Instead of replacing a press, which can be costly and time-consuming, retrofitting them might be a better solution.
Presses are hard-working machines, and many have been in service for years—some since the early 1950s. As presses age, problems can occur, and even the most robust of presses will eventually require retrofitting or replacement. The initial symptoms may simply be increased or more frequent downtime while components are replaced.
As time goes on, however, technological obsolescence may mean that the needed replacement parts no longer are available. Perhaps more importantly, as technology advances, a 1950s-era press may not be able to make parts that meet the requirements of the 21st century. Modern automotive parts are an excellent example: sheet metal used in today’s cars is significantly different from that used several decades ago, and controls from presses of that era simply do not offer the type of precision needed to create today’s intricate designs.
So why not simply replace the machine with a new one? Cost is an immediate consideration for most, especially if the plant has a good number of machines that will need to be replaced. It might also take longer to put a new machine into an established production flow, and result in more downtime than a retrofit might cause. Extrusion presses and forging presses, especially, are substantial pieces of equipment that might cause considerable disruption to facility operations if replaced outright. Of course, there are times when a new machine is the answer. But since most presses are designed for years of service, retrofitting an older machine often can bring surprisingly cost-effective benefits that can add another decade or more to a machine’s service life.
In addition to understanding the needs of the application and the company, manufacturers should analyze any available data and known pain points to make an educated decision. What are some technology choices to make when considering a retrofit? Can it be accomplished without a lot of downtime? How much of an upgrade in functionality is really needed? Can a retrofit bring older machines into the age of the Industrial Internet of Things (IIoT)?
Here are five reasons why a retrofit is both possible and cost-effective.
1. Improved performance
Technology is advancing and provides a wider range of choices than ever. In certain cases, switching from older technology may be the best move for machine performance. Upgrading the hydraulics in an existing machine from traditional hydraulics to servo-hydraulics or a hybrid system can bring a substantial upgrade in machine capability: speed control, force control, torque control, and other enhancements all come from upgrading to a servo system. Adding a servo motor to a pump to create a hybrid system can yield similar benefits.
Upgrades in linear motion technology also can bring significant benefits, especially with older presses.
For example, if a press has an older plain or solid type linear bearing, swapping the plain bearing with a modern rolling element linear bearing can improve energy efficiency drastically. Due to the design of a plain bearing, it generates surface-to-surface contact, increasing friction and the energy required to power it.
Modern ball and roller bearings offer a nearly limitless variety of options too, in precision, sealing capabilities, bearing size and shape, so it’s easy to find a suitable level of performance upgrade. Retrofitting the older components provides cost-saving benefits to the machine, extending its life significantly, and improving overall production.
For smaller presses, a technology switch from hydraulics to electromechanical technology may bring additional benefits, such as noise reductions and improved factory floor cleanliness. There’s no more hydraulic fluid to deal with, and today’s electromechanical cylinders provide high-force, precision movement with extremely quiet operation. Some cylinders use either ball or roller screws depending on the force requirements and reduce plant noise because there is no hydraulic fluid in action.
Electromechanical technology has a limited force application range, however, maxing out at around 30 tons of force. Dynamic loads during operation and the required press duty cycle might reduce this even further. While electromechanical retrofits as a replacement for hydraulics are possible in a range of applications, the power density of hydraulic drives means that most hydraulically-powered presses will stay in the hydraulics family.
But even in these high-force applications, users still have options to reduce noise. Variable speed pump drives, like Rexroth’s Sytronix pump, for example, can achieve noise reductions of up to 20 dB in machine operation. When implemented in multiple machines within a single factory, the change in operator comfort and productivity can be considerable.
2. Improved worker and machine safety
With the advancement of safety technology and additions to government safety requirements, older machinery, in its original state, may not comply with all of today’s regulations and may need to be upgraded to fit current safety standards. In simple terms, an aging machine can cause environmental and operational hazards such as oil leaks, loose wiring, or components that fail.
While it can be relatively easy to make the necessary repairs to fix those types of problems, safety technology has progressed so significantly that taking such a reactive-only approach will miss the potential for healthy productivity upgrades.
Until recently, the definition of “E-Stop” meant cutting power to a machine immediately. This proven and necessary feature not only prevents injury to the machine operator, but also protects the machine by stopping moving parts from crashing and causing further damage to the machine. Once repairs have been made, the machine is turned back on and, after a lengthy boot-up cycle, resumes operation. Safety today has advanced significantly beyond this.
Today’s safety technology eliminates the lengthy boot-up cycle by taking a much more sophisticated approach to locking out just specific aspects of the machine. Instead of having to cut power entirely, modern safety technology allows stop operation of moving parts so that the machine can be repaired safely while it is still under power. Once repair personnel have safely exited the machine, operation can resume without having to re-boot the entire machine. The time saved in waiting for the machine to reboot can result in a substantial improvement to production efficiency and increase the parts-per-minute capabilities of the machine to increase overall equipment effectiveness (OEE). Less downtime means more production.
In addition to control electronics, safety features also continue to improve in the machine componentry. Press safety blocks can be implemented into the hydraulic circuit of existing machines for added safety. Used mostly in down-acting machines, such as stamping lines, cold-forming machines and peripheral equipment, these safety blocks are retrofit-friendly components that can add a good measure of protection.
Safety always should be viewed holistically when evaluating potential for a safety upgrade. If not integrated into the machine control, even simple upgrades like the safety blocks mentioned above will be ineffective. New controls, safety blocks, and safety programmable logic controller (PLC) or input/output (I/O) technology is being developed constantly, with each bringing new safety capabilities to the manufacturing sector. All the safety features and components can be implemented, but if they are not connected to a machine safety infrastructure, they are of little value to production.
3. Reduced cycle time and operating costs
Retrofitting opens doors to many untapped possibilities. Among these are improved cycle time, previously unrealized continuous improvement process (CIP) enhancements and better safety features, as discussed above. As part of ongoing CIP, improvement in OEE is another benefit of retrofitting a machine with modern components, resulting in improved quality, productivity, and machine availability.
When considering overall production efficiency, implementing analytics is vital to understanding what is going on with existing machines. Improvements in software analytics tools allows users to look deeper into different production factors, such as equipment availability, production output, and deviation information. Such software provides a simple solution for making educated decisions about which production components parts might benefit from an upgrade or retrofit to increase OEE.
For older presses, gathering information like this is a good first step in making the decision for retrofit, and may help quantify the benefits of doing so.
As for energy efficiency, while energy costs remain relatively low in the United States, the hidden cost of energy that is wasted can add up and offers real potential for savings. In reviewing potential opportunities for retrofitting presses, always look to eliminate wasted energy first. Leaky hoses and worn components can cause the system to work harder and increase the cost of operation.
If data suggests that energy savings may be substantial if action is taken across multiple machines, explore retrofit opportunities with modern variable-speed pump drive technology. These pumps provide power at the required levels only when needed during press operation, offering energy savings of 30% to 80% during typical operation. So even if energy is cheap, retrofitting presses with the latest energy-efficient technology can still lower energy-related operating costs significantly, as well as reduce plant noise.
4. Improved process visibility
Both electromechanical and electrohydraulic technologies now frequently offer self-diagnostic and connectivity capabilities that can help manufacturers benefit from the latest industrial revolution.
Other new products specifically designed to bring connectivity to older machines also are appearing now. The technology was initially demonstrated on a lathe used by Robert Bosch himself in the 1880s. By adding sensors to key functional components and connecting back to simple hardware with a web-based interface, it’s possible to gain real value from data you didn’t think you could get.
Getting this data can turn out to be vitally important, especially when considering a larger retrofit or even new equipment. It can more clearly define a company’s perceived problem. For example, by collecting OEE data and monitoring machine performance, it might be discovered that the press is operating just fine; instead, it’s waiting for parts that are not arriving when they should. With real-time data, there is instant visibility to equipment problems or deviations: manufacturers can know what is happening within their plants anytime, anywhere. Sensors can be calibrated to monitor machine part wear or temperature and keep operators informed on individual press operations or other key production processes.
The possibilities to retrieve data and act on it are virtually limitless in today’s connected world. In fact, in a wise implementation, integrated sensors can even predict production issues before they occur and alert machine operators to take action before production is affected. Consider torque monitoring as a relatively simple example. In a press, when a screw drive starts to wear out, the motor torque required to turn the screw increases.
If the servo drive detects this increased torque, it can send an automatic notification, allowing plant operations to take action before it completely fails. This reduces the chances of downtime caused by unplanned repairs. It truly is becoming a brave new world for manufacturers. The potential for improved OEE is immense with IIoT.
5. Technology upgrades
Automation and technological innovation is moving fast. It can be hard to stay abreast of new capabilities that might give a company a competitive edge. Implementing a retrofit gives companies an inside look and hands-on experience with the latest technologies. Even simply consulting with knowledgeable experts about what might be possible can yield unexpected insights.
Implementing a retrofit is not a minor decision.
When deciding on a retrofit, manufacturing engineers and machine operators must consider which factors are critical for their unique operation to stay financially and industrially competitive—and still deliver quality product. A retrofit may even reveal other cost-effective operation upgrades, particularly considering OEE across an entire production system.
Even if a manufacturer starts small by retrofitting equipment now, when it needs to add machines, the knowledge gained from the retrofit will help assess new equipment more effectively.
Industrial presses have long been the workhorses of manufacturing, expected to run forever with little maintenance. And because many presses do just that, it’s easy to overlook opportunities for improvement, or to anticipate impending failure. But with the rapid advances in connectivity and performance in both electromechanical and hydraulic systems, there has never been a better time to consider upgrading presses via retrofit. Optimized machine functionality and additional safety features can increase throughput and OEE, and as the industry becomes more connected, manufacturers can benefit even more by taking a systematic, step-by-step approach to a more connected production environment overall. A press retrofit is the smart first step. It’s more cost-effective than replacing the entire machine and can breathe years of new life into machines once thought to be long past their prime. With the right retrofit strategy, workhorse presses might just run better than they ever have before.
For Bosch Rexroth, Brian Van Laar is a senior sales engineer, Andrew Binversie is manager for press applications, series, Nathan Davis is product manager for screw drives, Monte Swinford is regional automation manager and Ken Rayden is controls manager.
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