In the actual production of biaxially‑stretched films, stretching machines are inevitably plagued by various faults that impair product quality and production efficiency. The capability to swiftly and accurately identify and resolve such issues directly determines the uptime of the production line, product qualification rate and overall operating costs. Nanjing sumino Machinery Co., Ltd. has summarized a systematic set of troubleshooting schemes to assist clients in restoring steady‑state production promptly.

Film Breakage: Systematic Troubleshooting Covering Temperature and Tension

Film breakage ranks as the top‑ranked anomaly triggering unplanned shutdowns in stretching procedures. Its triggers cover multiple working stages: insufficient pre‑heating temperature that prevents full softening of the film, excessive stretching temperature weakening melt strength, over‑stretching caused by excessive longitudinal tension, transverse draw ratio exceeding the material’s bearing limit, and concentrated edge stress brought by uneven clamping force of chain clips.

During inspection, verify sequentially whether temperature settings for each section fall within the material processing window, whether longitudinal and transverse tension parameters are properly matched, and check the clamping condition of chain clips. Stretching machines manufactured by Nanjing sumino are fitted with an on‑line tension monitoring and automatic adjustment system. It detects real‑time tension fluctuation and sends out early warnings to greatly lower film‑break risks.

Thickness Deviation: Targeted Inspection From Die Head to Chain Clips

Uneven film thickness will undermine the performance of subsequent processes such as laminating and printing, and cut down the finished‑product yield. Factors behind thickness deviation are mainly located in the extrusion die head and chain‑clip assemblies.

For the die head, inspect the uniformity of die‑lip gaps and consistent temperature across all die‑head zones. For chain clips, confirm synchronized travelling speed between the left‑hand and right‑hand clip chains and check track abrasion which may lead to running‑path offset.

Our stretching machines incorporate an on‑line thickness detector and closed‑loop control system, which monitors real‑time thickness distribution and fine‑tunes process parameters automatically.

Surface Defects: Comprehensive Inspection of Roller Surfaces and Production Environment

Scratches, stains, indentations and other film surface defects generally stem from foreign substances or scratches on roller surfaces, excessive airborne dust in the workshop and static‑electric adsorption.

Priority should be given to cleaning and inspecting every roller surface, checking the operational status of static eliminators, and verifying clean‑room environmental standards. Nanjing sumino Seiko supplies matched static‑removal and dust‑removal equipment for clients to build up a clean manufacturing workspace.

Routine Maintenance Serves as the Fundamental Preventive Measure

Nanjing sumino Machinery Co., Ltd. provides detailed maintenance manuals and on‑site technical training for customers. We help operators establish a preventive maintenance mechanism to eliminate hidden troubles at the initial stage and guarantee long‑term, reliable operation for stretching equipment.