Extrusion Machine Commissioning Procedures
Before an extrusion machine enters formal production, it is crucial to perform both no-load test runs and load test runs to ensure optimal performance and safety. These procedures are fundamental in extrusion tech, as they verify that all components function correctly and meet the required specifications. Proper commissioning prevents costly downtime and ensures product quality from the start of operations.
This comprehensive guide outlines the detailed steps and inspection criteria for both no-load and load testing, incorporating essential extrusion tech principles. Following these procedures meticulously ensures that the extrusion machine operates efficiently, safely, and produces consistent results in production environments.
1.5.2.1 No-Load Test Run
The no-load test run is performed under unloaded conditions, with an appropriate amount of lubricating oil added to the barrel. This test should run for several minutes (no less than 3 minutes but not exceeding 10 minutes) to inspect the assembly of various components and check for any blockages or leaks in the piping systems. This initial phase is critical in extrusion tech as it identifies potential issues before introducing material into the system.
The primary purpose of the no-load test is to verify the basic functionality of all machine components without the stress of material processing. This step in extrusion tech allows technicians to detect mechanical issues, alignment problems, and system inefficiencies that could cause more serious damage during actual production.
Figure 1-78: No-Load Test Flow Diagram
① Screw Rotation Direction Check
Verify that the screw rotation direction is correct: For a right-handed screw, when viewed from the screw head direction, it should rotate clockwise. This is a fundamental check in extrusion tech as incorrect rotation can cause severe damage to the machine and produce defective products. Technicians should mark this verification in the equipment log, noting the exact rotation direction observed during the test.
② Screw and Barrel Clearance Inspection
Check that there is no scratching or jamming between the screw and the inner wall of the barrel. This inspection verifies that the screw outer diameter and barrel inner diameter meet standard specifications. Any异常 (abnormalities) should be recorded in the equipment档案 (file). Proper clearance is essential in extrusion tech to ensure efficient material processing and prevent excessive wear on components. Measurements should be taken at multiple points along the length of the screw to ensure consistent clearance.
③ Main Shaft Speed Range Verification
Determine whether the main shaft speed range meets the rated specifications. This involves testing the full range of speed settings from minimum to maximum, ensuring smooth transitions between speed levels. In extrusion tech, accurate speed control is vital for consistent product quality. During this test, record the actual speeds achieved at various settings and compare them to the manufacturer's specifications. Any significant deviations should be addressed before proceeding to load testing.
④ Noise, Vibration, and Temperature Monitoring
During the no-load operation, check for any abnormal noise, vibration, or temperature rise. Ensure all fasteners are secure, including checking for loose connecting bolts and verifying that connecting shafts have no deflection. Unusual vibrations can indicate misalignment or bearing issues, which are critical to address in extrusion tech. Temperature monitoring should include regular checks of bearing housings, motor casings, and gearboxes, with any unexpected temperature increases documented and investigated.
⑤ Lubrication System Check
Inspect the lubrication system to ensure it is functioning properly and check for any leaks. This includes verifying that all lubrication points receive adequate oil or grease, checking pressure levels in forced lubrication systems, and ensuring proper flow rates. In extrusion tech, proper lubrication is essential to prevent premature wear and ensure smooth operation of moving parts. Technicians should check all hoses, fittings, and reservoirs for leaks, damage, or blockages that could impair system function.
⑥ Cooling System Inspection
Verify that the cooling system is unobstructed and check for any leaks. This involves checking the flow of cooling water or oil through the system, ensuring that all valves function correctly, and verifying that temperature control devices operate as intended. Effective cooling is critical in extrusion tech to maintain optimal processing temperatures and prevent overheating. During this inspection, check all hoses, heat exchangers, and cooling jackets for signs of blockage or leakage that could compromise system performance.
⑦ Temperature and Speed Measurement Devices Check
Inspect temperature measurement devices and speed measurement devices to ensure they are sensitive and provide accurate data. This includes calibrating sensors against known standards, verifying that readings are transmitted correctly to control systems, and ensuring that alarms activate at appropriate thresholds. Accurate measurements are fundamental in extrusion tech for maintaining process control and product consistency. Technicians should compare readings from machine sensors with independent measuring devices to verify accuracy. Any discrepancies should be addressed through calibration or replacement of faulty components. Special attention should be paid to thermocouples or RTDs in the barrel sections, as these are critical for maintaining proper melt temperatures in extrusion tech processes.
Key Considerations in No-Load Testing for Extrusion Tech
- Always follow proper lockout/tagout procedures before starting any testing
- Ensure all safety guards are properly installed and functioning
- Have emergency stop procedures in place and known to all personnel involved
- Record all measurements and observations in the equipment log for future reference
- Address any identified issues before proceeding to load testing
- Verify that all control systems are properly calibrated and functioning
- Check that all warning indicators and alarms are operational
1.5.2.2 Load Test Run
After successfully completing the no-load test run, a load test run of no less than 2 hours is required. This phase of testing is critical in extrusion tech as it evaluates the machine's performance under actual operating conditions, providing valuable data about its capabilities and limitations. The load test run simulates production conditions to ensure the machine can handle the required processing demands consistently.
The load test run is designed to verify that all systems work together harmoniously under production-like conditions. This comprehensive evaluation in extrusion tech ensures that the machine can maintain performance specifications over extended periods, identifying any issues that may only appear during sustained operation.
Extrusion machine undergoing load testing with proper monitoring of key parameters
Figure 1-79: Load Test Inspection Items
Test Temperature Control System
Determine Plasticizing & Process Parameters
Establish Parameter Standards
Measure Noise Levels
Inspect Component Assemblies
Check All Piping Systems
① Testing the Temperature Control System
Install a dedicated test die or production die and set the temperature for each section of the extruder according to material requirements. During heating, verify that the temperature controllers for each section are responsive and that temperature measurements are accurate, selecting sensitive and reliable temperature measuring instruments. The heating time should generally not exceed 2 hours.
In extrusion tech, precise temperature control is paramount as it directly affects material viscosity, melt quality, and final product properties. Technicians should record temperature readings at regular intervals, comparing the actual temperatures with the set points. Any significant deviations should be noted and adjusted. This process ensures that the temperature control system can maintain stable conditions throughout the extrusion process, which is essential for consistent product quality in extrusion tech applications.
② Determining Plasticizing and Process Parameters
Start the machine and operate the screw at low speed while feeding material, beginning with a small amount and gradually increasing until normal operation is achieved. Then check if the extruded product surface is smooth and the cross-section is uniform.
Once satisfactory plasticization is observed, gradually increase the screw speed to determine the maximum output the machine can achieve, along with screw speed, main motor current, and other process parameters. Record process parameters under different speed conditions. This data collection is fundamental in extrusion tech for establishing optimal operating ranges and understanding machine capabilities.
In extrusion tech, the relationship between screw speed, motor current, and output is critical for determining efficient operating points. Technicians should document these relationships in detail, creating performance curves that guide production settings. Special attention should be paid to how plasticizing quality changes with different speeds, as this affects both product quality and machine wear in extrusion tech processes.
Extrusion Tech: Parameter Relationships During Load Testing
③ Establishing Parameter Standard Requirements
Based on the test records, compile and convert data to determine the extruder's output, nominal specific power, specific flow rate under various speed conditions, and the standards that each parameter should meet. This step in extrusion tech formalizes the operating parameters that will guide production, ensuring consistent results and efficient operation.
These standards serve as the benchmark for production operators, providing clear guidelines for acceptable operating ranges. In extrusion tech, having well-defined parameter standards helps minimize waste, reduce setup times, and ensure product consistency. The standards should be reviewed regularly and updated as needed based on production experience and material changes.
Additionally, these parameters form the basis for preventive maintenance schedules in extrusion tech, as deviations from standard operating parameters can indicate developing issues that require attention before they lead to equipment failure or quality problems.
④ Measuring Noise Standards
To ensure operator health and safety, the noise level at 1 meter distance and 1.5 meters height from the extruder should not exceed 85 dB. This measurement is crucial in extrusion tech environments, as prolonged exposure to excessive noise can lead to hearing damage and other health issues for operators.
Noise measurements should be taken at multiple points around the machine during different operating conditions to ensure compliance across all scenarios. In extrusion tech, noise levels can indicate mechanical issues such as misalignment, bearing wear, or inadequate lubrication. A sudden increase in noise levels during production can signal developing problems that require immediate attention.
When noise levels exceed the standard, corrective measures should be implemented, which may include installing additional sound insulation, replacing worn components, or adjusting machine settings. Maintaining acceptable noise levels is not only a safety requirement but also contributes to a more productive work environment in extrusion tech facilities.
Technician measuring noise levels during extrusion machine load testing as part of extrusion tech best practices
⑤ Inspecting Component Assemblies
During the load test, observe whether the gears in the gearbox operate with abnormal noise or impact sounds to determine if their assembly is appropriate and ensure smooth operation of the entire machine. Check that bearing temperature rise does not exceed 60°C and that the temperature rise of oil in the gearbox does not exceed 35°C. The gearbox should be free from oil leakage.
After the load test, inspect the screw and barrel inner wall for signs of severe wear or deformation. These checks are vital in extrusion tech to ensure that components are functioning within acceptable limits and to identify any premature wear patterns that may indicate alignment issues or material incompatibilities.
In extrusion tech, proper gearbox function is critical for transmitting power efficiently to the screw. Abnormal noises can indicate misalignment, inadequate lubrication, or manufacturing defects. Temperature monitoring during the load test helps identify potential overheating issues that could lead to premature failure if not addressed.
The post-test inspection of the screw and barrel is particularly important in extrusion tech, as these are the primary working components. Any signs of abnormal wear patterns can provide valuable insights into machine performance and help optimize operating parameters for longer component life.
⑥ Rechecking All Piping Systems
再次检查各管路系统工作是否正常，有无堵塞或泄漏。 (Recheck that all piping systems are working normally and check for any blockages or leaks.) This includes hydraulic lines, cooling water circuits, lubrication systems, and any other fluid-carrying pipes.
In extrusion tech, proper functioning of all piping systems is essential for maintaining machine performance and preventing unexpected downtime. The load test can reveal leaks or blockages that may not have been apparent during the no-load test, as system pressures and flows are significantly different under operating conditions.
Special attention should be paid to connections and joints, as these are common points for leaks to develop. In extrusion tech, fluid leaks can not only affect machine performance but also create safety hazards and environmental concerns. Any identified issues should be repaired and retested before the machine is put into production service.
Additionally, filters in various systems should be inspected after the load test. In extrusion tech, contaminants can be dislodged during initial operation and collect in filters, potentially causing blockages if not addressed. This final check ensures that all systems are clean and functioning properly before regular production begins.
Acceptance Criteria
The extrusion machine can be accepted only after all the above items have passed inspection. This comprehensive testing process ensures that the machine meets all performance and safety requirements before entering production service.
Proper documentation of all test results is essential in extrusion tech, providing a baseline for future performance comparisons and troubleshooting. A formal acceptance report should be completed, signed by all relevant parties, and filed in the equipment records for future reference.
This rigorous testing and acceptance process in extrusion tech ensures that the machine operates safely, efficiently, and produces consistent quality products, maximizing return on investment and minimizing production issues.