How to Eliminate Defects in Injection Molded Silicone Optics

Overview of virtual molding simulation for use with silicone optics. These simulations identify potential quality defects in the design and manufacturing process for optically clear liquid silicone rubber injection molded parts. Sur-Seal uses software to help identify and eliminate these before time and money is spent in production.

Prototyping Silicone Optics with Sur-Seal

Looking to prototype your next silicone optic concept? Sur-Seal can help you get your product prototyped & launched into production faster and for less money. Here’s how: 


Sur-Seal designs prototype tools that deliver the best combination of speed, flexibility, and quality.  

  1. Before the first chips of steel are cut, Sur-Seal is running molding simulations to optimize both the tool design & processing parameters. This minimizes tooling modifications, as well as eliminates the need for extensive process modifications once the mold is in the press.
  2. Sur-Seal’s in-house tooling center allows for us to control the entire timeline. We are not subject to the workload and availability of outside tooling vendors, shortening the time it takes to get parts in your hands.
  3. Because we build our prototype molds out of the same material as our production molds, your prototype parts will have the same level of quality as expected from a production mold.
  4. Sur-Seal builds its tools using a combination of mold bases & inserts – meaning that if you need to make a design modification after testing your concept, only the insert needs to be changed and we do not have to build an entirely new tool. This saves both time and money between design iterations. 
  5. We understand that getting parts in-hand as fast as possible is key for testing the form & fit of the component. That’s why Sur-Seal will sample your prototype mold both before and after the mold is polished. This gets you parts in-hand as fast as possible, allowing for form & fit checks in your assembly right away. 
  6. Sur-Seal can build prototype tools that are expandable, allowing your existing prototype mold to be transformed into a full production mold by adding cavities to the existing base. Your prototype mold is now equity applied towards your production tool, saving time and money versus a stand-alone production mold.

Experience & Expertise:

Our focus in optical grade silicone molding gives us a unique level of experience that ultimately translates to faster turnaround, better quality, and less wasteful spending. 

  1. Since Sur-Seal specializes in molding optical grades of silicone, we have multiple grades in-stock and ready to go. In-fact, the material is always in the press and ready to mold. No more waiting around for another material to be changed out, or for cross-contamination of different materials between runs.
  2. Sur-Seal has taken extensive steps to bring all of the necessary expertise under one roof. From running mold flow simulations, to designing the tools, to machining the molds and molding the parts – Sur-Seal is the one-stop-shop for everything you need.
  3. Our operators have a vast array of experience molding parts from these materials. They are keenly aware of the quality expectations of such applications and how the requirements go well beyond those of regular molded LSR components. This expertise translates into high-quality samples on the first try.

To get a quote on your next prototype mold, visit our website at

Optical Silicone Vs. PC & PMMA

Optically Clear Silicone is rapidly replacing traditional optical grade materials such as Polycarbonate, PMMA, and Glass.  An evolving list of design demands that only silicone can solve is driving this revolution. 

Silicone’s unique combination of material properties set it apart from the alternatives. Some of the key highlights include: 

1.     Wide Operating Temperature Range (-40F to 400F) 

2.     Superior UV Aging & Weathering Resistance  

3.     Strong Impact Resistance (against vibration and vandalism)  

4.     Extremely Light Weight 

5.     High UL 94 Flammability Resistance Ratings 

Optical Silicone After Heat Aging, Compared to Polycarbonate and PMMA
Image courtesy of Dow

Beyond durability, the unique properties of injection molded liquid silicone rubber offers design freedoms that other materials cannot. Unlike thermoplastics that contract when injected into a mold, silicone expands in the mold – helping solve several issues such as:  

1.     Sink Marks from Thick Cross-Sections  

2.     Micro-Feature Replication (such as textures) 

3.     Under-Filled Sharp Features 

Silicone’s flexibility and forgiveness is an added bonus that other materials do not have, making it possible for designers to incorporate unique design features such as: 

1.     Small Angles & Undercuts (without sticking in the mold) 

2.    Long, Thin Features (without breaking when ejected) 

Optically Clear Silicone is also finding a home in medical applications thanks to its purity, with several grades meeting USP Class VI standards for biocompatibility.  These clear silicones have very low levels of both leachables and extractables, making it ideal for use in medical, diagnostic, and dental applications.

If you believe that silicone optics can help solve one of your design challenges, visit our website at to get in-touch with an application engineer. 

Manufacturing Marvels

Sur-Seal was featured on the Manufacturing Marvels segment of the Lou Dobbs Tonight program that aired Monday, November 2, 2020.  In case you missed it, below is the feature. Watch to learn more about Sur-Seal’s history and growth into America’s leading producer of silicone optics, sealing technology, and thermal management materials.

See the Light with Silicone Optics

Sur-Seal is a leading manufacturer of custom silicone optical components. As one of the first companies to specialize in molding optical-grade liquid silicone rubber (LSR), Sur-Seal has developed world- class expertise in all phases of the LSR molding process. From virtual molding simulation, to prototype development and full-scale production,
Sur-Seal can help you manage the entire life cycle of your optical silicone component.

At Sur-Seal we have the ability to mold all varieties of optical LSR. These materials are incredibly versatile and used as secondary lenses for light fixtures, optics for medical lighting, light pipes, and even optics for UV-C sterilization. Product designers now have a material choice that offers light transmission on par with glass and acrylic, without the fragility and design limitations.

Optically clear silicone allows product designers to create parts that are more durable and higher-performance than traditional optical grade materials. Unlike thermoplastics, optical silicone is UV and vandal resistant and is less susceptible to hazing and cracking.

Before tooling is started, Sur-Seal completes a virtual molding simulation to identify any potential manufacturing challenges such as entrapped air, scorching, or non-fill.

After consulting with OEM design engineers and optimizing their design for manufacturability, Sur-Seal’s in-house tooling team produces rapid prototype and production molds. These capabilities allow Sur-Seal to help bring your products to market faster and with fewer trials.

Please be sure to follow Sur-Seal on LinkedIn to read our series of articles on silicone optics.

Sur-Seal Operations – Critical Infrastructure During COVID-19

To Whom It May Concern:

Local and state governments continue to issue COVID-19 related Emergency Orders requiring all non-essential businesses to close their facilites and for citizens to remain at home. We are writing to confirm our status as an “Essential Business” as defined by the Department of Homeland Security and the State of Ohio. Sur-Seal supplies a variety of critical components to “Essential Businesses” and does not take that responsibility lightly. I want to confirm that we remain open to provide you the highest level of service possible.

We are making decisions with the health and well-being of our associates, suppliers and their families as our top priority. All employees have been instructed to comply with the CDC’s healthy habits and social distancing requirements, and we can assure you that we are executing complete and rigorous protocols in our factory and distribution center in order to minimize the risk of infection by COVID-19.

During these unprecedented times of National Emergency, we are experiencing an increase in demand across our business. Although our supply chain is strong, the increase in demand along with the modifications to our normal course of business to meet all the government regulations, could potentially delay orders in the short term. Your business is important to us and we will do all that we can to support you during this time.

As we navigate through this difficult time, we will not be able to cancel P.O.’s that are not late. If we have finished goods inventory, we will ship what is available and schedule the balance for a future date. All expedited requests may be subject to an expedite surcharge.

We appreciate your understanding as we, together, will fight this and come out stronger!

Thank you for your business.


Larry Faist

CEO & President

Sur-Seal LLC

Sur-Seal Named Rubber & Plastics News’ Best Places to Work in 2019

Sur-Seal has been named one of Rubber & Plastics News’ Best Places to Work in 2019!

We’re very pleased to announce that Sur-Seal has recently been named a Best Place to Work by Rubber & Plastics News. This recognition reinforces our commitment to our employees and to our customers to deliver our best every day.

The Rubber & Plastics News’ Best Places to Work program, recognizes and honors companies in the rubber industry for outstanding employee satisfaction. The rubber industry was defined as companies that make end rubber products, as well as suppliers or providers of services for the rubber industry. The survey resulted in Sur-Seal emerging as one of ONLY eight firms in the US/Canada to receive such award.

Determining the best places to work involves a two-step process. The first step involves an evaluation of participating companies’ workplace policies, practices, and demographics. In the second step, employee surveys are conducted to directly assess the experiences and attitudes of individual employees with respect to their workplace. The combined scores determine the top organizations and the final ranking.

One team member stated, “Sur-Seal has an engaged leadership that cares about people and is open to new ideas. It is a customer-focused organization with a culture of working together. We work hard and we know what we do matters.” Another wrote, “Sur-Seal, for a manufacturing business, has a very unique feel in that it exudes the feeling that people matter. It’s a personable environment with challenging work.” It is evident that the partnerships among our associates are built on a strong foundation of trust.

While the emphasis on this recognition is that Sur-Seal is a great place to work, our associates are not the only ones that experience the difference of Sur-Seal’s culture. Our customers notice it too because an engaged, happy team delivers outstanding service.

For more information or questions related to Rubber and Plastics News’ Best Places to Work program, please visit and

Cincinnati Enquirer recognizes a growing company as one of the city’s best places to work for 2019

CINCINNATI, Ohio – Sur-Seal has been named a Top Workplace for 2019 by the Cincinnati Enquirer. Recognition of Top Workplaces is based on employee feedback gathered by Energage, LLC through an anonymous third-party survey containing numerous questions around the workplace environment, including connection, execution and alignment. Sur-Seal is among the very top of manufacturing companies in the region to receive the award in 2019.

“We’re honored to be named a Cincinnati top workplace.” says Larry Faist, President and CEO of Sur-Seal. “The environment we work hard to create at Sur-Seal centers around people. This recognition tells us we are on the right path.” “It is a top priority at Sur-Seal to foster an environment that cares for each other, embraces the curiosity to learn, and encourages a courageous mindset to step into the uncomfortable. We believe strongly in our values of caring, curious, and courageous.”

The relaxed, yet professional environment, the feeling of being a part of a growing business and the support individual employees receive with learning and growth are just a few of the highlights of working at Sur-Seal, according to Marcia Ernstes, Organizational Development Leader.

“The people here are a one-of-a-kind bunch from the President all the way to the people who have only been here a year, it is truly the best place I’ve have ever worked at,” was just one of the comments received, Ernstes says. “People enjoy working here and they like that each day is a little different. They like knowing the parts they make go into furnaces, lights and hospitals all over the world. They like knowing that they are making the world cleaner, brighter and safer.”

Founded in 1965, Sur-Seal employs about 230 people, mostly at its Cincinnati-based headquarters. It also has locations in Harrison, Ohio; Nuevo Laredo, Mexico; Monterrey, Mexico; and Suzhou, China. The company specializes in highly engineered sealing solutions for a variety of industries. The fast-growing Sur-Seal differentiates itself by being rapid, right and reliable to the customers.

Learn more about Sur-Seal and its current job opportunities here:

For more information on the Cincinnati “Top Workplaces” list, please visit:

Sur-Seal Named One of Cincinnati’s TOP Workplaces for 2019

We’re pleased to announce that Sur-Seal was recently named one of Cincinnati’s Top Workplaces for 2019. This recognition reinforces our commitment to our employees and to you – our customer – to deliver our best every day.

The Cincinnati Enquirer, in partnership with the research firm Energage, LLC, honored Sur-Seal after collecting anonymous feedback from employees throughout Cincinnati. The survey resulted in Sur-Seal emerging as a great place to work.

While the emphasis on this recognition is that Sur-Seal is a great place to work, we also feel that it results in the benefits that you receive as a Sur-Seal client. We strongly believe that engaged, happy employees deliver the best results for our customers.

According to Marcia Ernstes, Organizational Development specialist for Sur-Seal, one of the areas that makes Sur-Seal a great place to work is its focus on working together to ensure a great customer experience. The partnerships created with our customers are built on a strong foundation of trust. We work hard to improve our internal and external processes to create a safer, smoother and quality-oriented workplace. It’s a win for us as well as our partners.

“Employees at Sur-Seal enjoy working here,” Ernstes says. “They like being a part of a growing business and being able to grow as individuals. With our strong values, people feel like family, not just coworkers, they feel cared for and know that their opinions are valued.”

As we finish out 2019 and move into 2020, we want to hear from you about how we can better serve you. We look forward to continuing to work on your behalf!

Thank you for your part in helping us becoming a Top Workplace in 2020!

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Energy Efficiency: Sealing Matters

Consumer trends, government regulations and increasing energy costs all point to one concept that isn’t going anywhere: Energy Efficiency. Basically, better utilization of energy. Learn more about how Sur-Seal improves the energy efficiency in the HVAC industry through material innovation.

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