Bag Making Machine for Sale: Comprehensive Inspection and Factory Acceptance Test Guide
When evaluating a bag making machine for sale, whether new or used, a thorough inspection and a factory acceptance test (FAT) are essential to verify that the machine meets specifications and will perform reliably. For new machines, the FAT is conducted at the manufacturer's facility before shipping. The buyer should send a qualified engineer or hire an independent inspector. The inspection starts with a visual check: examine the frame for straightness, welding quality, and surface finish. Check the electrical cabinet for neat wiring, proper labeling, and cooling fans. Verify the safety features: emergency stops, light curtains, and guards. Then, run the machine with the buyer's film (or a representative film) at the rated speed. Measure bag length, width, seal strength, and registration accuracy. The seal strength should be tested by peel test on at least 10 samples; the average and standard deviation should be within specification. The bag length variation should be within ±1 mm. The registration accuracy for printed bags should be within ±0.3 mm. The machine should be run for at least 2 hours to check thermal stability and any temperature drift. The noise level should be measured; it should be below the specified limit (e.g., 80 dB(A)). Check for any oil or air leaks. The HMI should respond quickly and the recipe changeover should work.
For used machines, the inspection is even more critical. The buyer should ask for the machine's service history, including maintenance logs, repairs, and parts replacements. The machine should be inspected for wear: sealing bars (flatness, coating), cutters (blade sharpness), bearings (noise, play), and rollers (surface condition). Run the machine at low speed and then gradually increase to maximum, listening for unusual noises. Check the temperature uniformity using a thermal camera. Inspect the electrical panel for any signs of overheating (burnt components). Run test bags and measure quality. The machine should be run for at least 30 minutes to allow the oil to warm up and reveal any hidden issues. If the machine is sold "as-is," the buyer should negotiate a lower price to account for potential repairs.
Plastic Bag Making Machine
Performance verification: For both new and used, verify the following parameters: maximum speed vs. claimed speed, bag length range, bag width range, film thickness range, sealing temperature accuracy, and repeatability. Test the automatic functions: splicing, stacking, and discharge. Check the registration system by running printed film and measuring registration error. The machine's control system should log production data; verify that the data is accurate. The FAT report should document all test results, with photos and videos. The buyer should sign off only when all parameters are met. If not, a corrective action plan should be agreed upon.
Used machine inspection checklist: 1) Frame condition – rust, cracks, repairs. 2) Sealing bars – flatness, pitting, coating wear. 3) Heating elements – resistance and insulation. 4) Thermocouples – calibration. 5) Cutters – sharpness, alignment. 6) Rollers – surface, bearings. 7) Servo motors – noise, encoder. 8) Pneumatics – leaks, cylinder seals. 9) Hydraulics – oil leaks, pump noise. 10) Electrical – wiring, contactors, SSR. 11) Safety – emergency stops, interlocks. 12) Documentation – manuals, drawings. The inspector should also run the machine with the buyer's film to test real-world performance. A used machine that passes a rigorous inspection can be a cost-effective purchase. However, the buyer should budget for refurbishment if needed.
Post-inspection negotiation: If issues are found, the buyer can ask for a price reduction, request that the seller fixes the issues, or walk away. For new machines, any deviations from the specification should be corrected before shipment. The machine should be shipped with a spare parts kit and documentation. By following a comprehensive inspection and FAT procedure, buyers can avoid unpleasant surprises and ensure that the
bag making machine for sale delivers the expected performance and reliability.
