Reverse Engineering: Replacing Old Rubber Parts with New Sealing Solutions

Reverse Engineering

What happens when a search for old rubber parts doesn’t deliver results? Engineers have options.

Do you need an industrial rubber product from a supplier that’s no longer in business? Maybe you need a rubber part that’s become obsolete instead. If you can’t get the rubber products that you need, it might be time to reverse-engineer them. Reverse engineering, or back engineering, is the process of reproducing a part such as a gasket based on a detailed examination of its composition and construction.

Reverse engineering may seem straightforward enough, but there’s plenty to think about here. For starters, how much do you really know about the drawing or part sample that you have? Is the information accurate, current, and complete? Let’s take a closer look at what engineers need to ask themselves when it’s time to replace old rubber parts with new sealing solutions.

Do you have a part drawing?

Sometimes, all that an engineer has to work with is a vague drawing or a page from an old catalog. This isn’t optimal, but it’s a start. By partnering with a rubber fabricator who provides design assistance, you may be able to discern additional details. You’ll also need to determine part dimensions and materials of construction. Elastomers like EPDM, neoprene, and polyethylene have different properties – and prices.

Are the callouts current?

Part drawings and old catalog pages may contain callouts that are no longer valid. Some standards are updated more frequently than others, but ones that are decades old are probably out-of-date. With a rubber part from the 1950s, for example, a callout for lead paint won’t meet today’s environmental requirements. Military standards from the analog age don’t account for digital technologies either.

If you have a sample part, what do the tolerances tell you?

Tolerances are allowable variations in physical dimensions. For engineers who are used to working with metal components, it’s important to understand that the tolerances for rubber parts aren’t as tight. With older rubber products, it’s also worth appreciating that a sample part could be at either the high end or the low end of a range of allowable tolerances. Temperature can change a rubber part’s dimensions, too.

Are you willing to pay for reverse engineering and tooling?

Reverse engineering can be expensive if you need to pay an extruder to create custom tooling. That’s why order quantities are so important. If the quantities you need are low, spreading your tooling costs across a small number of gaskets probably isn’t cost-efficient. Even if a vendor supplies the minimum order quantity (MOQ) that you need, the price for extrusions could be too high.

Can you update the part with a standard product?

Fortunately, engineers have options. You could update the part design and use a newer, standard product instead. For example, is there a catalog part that could meet your requirements? If so, you might like to know that Elasto Proxy keeps 700 standard profiles in stock and also provides custom fabrication services. Because we use water jet equipment, there aren’t any tooling costs during cutting either.

Are you ready to proceed?

Now that you’ve asked and answered this series of questions, are you ready to replace old rubber parts from suppliers who are no longer in business? Do you need to source replacements for obsolete parts instead? Either way, you’ll find that Elasto Proxy combines design assistance, help with material selection, and water jet cutting with value-added services that can ease the pain in your supply chain.

Would you like to learn more? Then contact Elasto Proxy.

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Adhesive Taping for Industrial Rubber Products

Adhesive Taping

Adhesive taping speeds installation, but you’ll need to select the right tape and the right fabricator.

What’s the best way to attach industrial rubber products like gaskets, edge trim, and weather-stripping to glass, plastic, or metal surfaces? Mechanical fastening is reliable, but it’s also time-consuming. Adhesive taping can speed assembly, but you’ll need to select the right tape and then fabricate it efficiently.

In this article from Elasto Proxy, you’ll learn about the advantages of adhesive taping. You’ll also learn how to select the right high-strength tape for your specific application. By choosing taped gaskets for sealing and insulation, you can save time and money during assembly operations.

Adhesive Taping Advantages

Adhesive taping provides faster installation times than plastic pins, which require drilling a hole for each pin and then pushing the pins through. Adhesive taping is also a plus when space is limited. Products such as acrylic foam tapes are compressible and can provide cushioning, noise control, and vibration resistance.  By comparison, mechanically-fastened assemblies can loosen over time and cause noise and vibration.

Adhesive tapes provide strong, reliable bonds and can expand or contract with changes in temperature. Stress dissipates throughout the tape’s core and isn’t just concentrated at the bond line. By contrast, stress in screwed joints concentrates in the screw’s threaded portions. Under variable load conditions, these threaded sections are especially vulnerable.

Adhesive tapes also conform to surface irregularities. Glass, plastic, and metal surfaces remain clean and smooth since there aren’t any raised areas with bolts, pins, or screw heads. Adhesive taping also provides engineers with a variety of options. For example, you can choose gasket tapes that provide temporary or permanent fastening, or that can withstand indoor or outdoor conditions.

Adhesive Tape Types: HATS and PSA

Adhesive tapes for rubber gaskets typically use either a pressure-sensitive adhesive (PSA) or a heat-activated taping system (HATS). PSA tapes can be single-sided or double-sided. Some use a high-performance adhesive for high tack and peel resistance. Installers like PSA tapes because assembly involves removing a release liner, positioning the rubber product, and applying hand pressure.

HATS tapes use heat and curing so that the tape and gasket are fused together. HATS high-bond tapes are a good choice for door seals that might otherwise come apart from repeated pushing on the door assembly. These gasket tapes also feature strong stress-handling and weather-stripping capabilities for outdoor use. In mobile equipment, they can dampen vibrations and provide a quieter ride.

During adhesive tape selection, engineers need to consider all of their application requirements. For example, do you need a gasket tape that’s compatible with a vehicle paint system or that can withstand conditions such as a high-humidity, tropical environment? If your sealing application is in the aerospace industry, do you need an adhesive tape that can withstand deicing agents or cold temperatures instead?

Taped Gasket Fabrication

Elasto Proxy sources 3M™ tapes and fabricates taped gaskets from lengths of rubber that are cleanly cut and spliced. With HATS products, the taping machine in our manufacturing center uses an infrared (IR) pre-heater for improved bond strength and reduced energy consumption. The IR pre-heater is used to heat the surface of the tape before it passes through the taping machine, where hot air finishes the job.

To speed this labor-intensive operation, our taping machine has an automatic feeder. With both HATS and PSA tapes, automatic feeding reduces setup times and streamlines production by eliminating the need for operator intervention. The taped gaskets that you’ll receive from Elasto Proxy are fabricated efficiently and can speed your own assembly operations because they arrive ready-to-install.

To learn more about taped gaskets, contact us.

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Four Types of Extruded Rubber Seals

Extruded Rubber Seals

Extruded rubber seals support complex cross-sections and have a smooth surface finish. Examples include bulb, lip, door, and accordion seals. These aren’t the only types of extruded rubber products, but they’re used in many applications. They’re also available in various compounds, durometers, shapes, sizes, and colors.

Bulb, lip, door, and accordion seals are supplied in standard lengths of sponge or solid rubber. These lengths are cut-to-size and then spliced or bonded into finished gaskets. Elasto Proxy’s Extruded Rubber Products catalog describes some of the hundreds of rubber profiles that we keep in stock and can custom-fabricate for you.

Let’s take a closer look at what you need to know about these four main types of extruded rubber seals.

Bulb Seals

Bulb SealBulb seals have an open, rounded, or teardrop-shaped section that supports compression. Some bulbs have a rounded section that looks like a half-moon with a  flat bottom instead. Bulb seal dimensions vary, but generally include height, inner diameter (ID), and outer diameter (OD). Often, bulb seals are installed between doors and door frames in vehicles or buildings.

To support compression, bulb seals are usually made of sponge rubber. Softer bulbs made of materials such as EPDM foam can create a watertight seal. With mobile equipment, bulb seals can be attached to metal surfaces such as frames with strong, weather-resistant tape. These tapes can provide either temporary or permanent fastening.

Lip Seals

Lip SealLip seals feature an edge or sealing lip and, in some cases, an opening. Often, these extruded rubber seals are used to protect the bearing that supports a rotating shaft or bore. Rotary shaft seals, a type of lip seal, retain the bearing’s lubricant and help to prevent the ingress of dust, dirt, and other contaminants that can impede performance or shorten bearing life.

Radial lip seals are used in high-speed crankshaft applications for diesel and gasoline engines. These extruded rubber seals are also used in other types of vehicles and with pumps, mills, and industrial equipment. Compounds vary in terms of material properties, so it’s important to choose an oil-resistant rubber if required by your application.

Door Seals

Door SealDoor seals are designed to fill the gaps between doors and door frames in vehicles or buildings. Depending on the application environment, these extruded rubber seals may need to resist wind, water, weather, or a wide range of temperatures. Applications include mobile equipment, military vehicles, and residential and commercial construction.

Door seals are generally defined by their application rather than by geometric features or material composition. However, most door seals are rectangular. Hatch seals, a type of door seal, are used with fuel tanks, electronic enclosures, and rooftop HVAC systems. This category of extruded rubber seals includes custom weather stripping and some types of bulb seals.

Accordion Seals

Accordion SealAccordion seals have folds like the bellows of an accordion. Consequently, the physical dimensions for these extruded rubber seals are very different when they’re stretched or compressed. Many accordion seals are made of EPDM rubber because this elastomer imparts weather and abrasion resistance. Some products also feature an internal spring steel loom.

Accordion seals are often used with mobile equipment and other transportation-related applications. For example, accordion boot seals are used to weatherproof access points such as between a truck cab and a trailer. Without this type of sealing, the splash of water from roadways may cause or contribute to the formation of rust.

How Can We Help You?

Do you need bulb seals, lip seals, door seals, or accordion seals? Would you like to see drawings of standard rubber products that Elasto Proxy can custom-fabrication into specialty sealing solutions?  To learn more, download the Extruded Rubber Products Catalog.

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Six-Axis Abrasive Water Jet Cutting for Industrial Rubber Products

Six-Axis Abrasive Water Jet Cutting

Six-axis abrasive water jet cutting puts precision cutting in a robotic cell for greater fabrication freedom. 

Abrasive water jet cutting provides a powerful way to cut industrial rubber products like bulb trim that’s reinforced with metal wire. Unlike traditional water jet cutting, abrasive water jet cutting mixes water with garnet abrasive in a high-pressure, high-velocity stream that can cut harder, thicker materials such as sheets and profiles made of rubber, plastic, metal, stone, and bulletproof glass.

Elasto Proxy offers abrasive water jet cutting services and uses an ABB IRB-4400 industrial robot to optimize this technology. Abrasive water jet cutting doesn’t require a robot – but using a robot provides important advantages. For example, Elasto Proxy’s six-axis, abrasive water jet cutter can make fast, precise, cost-effective cuts like 45° angles on reinforced bulb trim. It’s great for reinforced edge trim, too.

Advantages of Six-Axis Robots

Elasto Proxy’s ABB IRB-4400 is a compact, six-axis industrial robot with a working environment of 40” x 60” (101.6 cm x 152.4 cm). Unlike gantry robots, this articulated robotic arm is equipped with rotary joints that combine freedom of movement with dexterity. As the table below explains, our robot’s six degrees of freedom (DOF) supports movement anywhere in the work envelope.

Axis Description
1 Rotates the robot
2 Forward and backwards extension of the robot’s lower arm
3 Raises and lowers the robot’s upper arm
4 Rotates the robot’s upper arm (wrist roll)
5 Raises and lowers the wrist of the robot’s arm
6 Rotates the wrist of the robot’s arm

Six-axis robots like the ABB IRB-4400 can perform a wider variety of operations than robots with fewer axes. These operations, or motions, control the actions of the end effector – the device or tool that’s connected to the robot’s arm. At Elasto Proxy, this tool is a nozzle that directs the high-pressure, high-velocity stream that provides the cutting action.

Advantages of Abrasive Water Jet Cutting

bulb trimCompared to guillotine cutting, a manual or semi-automatic process, abrasive water jet cutting costs less because there’s no surface finishing required. Once a length of rubber is cut, it’s ready to bond. Abrasive water jet cutting is also faster than manual cutting and puts less stress on the workpiece. Abrasive water jet cutting requires water, of course, but the environmental impact is less than you might realize.

At Elasto Proxy, abrasive water jet cutting combines digital manufacturing with industrial automation. Thanks to computer-aided design (CAD) and the absence of metal tooling, quick-turn prototyping is achievable. Abrasive water jet cutting also has fast setup times since there usually isn’t a need for clamping or special fixturing.

For customers with sustainability initiatives, abrasive water jet cutting is more environmentally-friendly than other cutting methods. For starters, there’s no hazardous waste. Any vapors, smoke, or dust particles are trapped in the water and then filtered out. Because it’s a closed-loop system, abrasive water jet cutting also uses relatively little water. Scrap materials from cutting can be recycled, too.

As a cold cutting process, abrasive water jet cutting won’t create heat-effected zones or cause hardening that requires expensive secondary processing. Any heat that’s produced by the cutting process is cooled by the water stream. By contrast, both laser cutting and CNC machining can cause warping, distortion, or material hardening. With rubber, die cutting can distort the edges of sheet materials.

Depending on the material and thickness, abrasive water jet cutting can achieve accuracies measured in tenths of a millimeter. In addition to intricate cuts and 3D shapes, this cutting technique can produce near-net shapes that don’t require time-consuming secondary processing. Edge quality is excellent, and abrasive water jet cutting can make cuts in any direction.

Additional advantages include the ability to create chamfered edges, radiused corners, bevels, and shapes with tight inner radii. Stacking, nesting, and a 40” x 60” working environment can optimize material usage and reduce cutting times. Once parts like edge trim or bulb trim are cut, they’re easy to assemble. To learn more about six-axis abrasive water jet cutting for industrial rubber products, contact Elasto Proxy.

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Dimensional Tolerances for Rubber Products

Dimensional tolerances for rubber products are allowable variations in part or material size. They’re expressed as plus or minus values, or as a range of measurements. During the seal design process, engineers record tolerances on part drawings so that vendors can source materials and fabricate products that meet or approximate the required dimensions.

If parts or materials are out-of-tolerance, seal failure can occur. For example, if a door seal is too large, the door may not shut. If the seal is too small, water or weather could enter. Coils and cut lengths also need to have the proper dimensions. That’s why your part drawing represents a contract that your distributor or fabricator needs to keep.

Yet engineers have an important responsibility, too. If the tolerances you specify are impossible to achieve, you won’t be able to get the sealing solutions that you need. It’s not because you selected the wrong vendor or manufacturing process. It’s because rubber isn’t like metal.

Rubber vs. Metal

Sometimes, designers specify tolerances that are too tight for rubber products. This leads to confusion and frustration during the seal design process. Typically, these engineers are used to working with metal – a material with different properties. Because metal parts support tight tolerances, it’s assumed (incorrectly) that rubber also supports a high degree of precision.

Rubber has many useful properties, but it can’t match metal’s tolerances. That’s because rubber is more sensitive to environmental conditions such as heat, cold, and humidity. The kind of tooling and equipment that’s used with rubber affects tolerances, too. If you’re used to working with sheet metal or metal profiles, you may find there’s a learning curve with rubber materials.

Fortunately, there’s a resource that explains what you can expect.

The RMA Handbook

The RMA Handbook is a technical publication that contains dimensional tolerances for molded and extruded rubber products. The U.S. Tire Manufacturers Association (USTMA), an organization formerly known as the Rubber Manufacturers Association (RMA), publishes the RMA Handbook and shares this information with distributors and fabricators of industrial rubber products.

If you’re wondering whether this resource is authoritative, consider the organization’s membership:

  • Bridgestone Americas
  • Continental Tires, The Americas LLC
  • Cooper Tire & Rubber Company
  • Giti Tire (USA) Ltd
  • Goodyear Tire & Rubber Company
  • Hankook Tire America Corp.
  • Kumho Tire U.S.A., Inc.
  • Michelin North America, Inc.
  • Pirelli Tire North America
  • Sumitomo Rubber Industries
  • Toyo Tire Holdings of the Americas
  • Yokohama Tire Corporation

Across the supply chain, the RMA Handbook provides a common language that’s easy to understand. Dimensional tolerances are organized into tables and assigned classes. By adding an RMA class to your part drawing, you can clearly explain what a distributor or fabricator needs to know.

RMA Drawing Designations for Molded and Extruded Parts

It also helps to have a basic understanding of how the RMA Handbook is structured. Molding and extrusion are both rubber manufacturing processes, but they subject elastomers to physical changes in different ways. Consequently, molded parts and extruded parts are covered in different chapters. Moreover, there are different RMA classes for molded parts and extruded parts.

Chapter 1 of the RMA Handbook describes four levels of dimensional tolerances for molded rubber products. There’s a separate table for each class along with information about dimensional terminology.

A1 High Precision
A2 Precision
A3 Commercial
A4 Basic

Chapter 2 of the RMA Handbook describes three levels of tolerances for extruded rubber products.

1 Precision
2 Commercial
3 Non-Critical

There are also separate tolerance tables for spliced extrusions (cut and spliced lengths) and for unspliced extrusions (cut lengths). Spliced extrusions use drawing designations S1, S2, and S3. Unspliced extrusions use drawing designations L1, L2, and L3 instead. Complete this form to see these tolerance tables.

Get Help with Dimensional Tolerances for Rubber Products

Elasto Proxy is a distributor and fabricator that can help you specify dimensional tolerances for rubber products. To get started, contact us.

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Seal Design Starts With This Formula

Seal Design

Finished gaskets follow a formula. Seal design begins with compound, hardness, and profile selection. Custom seals and gaskets that account for these factors can fill the gap, withstand the environment, and meet business and technical requirements.

Let’s take a closer look at what you need to know. Continue reading Seal Design Starts With This Formula

Enclosure Sealing and Insulation: Performance Properties and Applications

enclosure sealing

What’s the right enclosure sealing and insulation for your application? There’s a lot to consider.

Elasto Proxy custom-fabricates seals, gaskets, and insulation for enclosures that house machinery and equipment. These industrial rubber products can provide environmental sealing, acoustic insulation, flame resistance, EMI shielding, chemical resistance, and other performance properties. As the following examples show, enclosure sealing and insulation varies by application.

Environmental Sealing and Acoustic Insulation 

Gensets or generating sets supply off-grid electricity. They consist of a diesel or gasoline-powered engine and an electrical generator (such as an alternator) that converts mechanical power into electricity. To support repairs and maintenance, this equipment is housed in an enclosure with a door. The genset’s door gaskets provide environmental sealing, but the enclosure also needs acoustic insulation.

Sealing a genset door isn’t a job for just any rubber product. Static seals are fine when there’s no relative motion between mating surfaces, but dynamic seals are recommended when there’s motion or movement between sealing interfaces such as a door and door frame. Rubber gaskets also need to resist compression set – the permanent deformation of a material – when the enclosure door is closed.

Rubber gaskets provide some acoustic insulation, but an engine in an enclosed space is loud. Sound absorbers made of acoustic foams can be “tuned” to address these frequencies. Sound barriers and vibration dampers also support noise control. That’s important for complying with workplace limits on noise exposure and avoiding “noise pollution” in areas such as neighborhoods.

Flame and Fire Resistance 

Manufacturers of electrical and electronic systems may need enclosure gaskets that are made of fireproof rubber. The UL 94 standard from Underwriters Laboratories (UL) defines 12 different flame ratings, so it’s important to determine which rating applies to your design. Engineers also need to consider whether the rubber gasket or the entire enclosure needs to meet this demanding standard.

Compounds that are described as “capable of passing UL 94” or “compliant with UL 94” probably don’t have a UL yellow card – proof that Underwriters Laboratories (UL) has tested and recognized the material. However, these less-expensive materials may still meet your requirements. Before selecting a compound then, engineers need a complete understanding of the application.

EMI Shielding 

Electronic devices and equipment that are housed in an enclosure may require protection against electromagnetic interference (EMI) that can disrupt or damage circuits. The causes of EMI are numerous and can include both manmade and naturally-occurring sources. In industrial and commercial settings, the causes of EMI typically include brush motors, computer circuits, and lighting.

Gaskets made of particle-filled silicones provide both EMI shielding and environmental sealing. These metal-filled elastomers also provide electrical conductivity and resist a wide range of service temperatures. For applications that require resistance to fuels and industrial fluids, EMI gaskets made of particle-filled fluorosilicones are used.

Chemical Resistance

Enclosure gaskets are also needed by the pharmaceutical industry, which uses solid dosage processing equipment to manufacture finished doses of medication in tablet or capsule form. Often, these solid doses are coated to mask the medicine’s taste or odor, protect the drug in the stomach, and to control its release profile. In turn, these coatings may contain chemicals that can attack rubber.

Fluorosilicone enclosure gaskets can withstand these chemicals. These rubber gaskets also provide other performance properties such as excellent stability over a wide temperature range. Fluorosilicones gaskets resist compression set, too. Fluoroelastomers are more expensive than some other compounds but are cost-efficient to produce with the right cutting and bonding techniques.

Choose Enclosure Sealing and Insulation from Elasto Proxy

Elasto Proxy custom-fabricates enclosure seals, gaskets, and insulation with the right performance properties for your application. We use water jet cutting, offer a variety of bonding methods, and can help you with seal design and compound selection. If you need enclosure sealing and insulation solutions, please contact us.

Value-Added Manufacturing: Parts Marking, Kitting, and Custom Packaging

Value-Added Manufacturing

Value-added manufacturing transforms engineered products into goods that save you time and money. It’s different than fabrication, the process of manufacturing a product like a gasket from a semi-finished material like an extrusion. By outsourcing fabrication and leveraging a vendor’s value-added services, you can reduce costs and improve efficiency.

Consider the following example. Instead of paying your employee to cut and bond gaskets, you outsource the gasket fabrication. If you’re using a relatively expensive employee to cut-and-bond, you’ll save money on labor costs. You’ll also reduce material waste from mis-cuts and improve material yields. Yet outsourced fabrication can do even more.

Value-added manufacturing like parts marking, kitting, and custom packaging make your products faster, easier, and less expensive to order, receive, stock, pick, and install. That’s true for gaskets as well as for thermal and acoustic insulation. Even rubber floor mats provide an opportunity for added value.

Let’s take a closer look. Continue reading Value-Added Manufacturing: Parts Marking, Kitting, and Custom Packaging

Better Bonded Gaskets for Sealing and Insulation

Better bonded gaskets improve quality and perceptions of quality. They reduce labor costs and support sales, too.

Bonded Gaskets

Finished gaskets need strong bonds to provide reliable sealing and insulation. In applications where rubber gaskets are visible, bonds that look better also suggest higher product quality. Buyers of specialty vehicles, commercial ovens, and electrical enclosures (just to name a few) don’t want to see bonded gaskets that look like they’re ready to pull apart in the corners or that need touch-ups.

Even in applications (such as HVAC systems) where finished gaskets are hidden, failure is expensive. Replacing the rubber seal in an air conditioning unit may cost more than you realize. In addition to paying for a replacement part, there are direct labor costs. Indirect costs including traveling to and from the job site, scaling ladders, pulling and replacing panels, and completing paperwork. Over time, it all adds up.

Gasket bonding may seem simple, but it’s skilled labor. You can buy your bonded gasket equipment, but machines don’t come with expertise. Even in an age of digital manufacturing, some activities still require craftsmanship. Plus, some bonding methods require cuts that you don’t have the equipment to make. You can try using guillotine saws or hand tools, but you can’t match water jet cutting. Continue reading Better Bonded Gaskets for Sealing and Insulation

Vendor Consolidation is Right for Rubber Products

Vendor ConsolidationVendor consolidation is a procurement strategy where you reduce the number of vendors that your company buys from. Businesses don’t want to become overly dependent on a single vendor or a handful of vendors, but there are costs – and risks – from having too many suppliers. There are also benefits to lowering the number of vendors that you do business with. Let’s take a closer look. Continue reading Vendor Consolidation is Right for Rubber Products