Repair, maintenance and use specifications of large blow molding machines

1. Machine Assembly Inspection: For newly purchased extrusion blow molding machines, an assembly inspection should be performed. After the equipment is installed according to the manual, the entire unit should be aligned, including alignment of the extruder head and clamping mechanism; installation of the mold water cooling pipe and verification of its correct routing; operator convenience and accessibility of the control devices (electrical control box, programmable controller, keyboard, etc.); smooth loading, finished product placement, and scrap collection processes without disrupting normal operation; and appropriate positioning of related auxiliary equipment. Only after the assembly inspection results meet production and safety requirements is the equipment considered optimally assembled.

2. Hydraulic and Lubrication System Inspection: Check the hydraulic oil level gauges on the extruder and various hydraulic devices to ensure the oil level in the tank remains above the reference level.

3. Pre-startup preparations are as follows:

1) Materials used for extrusion blow molding should meet the required dryness requirements and require further drying if necessary. 2) Select the die specifications based on the product type and size. Assemble the die in the following order: install the die flange, die body, die head, perforated plate, and filter. 3) Connect the compressed air line and install the core die electric heating rod and die head heating coil. Check and start the water system. Adjust the gaps at the die head for uniformity and check the alignment of the main and auxiliary equipment centers. 4) Start the extruder, clamping device, manipulator, and other operating equipment and run them at no load. Check that all safety and emergency devices are functioning properly and eliminate any faults promptly. 5) Set the temperature of the extruder die head and each heating section according to the process requirements and heat each section. Test the integrity of each heating section with scrap material to check for any non-heating issues. After each section reaches the set temperature, maintain the temperature for 0.5-1 hour. 6) Set the parison wall thickness at each point on the programmable controller according to the process requirements. 7) When starting the machine for unloading, the outer layer should generally be opened first to prevent excessive pressure from the inner layer, which could cause material to flow back out of the outer layer. The unloading frequency should be gradually increased from low to high to prevent excessive opening frequency, which could damage the screw due to low temperatures. 8) Process Conditions: a. The process temperature during plasticization and melting of the raw materials should be controlled within the range of 170-230°C. b. The blow-up ratio for preform tube blow molding of bottles should be controlled within the range of (1.5-3):1. c. The compressed air pressure for preform tube blow molding of bottles should be 0.3-0.6 MPa. d. The mold temperature for the molded bottles should be 20-50°C, and the cooling and setting time should account for approximately 50%-60% of the total product start-up production cycle.

4. Shutdown Precautions: When shutting down, reset all speeds to zero and shut down each heating section one by one. Close the mold and, in the closed position, keep the blow needle half a centimeter away from the mold to prevent hard objects from falling into it and damaging it. Apply rust inhibitor to the mold. Turn off the main power supply, lubricate and maintain the equipment, add lubricating oil, clean the entire machine, and shut off all water leaks. If the shutdown period is long, drain all water from the mold to prevent rust and blockage.

To prevent personal injury, all transmission parts of the machine should be equipped with safety guards and safety gratings; the product demolding and removal outlet should have a safety door; the heating area of ​​the machine should have safety and thermal insulation guards; the crusher should have a protection against falling steel, and operators should be prohibited from reaching into the machine; emergency brake buttons and alarms should be installed on key parts of the equipment; and all pressurized vessels should undergo regular hydraulic tests. During molding operations, if more than two people are involved, a clear division of labor must be established. When unloading or installing equipment or molds, the power and air supply must be turned off, and a "Maintenance" sign must be displayed at the repair location. During the production of large containers, due to the large mold cavity volume, safety doors must be installed to prevent human entry. The mold cannot be closed until the door is closed and personnel have left the mold. During molding operations, high-temperature operations such as welding and gas cutting should not be performed near the machine head. When operating a cold machine, operators must not stand under the machine head to prevent injury from overheated melt splashing. When performing material crushing operations, the power must be turned off and the cover must be opened for maintenance.
6. Daily Maintenance and Use of Blow Molding Machines

1) Before starting the machine each shift, all moving parts must be lubricated once. (Robot, robot guide rails, mold opening and closing guide rails)

2) The swing arm can be lubricated every 3-4 days. The large and small chains of the heating machine can be lubricated once a month. Regularly check the reducer of the main machine and the heating machine for oil depletion. The main machine bearings can be refilled every 2-3 months. Before production, check all moving parts for tightness and loose screws, especially those in areas subject to high impact forces, and any abnormalities in the belt drive.

3) Check the high-pressure and low-pressure air sources, power supply, and water supply for proper function.

4) Check the emergency stop switches, safety door switches, and protective device detection switches for proper function.

Check the heating head for proper functioning of the preform insertion and removal mechanisms. If preform insertion is not in place, adjust the preform pressing mechanism nuts.

5) Check the lamps for damage or breakage. Replace them promptly.

6) Check all pneumatic components for leaks and responsiveness.

7) Check the triplex for abnormal leaks, blockages, and overfilling of the water tank.

8) Clean the blow molding machine's solenoid valve if any abnormalities occur.

9) Blow molding molds must be cleaned and polished regularly.

10) When turning on the high and low pressure air switches, operate slowly to prevent excessive air flow and the possibility of dirt being blown into the solenoid valve. Simultaneously, open the exhaust valve for 30 seconds to ensure clean air.

11) When starting the machine, ensure that all mechanical components are in good condition and that no one and no foreign objects are inside. Pay particular attention to the crank and mechanical movement to prevent injury. Also, close the safety door.

12) When starting the machine, start the motor first, delaying the heating unit for 30 seconds to prevent voltage fluctuations. Ensure the cooling water is turned on before starting the heating unit.

13) After the heating unit has been running for 2-3 minutes, wait until the oven temperature has risen evenly before pressing the preform button. Simultaneously, turn on the blow molding power supply; otherwise, the blow molding process will not occur.

14) While the machine is running, pay close attention to any unusual noises. Early detection and prompt shutdown are essential for immediate resolution.

15) In the event of an emergency, press the emergency stop button to initiate an emergency stop. Then, analyze the cause based on the on-site situation and quickly resolve the problem.

16) When the machine is operating normally, do not insert any body part into the machine to avoid injury. If the machine makes unusual noises, slow down the machine and observe again.

17) When the machine is operating normally, the operator must regularly inspect the bottle quality to prevent voltage fluctuations or other factors from affecting blow molding quality.

18) When repairing the machine, press the fault repair button on the screen and post safety notices to ensure safe repairs. If you need to manually observe the operation of each individual mold cavity, pay attention to the position of the robot arm. Also, be sure to understand the function of each button before operating it. Ensure that any inadvertent operation does not cause unnecessary trouble.

19) After each blow molding machine repair, be sure to clean tools, screws, and other items to prevent them from being left inside the machine and affecting normal operation.