For presses featuring light curtain safety guards, it is important that a stop-time analysis be performed in order to determine the appropriate distance the light curtains are placed relative to the press opening.
In order to determine this distance, Stopping & Speed Analyzers can be used. These devices take into consideration standard body speeds which have been researched and recorded. Trained safety operators then utilize the stop-time analysis results, coupled with the known ram speed information for the particular press in order to establish the safe mounting distance which the curtain must be placed to allow for moving operator limbs, etc.
Requesting that this procedure be performed by your hydraulic press manufacturer or safety specialists will ensure your investment in safety guarding is fully employed.
by Michael Riehn
1. Follow the prescribed preventive-maintenance schedule supplied with your press. Different presses with varying capabilities require special maintenance. While most hydraulic presses share the same core needs for maintenance, start by following the specific schedule supplied in your machine manual.
2. Check hydraulic lines and fittings regularly for leaks. Small leaks can lead to large problems and large messes. If a leak is detected, tighten or replace the hose or fitting and then monitor the correction.
3. Check for proper oil level and operating temperature. Improper oil levels can lead to pump inefficiency due to cavitation, where air enters the liquid being pumped. Oil that runs too hot can lead to premature breakdown. Monitoring oil temperature also serves as a warning that some circuit components may not be performing adequately. Press systems traditionally running cool and then suddenly changing to run hot, may have a failing component that is passing oil and detracting from efficiency, not to mention adding heat to the system.
4. Ensure oil cleanliness. Contaminated oil can cause complete system failure and significant damage, and lead to extended downtime. Many basic hydraulic systems can run with simple return-line filtration circuits using 10-micron filters. Higher-performance systems utilizing proportional or servo valves will require more advanced or cleaner filtration (perhaps 6-micron filters) and the use of in-line pressure and return-line filters. The type of system and required cleanliness should be specified by the manufacturer. Periodic oil sampling is suggested, and can be analyzed by a third party or dedicated oil-testing service. Often, a local hydraulic-component distributor can perform this duty or suggest a reliable company.
5. Mind the fasteners. Whether the press is of all-welded construction or is a tie-rod model, it relies on numerous nuts and bolts for proper operation. Monitor cylinder attachment monthly. Once the bolts have been checked to the proper torque, baseline marks can serve as at-a-glance indicators for future monitoring. Many presses carry marks on all attachment bolts when the bolts have been certified to the proper torque. Also, monitor bolster-plate fasteners and tie-rod pre-tensioning nuts.
6. Monitor the safety system on a daily basis. Press systems with light curtains, gate interlocks, safety mats, etc., should be tested prior to operation. If a safety device has been found defective or unreliable, lockout the press and perform needed service immediately. Also, test the E-stop safety circuit daily.
7. Record press data. Data logging, though not often used, is one of the best tools for monitoring press-system performance. Recording items such as operating pressures during rapid-advance, pressing and rapid-retract portions of the press cycle can provide valuable data as to press-system efficiency. Your equipment manufacturer should capture this data during equipment testing and report it to you. Ideally, record this data when the press is commissioned and refer back to it periodically. If you start to see increases in operational pressures, components may have begun to fail or are performing below optimum levels.
8. Be proactive in replacing press components. Most presses are constructed of several hydraulic components either from a single manufacturer or from multiple companies. Each manufacturer has an expected service life for each component. Replacing components proactively before a failure saves unexpected downtime and costly repairs. A hydraulic component can fail and introduce contamination into a hydraulic system–especially true for pumps. It is far easier and less costly to change out components on a regular basis than to wait for a component to fail and possibly contaminate the system.
by Michael Riehn
In this video from the how to series, Beckwood Press Company highlights a standard Inch & Semi-Auto operation for a hydraulic press. The Beckwood Press model is from their DJ Series Benchtop Press line, and includes a light curtain feature (which is demonstrated). Ryan Pendleton, from Beckwood, runs the press in both Inch and Semi-Auto Mode. In Semi-Auto Mode, he intentionally breaks the light curtain guard to show the safety feature.