It probably comes as little to no surprise that products rely on various materials and components in order for them to perform successfully. But what may be a little less clear is the question of what’s rubber got to do with it? The fact is that engineered rubber materials have got quite a lot to do with it. For thousands of products every day, they rise to the occasion and overcome application challenges in which other materials fall short.

What’s Engineered Rubber & What is it Used For?

Engineered rubber materials have earned their status due to their unique physical properties and ability to meet performance objectives. Also referred to as elastomers, they provide toughness in the face of application challenges where pressure, wear, impact and other factors are concerned.

When it comes to rubber, several types are available. However, a plethora of variables are also involved that can affect performance, including formulation and temperature. Through the blending and combining of different ingredients, along with the 14 basic polymer groups, engineered rubber is formulated to meet specific design needs. Its specialized nature leads to its enormous span of application uses. Just check out a few examples of its range:

• Engineered rubber can be used for sealing in applications where liquid is manipulated, including fuel systems, valves, hydraulics and beverage dispensing.

• It can be used for sealing in applications that manipulate air media such as pneumatic systems, heat ventilation and exhaust, diaphragms and riveting equipment.

• The high-performance capabilities of engineered rubber also suit preventative or protective applications like impact absorption, wear resistance and crash stops, vibration dampening and the exclusion of dust debris.

• In addition, it can be used for functional applications such as insulators, isolators, drives and linkage parts, as well as aesthetic applications like mounts, caps, plugs and protectors.

Engineering the Solution

Undoubtedly unique, engineered rubber materials have proven themselves to be just the right answer to many application needs. This is especially true when materials like metal and plastic cannot fulfill the requirements. However, understanding the needs and parameters of a specific application challenge is just the beginning.

At Real Seal, we can be a real resource when it comes to engineering a solution. Known for high quality seals and seal systems, our San Diego facility also offers the service of engineering and design support. Utilizing an extensive knowledge base, and maintaining a focus on performance and economic factors, our engineers will strive to help develop a solution that meets your objectives. So, if you are looking for an engineered rubber solution for your application or have any questions, please contact us today or give us a call at 800.542.6162.

When one hears the word “silicone”, many images are conjured.  In the seal and gasket end of the world, however, silicone seals are used in a fairly limited range of applications.

High Heat – silicone rubber is often specified for higher (dry) heat applications, as it has one of the highest heat resistance ratings of any of the polymer groups.  Applications including welding equipment, hot air exhaust systems, hot metal insulation, oven seals and insulation, electrical insulation units, and manifold seals.

Medical Applications – since silicone is organically based, and has naturally low modulus properties with generally fewer additives required for processing, it can be more easily formulated for FDA and medical applications.  Silicone is widely used for baby nipples, hearing aid insulation and fit, IV Connector seals, syringe plungers, and device covers and insulators.  Since silicone is more inert than conventional materials, it is often specified in medical applications that mix or react with multiple fluids, such as drug testing test kits, diabetes glucose level kits, pharmaceutical applications, and other similar medically oriented devices and processes.

High Temperature Range Applications – Silicone retains its physical properties over the widest range of temperature, so even when the temperatures get very low, it will likely still perform according to design.  Applications including sensors, lighting, electronic actuators, and seals for instrumentation will perform over a higher range of environmental conditions without succumbing to temperature extremes on either end of the spectrum.

Aesthetic Applications – Silicone rubber generally possesses a unique low modulus characteristic that makes is desirable for applications that require a softer feel, like handles, button covers, display bumpers, or other devices that have some kind of engineered protection or aesthetic angle to their design.  Silicones also tend to color more vibrantly, which enhances their aesthetic appeal.

Complex Shapes – Although the raw material is normally more expensive than conventional rubber materials, silicone has unique flow properties that may be more easily molded into complex shapes.  For more complex connectors, electronic insulation parts, or other critical designs that require a more complex mold, silicone rubber is more tolerant of blow molding or other processes that require a pliable and highly moldable raw material.

Silicone rubber is widely specified for these sorts of unique applications, and Real Seal is qualified to help engineer and develop materials for more unique design requirements.  From silicone o-rings to silicone rubber to metal bonded gaskets, Real Seal has the experience and expertise to add value to the process for more highly engineered applications.  Please contact Real Seal with your rubber and plastic application projects, and we’ll help to steer you in the right direction.

Engineered rubber materials drive the performance of thousands of products every day.  The unique physical properties of rubber (elastomer) materials make them the preference for engineers who are tasked with overcoming engineering challenges that conventional materials cannot.  Examples of applications for engineered rubber materials include:

• Sealing in applications that manipulate liquid media
  • Hydraulics
  • Pump systems
  • Beverage dispensing
  • Fuel systems
  • Valves
  • Sealing in applications that manipulate air media
    • Pneumatic systems
    • Heat Ventilation / Exhaust
    • Impact / Riveting Equipment
    • Diaphragms
    • Functional Applications
      • Linkage Parts
      • Isolators
      • Insulators
      • Drives
      • Preventive / Protective Applications
        • Prevention of liquid ingress
        • Exclusion of dust debris
        • Impact absorption
        • Crash Stops / Wear Resistance
        • Vibration Dampening
        • Aesthetic Applications
          • Caps / Plugs / Protectors
          • Mounts

With (14) basic polymer groups, and thousands of possible material possibilities which can be engineered to meet an enormous number of criterion, engineered rubber materials can be used to meet a multitude of application challenges.  While Real Seal is primarily known for high performance seals and seal systems, we have engineered materials and designs for a wide range of engineered applications here in San Diego.  When metals and/or plastics don’t offer the kind of solutions you are looking for to meet performance objectives, Real Seal can be a valuable resource.  Give us a call and speak to one of our engineers about your application – chances are we can help develop an engineered rubber solution for your application.

The acronym PPAP has become more commonplace in industry, and is trickling down from automotive and heavy equipment OEM’s to smaller organizations, which are now adopting the concept.  One’s 1^st experience with PPAP can be harrowing, but if you break it down in to bite sized pieces, it can be handled without undue stress.

The PPAP “package” starts with a Part Submission Warrant (PSW).  The PSW outlines an overview for the PPAP, which includes the Customer, control document identification and revision, PPAP Level, and a proven production rate, which is to reflect the capacity of the process and tooling.  This PSW also serves as the official document to formalize the entire PPAP “package”, as the vendor must sign and take responsibility for the accuracy and completeness of the details of the PPAP.

The next document is normally the Process Flow Chart (PFC), which is normally an illustrated flow chart showing the steps for the process, and the sequence of steps to complete the finished product.  This document should detail the process steps, and identify movement between departments.  It should also identify validation or measurement steps.  This document is normally used as the basis for setting up audits, and for differentiating other possible process options that may be chosen to produce a product.

Generally, the next document is the Control Plan.  The Control Plan follows the outline of the PFC, but gets into much greater detail regarding each of the process steps, and how they will be validated and ultimately controlled.  Control Plans break down the process flow into exact steps, and detail the quantity of product that will be checked when validation steps occur.  Control Plans also reflect what happens if one of the process steps is found to be out of control.  The Control Plan steps are important, as they are numbered, and will correspond to the same number in subsequent documentation.

The Control Plan sets the stage for the PFMEA (Process Flow Material Element Analysis), which is essentially a document that applies “Murphy’s Law” to the Control Plan.  This document asks the vendor to outline possible processing problems, and what the contingency/correction plan is for if/when they happen.  This document should rate the possible issues in terms of severity and likelihood of occurrence, and should be rated statistically accordingly.  If the process shows possible problems that should be addressed, the vendor should detail the specific steps it is taking to minimize the possibility of occurrence, and rank them before and after the minimization moves.  Vendors should be cautious, as this is the document that will raise the most questions from customers, and be the focal point of audits.

PPAP’s may vary in terms of sequence, but a report showing the dimensional results of the 1^st parts produced is normally expected, along with a statistical analysis of the results, referred to as Cpk.  Most customers will require that the dimensional results be provided per cavity for molded parts, and most customers require a Cpk of 1.67 or higher to show statistical capability in the process.  If the Cpk falls below 1.25, the process is normally regarded as not capable of meeting the control dimensions.

The dimensional results are generally supported with a Gauge R & R Study, which is a document showing that the measurement equipment used to capture the dimensional details provides consistent and reliable results, regardless of operator.  This document reflects measurements taken by (3) independent personnel with the same measurement equipment, and the results are captured and tabulated.  The range in any difference found in this document should be within (1) standard statistical deviation, which should reflect a capable measurement system.  If the range is greater than (1) standard deviation, the measurement system will likely fall into question.

PPAP’s normally will also include physical testing results and packaging specifications, as well as APAP documentation, and in some cases, capability studies.  If properly done, the PPAP process can be an advantage for both customer and vendor, and establish metrics for finished product that minimize the potential for non-conformances.

For most people, the acronym APQP does not resonate as anything important, but in the world of engineering, it has become a familiar point of reference.  Beginning with major industries like automotive and heavy equipment, APQP has trickled its way down to specific components, and many customers are getting sophisticated enough to ask for specific APQP data as a condition of doing business with them.  A general outline of what APQP means to the rubber and plastics industry would include a number of considerations.

APQP starts with a control document and raw material specification.  The control document must specify measurable product dimensions and tolerances, and accurately reflect constraints such as parting line restrictions, gate locations, allowable flash extension, and allowable radii.  It is practically impossible to include every conceivable constraint or to specify any conceivable outcome for the finished product, but generally accepted norms are published by RMA and SPE, and can be referred to by default.  The raw material specification should be objectively identified with ASTM (American Standard Test Methods) or better yet, with a specific material, as this will limit variables of different materials that still meet a specification.

The next step for APQP is to coordinate the results of the control document and specifications with a capable vendor, and develop an assessment of capability and competitiveness.  A wise engineer will request a “self-audit” of a prospective vendor, and ask them to score their strengths against a checklist of resources that will determine product quality.  At this stage, basic variables such as machine tonnage, tool size and complexity, and number of cavities should be reasonably determined.  These variables will begin to paint the picture related to product cost, and begin to standardize the competitiveness of the vendors being considered for full production.  Paying specific attention to control resources such as raw material test/validation and measurement test/validation should provide advantage, as the better a vendor can validate defined process steps, the less the likelihood that non-conforming product will be realized.  A capable vendor should be able to qualify the major variables, and provide a preliminary cost model.

Once the cost estimate is deemed acceptable as a part of the overall project cost model, the unit should be put through a more rigorous design and engineering review, including design for tooling, design for manufacturability, design for assembly, and aesthetics.  This is a prime opportunity to catch “downstream” issues before they become obstacles to production.  The opportunity is prime because vendor input is normally very valuable in determining these variables, and in developing alternatives and options to improve cost and control.  This will also lay the groundwork for the process flow, Control Plan, PFMEA, and Cpk if/when a PPAP is developed.

This design/engineering review should yield a control document and specification that balances required engineering and controls with cost control, and should empower purchasing with the most objective and well-articulated basis with which to negotiate terms with prospective vendors.  It should also determine the measurement features and controls for Quality Assurance, so that any validation that occurs at the point of manufacture can be reasonable replicated when the product is received, and apples are indeed compared to apples.

Real Seal has extensive experience in dealing with the sometimes complex task of product development, and can offer considerable value to customers with product development.  Rubber and plastics bring unique variables to the game, so the experience, systems, and guidance Real Seal can provide can equate to considerable long term savings.

When planning for the processing of rubber seal products or plastic seal products and mechanical components, there are several factors that must be considered to satisfy customer requirements.  Although the conventional wisdom is to bring larger volume projects to China for the low prices, American manufacturing innovation and good old fashioned productivity have created many opportunities to produce products domestically – and do it competitively.

The first consideration is the material requirement or specification for the part being considered.  The physical requirements for the application will largely determine  the  material selection, which, in turn, will create the pathways for processing options.  As a general rule, thermoset rubber materials have superior physical characteristics over thermoplastics.  Theroset rubber materials have traditionally been processed with compression and transfer molding methods, which are quite labor intensive.  In the last several years, however, great advances in injection molding technology of thermoset rubber materials have been made domestically.  The materials are modified chemically to improve their flow properties, which then allow them to be molded in much the same way that plastics are.  They still require secondary finishing to remove flash, but the productive processing rate could make a strong competitive base to work from.  If the material is to be thermoplastic, domestic manufacturing is generally more competitive than comparable

The next consideration is the geometry of the part, and the type of tooling necessary to meet geometric, size, and tolerance requirements.  There is a limit to the layout of cavities for all processes of molding, so considering spacing and symmetry, the broad rule of thumb is the smaller the geometry, the higher number of cavities.  The total volume of the cavities, however, cannot exceed 4 X the projected area of the hydraulic ram tonnage of the press, or the press will not be capable of closing the mold.  Generally speaking, thermosetting rubber materials will have a longer cycle time to vulcanization than plastics will to set up, so the productive rate multiplied by the # of cavities will begin to set the stage for the most economical approach to production.

When these parameters begin to be fleshed out, one of the important considerations is what kind of repeatability can be achieved in meeting customer requirements.  The more capital intensive the process (generally speaking), the more repeatable the process.  Processes that require human interaction will by their very nature vary with the nature of the human element.  Advances in controls that include large quantities of sensors create conditions that are optimized by machines, so that any variables are minimized, and so that the process can be stopped at any time if the variables begin to drift away from optimized limits.  The result of this approach normally includes a higher yield, better dimensional consistency, and more consistent results overall.

American innovation is on the forefront of advances in capital equipment, primarily in electronic sensors and controls that create higher and higher degrees of control.  There is much to be gained by utilizing a more capital intensive approach to production, but the cost of capital can be considerable.  While there is still a strong argument for the old fashioned approach in many cases, engineers and designers are wise to keep up with advances in production, and design their rubber and plastic seal products and mechanical components accordingly.

When planning for the processing of rubber or plastic seal products and mechanical components, there are several factors that must be considered to satisfy customer requirements.  Although the conventional wisdom is to bring larger volume projects to China for the low prices, American manufacturing innovation and good old fashioned productivity have created many opportunities to produce products domestically – and do it competitively.

The first consideration is the material requirement or specification for the part being considered.  The physical requirements for the application will largely determine  the  material selection, which, in turn, will create the pathways for processing options.  As a general rule, thermoset rubber materials have superior physical characteristics over thermoplastics.  Theroset rubber materials have traditionally been processed with compression and transfer molding methods, which are quite labor intensive.  In the last several years, however, great advances in injection molding technology of thermoset rubber materials have been made domestically.  The materials are modified chemically to improve their flow properties, which then allow them to be molded in much the same way that plastics are.  They still require secondary finishing to remove flash, but the productive processing rate could make a strong competitive base to work from.  If the material is to be thermoplastic, domestic manufacturing is generally more competitive than comparable

The next consideration is the geometry of the part, and the type of tooling necessary to meet geometric, size, and tolerance requirements.  There is a limit to the layout of cavities for all processes of molding, so considering spacing and symmetry, the broad rule of thumb is the smaller the geometry, the higher number of cavities.  The total volume of the cavities, however, cannot exceed 4 X the projected area of the hydraulic ram tonnage of the press, or the press will not be capable of closing the mold.  Generally speaking, thermosetting rubber materials will have a longer cycle time to vulcanization than plastics will to set up, so the productive rate multiplied by the # of cavities will begin to set the stage for the most economical approach to production.

When these parameters begin to be fleshed out, one of the important considerations is what kind of repeatability can be achieved in meeting customer requirements.  The more capital intensive the process (generally speaking), the more repeatable the process.  Processes that require human interaction will by their very nature vary with the nature of the human element.  Advances in controls that include large quantities of sensors create conditions that are optimized by machines, so that any variables are minimized, and so that the process can be stopped at any time if the variables begin to drift away from optimized limits.  The result of this approach normally includes a higher yield, better dimensional consistency, and more consistent results overall.

American innovation is on the forefront of advances in capital equipment, primarily in electronic sensors and controls that create higher and higher degrees of control.  There is much to be gained by utilizing a more capital intensive approach to production, but the cost of capital can be considerable.  While there is still a strong argument for the old fashioned approach in many cases, engineers and designers are wise to keep up with advances in production, and design their rubber and plastic seal products and mechanical components accordingly.

Since it became commercially available in the early 1990’s, TPE (Thermoplastic Elastomer) materials have provided a new dimension to the engineering of elastomeric parts in a multitude of applications.  While there are a number of possible advantages in designing TPE’s into applications, there are also quite a few drawbacks.  When considering TPE as an option, bear in mind that there are several considerations that should be taken into account.

TPE’s offer process advantages that traditional rubber does not.  Since TPE’s are processed in the same manner as traditional plastics, the production process is normally more capital intensive, repeatable, and generally produces a shorter cycle time.  TPE’s normally don’t require finishing or post cure, so the TPE process is generally going to be leaner with fewer variables.  On the down side, the tooling to produce TPE materials will generally be more expensive, and considerably more expensive if the geometry of the part is challenging.

TPE materials may offer economic advantage, depending on the productive throughput of the process.  This normally boils down to the number of cavities that can be fabricated for each process.  Comparing TPE materials with thermoset rubber, we can look to the following examples for comparison:

Product “A”:

TPE Process: 4 Cavity mold, 30 second molding cycle, no secondary processing required

4 Cavities X 30 second cycle = 8 parts per minute (480 per hour)

Rubber Process: 24 Cavity mold, 3 minute molding cycle, secondary processing required

48 Cavities X 20 cycles per hour = 12 parts per minute (960 per hour)

Even with required secondary processing (finish/post cure), the higher productive throughput means the rubber process will offer considerable economic advantage.

Product “B”:

TPE Process: 8 Cavity mold, 30 second molding cycle, no secondary processing required

8 Cavities X 30 second cycle = 16 parts per minute (960 per hour)

Rubber Process: 15 Cavity mold, 3 minute molding cycle, secondary processing required

15 Cavities X 20 cycles per hour = 3 parts per minute (180 per hour)

Although the rubber process includes almost twice the number of cavities, the TPE process will likely offer substantial economic advantage.

There are dozens of other considerations which could impact processing considerations and resulting economic advantage, and Real Seal engineering and design support has helped hundreds of customers make this determination.

Although TPE materials have improved dramatically in the last 20 years, they are still generally inferior in terms of physical properties.  All else being equal, rubber materials will normally have better tensile strength, elongation, and especially compression set.  TPE’s offer environmental advantages, as their thermal bonds are reversible, so they can be widely used as “filler” or regrind in a multitude of applications.

As technology continues at a blistering pace, Real Seal technical staff remain on the front of the wave, and are available to help support material and design engineering for elastomeric products.