an even material flow and reducing the risk of defects. As a result, manufacturers benefit from better part integrity, less material stress, and a reduction in blowing pressure by up to 25%. This technology is claimed to allow for the creation of sharp, detailed shapes with improved surface quality, while minimising the need for excess material or energy.
Sharp-shouldered PET jar for cosmetics
A recent application of this technology was seen in the development of a 500 ml PET jar for the cosmetics sector, featuring a sharply defined shoulder design. The Extreme Venting solution helped eliminate surface imperfections and achieve the intended geometry with minimal stress on the material. The sharp bottle shoulders, a distinctive visual feature of this design, were precisely formed without distortion, says Flexblow. The selected closure complemented the shoulder profile, resulting in the required clean, uninterrupted silhouette and seamless overall appearance. The final 500 ml container is made from 100% PET, features a 90 mm neck size, and is fully recyclable. Its material clarity, defined contours, and overall design consistency make it suitable for moisturisers, toners, lotions, and other personal care or chemical products.