UNCOMPLICATED HYDRAULICS
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FITTING SELECTION FUNDAMENTALS p.14
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FLUIDLINES Mary C. Gannon • Editor-in-Chief
Taking ownership of fluid power hose safety LAST MONTH, I HAD THE OPPORTUNITY hose life, such as salt spray’s effects on fittings Tracey stressed how safety begins with to sit in on some sessions presented by the in offshore environments. the sale. “It’s OK to tell a customer no, I Hose Safety Institute of NAHAD (National The final safety discussion for the day won’t sell you an unsafe product. Nobody Association of Hose & Accessories Distribcame from Rob Williams, from Alliance Hose wants anybody to get hurt,” he said. “So utors). This hands-on training event was a & Rubber Powered by TIPCO, who discussed educating our customer when they’re doing mix of presentations, hands-on inspections the importance of visual inspections. Attendsomething the wrong way is our job. That’s of proper and improper hose assemblies, ees all sat at tables with a variety of hose the number one thing you want to come opportunities to learn from local manufactur- assemblies which they were required to away with from here. It’s to sell the safe ers and distributors, and even some games. inspect, to see if they matched their order solution, not the least expensive solution.” The event kicked off with two presenrequirements, ensure they were safe designs That same mindset should apply to every tations on STAMPED and what that term and used all the correct materials and comcomponent, even the simplest seal used to means from an industrial hose perspective ponents. ensure a leak-tight connection. Everyone and a hydraulic hose perspective. Presenters Williams kicked things off by stressing who touches a hydraulic or pneumatic comBen Tracey, Head of Product Management – the importance of proper PPE when working ponent has a role in ensuring it is properly Fluid Handling Solutions – Americas at Conwith hose assemblies. He also highlighted selected, designed, installed and maintained tiTech and Scott Bauman, Rubber Hydraulics the need for pre- and post-assembly inspec- — and in understanding how its failure could Hose & Fittings Product Manager and Prodtions to ensure safety and assembly integrity. put others at risk. uct Application Engineering Manager at Dan- Attendees evaluated assemblies based on Last month, NAHAD encouraged manfoss Power Solutions, wrapped up their edumaterial differences, attachment methods, ufacturers to take a pledge for hose safety. cational discussions with a game of Kahoot. torque ratings and more. It’s time we take that same approach across Throughout the game, attendees were In both interactive sessions, it was fluid power. Safety shouldn’t belong to one challenged with questions and images to help stressed that hose safety is not solely up person, one department or one point in the them understand what might have caused a to the person crimping and assembling supply chain. It belongs to all of us. hose failure and ensure they match the right the hose or the person who operates the hose materials with the right applications, machinery the hose is attached to. Everyone pressures, fluids, fittings and more. Questions — from engineering, manufacturing, testcovered the dangers of using incompatible fit- ing and sales to order management, shiptings and the need for proper hose assembly ping and receiving, and assembly, operation, to avoid leaks and damage. Additionally, fluid warehousing and maintenance — is responcompatibility, such as with phosphate ester sible for understanding what constitutes a hydraulic fluids, was also stressed, along with safe hose design and recognizing when a Mary C. Gannon • Editor-in-Chief mgannon@arrowfly.com the impact environmental factors have on hose is at risk of failing. FPW
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F E AT U R E S 14 INDUSTRIAL PNEUMATICS Surface protection versus holding force in vacuum handling How engineers can reduce suction-cup marks on sensitive surfaces without compromising gripping safety.
20 INDUSTRIAL HYDRAULICS Hydraulics— simple where it matters Hydraulics offers a simpler system design, with fewer parts requiring replacement and repair for industrial machinery.
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D E PA R T M E N T S 1
FluidLines
4
Perspectives
6
Design Notes
9
Energy Efficiency
10
Component Focus
12
Fundamentals
ON THE COVER
Tunnel boring machines require consistent and reliable fluid purification and filtration systems due to their complicated nature as well as the dirty and humid environments where they operate. GETTY IMAGES
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November 2026 • vol 14 no 10 • www.fluidpowerworld.com
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PERSPECTIVES Josh Cosford • Contributing Editor
Is there a sweet spot for cyber security in fluid power?
speak with you, email with you, or in any way held hostage until millions were paid to release make doing business with us easy. We need you them. to create an account on our portal and then Are there benefits to cloud computing? Sure come back and check for RFQs and purchase — mobile CRMs, shop-floor connectivity, wideorders six times per day. Don’t forget to upload area networks, and all the security features that your company’s financial statements, so when let you recover your information after a failour portal gets hacked, the criminals can hold ure or breach (yes, it's not all bad, you know). them hostage while we figure out how to get But in my opinion, the sweet spot of techback control of our ERP system.” nology was a decade ago. We had quick, effecDon't get me wrong, I don't want to go back tive email communication, secure VPNs for to the era of fax machines, and in fact, we can- accessing the ERP company-wide, and just celed all our fax lines last year (local and toll- enough online capacity to be useful. My only free lines for two companies). But are we going regret is sending my life's savings to try to too far with cloud computing? I would argue, access my inheritance from my long-lost uncle yes, because it's clear that manufacturers have in the Nigerian royal family. pushed some technologies to market to meet demand without proven security. SAP, Danfoss, Copeland, and Oracle have all seen their ecosystems hacked. The range of consequences has included thousands of pounds of rotten meat when hackers raised Josh Cosford • Contributing Editor industrial freezer temperatures, or credenjcosford@higginson.ca tials stolen from various ERP systems that were linkedin.com/in/joshcosford FPW
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I HEAR STORIES OF COMPANIES whose data is stolen, servers are held hostage, or employees are scammed, and I can't help but chuckle. Cybercrime isn't funny, but the stories of Boomers who fall for obvious flimflam can definitely be (no, not you … a different Boomer). Perhaps it's more about ease of trusting, but for me, the instinct to hover over a "Netflix Payment Link" to discover a URL that doesn't even mention Netflix yet ends in .ru is just too strong. Once bitten, twice shy. Here are some of the scams I’ve seen attempted in my time in the fluid power business world: 1. A customer’s legit email address, but asking me to "bid" on their latest project and find the details by clicking their HTML link. (Nice try, send me a PDF.) 2. An internal email from the owner of Higginson asking me to send him the company credit card details ASAP so he can pay for a tow truck. (Nice try, he was in the next office over.) 3. A request to prepay for an upcoming hotel stay. (Nice try, I already bought the “Prepay & Save” option.) I’d like to say that I don’t fall for these things because I’m a genius detective, but the reality is just a combination of experience and our IT partner who keeps us locked down like Fort Knox. We use Defender 365, Bitdefender, daily backed-up servers, 2-factor authentication, Time of Click protection, and training for office staff to spot phishing scams. And we never ever click on web links from anyone outside the company we don’t fully trust. When you stop and think about it, there is a shocking trend that I personally hate, feel is a waste of time and seems to be overlooked as an obvious vulnerability — online portals. “Oh hey, Mr. Supplier, we’re no longer going to
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FLUID POWER WORLD • NOVEMBER 2026
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From the original STAUFF Pipe Clamps to our Metric Tube Fittings and Quick Release Couplings, STAUFF offers port-to-port hydraulic solutions, components, and accessories for hydraulic systems and applications. STAUFF is your trusted source for industrial and mobile fluid power components and solutions worldwide.
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SAVE THE DATE! SICFP ’27 – The 20th Scandinavian International Conference on Fluid Power June 1-3, 2027 A Key Meeting Place for Fluid Power and Off-Road Mobile Machinery
Hosted by the IHA - Innovative Hydraulics and Automation at Tampere University/ Finland, the conference covers relevant topics of robotics, automation and digitalization through: • More than 50 scientific paper and research presentations • Industrial exhibition • Networking between international academia and industry
Sponsors and exhibitors are welcome
Learn more at events.tuni.fi/sicfp2027
DESIGN NOTES By Mary C. Gannon • Editor-in-Chief
THE COMPLICATED NATURE OF TUNNEL BORING MACHINES, AS WELL AS THE HIGHLY HUMID AND DIRTY UNDERGROUND ENVIRONMENTS IN WHICH THEY OPERATE, MEANS THEY REQUIRE CONSTANT CARE OF ALL THEIR HYDRAULIC FLUID SYSTEMS.
Keeping things underground clean and dry THE COMPLEXITY OF TUNNEL BORING MACHINES is vast. These massive machines
ensure continuous forward progress, transport excavated material, install concrete segments for tunnel lining and maintain the stability of the tunnel face. They are usually more than 100 m in length, integrating the cutterhead, trailing gear segments, conveying technology and energy supply. The available space within the tunnel cross-section is extremely limited. Tunnel boring machines can have hundreds of meters of hydraulic lines, multiple hose connections and many sealing points exposed to humid underground environments. On a tunnel boring machine, water can enter through
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ambient humidity, condensation, cooling systems, leaking seals and the many hose connections and sealing points throughout the hydraulic network. High groundwater pressure and changing temperatures can add to that exposure. “Tunnel boring machines can present a particularly demanding hydraulic environment, with long piping runs, numerous connections and seals, temperature changes and limited space for additional equipment. In many applications, these systems also operate in wet, contamination-prone underground conditions where minimizing downtime and maintenance interruptions is important,” said Simone Ortner,
Hydraulic Filtration Engineering and Product Manager, Eaton Filtration Division. Water can enter hydraulic fluid not only in dissolved form but also as free or emulsified water, which often cannot be removed using conventional filters, centrifuges or separators. Any water presents a significant risk to the operational safety of tunnel boring machines. It attacks metallic components such as valves, pumps, cylinders and piping which facilitates corrosion and causes leaks. It also degrades the lubricating properties of the fluid, increases friction and accelerates wear. Finally, it speeds up oxidative aging processes, promotes sludge and varnish formation and impairs the function
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Tunnel boring machines, which perform several operations underground, require advanced systems to ensure hydraulic systems remain dry and contaminant free.
DESIGN NOTES
of finely tuned hydraulic components. Eaton’s solution for this risk is using the IFPM 10 fluid purifier system, as it packages vacuum dehydration, degassing and particulate filtration into a compact and mobile offline unit, Ortner said. “The vacuum process is particularly important because it is designed to help remove dissolved and emulsified water, as well as free water, from the hydraulic fluid. The conditioned fluid then passes through an integrated particulate filter before returning to the tank,” she continued. “That means the IFPM 10 can address several contamination mechanisms in one process. The unit is also fully automatic and PLC controlled, which can help reduce the amount of manual intervention required during fluid conditioning.” Ortner explained the difference between contaminant filtration and water dehydration. “Particulate contamination is generally more straightforward because solid particles can be captured by a properly selected filter. Water behaves differently because it can be present as free, emulsified or dissolved water. Dissolved water is particularly difficult to control because conventional particulate filters do not remove it, and centrifuges or separators may not remove it effectively,” she said. “That is why simply adding a finer filter does not solve the whole problem. The IFPM 10 uses vacuum evaporation to help remove
free, emulsified and dissolved water, as well as free and dissolved gases. The dehydrated fluid then passes through an integrated spinon filter that retains particulate contamination before the fluid is returned to the reservoir,” she concluded. Hydraulic oil is not the only fluid that may require filtration on a tunnel boring machine, however. In many applications, closed-loop cooling-water circuits are also used to manage heat around critical components such as the cutting wheel. Because the water may be continuously recirculated through the system and a heat exchanger, it requires its own filtration approach. In these applications, bag filtration can be used to capture particulate contamination from the cooling water before it continues through the loop. Eaton Sideline 16-bar bag-filter housings may be used with 150- or 200-micron monofilament filter bags for this type of service. Depending on the system design and required availability, the setup may use a single housing or multiple housings, including a runand-standby duplex configuration that allows
one side to remain in service while the other is taken offline for maintenance. This system is often used as needed, and there is no set time on how long it can take to ensure hydraulic fluid is water free, Ortner said, because it depends on the reservoir volume, the initial water concentration, the rate at which new contamination is entering the system and the cleanliness target the operator is trying to achieve. “The IFPM 10 has a published flow rate of up to approximately 9 to 10 lpm and a water-removal capacity of up to about 3 liter per day, depending on operating conditions. Those figures can help with application sizing, but they should not be interpreted to mean the entire hydraulic system will be ‘clean’ after one reservoir turnover. Water is removed progressively as the fluid circulates through the purifier, so reaching the desired condition may require multiple cycles.” In many applications, the IFPM 10 may be used as needed rather than operated continuously. When integrated with the machine’s control system and fluid-condition monitoring, operators can use water-saturation data to help determine when purification is needed and when the desired fluid condition has been restored.
LEFT TO RIGHT: EATON SPIN-ON FILTERS, SIDELINE-SINGLE-BAGFILTER-HOUSING, IFPM 10 FLUID PURIFIER SYSTEM, AND IFPM 73 FLUID PURIFIER SYSTEM
EATON (4)
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Ortner said that offline conditioning should be viewed as a preventive reliability tool. “Oil changes can remove contaminated or degraded fluid, but they do not prevent new contamination from entering the system. A traditional kidney loop can be effective for controlling particulates, but its ability to address water depends on the technology built into the system, and a conventional filter element will not remove dissolved water. By the time fluid degradation or component damage becomes visible, wear, corrosion or oxidation may already be underway,” she said. “An offline purifier can help engineers manage fluid condition while supporting continued operation of the main system. The goal is to help keep the oil within an acceptable operating range, maintain its lubricating properties and extend the useful life of the fluid and hydraulic components. Water saturation also deserves particular attention because free water can alter fluid properties and contribute to corrosion and other damage,” she continued. “Eaton advises customers to keep water saturation below 70% to help minimize the risk of free water building up. Oil analysis, sealing and breather practices, filtration and offline purification should therefore be viewed as complementary parts of a broader contaminationcontrol strategy." There is limited space to play when it comes to
BAG FILTRATION USING EATON'S MONOFILAMENT FILTER BAGS CAPTURES PARTICULATE CONTAMINATION FROM COOLING WATER BEFORE IT MOVES THROUGH THE LOOP SYSTEM.
machines like tunnel borers, and it’s important to consider capacity versus footprint, Ortner said. Eaton’s purifier technology is available in several sizes so engineers can evaluate the sys- evolve to support more automated and datatem against both fluid volume and the available driven equipment in mining, she expects there installation space. According to published prod- will be closer integration between fluid-condiuct specifications: tion monitoring and purification equipment. • IFPM 10 provides a flow rate of up to approx- “Moisture-, particle- and oil-condition data imately 10 lpm and water-removal capacity could be incorporated into equipment mainof up to approximately 3 liters per day. tenance systems, allowing operators to identify • IFPM 33 provides up to approximately 29 contamination trends earlier and make decilpm and up to approximately 22 liters of sions based more on actual fluid condition than water removal per day. on fixed service intervals,” she said. “Over time, • IFPM 73 provides up to approximately 72 that could create a more connected process in lpm and up to approximately 54 liters of which monitoring data indicates when purifiwater removal per day. cation is needed, tracks whether fluid condiEaton also offers stationary IFPS units for tion is improving, and helps teams distinguish applications where a fixed installation is pre- between a temporary event and a persistent ferred. issue elsewhere in the hydraulic system. The Placement is another important consider- IFPM platform’s automated, PLC-controlled ation and should be evaluated for the specific operation may provide a useful foundation machine and operating environment. In general, for that type of approach. One possible direcshorter hose runs can help limit flow resistance, tion is deeper integration between purification while longer hoses can reduce the volume flow equipment, condition-monitoring sensors and rate through the purifier and affect overall effi- broader equipment reliability data.” ciency. The unit should also be positioned with operation, maintenance access and protection Eaton from damage in mind. Suction and return eaton.com points, hose routing, elevation and inlet conditions should be determined using Note: Application requirements vary, and customers Eaton’s installation guidance for the spe- should consult Eaton product literature and technical cific application. representatives to confirm appropriate product selecOrtner said that as contamina- tion, installation and maintenance practices for their tion monitoring and fluid conditioning specific equipment and operating conditions. FPW
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FLUID POWER WORLD • NOVEMBER 2026
EATON (2)
01.E PRESSURE FILTER ELEMENTS PROTECT SYSTEM COMPONENTS SUCH AS VALVES AND HYDRAULIC MOTORS.
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ENERGY EFFICIENCY Ron Marshall • Contributing Editor
Rid yourself of remote frustration with connected monitoring I HAVE SPENT MORE THAN TWO DECADES traveling from plant to plant
RON MARSHALL/AI GENERATED
performing compressed air audits, and over the years I’ve learned one frustrating truth: sometimes the hardest part of an audit was not diagnosing the system, but simply getting good data. Like many compressed air auditors, I have driven thousands of miles carrying pressure sensors, flow meters, and data loggers into noisy compressor rooms. More than once, I have returned to a plant only to discover a dead battery, a disconnected wire, or a valve that someone had accidentally closed during the test period. Entire trips were wasted. One failed logging session especially stood out. I had driven for hours to install monitoring equipment at a remote plant. Everything appeared normal when I left. But upon returning a week later, I discovered an isolation valve had been closed shortly after installation, leaving the flow meter with almost no usable data. The customer was frustrated, and we now needed to start the entire process all over again. For years, situations like this were simply accepted as part of compressed air auditing. Then cell-connected monitoring systems began changing everything. The first time I used a connected monitoring system, I immediately saw the difference. Instead of waiting days or weeks to retrieve information, I could now monitor pressure, power, flow, and compressor performance remotely from my laptop or phone. That technology quickly proved its value at a bean processing facility that had installed a new variable speed drive compressor. Minutes after startup, I noticed the pressure settings were too high, and the compressor
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TECHNOLOGY HAS CHANGED IN THE COMPRESSED AIR INDUSTRY. THERE ARE MANY NEW WAYS TO GATHER REMOTE DATA FROM A SYSTEM TO HELP DIAGNOSE PROBLEMS AND KEEP THE SYSTEM RUNNING SMOOTHLY.
was spending too much time unloaded. In the past, this problem might not have been discovered until long after I had left. Instead, I called immediately, the settings were corrected on the spot, and system efficiency improved before the project was even completed. At another meat processing facility, the remote dashboard showed that the least efficient compressor was doing most of the work while a newer VSD unit sat nearly idle. A simple pressure adjustment corrected the issue and saved the plant approximately $10,000 per year in electricity costs. The biggest surprise came from a sawmill located more than 1,200 miles away. Without leaving my office, I was able to view live system data and realize the compressors
were operating inefficiently. After guiding the maintenance team through a few control changes remotely, the plant reduced wasted energy enough to save roughly $22,000 annually. Today, I believe connected monitoring systems are transforming compressed air auditing. Problems that once took weeks to discover can now be identified in minutes. For auditors, service providers, and plant personnel alike, these systems mean faster troubleshooting, lower operating costs, and fewer surprises. FPW
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COMPONENT FOCUS Josh Cosford • Contributing Editor
IMAGINE DRIVING YOUR CAR AROUND with fixed wheels and no suspension. If it weren’t for the pneumatic tires, it would feel like riding across the grocery store parking lot in a shopping cart. Not only would the ride quality shake the stones from your kidneys, but it would also shake the nuts from your Johnson Rod, if so equipped. Indeed, your vehicle wouldn’t get very far down the road before impacts and instantaneous forces made quick work of wheels, seat frames, and everything in between. Springs help absorb shock, but also store much of the energy absorbed, only to release it immediately in the opposite direction. The resulting oscillations are often benign, but they reduce precision and increase cycle times in applications that require predictability and repeatability. Shock forces occur in fluid power systems, especially in air and hydraulic cylinders capable of high velocity, as well as in the parts of machinery powered by them. Most manufacturers offer cushions on their air and hydraulic cyl- sure drop. Many shock absorbers can be tuned inders, which act to rapidly decelerate the load by adjusting the orifice size or switching to a difby forcing hydraulic fluid through an orifice over ferent size. Motion applied to a shock absorbthe last inch or so of piston travel. However, in er's piston forces pressurized fluid through spemost cases, cushions operate only over the last cially designed internal orifices. That restricts inch or so of travel and may not have enough flow and generates heat which, in turn, transtime to decelerate the load safely. fers to the metal body and dissipates to the enviThe ideal shock absorber slows machine ronment. movement at positional extremes to spread When applications such as presses, highforces out over time, lowering peak forces by speed automation, robotics, or material hanconverting inertia into heat. Engineers must dling experience high shock loads, those forces calculate an ideal maximum g load based on can damage bearings and bushings, stress strucmass, velocity, and fragility of the equipment, tural components, and pose personal injury risk. and then select shock absorbers to achieve the The strain of high impact forces is transmitted appropriate damping. through connecting points, pivot joints, fastenShock absorbers, also called dampers, are ers, and welds, slowly degrading them through essentially linear braking systems. They convert mushrooming, fissuring, or material fatigue. linear motion energy into heat by pushing fluid Shock absorbers are available in various force through an orifice. The smaller the orifice, the capacities, lengths, and damping rates, providmore rapid the damping due to increased pres- ing solutions for everything from small material-
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FLUID POWER WORLD • NOVEMBER 2026
handling carts to multi-ton coil cars. The ideal shock absorber selection should decelerate the load over the entire stroke length, which should be factored into machine cycle times. Shock absorbers allow higher-speed operation that would be limited when the machine deadheads against stops or when the cylinders bump into their heads and caps, both of which are options that reduce machine life. With such disregard for machine function, you can also expect terrifying noises and reduced safety. If you're experiencing shock loads on your machine, explore the various shock absorbers available. They often look like miniature cylinders and are available in various mounts to suit any machine, including rigid, trunnion, or clevis styles. Shock absorbers not only improve machine performance but also extend machine longevity, so be sure to specify them for your demanding applications. FPW
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DON’T MISS OUR DESIGN GUIDE LIBRARY!
Fluid Power World’s Design Guide library features a variety of downloadable resources to help educate you on fundamental hydraulic and pneumatic technologies and components.
Design Guide: Preventing Failure in Your Fluid Power Systems Failure is a term that no engineer or technician wants to hear. Reliable uptime is crucial for every system and machine. In this design guide, we highlight key system prime movers as well as accessories that fail. Here, you will learn to recognize some of the signs of systems that are at risk of failing, how to diagnose them, and how to prevent them from failing in advance.
Design Guide on Pneumatic Cylinders Pneumatic cylinders use compressed air to produce linear motion. They consist of a cylindrical chamber, a piston, and a rod, and convert energy from compressed air into mechanical force. Learn about the many types, including single-acting, double-acting, and rotary cylinders, that are used in industrial automation and motion control applications.
Design Guide on Metric Fittings Many different standards of fittings exist throughout the world — JIC, O-ring face seal, BSP, JIS, and more. Metric hydraulic fittings connect hydraulic hoses, tubes, and pipes to pumps, valves, and other hydraulic components. Learn where they’re used and how to specify them.
Design Guide on Symbology Building Blocks Hydraulic symbology is a standardized system of symbols used to represent the components and functions of hydraulic systems. These symbols provide a clear and universal way to communicate the design, operation, and flow of hydraulic circuits. Here, we build upon basic elements and shapes to discuss the most common components in a hydraulic system.
Design Guide on Hydraulic Filtration Filtration quality is the single most important measure of hydraulic machine health. More hydraulic failures are a result of particle contamination than any other cause. To effectively apply filtration, it is important to know the size, location and quality. Learn more on this critical system technology.
Design Guide on Hose Safety Hose Safety Hose safety is Resource critical in our industry, as it accounts for some of the most dangerous and life-threatening injuries in industrial operation. This design guide curates a selection of articles dedicated to designing safe hose assemblies, maintaining them, and special tools and accessories that keep them secure and reliable. September 2026
Visit www.fluidpowerworld.com/category/design-guides/ to learn more and download these helpful resources now!
FUNDAMENTALS By Ryan Stacy • Senior Director of Marketing & Product Management, Alkon Corp.
Fitting selection fundamentals: how small connections protect pneumatic system performance FITTINGS RARELY DRAW ATTENTION when ducted in accordance with SAE J2494-3. functioning appropriately, holding airline presThe fitting also needs to match the type of sure, keeping tubing secure and allowing cyl- fluid power system it supports. Pneumatic sysinders and actuators to respond predictably. tems move air, while hydraulic systems move That changes when a leak or connection issue liquid under pressure. Even when connections interrupts operations. Technicians may spend look similar, the performance requirements are valuable time tracing lines through an entire not always interchangeable. assembly to identify the source. From there, the issue can turn into rework, delayed pro- Evaluate pressure, temperature, and duction, service calls, or equipment that can- material compatibility not perform as intended. The application sets the demands. The fitting’s In regulated, sanitary, and safety-critical ratings and materials determine whether it can environments, the consequences reach even meet them. further. Warranty exposure, failed inspections, Pressure and temperature ratings define the legal liability, loss of customer trust, and safety fitting’s working range. For example, Alkon’s risks can all trace back to a connection point standard brass DOT push-to-connect fittings that was treated as a minor detail. are rated for 150 psi maximum pressure and Addressing fitting selection earlier in the a temperature range of –40° to 220°F. Those design process helps prevent those issues values give engineers and purchasing teams a from reaching the production floor, the field, useful starting point, but ratings alone do not or the road. determine whether a fitting is right for the job. Certain operating conditions require Understand the system and changes to the standard fitting configura-
A push-to-connect fitting relies on the tubing to complete the connection. The tubing must fit securely within the fitting and provide a consistent sealing area for the O-ring. Its dimensions, shape, and condition therefore play a
Pneumatic fittings used in industrial automation, packaging and processing equipment, and mobile air systems are often asked to do the same basic job under very different conditions. In a protected industrial setting, clean routing, repeatable assembly, and pressure stability may drive the decision. Packaging and processing environments can introduce external exposure to washdown, cleaning agents, chemicals, oils, lubricants, and sanitary requirements that affect material and seal selection. Mobile equipment brings its own exposure, including vibration, road spray, moisture, temperature swings, debris, and corrosion risk. Because of these operating demands, fittings used in air brake applications must be designed to meet the federal performance requirements of FMVSS 49 CFR 571.106, with testing con-
ALKON DOT PUSH-TO-CONNECT FITTINGS ARE ENGINEERED TO SUPPORT RELIABLE CONNECTIONS IN DEMANDING MOBILE AIR BRAKE APPLICATIONS.
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FLUID POWER WORLD • NOVEMBER 2026
Consider the role tubing plays
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ALKON CORP. (2)
surrounding environment
tion. When temperatures exceed the range supported by standard NBR seals, the fitting requires an O-ring material rated for higher temperatures, such as Viton. In vacuum systems, a standard fitting without tube support will not suffice. Adding a tube support prevents the line from collapsing when vacuum is applied. Material choice carries the same weight. Brass is widely used across pneumatic applications because it offers durability, machinability, and corrosion resistance. Sanitary or specialized environments may require stainless steel. Simply adding nickel plating to a standard brass fitting can provide an economical way to increase corrosion resistance.
CUTAWAY VIEW OF AN ALKON DOT PUSH-TO-CONNECT FITTING, SHOWING PROPER TUBE INSERTION AND INTERNAL COMPONENT ALIGNMENT FOR A SECURE CONNECTION.
direct role in preventing leaks and maintaining the integrity of the line over time. Details such as outside diameter, wall strength, and flexibility influence how well the tubing engages with the fitting. In fast assembly environments, bias-cut tolerance minimizes leak risk from imperfect tube cuts while allowing OEMs and installers to maintain speed and consistency. Vacuum applications require separate consideration. Under negative pressure, unsupported tubing may collapse and restrict flow. A support tube may be required to keep the passage open, while a stiffer tubing material can provide additional resistance to collapse. Routing is another area where the tube and fitting need to be evaluated together. Sharp bends, confined spaces, and moving components place added stress on the assembly. Fitting designs with tighter-routing capability or floating support create cleaner paths, reduce labor, and keep unnecessary strain away from the pneumatic line.
Design around installation and service
Installation requirements are another key consideration when selecting the proper fitting for an application. Assembly teams must be able to reach the port, tighten the fitting, confirm orientation, and verify the connection without adding unnecessary handling or rework. Fitting configuration affects both assembly efficiency and service access. A straight fitting may work in one design, while another layout may require an elbow, swivel, compact body, nonstandard thread, or custom configuration. Beyond shape and orientation, the internal design of the fitting also affects serviceability. Deep gripping teeth keep the tube secure during use, while a controlled release design allows maintenance teams to disconnect the line when service is needed. Error proofing also improves build consistency. The supplier can factory-assemble the
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fitting on the mating valve, cylinder, or manifold, removing one production step for the OEM and lowering the chance of improper installation. In high-volume production, those small gains protect more than assembly time. Fewer leaks at startup, fewer service calls, and less troubleshooting all preserve confidence in the finished equipment.
Look beyond the D.O.T. mark
Fittings used in air brake and air suspension systems should be designed and tested to FMVSS 49 CFR 571.106 and SAE J2494-3 standards. The D.O.T mark matters, but it is not the whole story. Manufacturers generally certify their own compliance, meaning every claim is not independently validated before a fitting reaches the market. That is why buyers must know who made the part, what test data supports the compliance claim, and whether documentation is available. A compromised connection can cause air loss, failed inspections, warranty claims, and serious safety concerns. Saving a few cents on a fitting can quickly lead to thousands of dollars in downtime and repairs, along with damaged equipment and legal exposure. Beyond the immediate costs, one failure can undermine a company’s hard-earned reputation and customer trust. Documented test results give the DOT marking credibility. Leak performance, vibration resistance, corrosion resistance, burst performance, and tensile strength demonstrate the fitting’s ability to withstand harsh on- and offroad vehicle conditions.
Choose a fluid power partner, not just a part number
A strong fluid power partner brings more than inventory. The right supplier understands that
the fitting must match the surrounding pneumatic components, pressure requirements, assembly process, and service expectations around the equipment. However, that knowledge should be paired with dependable delivery, promised performance, and responsive technical support. North American manufacturing gives OEMs a shorter path to answers, stronger quality control, and less exposure to overseas delays. When a component is stuck at sea, it is not just a supply chain issue. It can leave equipment incomplete, delay delivery dates, and frustrate customers waiting on the finished product. For Alkon Corp., engineering expertise and a full-system approach bring fittings, tubing, valves, cylinders, and controls into one fluid power offering. That gives customers one source for components selected with the larger pneumatic assembly in mind, not isolated parts chosen one at a time. Dependable equipment starts with dependable partners behind the parts.
Specify with the whole system in mind
Fitting selection should not be treated as a final detail once the larger design is already set. The earlier it is considered, the easier it becomes to account for the way the connection will be built, used, serviced, and supported. A fitting may match the port, but still create issues if the tubing is not compatible, the material is wrong for the environment, the release mechanism is hard to access, or the supplier cannot provide the documentation the application requires. When fittings are specified with that level of intention, they do more than complete an air line. They give OEMs, installers, and end users greater confidence in every connection the equipment depends on. FPW
Alkon Corp. alkoncorp.com
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Surface Prot vs. Holding F Vacuum Han 14
FLUID POWER WORLD • NOVEMBER 2026
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INDUSTRIAL PNEUMATICS
How engineers can reduce suctioncup marks on sensitive surfaces without compromising gripping safety By Kevin Lai, EUROTECH Vacuum Technologies
tection V Force in ndling ADOBE STOCK
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ACUUM GRIPPING IS USUALLY DESIGNED AROUND HOLDING FORCE, cycle time and reliability. But when the workpiece is glass, coated metal, painted panels or another appearance-critical surface, the contact itself becomes an engineering variable. Reducing visible marks can require changes in material, maintenance, motion and even the interface between cup and workpiece — and every change must be checked against the available holding-force margin. Vacuum suction cups are attractive grippers because they are simple, fast and adaptable. In many applications, the design question is straightforward: can the selected cups generate enough force to hold and accelerate the workpiece with an appropriate safety margin? For surface-sensitive products, however, successful grip-
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INDUSTRIAL PNEUMATICS
ping has a second requirement. The part must arrive without a visible contact pattern, transferred contamination or unnecessary cleaning. The issue is familiar in glass handling, but it is not limited to glass. Painted sheet, coated panels, polished metal, decorative plastics, appliance surfaces and other finished components can all reveal a ring, haze or local change in appearance after contact with an elastomer cup. The result may be cosmetic only, yet it can still create rework, cleaning, inspection or rejection costs. The engineering challenge is therefore not simply to maximize vacuum. It is to achieve sufficient and stable holding force
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while controlling what happens at the contact interface.
WHY SUCTION-CUP MARKS OCCUR A visible mark does not necessarily indicate that the cup has damaged the surface. Depending on the application, the appearance may result from a combination of elastomer characteristics, surface contamination, local pressure, friction and relative movement. The same cup may perform cleanly on one material and leave a visible pattern on another. • Elastomer and surface interaction: Different elastomers have different hardness, friction behavior and formulation.
•
•
•
A sensitive coating may reveal contact that is invisible on ordinary float glass or unfinished sheet. Contamination: Dust, process residues, oil, cleaning agents or material transferred to the cup can be redeposited on subsequent workpieces. Cup condition therefore matters as much as cup material. Wear and surface condition: A worn sealing lip or roughened contact face can change the real contact area and increase localized friction. Vacuum level and contact pressure: Higher differential pressure increases the force drawing the cup and work-
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EUROTECH (2)
EUROTECH’S MTC MICROPERFORATED COVER FITTED TO A SUCTION CUP.
INDUSTRIAL PNEUMATICS
•
piece together. More vacuum is not automatically better if the application already has adequate gripping margin. Micro-sliding: Acceleration, deceleration and lateral loading can create small relative movements at the interface. On a visually sensitive surface, repeated micro-sliding can make a contact pattern more noticeable.
SUCTION CUPS CAN LEAVE RINGS, HAZE OR OTHER APPEARANCE CHANGES AFTER HANDLING GLASS, PAINTED SHEET, COATED PANELS, POLISHED METAL, AND OTHER FINISHED COMPONENTS.
START WITH THE HOLDING-FORCE REQUIREMENT Before changing the contact interface, engineers should establish the force the gripping system actually needs. For an idealized cup on a sealed surface, the theoretical normal holding force is governed by the pressure differential and effective suction area: F = Δp × A where F is theoretical holding force, Δp is the pressure difference between atmospheric pressure and the pressure inside the cup, and A is the effective suction area. Real systems require additional allowances for orientation, acceleration, leakage, surface condition, cup geometry and a suitable safety factor. Example
Effective diameter
Vacuum level
Theoretical force*
Direct contact
100 mm
-0.70 bar
≈ 550 N
With permeable 100 mm -0.50 bar ≈ 393 N interface *Illustrative calculation only: F = Δp × A using a 100 mm circular area. Actual usable force must be determined for the real cup, workpiece, motion and safety requirements.
1.
2.
3. This simplified example illustrates the central trade-off rather than a typical or guaranteed vacuum loss. If, in a particular tested system, an interface layer caused the achieved vacuum to fall from -0.70 to -0.50 bar, the theoretical force would fall by roughly 29% before any other system losses were considered. The actual change in vacuum cannot be assumed in advance: it may vary substantially with suction cup design and size, workpiece material and surface finish, interface fit, vacuum source, flow capacity and operating conditions. A sur-
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face-protection measure is therefore part of the gripping-system design, not an accessory that can be added without applicationspecific testing and validation.
REDUCE MARKING BEFORE ADDING ANOTHER INTERFACE A protective layer can be useful, but it should not be the first response to every marking problem. Several lower-complexity checks can resolve or reduce the issue while preserving the original pneumatic performance.
4.
5.
6.
Confirm that the cup material and hardness are appropriate for the workpiece and process environment. Inspect sealing lips and contact surfaces for wear, embedded particles and residues. Review cleaning methods for both the cup and workpiece; aggressive or incompatible cleaners can create new problems. Check whether the system is using more vacuum than required for the load and safety margin. Review acceleration, deceleration and lateral motion. A cup that holds statically can still experience micro-sliding during a fast cycle. Verify cup quantity, spacing and load distribution so individual cups are not unnecessarily overloaded.
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VACUUM LEVEL IS ONLY ONE PART OF THE CHECK A vacuum gauge reading alone does not prove that a modified gripping arrangement is safe. Engineers should evaluate the complete handling sequence. A practical validation should include the worst expected workpiece, the actual cup arrangement, the intended motion profile and the lowest acceptable vacuum condition. • Measure the vacuum level at the cup under representative operating conditions, not only at the pump. • Confirm that the vacuum source has sufficient flow capacity to accommodate any additional leakage. • Recalculate available holding force using the measured pressure differential and effective cup area. • Apply the required safety factor for the handling direction and application. • Test acceleration, deceleration, vertical lifting and any lateral movement that creates shear loading. • Verify behavior as the cup and protective interface age or become contaminated. • Define inspection and replacement intervals based on the process rather than waiting for visible failure.
required force in either orientation. This distinction is especially important when the objective is to reduce surface marking. Lower friction at the interface may be desirable cosmetically, but in a vertical or highly dynamic application it can also reduce resistance to shear. Engineers should therefore avoid evaluating surface protection and holding force as independent variables.
DESIGN FOR THE PROCESS, NOT THE MAXIMUM VACUUM Vacuum handling is often treated as a binary condition: either the part is held or it is not. Surface-sensitive automation benefits from a more balanced approach. The goal is not necessarily the highest possible vacuum level, the softest possible contact or the lowest possible friction. It is a controlled operating window in which the part is held reliably and the finished surface remains acceptable.
ORIENTATION AND MOTION CHANGE THE PROBLEM The same workpiece can impose very different demands depending on how it is handled. In a horizontal lift, gravity primarily acts normal to the cup face. In a vertical orientation, gravity acts parallel to the surface and the system relies much more heavily on friction to resist sliding. Dynamic acceleration can further increase the
MTC MICRO-PERFORATED SUCTION CUP COVER USES A THIN, PERMEABLE NONWOVEN MATERIAL FITTED OVER THE SUCTION CUP TO HELP REDUCE DIRECT TRANSFER FROM THE ELASTOMER AND MAKE THE CONTACT SURFACE EASIER TO MANAGE ON GLASS, COATED MATERIALS AND OTHER APPEARANCE-SENSITIVE WORKPIECES.
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EUROTECH
USING A PERMEABLE PROTECTIVE INTERFACE When direct elastomer contact remains undesirable, one engineering approach is to place a thin permeable interface between the suction cup and the workpiece. The interface separates the elastomer from the finished surface while allowing air to pass through so that vacuum can still be established. One practical implementation of this principle is the MTC micro-perforated suction cup cover, originally invented and patented by euroTECH Handling GmbH. Designed for applications where reducing direct elastomer contact is desirable, the cover uses a thin, permeable nonwoven material fitted over the suction cup. In suitable applications, this approach can help reduce direct transfer from the elastomer and make the contact surface easier to manage on glass, coated materials and other appearancesensitive workpieces. Because every combination of suction cup, workpiece surface and vacuum system behaves differently, however, the resulting vacuum level and holding performance should be established by testing on the actual application before the cover is adopted for production use. The important engineering point is that permeability also introduces an intentional leakage path and flow resistance. The resulting vacuum drop is not a fixed characteristic that can be applied universally. It can differ with suction cup type and diameter, elastomer geometry, workpiece material, surface texture or coating, cover fit, vacuum source, hose and valve restrictions, and available flow. Even two applications using the same cover may therefore produce different vacuum readings. Published or example values should be treated only as reference points; the achieved vacuum and holding capacity must be measured and validated on the user’s actual system.
INDUSTRIAL PNEUMATICS
That operating window can be widened through appropriate cup selection, good maintenance, controlled motion, sufficient vacuum flow and, where necessary, a protective interface. Any change that improves one side of the problem should be checked against the other. A cleaner contact is only an improvement if the remaining gripping margin is still adequate.
ADOBE STOCK
A PRACTICAL ENGINEERING WORKFLOW 1. Define the surface requirement. Identify what constitutes an unacceptable mark, residue or cosmetic change. 2. Establish the load case. Record mass, orientation, acceleration, cup quantity and required safety factor. 3. Measure the existing system. Record vacuum at the cups and inspect actual contact conditions. 4. Address maintenance and motion. Eliminate contamination, wear and unnecessary sliding before changing the interface.
5. 6. 7.
Evaluate the protective measure. If a permeable interface is used, measure the resulting vacuum level and leakage. Recalculate and test. Confirm adequate holding force under worst-case dynamic conditions. Standardize the result. Document cup condition, vacuum limits, inspection intervals and replacement criteria.
CONCLUSION For surface-sensitive workpieces, suction-cup selection is not only a question of whether a gripper can lift the load. The condition in which the part arrives matters as well. Marks can originate from material interaction, contamination, wear, pressure and micro-sliding, and the best solution is often a combination of pneumatic and mechanical adjustments. A permeable protective interface can reduce direct elastomer contact, but it changes the vacuum circuit and may reduce the available pressure differential. The magnitude of that change is application-specific and should not be inferred from a generic percentage or from another installation. Suction cup geometry and material, workpiece surface, vacuum generation and available flow can all affect the result. Users should therefore measure the achieved vacuum and verify holding performance on their own equipment under representative and worst-case conditions before production use. The most robust solution is one that treats surface quality and gripping safety as two requirements of the same vacuum-handling system. FPW
EUROTECH eurotech-vacuum-technologies.com/ vacuum-suction-cup/suction-cup-covers
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INDUSTRIAL HYDRAULICS
STEEL MILLS ARE AN EXTREME EXAMPLE OF AN APPLICATION WHERE YOU WANT THE ACTUATOR TO BE SIMPLE AND RUGGED.
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INDUSTRIAL HYDRAULICS
FIGURE 1: HYDRAULIC CYLINDERS HAVE ONLY ONE FORCE TRANSMITTING MOVING COMPONENT, THE PISTON, MAKING THEM HIGHLY TOLERANT OF SHOCK LOADS.
HYDRAULICS— SIMPLE WHERE IT MATTERS Hydraulics offers a simpler system design, with fewer parts requiring replacement and repair for industrial machinery. By Jacob Paso, President, Delta Motion | Photos courtesy Delta Motion
F
OR LINEAR MOVEMENT in demanding applications, hydraulics are often the best choice by far. The reason: hydraulic cylinders, the prime mover of the system, are inherently simple and rugged. They have one moving part — the piston rod assembly — that is cushioned by the hydraulic fluid. This is why hydraulics can withstand high shock loads (Figure 1). Electromechanical systems are also an option for machine motion. For simple rotary motion, 3-phase ac induction electric motors are amazing — one critical moving part and efficiencies as high as 97%. However, to get variable linear motion out of an electric motor, things get more complicated.
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Most solutions rely on converting from rotary to linear motion using some type of gear train (Figures 2 and 3). To achieve high-performance closed-loop motion, both hydraulic and electromechanical systems require additional components. In the case of industrial hydraulic actuators, you need a valve to control the flow of oil in and out of the cylinder, a position feedback sensor, and a source of pressurized hydraulic fluid, commonly referred to as a hydraulic power unit (HPU). For precise control of the electric version, commonly called an electromechanical actuator (EMA), a servo motor and drive are needed along with a position sensor.
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FIGURE 2 (ABOVE): ELECTRIC CYLINDERS HAVE MULTIPLE FORCE TRANSMITTING MOVING COMPONENTS, MAKING THEM MORE SUSCEPTIBLE TO WEAR AND PROVIDING VERY LITTLE TOLERANCE FOR SHOCK LOADS. FIGURE 3 (LEFT): CLOSE-UP OF A PLANETARY GEAR MECHANISM. FORCES ON THE CYLINDER ARE APPLIED TO THIS GEAR TRAIN.
HYDRAULICS TAKES THE ADVANTAGE For industrial applications, it is important to consider where these additional components must be placed. For optimum control of the hydraulic system, the valve must be placed on or near the cylinder, and the position feedback sensor is often placed within the cylinder (a well-protected environment). Other components, such as the HPU, can be located remotely and do not need to take up space in the machine at the location of motion. This results in an actuator with an incredibly high ratio of power to space and mass. This is especially important if the entire actuator itself needs to move and is often very helpful in keeping as many components out of the working environment as possible. Hydraulic actuators tolerate hot environments and generate only a modest amount of heat at the actuator. Much of this heat is then carried away by the hydraulic fluid where it can be cooled in a controlled environment. With EMAs, a motor needs to be directly attached to the geartrain, resulting in more components placed in the “dirty” environment. In addition, in order to keep wiring costs down, the servo amplifier (motor drive) is often also included. The EMA system must be rated for the peak load, and
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for sustained loads, the duty cycle rating of the motor must be considered. With EMAs, force is proportional to current through the motor, and power dissipation is proportional to the square of the current. Due to this, the efficiency of electric motors decreases significantly in applications that require maintaining significant force. These factors result in an actuator that is often much larger and heavier than the hydraulic equivalent. In applications featuring cascaded axes (where one actuator moves another), the added mass of the EMA system increases the load on the primary actuator, requiring it to be even larger. Thermal management is another major design constraint. EMAs inject a lot of heat into the local environment, and they are also highly susceptible to ambient heat. Motors and drives can be limited by temperature, forcing a change to even larger motors or implementing exotic cooling systems.
In addition to their simplicity, ruggedness, and compactness, another advantage of hydraulic cylinders is their serviceability. Because the cylinder itself is mechanically simple, many wear components, such as seals, wear rings, and rod guides, can be inspected and replaced without replacing the entire actuator. Cylinders can often be rebuilt or refurbished multiple times over their service life, while other hydraulic components can be serviced or replaced individually. This can be especially valuable in demanding industrial applications where equipment is expected to remain in operation for decades. Electromechanical actuators contain many force transmitting components, including screws, nuts, bearings, and other mechanical elements that are subject to wear. When these internal components wear or become damaged, repair can be more involved and may require specialized service. In some designs, replacing the complete actuator may be more practical than rebuilding it. This can increase both replacement cost and downtime, particularly when compared with a hydraulic cylinder that can often be rebuilt and returned to service.
BRINGING HYBRID INTO THE PICTURE When considering hydraulic versus electric linear actuators, there is a hybrid option — an electric motor driving a hydraulic pump that directly controls a cylinder. These systems offer the shock absorbing capabilities of hydraulics and, in some applications, much higher efficiencies because there is no hydraulic valve.
FIGURE 4: THE SERVO MOTOR DRIVING THE ELECTRIC CYLINDER NEEDS TO BE PART OF THE ACTUATOR. THE DRIVE CAN BE REMOTE, BUT THAT ADDS TO THE WIRING COSTS.
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INDUSTRIAL HYDRAULICS
AMPELMANN
FIGURE 5: THE MOVING PARTS ON AN ELECTRO-HYDROSTATIC 6DOF SYSTEM CAN BE VERY LARGE.
However, these hybrid systems (sometimes called electro-hydrostatic actuators) are complex and expensive and add even more size and mass to the actuator itself (Figure 5). For multi-axis applications, such hybrid systems incur the pump, motor, drive, and geartrain costs for each axis, whereas for standard hydraulic cylinders, the motor, drive and pump of a single HPU is shared by multiple axes. Hybrid systems also cannot achieve the same precise and dynamic control as a traditional valve-controlled hydraulic cylinder. A motor and pump cannot respond as quickly as the small spool in a valve responds. The pump, geartrain and other hydraulic components of a hybrid system all introduce backlash or other nonlinearities that can degrade control.
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In some cases, the benefits of hybrid systems outweigh the drawbacks. For example, in machines with large power usage, usually a combination of high speed and high force at a high duty cycle, the energy savings can be significant. But for most applications involving high shock loads, or where it is important to minimize the actuator size or where it is advantageous to minimize the number of components exposed to the environment (think steel mills), standard hydraulic cylinders are a great choice. Hydraulic fluid, because of its slight compressibility, is especially well-suited to pressure and force control. This can be achieved with pressure sensors on the cap and rod end of the cylinder, fairly well-protected
from the actual machine motion, or via a load cell, which provides higher accuracy but presents environmental exposure and wiring challenges. Hybrid systems can also provide force control via two pressure sensors, although the backlash and nonlinearities mentioned earlier prevent them from achieving the same precise control as a standard cylinder. Electromechanical systems typically use either motor torque, which is subject to geartrain friction, or an external load cell. In this age of electrification, digitalization, smart manufacturing, and AI, standard hydraulic systems are sometimes mistakenly sidelined as not being electric or being old and outdated. However, in a factory setting, they are indeed electric because the primary mover is an electric motor. Modern hydraulic systems also employ precise position, pressure, and force sensors, and motion controllers with advanced algorithms connected to factory systems, providing a large amount of data on the manufacturing process. They are certainly worthy of their place in modern manufacturing. There are applications where the risk of leaking hydraulic fluid is too great to tolerate, and there are rare cases where the magnetic fields or electrical “noise” generated by EMA systems are problematic. These specialty cases are beyond the scope of this article. Delta Motion’s RMC controller can connect to hydraulic, electric, and hybrid systems and can precisely control both position and pressure or position and force with one actuator. Which system you choose depends on the machine requirements. With their simplicity and unmatched energy density, shock and vibration tolerance, and high precision, hydraulic cylinders certainly have a prominent place in any machine designer’s toolbox. FPW
Delta Motion deltamotion.com
NOVEMBER 2026 • FLUID POWER WORLD
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September 20–22 | M Resort Las Vegas Join engineers, technical leaders, and editors for a focused event on AI systems moving from experiment to engineering practice.
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