In addition to the host companies, a world class line-up of material and equipment suppliers unveiled their technological LSR advancements including; Fluid Automation, Gayson SDI, Roembke Mfg. and Design, Milliken Chemical, and G&F Medical.


PLAY VIDEO TO SEE LIQUID SILICONE MOLDING PROCESS

The platform for the Shin-Etsu/Engel LSR Symposium focused on new developments in LSR technology including; molding and process equipment, molds, dispensing equipment and materials. Additionally, dedicated tracks addressed issues and advancements in Anti-Microbial additives for Liquid Silicone Rubber - an increasingly vital topic in Medical and Consumer LSR Product applications. Presentation profiles also included LIMS (Liquid Injection Molding System) products for medical and multi-component molding, silicone dispersions, electric vs. hydraulic LSR applications, and business considerations facing LSR markets.
 
The November 2009 event drew over 150 industry attendees from around the world and featured the following highlights from keynote speakers:

SHIN-ETSU SILICONES OF AMERICA, INC. (Akron, OH)
Presentation: LIMS for Medical/Multi-Component Parts
Presenter: Eric Bishop: North America Marketing Manager
 
According to Eric Bishop, North America Marketing Manager for Shin-Etsu Silicones of America, Inc. (A U.S. subsidiary of Shin-Etsu Chemical Co. Ltd., Japan), “The growing silicone market in healthcare is due to its inherent biocompatibility, clarity, chemical resistance, resiliency, design versatility, and high tear strength.”
 
Offering an expansive range of healthcare grade silicones for a variety of applications including: KE1950, KEG2000, KE2090/2095 Select-Hesive, KEG2003 and KE2004 Series, Bishop noted that, “All of Shin-Etsu’s healthcare series products are tested to meet medical device biocompatibility standards including: ISO 10993 / USP Class VI / CFR 177.2600.”

AVERAGE TEAR STRENGTH

Notably, Bishop premiered Shin-Etsu’s High Tear Strength Grade KEG-2005 series which is engineered to resist tear propagation; ideal for highly strained applications. The series advanced material properties offer better toughness for applications like baby bottle nipples, and peristaltic pump tubes for dispensing food products and pharmaceutical nutrients into patients; amongst others.
 
According to Bishop, “The high tear strength LSR rubber material is formulated to prevent cracks from propagating straight through the silicone. It’s called ‘knotty tear’ which is harder to pull apart, and results in higher tear resistance values.”
 
The KEG-2005 series was tested against other leading materials to see how it tears under tensile force. The results were measured in force per meter; with a straight crack representing the lowest values, a curved crack rating better, and a vertical crack rating the best.

The series higher tear strength not only yields confidence in the final application; combined with outstanding release properties, it also allows for demolding parts√¢‚Ǩ”particularly those with thin wall thicknesses√¢‚Ǩ”without tearing and creating scrap. Bishop indicated that the KEG-2005 series has been sold in European markets successfully for the past year, with the U.S.A. introduction rolling out at the beginning of 2010 for the healthcare market; medical and food market applications forthcoming.
 
ENGEL MACHINERY NORTH AMERICA (York, PA)
Presentation: Engel Electric vs. Hydraulic for LSR Applications
Presenter: Steve Broadbent: LSR/ELAST Project Engineer
 
World-wide leading injection molding machine manufacturer Engel Machinery North America conducted a LIMS molding demonstration using Shin-Etsu's KEG2000-50 silicone and Engel's e-max 200/55 injection molding machine. In addition to premiering the state-of-the-art, fully electric, energy efficient, and compact footprint unit, Engel’s ELAST Project Engineer Steve Broadbent offered an analysis of developments and benefits of selecting electric vs. hydraulic injection molding machines based on matching the optimal requirements of the job at hand.
 
Expounding on the unique attributes of both technologies, Broadbent stated that, “Electric units are ideal for micro-shot molding where tight tolerances are required on the injection unit. Hydraulic technology is best leveraged for the repeatability of multi-cavity molding where the shot sizes are big enough for the resolution to work. In this scenario, hydraulic units are just as effective as electric and the capital investment is lower.”
 
Another variable in the electric vs. hydraulic analysis involves the clamping unit which provides the size/tonnage force required to overcome expansion of silicone during vulcanization. According to Broadbent, “The electric toggle clamp offers more precise precision control for injection parallel to closing; whereas there’s not as much flexibility and precision positioning with hydraulic. However, hydraulic clamping does provide more flexibility in the mold size as there are not as many height restrictions for the mold. Additionally, hydraulic offers simple operation, has less moving parts, and is easier to set up.”

ROEMBKE MFG. & DESIGN, INC. (Ossian, IN)
Presentation: Developments in LSR Molding
Presenter: Greg Roembke / President
 
Industry leading experts in the design and build of inserted flashless rubber molds, Roembke Mfg. & Design President Greg Roembke offered insights into developments in LSR flashless tooling. Notably, Roembke focused on internal cavity mold pressure sensors which can measure imperfections and correct them during each shot.
 
According to Roembke, “In the past, manual choke systems were used to balance a cold-runner system from cavity-to-cavity. Over the last several years we’ve been incorporating internal mold pressure sensors from RJG (Traverse City, MI) which allows complete control of the valve gates including: balance of the cold runner, monitoring the internal cavity material, and its temperature and/or pressure.”
 
Roembke indicated that the internal mold cavity pressure sensors are an add-on based on client need (per project requirements) and are designed to fit in varied situations and molding environments. Once specified, they establish the parameters and prepare the tool to accept the mold sensors. Upon installation, they essentially create a closed-loop molding system. For example; viscosity changes from material from LSR-kit-to-kit may happen, thus internal mold cavity pressure sensors will detect these changes and make the necessary adjustments.
Roembke noted that, “Interest is growing fast in this technology as it allows molders to achieve a window into what's happening inside the mold with each process. Also, it can be used for high-precision, low-volume parts as well as high-volume parts. The bottom line savings can be substantial as it can reduce scrap to less than 1%; which on a 100 million range volume would be huge.”
 
 
GAYSON (Barberton, OH)
Presentation: 3rd Stream LSR Metering Materials
Presenter: Tom Manello / Sales Manager
 
Gayson Silicone Dispersions, Inc. (GSDI), a leader in pigment, chemical additive, and catalyst dispersions for HCR/LSR/RTV applications since 1979, has been expanding their medical market niche in areas such as needle-free valves and surgical grips which are color coded for quick recognition in OR/ICU applications. An ISO 9001: 2000 Certified company, GSDI manufactures the only line of pigment dispersions to be certified for use in long term implants.
 
Developing and manufacturing over 10,000 custom color variations, GSDI focuses on three key product lines for silicone: Silcopas (dispersions line for LSR/RTV Silicones), Silcogum (dispersions for HCR/HCE silicones), and Silcosperse (dispersions of chemical additives; i.e.-antimicrobial, heat stabilizer, etc. to modify silicones). These dispersions break down pigments or additives to their primary particle size and uniformly distribute the pigment or additive throughout the silicone carrier.
 
According to GSDI Sales Manager Tom Manello, “Colorability is a growing trend in medical applications for three key reasons; easy recognition for patient safety, corporate product branding, and aesthetics. In the case of aesthetics, many of today’s children’s medical devices are incorporating vibrant colors to add a sense of calm, or even fun to an otherwise intimidating experience for a child.”
 

MILLIKEN (Spartanburg, SC)
Milliken & Company
Presentation: Antimicrobials for LIMS
Presenter: Mark Wiencek
 
One of the largest privately-held textile and chemical manufacturers in the world, Milliken & Company (Est.1865), introduced its new generation antimicrobial additive designed for use in LSR silicone elastomers named SelectSilver SR12. Rebranded (formerly AlphaSan CW 12) for use beyond its key consumer-products applications, the completely inorganic additive contains silver ions as its active antimicrobial ingredient and has high thermal stability, low moisture content, and a small particle size.

According to Milliken Senior Microbiologist Mark Wiencek, “Biofilm (the growth of microbes on a surface) is a serious problem in many applications. Biofilms on silicone components of medical devices (e.g. implants, catheters, IV connectors, respiratory therapy, etc.) can lead to infections which are very difficult to treat because the biofilm is more resistant to systemic antibiotics, topical antiseptics and host immune defenses than microbes not associated with surfaces. On surfaces treated with SelectSilver SR12, biofilm growth is inhibited by silver ions which interfere with the metabolism of the microbes. Silver has been used for infection control in medical devices for decades because of its efficacy against microbes and its low toxicity to human tissue.”
 
Wiencek indicated that several other silver-based antimicrobials have been tested by Milliken & Company and that SelectSilver SR12 exhibited the best overall performance. Some of these antimicrobial efficacy tests utilized LSR pistons to test effectives against Methicillin-resistant Staphylococcus aureus (MRSA), a common culprit in devices-related infections. The test involved touching pistons to agar plates inoculated with 1,000-100,000 bacterial cells. The pistons were then touched repetitively to a clean nutrient agar plate to determine how many touches are required before no living microbes are transferred.
 
Wiencek concluded, “The results indicated that the presentation of the silver-based antimicrobial at the surface of the treated material is important because if the additive is buried it won’t become wetted and release silver ions. It appears that SR12 is not ‘skinned over’ by the LSR at the material surface like several other silver-based antimicrobial treatments that are incorporated directly into the LSR during the manufacturing process.”

Typically, 0.1 - 0.2 % silver is required to achieve the performance needed by the USA FDA for approval of the device under the 510(k) program. However, if two much additive is loaded into the LSR, it can alter functional properties like the flex modulus. This is a key component for medical applications like piston compression where the LSR must compress effectively and seal back up to prevent ingress of microbes.

 
FLUID AUTOMATION, INC. (Wixom, MI)
Presentation: LSR Dispersing Techniques
Presenter: Bob Pelletier: VP of Sales 
 
Fluid Automation VP of Sales, Bob Pelletier premiered Fluid Automation Inc.’s Model 622 Miniature 1:1 Ratio Single-Acting Plunger Meter-Mix Unit that is designed for customers dealing with micro-molding applications and implant grade silicone. Since silicone applications tend to be smaller parts in general, the system is ideal for micro-molding of tiny shots with high-precision, high control, and without much material. Typical medical applications would include; intraocular lenses, tear duct plugs, coating leads for intracranial, or heart pacemaker leads, etc.
 
The stand-alone unit incorporates a cartridge feeding system that takes LSR material (from typical 5 gallon buckets which often sit longer on a shelf) and uses cartridges up to 20 oz. of A & B silicone (20a/20b=40 oz total material volume) that feed into a proportionate controlled metering unit with a pneumatic cylinder valve. A total shot of 46cc grams allows it to accumulate into two pistons (filled as specific press/volume for 1:1 ratio) that feed into the injection molding machine when it receives a signal from press. For small shots, the unit can be programmed via its own PLC controls and operator interface panel, to refill after multiple shots to increase the efficiency of the system.
 
According to Pelletier, “This configuration allows the unit to maintain consistent feed pressure to the feed throat without the need of a mechanical regulator. In short, it eliminates any item in the stream that would have had to been cleaned over time; which translates into cost efficiency.”

 
G & F MEDICAL INDUSTRIES (Danvers, MA)
Presentation: Doing Business in LSR Markets
Presenter: Nirav Patel / General Manager 
 
G&F Medical Inc., formerly UPCOA, is a leading specialist in the Liquid Injection Molding of Silicone materials for medical OEMs. With a focus on certified clean room quality systems, the company is ISO-9001 certified by TUV registrar and also provides value-added product design assistance, medical thermoplastic molding, pad printing, assembly, and packaging. G&F Medical GM Nirav Patel concluded the event by emphasizing the importance of reducing program/project risks by managing the communication channel’s program focus at the onset.
 
According to Patel, “This step helps us understand the requirements and expectations of our customers in-depth. We then gage the risks in tooling and processes by performing Process Failure Mode and Effects Analysis (FMEA). This helps us identify where the risks are and provides the opportunity to address them in advance. Therefore, we are exceptionally thorough in process troubleshooting, design of experiments, and process validation.”

Patel emphasized that in the medical industry it’s paramount to have enough separation from other processes. For example, if it’s a LIMS process people must be focused on LIMS disciplines throughout. This prevents generation of mixed messages that could lead to cross contamination as cleanliness is vital since silicone attracts particles easily.

According to Patel, “Communication is the key to success in establishing a clean room focus in the design phase of product cycles to eliminate risk, reduce cost, and remove long lead times.”
 
Patel continued to emphasize educating customers upfront to calculate risk on material selection, process development, ISO 2001 quality standards, and process validation which is FDA-driven for medical OEM’s to make sure processes are stable and capable over the long haul. Patel concluded that, “Silicone is a unique material, therefore identifying process development and control upfront is critical. You can’t underestimate process evaluation as every part and process is unique, and it’s vital to establish a strong base for longevity and stability.”
 
ABOUT SHIN-ETSU SILICONES: A U.S. subsidiary of Shin-Etsu Chemical Co. Ltd., Japan, Shin-Etsu Silicones of America Inc. offers vast technical and capital resources to formulate solutions as a major supplier of silicone materials to North America's medical, automotive, electronics, aerospace, and manufacturing industries. Shin-Etsu’s premium silicone compounds incorporate leading-edge technology, staff expertise, and value-added service; offering customers the highest levels of quality and consistency in specialty silicone materials.

For more detailed information, visit the Shin-Etsu Silicones web site at: www.shinetsusilicones.com or call: 1-330-630-9860

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