Packages can deform from heat shrink squeezing in a side-seal shrink wrapping machine for four common reasons: temperature set too high, conveyor speed too slow, shrink film bag too small, and shrink tension of the heat shrink film too high. Improper equipment maintenance and off-center package placement can also cause deformation.
Temperature set too high
When the temperature of a heat shrink packaging machine exceeds the tolerance limit of the packaging material or product, the material can soften or melt excessively and deform irreversibly. Plastic film may over-shrink at high temperatures, causing dents or structural distortion on the package surface. Operators should adjust temperature parameters according to the packaging material, keep the temperature at the lower end of the material's shrink range, and avoid local overheating.
Conveyor speed too slow
A conveyor speed that is too slow extends the dwell time of the package in the heating zone. The material keeps receiving heat and over-shrinks. After long heating, the film may concentrate shrink force and squeeze the product edges. Operators can gradually increase conveyor speed through the equipment control panel so the dwell time in the heating zone matches the material's shrink time. They should also check whether the shrink result is uniform.
Shrink film bag too small
If the circumference or length of the shrink film bag is smaller than the unfolded size of the package, the bag cannot stretch enough during heat shrinking and applies extra pressure to the product. For example, using a square film bag for a round product can cause over-shrinking at the corners. Operators should re-measure the package size and choose or customize a matching film bag. The bag should fully wrap the product when unfolded and leave a shrink allowance of 5% to 10%.
Shrink tension of the heat shrink film too high
Heat shrink films of different materials have different shrink rates. POF film has a shrink rate of about 60% to 70%, and PVC film has a shrink rate of about 40% to 50%. If the film has shrink tension that is too high, the package may deform from excessive shrink force. Operators should choose a film with a shrink rate that matches the product. Fragile items can use low-shrink-rate film, while regular-shaped products can use high-shrink-rate film for better tightness.
We can machine precision parts such as heating tube mounts, conveyor rollers, cutter seats, and sealing and cutting blades according to customer drawings. We support single-piece and small-batch production. Hansheng Automation machines to drawings, with materials and surface treatments selected for the actual working conditions.
Additional note: Improper equipment maintenance, such as aging heating tubes that cause uneven temperature, and off-center package placement that causes local over-shrinking, can also lead to deformation. We recommend regularly checking equipment condition and verifying parameters through trial packaging during setup.
Beyond shrink packaging machine parts, our custom precision parts machining capability also serves several industries. Hansheng Automation can machine printing machinery parts, food machinery parts, medical device parts, and filling machinery parts to drawings. We can also machine tobacco packaging machinery parts, yacht precision parts, and RC car precision parts. We machine to drawings with attention to dimensional consistency and delivery responsiveness.
