Hydraulic press brakes are widely used in the hardware industry, involving complex hydraulic technology that requires the integration of electrical, mechanical, hydraulic and PLC technologies.
When a malfunction occurs, ordinary maintenance personnel often do not know where to start or rely on experience to solve problems, which not only delays production but also fails to solve problems effectively.
This article discusses the unique nature of hydraulic press brakes and equipment management methods. By carrying out preventive maintenance operations, the failure rate of press brakes can be minimized.
I. Hydraulic press brake equipment management overview
According to the general knowledge of equipment management, the management of press brake equipment is mainly divided into autonomous maintenance and professional maintenance.
Autonomous maintenance is performed by the operator (production worker), while professional maintenance is performed by the equipment maintenance worker. Before preparing a maintenance document, an “Equipment Maintenance List” must be established.
This programmatic maintenance document for all equipment serves as a directory of projects to support autonomous maintenance and professional maintenance, maintaining the necessary preventive preservation of the equipment.
This ensures that equipment is maintained in good condition, reduces the occurrence of malfunctions, decreases the rate of equipment downtime, and ensures smooth production.
1.1 Autonomous Maintenance
Autonomous maintenance is mainly carried out daily or per shift by the operator, following methods, frequency, etc., stipulated in the “Autonomous Maintenance Operation Manual”. The inspection results are recorded in the “Autonomous Maintenance Checklist” and any abnormal problems discovered are immediately reported.
The main autonomous maintenance projects of hydraulic press brakes are as follows.
- Cleaning oil stains on equipment.
- Initial accuracy test of equipment bending operation.
- Checking oil pump noise and engine heat.
- Checking for abnormal noises and vibrations during equipment operation.
- Check for loose screws on the equipment.
- Checking for oil leaks in the equipment.
There are also regular 5S tasks. Please note that production operators do not need to inspect the electrical panel as it involves electrical work, which is carried out by professional maintenance personnel.
1.2 Regular professional maintenance
Autonomous maintenance of the press brake is only superficial, it especially requires professional maintenance personnel to regularly maintain the hydraulic press brake in accordance with effective and professional maintenance procedures, thereby increasing the stability of the equipment.
Maintenance workers carry out professional maintenance checks on equipment and regularly replace spare parts in accordance with the “Professional Maintenance Operation Manual”, eliminating faults at their early stage. This maintenance frequency is generally divided into fixed frequency checks performed monthly/quarterly/yearly.
Therefore, regular professional maintenance check items are particularly important, especially listing the content of the checks in accordance with the equipment manuals.
Of course, equipment manuals are often insufficient to support complex failures, which requires equipment engineers to gradually accumulate failure experience, analyze abnormal failures, use theoretical knowledge to deeply understand equipment failures, and prevent the recurrence of failures.
Or analyze recurring faults, fill out the “Recurrent Fault Problem Rectification Form” and, when necessary, modify and improve the equipment to reduce the failure rate. Key items to check during professional hydraulic press brake maintenance include:
- Regularly replace the valve group seals (O-rings).
- Regularly check the cylinder back pressure on both sides.
- Check the hydraulic system pressure.
- Regularly replace the hydraulic oil and oil inlet filter element.
- Lubricate guide rails and other sliding parts.
- Test the balance accuracy of the press brake.
- Check the guide rail slider clearance.
- Regularly check and replace the cabinet relay.
- Test the power supply voltage balance.
- Dust and clean the electrical panel and replace the filter.
The above items are common inspection items. In addition, each equipment operates differently, so some regular inspection items summarized from experience should also be added.
1.3 Planned Maintenance Management
Equipment problems discovered during autonomous maintenance should be recorded in the “PM Problem Card”, while problems found during professional maintenance should be recorded in the “Regular Maintenance Problem Report”.
Then the equipment management engineer will consolidate the problems of both aspects, schedule an appointment, prepare spare parts for maintenance, carry out maintenance as planned, fill in the “Planned Maintenance Management Table”, rectify the defects equipment and restore equipment accuracy and performance.
1.4 Emergency repair management
Most repair staff are deployed to handle emergency repairs. Emergency breakdowns also need to be managed, with usual occurrences being recorded in the “Fault Repair Table”.
Each month, analyze downtime, summarize the characteristics of press brake failures, or identify which press brakes malfunction frequently to make targeted improvements. The Breakdown Chart provides management with evidence and sources to identify problems.
1.5 Press brake spare parts management
All equipment repair and maintenance work mentioned above cannot be carried out without replacing equipment spare parts. To this end, the “Equipment Spare Parts Management Card” was created.
This document records the spare parts for a machine model type, marks the safe inventory information, and prevents a situation where there are no spare parts for repair after damage to the equipment. This is especially important for critical single-unit equipment, requiring enhanced spare parts management.
The types of spare parts required for hydraulic press brakes can be divided into cylinders, oil pipes, pumps, valve groups, electrical components, etc.
The cylinder mainly includes cylinder seals, the oil pipe mainly consists of high pressure braided hoses, the valve group mainly includes valve group sealing rings, solenoid valves, back pressure valves and especially the proportional reversing valve that controls flexion progress on both sides.
Electrical components mainly include grid scales (balancing accuracy of measuring equipment), relays, contactors and other electrical control components of equipment. These are all the necessary spare parts prepared specifically for the press brake, playing a vital role in its functioning.
II. Common problems in managing hydraulic press brake equipment
2.1 Problems in the maintenance log
- The logbook is not compiled in accordance with the company's equipment list, resulting in omissions and duplications.
- Only one maintenance record book is prepared for similar equipment. Each machine must have its unique maintenance log.
- The creation of maintenance logs requires a tripartite agreement (a consensus between the head of the equipment management department, the head of the production department and the equipment operator regarding the maintenance content necessary to ensure its viability and executability).
- Logbooks are not updated based on real-life situations after use.
- Maintenance items often ignore lubrication tasks.
- The contents of the maintenance diary are not covered by the machine's regular, independent maintenance checklists.
2.2 Regular Professional Maintenance Problems
- Unexpected daily breakdowns leave no time to execute regular maintenance plans, or there are too many regular maintenance tasks and not enough manpower to implement.
- Defined maintenance cycles are not reasonable, or maintenance tasks are overly comprehensive, not highlighting key points. Establishing equipment maintenance cycles requires long-term experience.
- Regular maintenance tasks and cycles are not adjusted to actual running conditions.
- The concepts of “regular maintenance” and “planned maintenance” are confusing and confusing. Misunderstanding “regular maintenance” as “routine work” leads to an overabundance of operational tasks and an inability to complete plans on time.
For these management issues, equipment managers need to take reasonable measures, analyze the causes and develop sensible equipment management strategies.
III. Conclusion
Through professional maintenance of hydraulic equipment, combined with the advanced management philosophy of Total Productive Maintenance (TPM), the management level of hydraulic bending machines will certainly be raised, reducing equipment failure rates and ensuring production safety.
