In manufacturing presses, lubrication is critical for reducing friction and heat, extending equipment life, and ensuring consistent product quality. Without a proper lubrication plan, presses are susceptible to catastrophic and costly failures, causing unplanned downtime. At HEL, Inc. we estimate that 90% of our emergency press repair calls are due to improper lubrication.
The primary functions of lubrication in presses:
1. Reduces friction and wear
- High-pressure press operations create intense metal-on-metal friction between moving parts like gears, pistons, bearings, and guides.
- Lubricants introduce a protective film that prevents direct contact, absorbing the mechanical forces and preventing components from grinding against each other. This significantly minimizes wear and tear.
2. Dissipates heat
- Friction converts kinetic energy into heat. If left unchecked, this heat can build up and cause parts to warp, seize, or suffer from premature degradation.
- Lubricants absorb and carry heat away from critical components, regulating the press’s operating temperature and preventing overheating and thermal damage.
3. Prevents rust and corrosion
- Many industrial lubricants are formulated with additives that protect metal surfaces from rust and corrosion, which is essential in environments with high humidity or exposure to coolants.
4. Flushes out contaminants
- Press operations can generate tiny metal particles, dust, and other debris. Lubricants help to suspend and carry these contaminants away from the contact points to filters, keeping the system clean and free of abrasive particles.
5. Absorbs shock and vibration
- The repeated impact of press cycles creates significant shock and vibration. The fluid film provided by the lubricant acts as a cushion, dampening these forces and reducing stress on components.
Consequences of poor lubrication:
Ignoring lubrication can lead to a cascade of expensive problems that disrupt production.
- Reduced equipment lifespan: Increased friction and heat from insufficient lubrication accelerate wear, causing components to degrade faster and leading to more frequent and costly part replacements.
- Unscheduled downtime: Lubrication-related failures are one of the most preventable types of equipment breakdowns, yet they account for a significant percentage of unplanned equipment shutdowns.
- Decreased part quality: Inconsistent performance due to improper lubrication can lead to defects, reduced dimensional accuracy, and poor surface finish, resulting in more scrapped parts and rework.
- Lower energy efficiency: A poorly lubricated machine requires more energy to overcome friction, increasing power consumption and operational costs.
- Safety hazards: Catastrophic machine failure due to a lack of lubrication can pose a significant risk to operators.
Tailoring lubrication to press applications:
Different press applications require specific lubrication strategies to optimize performance.
- High-speed operations: High-speed presses and those with hydraulic systems rely on high-performance hydraulic fluids and circulating oil to manage heat effectively and prevent varnish formation.
- Heavy-duty applications: Operations involving high loads, such as forging or heavy-duty forming, often require specialized greases with superior consistency and adhesion to withstand extreme pressure and protect high-wear components like guides and bearings.
- Metal forming: In metal stamping, special lubricants are often applied directly to the sheet metal (or “blank”) to reduce friction between the die and workpiece. These lubricants can be mill oils, pre-lubes, or hot melts, depending on the material and forming temperature.
Best Practices for Lubricants
The best practices for lubricating mechanical presses involve adopting a comprehensive approach that prioritizes the “4 Rs”: using the right lubricant, in the right quantity, at the right time, and in the right place. By following these principles, manufacturers can significantly extend equipment life, reduce costly repairs, and improve operational reliability.
Use the right lubricant
Choosing the correct lubricant is paramount for a press’s specific application and operating conditions.
- Follow OEM specifications: Always consult the original equipment manufacturer’s (OEM) manual for the recommended lubricant type, viscosity, and additives. The OEM is the most reliable source for your specific machine’s needs.
- Match lubricants to conditions: A press’s operating environment influences the best lubricant choice. For example, high-temperature operations may require synthetic lubricants for greater thermal stability, while mineral-based oils are often suitable for general-purpose presses.
- Prevent mixing: Never mix incompatible oils or greases, as this can lead to equipment failure. Store different lubricants in clearly labeled, sealed containers to prevent cross-contamination.
Apply the right amount
Both over-lubrication and under-lubrication can damage equipment.
- Use automated systems: A centralized automatic lubrication system delivers a precise amount of lubricant to all necessary points at the correct intervals. This eliminates guesswork, prevents over-application, and improves safety by removing the need for technicians to access hazardous areas.
- Train personnel: For manual applications, ensure that maintenance personnel are properly trained on the exact amount of lubricant required for each component. Over-greasing can lead to pressure buildup that damages seals and attracts contaminants, while under-greasing causes excessive friction.
Lubricate at the right time
The timing of lubrication is critical to maintaining a protective film and preventing wear.
- Establish a schedule: Develop and adhere to a strict lubrication schedule based on the manufacturer’s recommendations. This schedule should include tasks for daily, weekly, and longer intervals.
- Consider condition-based monitoring: For critical assets, use predictive maintenance tools like oil analysis, temperature sensors, and vibration monitoring. This can help you fine-tune the lubrication schedule and replace lubricants based on their condition rather than a fixed calendar.
Use the right location and methodology
Applying the lubricant to the proper location is just as important as using the right product.
- Ensure clean application: Store lubricants in a clean, temperature-controlled environment and use dedicated transfer equipment for each lubricant type. Keep lubrication points and fittings clean before applying fresh grease or oil.
- Maintain proper application settings: For automated systems, ensure the pump’s cycle time and volume settings are correct and maintained. In stamping presses, ensure applicators precisely target the die or sheet metal, avoiding waste and press contamination.
- Check ancillary systems: Remember to service related systems, like hydraulic and air systems. For example, check hydraulic fluid levels and clarity, and drain moisture from air counterbalance systems weekly.
Monitor and verify
Routine checks and detailed record-keeping are essential for a robust lubrication program.
- Perform regular inspections: Conduct daily visual inspections for leaks, loose fittings, and abnormal noises.
- Conduct oil analysis: For presses with circulating oil systems, perform regular oil sampling and analysis. Testing can detect wear metals, contamination, and signs of oil degradation, helping to predict and prevent failures.
- Document everything: Maintain detailed lubrication logs that document what was applied, how much, when, and by whom. This helps track maintenance history and identify potential issues.
At HEL, the majority of emergencies we are called in for are because of improper lubrication. Following these protocols will save you time and money by extending the life of your equipment and avoiding unnecessary repairs and downtime.
Call HEL, Inc. to check the current status of your equipment, get you back to a solid starting point for a lubrication program and make any repairs needed.
