In our latest Technology Tuesdays podcast, Design World’s Michelle Froese speaks with David Church, president of Sorbothane, about innovative shock and vibration solutions. Sorbothane has been developing materials and components that isolate vibration, attenuate shock, and damp unwanted noise for more than 35 years.
We discuss visco-elastic technology and the Sorbothane brand of material, including its properties, use cases, and history. We also cover manufacturing challenges and the diversity of industries that this shock and vibration-damping technology can work in.
The audio and a lightly edited transcript of this conversation follows below…
Design World (DW): Hello, Everyone! Welcome to Design World’s technology Tuesday’s podcast. I’m Michelle Froese. Thanks so much for joining us. Today, we are discussing innovative shock and vibration solutions with the president of Sorbothane, David Church. Sorbothane has been developing materials and components that isolate vibration, reduce shock, and dampen unwanted noise for more than 35 years now.
Company name aside, Sorbothane also refers to the brand name of an engineered visco-elastic polyurethane that flows like a liquid under load. It is ideal for engineering design applications that require shock absorption, vibration isolation, and acoustic damping. This proprietary material has been used in several industries and as a solution to a wide range of challenges, which we’ll discuss in more detail with David today.
David, I appreciate your time. Thanks very much for joining us.
David Church (DC): You’re welcome. Michelle!
DW: Can you please start by providing more insight about what Sorbothane, as a material, is exactly and what makes it unique and effective?
DC: Okay… Sorbothane is classified as a visco-elastic polymer. In other words, visco-elastic means material exhibits properties of both a liquid, which flows, and it has a solid elasticity. So, it is able to isolate in both X and Y applications. As a liquid, it deforms under load and then transmits the force in all directions. But as a liquid, it does not come back to its original shape since it’s a solid. Once it deforms, the elastic properties of the material allow it to come back to shape, so that it’s ready to take the next, either vibration or shock load that it’s being used for.
DW: That’s quite interesting. You provided a definition of what visco-elastic means, but is there a standard measurement in place for it?
DC: No, that’s the interesting thing about visco-elastic properties. There’s a wide range of visco-like properties that are out there in the marketplace, but there is no one standard. Each material, like Sorbothane, has its own set of properties in terms of how it works and the range that it works in. So, to compare us against another visco-elastic material — such as the silicones out there — it’s hard to do because they are not the same. They are not a polyurethane.
DW: I see. So, how does Sorbothane… how is it different than a mechanical fluid-power damper and how effective is the material as a vibration damper?
DC: Mechanical fluid-power dampers…well, there’s a difference between the two. I guess we could say, they’re different mechanical systems. Let’s say, for example, there are springs. And there are either elastomers or sometimes they use magnets in some of these applications. So, the difference between those types of situations is that they can only isolate in one direction because they don’t have properties similar to Sorbothane materials — where they can take the energy, dampen, and isolate it in both X and Y parts.
So, that’s the biggest difference between a stiff spring or piston-type of fluid-power isolator or damper when compared to Sorbothane or other types of viscoelastic materials.
DW: That makes sense. It leads me to another question. What applications or industries is this material ideal for?
DC: That’s a good question. And it’s a broad answer because we have 35-plus years of time where Sorbothane has been in the marketplace. We have been in applications in the shoe industry, where Sorbothane has been used as heel pads and metatarsal pads. It has also been used in space expeditions where over the last few years with SpaceX — isolating batteries on satellites or on the spaceship going into orbit.
So, there’s a wide range of markets that we service with our material. And that’s what makes it so versatile. It can be used for an application as simple as isolating a microscope in a lab from ambient vibrations due to people walking in the room, or from other parts being used around that microscope, which disrupts the focus or ability to work properly.
Sorbothane is also used in some severe or critical applications, such as on shipboards to isolate monitors or on a U.S. military vessel. As a versatile material, it can be used in any application or any market — from medical devices to sports industries, to heavy equipment, to construction equipment. There isn’t a market with either shock or vibration that doesn’t have an application for our material.
DW: That’s very diverse. Can you share a little bit about how Sorbothane began its history, as a company and as a product, how did it first develop?
DC: Yes, Sorbothane was part of a larger British company, called British Titan Rubber (BTR), back in the ’70s. There was a chemist in England, Dr. Maurice Hiles, who was a runner. Of course, back in those days, the sneakers or running shoes that were available were not very good compared to today’s shoes. So, he was interested in developing a material that he could put into a sneaker, which would help take away the shock…especially in his legs, ankles, and knees from running every day.
He developed an extensive study on natural materials and man-made materials to find out, which material had the best properties. And he was an interesting man because he actually went to witness cadavers to see if a body, when it got a blow to it, how it would bruise. He noticed that the fatty pad on the palm of your hand and the heel of your foot, never discolored. So, it didn’t matter if you’d fall and land on your hand, the part with the fatty pad never really bruises and practically always returns to its original shape.
Dr. Maurice Hiles’ goal was to create a material that would act like that fatty pat in the human body, which he saw had the best ability to absorb energy. That’s how Sorbothane came about. And he went through extensive testing, actually putting probes in his shins to test the Sorbothane material and see how much it would reduce the “g” level when he was running.
In ’75, he started developing Sorbothane and in 1980 is when it first started to gain commercial use. Then in 1981, a gentleman who was with a division of BTR here in the United States brought Sorbothane to America and started making it in Kent, Ohio at that time. So, from 1981 to now is when Sorbothane has been in the United States, and we’ve been manufacturing the material here.
DW: That’s so interesting. And so, I guess eventually or gradually, this led to use in other industries, right?
DC: Correct. I’ve been with the company for 13, almost 14, years now and one of the interesting facts that helped the material like leap-board or spring forward was that in the ’80s, there was a show called, That’s Incredible, and Sorbothane was featured on it, twice. From those two showings, it opened the doors for people to contact us and to ask, “Can it be used in my application?” That’s what helped the company really grow and get recognized, is from being on that show back then.
DW: Is it difficult to manufacture and has the formula changed or improved over time?
DC: Yes, it is difficult to manufacture because most urethane systems have a one-to-one ratio. So, you have part A and part B and, you know, it’s one-to-one. But for Sorbothane to maintain its properties and work as it does, this ratio is very small. It’s more like nine-to-one. And that one percent, if it varies even a little bit, this changes the material property. It doesn’t take much to make it harder or softer. The one percent is what does it.
So, we make a range of durometers with Sorbothane from 25 durometers on the double-lot scale, which is very soft, and the hardest we can make it is up to 85 on the double-lot scale. This is all done with the ratio of the two, A and B elements.
Now over the years, as you may know, many ingredients have been put on certain hazardous lists, such as the proposition 65 out in California, and there are REACH regulations and RoHS. Everything is worked out to ensure that the material does not have anything on those lists that we would have to classify it for, and we make sure that the material doesn’t have a substance that could cause cancer or anything like that.
So, we’ve had to change certain ingredients over time and have been fortunate that we’ve made the material better, either by making it with a better compression set, so the material doesn’t lose its shape as fast as in the past, or by making it with a better tensile strength or elongation. We’ve been fortunate that when we’ve had to change an ingredient, we’ve really been able to give it a better property.
DW: Right. So there’s some flexibility within it. I was going to ask you if you’re considering Sorbothane for an application, how does that application’s requirements affect the material choice… so, what I mean, for example, is if shock attenuation is more important for one device, but vibration suppression or even water resistance is more critical to another assembly, is there also flexibility in that and how the materials manufactured to meet those different requirements?
DC: Yes. When we look at an application, we right away try to find the environment that it’s going to be used in. If it’s going to be in a washed-down application with a lot of moisture, then we’ll need to use the Sorbothane with water resistance. If it’s going to be in a typical industrial application where there’s no water involved, the humidity is low then, and we can use our standard Sorbothane.
The next question is what’s the envelope we have to work with in the industry. We try to develop what we call, the perfect shape factor. So, if you can give us the frequency and the testing of the energy, etc… when we get all that information, we can feed it in.
We can then develop an isolator up to 94% isolation of whatever the energy is. But it depends on if you can use that shape in your application? And, and we know many times that they don’t have an envelope that the “perfect” shape could fit into. You have to then develop between the shape and the durometer…what the shape would be.
So, is a disc better for this application than a washer, or is a hemisphere better for this application? If affirmative, then either the disc or the washer works. Or, does it have to be a custom design rather than something we have off the shelf? There’s a lot of evaluation we go into. And from there, we have to go through the different steps of what is the best shape overall and what we estimate would be the best durometer overall. Next, is how close can we get it to that 94% isolation. Many times, we can’t hit exactly 94, but we’re closer to 75 or 80.
DW: Can you give a brief overview of Sorbothane’s features? I know we talked about the visco-elastic properties, but are there effective temperature ranges or levels of impact absorption?
DC: The temperature range for Sorbothane is not as wide as some of the synthetic rubbers out there. One reason for this is because of the way that Sorbothane works once you apply energy into it. The molecules start sorting, essentially creating their own heat to take that energy away. So, the material is creating heat as it is; it’s isolating the vibration or the impacts.
Sorbothane works best from a temperature range of -20° F up to 160° F. Now, it can be pushed to go a little bit higher if there are not a lot of cycles, let’s say of, of the material being compressed or of the vibration going into the material. But it doesn’t have the range of other materials, like silicone. This is just one of the things we have to work with, sort of thing
DW: What about its sustainability in relation to the environment?
DC: Well, environment-wise, it’ll last very long. And in dealing with applications, Sorbothane has a life expectancy that depends on that application. As I explained, if it’s being used on an electron microscope in a medical lab, the isolators on that would last for, you know…10, 20 years because it’s not seeing any real vibration or cycling, as I call it.
Now, if it goes into an application where we have been used, such as in a rollercoaster in one of the amusement parks, it’s used every two minutes or so. Then, that lasts maybe five or six years. And then in other applications, it will only last a year because of the severity of the environment. It all depends on the application. That’s the one thing we have to take into consideration in the life of Sorbothane.
We manufacture a line of Sorbothane insoles, and, and we have people who have used ours for five or six years and have no problems. We also have people who in two years, they say that the insole has worn out. But it’s all because of how they walk, their gate, and all of the other things that go into how it’s being used overall. We believe Sorbothane has the physical properties to last very long because if it didn’t, we wouldn’t be in business because nobody would come back to us as they would say it just wore out too fast.
Overall, Sorbothane has a very good physical properties and has the ability to perform over a long period of time.
DW: Understood. When working with engineers and product developers, have you encountered any major challenges or are there any trial-and-error stories that you might be able to share in relation to Sorbothane?
DC: The biggest challenge with working with somebody… and typically, Michelle, when we get contacted, we’re contacted when somebody has a problem that they haven’t been able to solve with other standard materials or products on the marketplace. You know, many of the challenges for us is then developing an isolator with Sorbothane that fits into an envelope that’s already designed for some other material. So that’s the biggest hurdle.
Trial and error wise, Sorbothane comes in a number of different parameters. Typically, when tested, they will send them or buy the different durometers and then test which one works the best for them. It’s not as much of a trial and error when it comes to what durometer you need, because the nice thing about our tooling is that you can use the same tooling to make a 25-durometer Sorbothane part or an 80-durometer Sorbothane part. We, then have the versatility to sample a number of different materials for people to try out of the same tooling. This is what makes it less costly for our customers.
DW: I see. What about success stories then, David? Is there one application where it was unique or even surprising because Sorbothane worked better than anticipated?
DC: There’s been many over the years. I mean, Ideal Toy Manufacturer came to Sorbothane to produce a toy called a Manglor, where the child would be able to pull the toy apart… like its legs, its arms, and then Sorbothane is naturally tacky so he or she would be able to put it back together. That was a unique one that we never thought would work, but it worked very well. And, you know, for a couple of years they were buying Manglors made out of Sorbothane.
The most recent one that we got involved in is with an entrepreneur out of California who was a professional tennis player, one time, his life. He, then, went on to teach tennis. Well, there’s a lot of shock and vibration that comes up through a tennis racket, into the handle. And, of course, through the arms. I’m sure everybody’s heard of tennis elbow below.
Anyway, he started playing around with our material, cutting shapes and little wedges out of it and strapping it onto his racket on the string. He liked it, but we had a hard time making it last because of the severity of the shock coming through the racket. So, we ended up developing a system that had two plastic parts that you sandwiched between two pieces that snap together and are placed onto the racket. Lo and behold, this gentleman has great success marketing this tennis dampener or racket dampener here in the United States and throughout the world.
When we first started working with him, we were not optimistic that this would ever get in turn into any type of viable business, but he’s turned out to be a very good customer. Now with this product that was, you know, one of those long shots that you never thought would really take off. So, we’re happy for him and, of course, we’re happy for us because it’s our name out there. And, you know, it’s a very unique application.
DW: That’s a great success story and definitely touches on the diversity of industries that Sorbothane can work in. You mentioned earlier that the majority of engineers or entrepreneurs come to you once there’s a problem, but is this typically early in the design process or how does it work in terms of someone learning about the material and then deciding that it’s ideal for their product?
DC: People will usually search on the internet, “shock, vibration, and material.” Our name comes up on the first page and then people will do a little research, you know… go to our website and read about the material and read about the success stories that we have posted on there. We also have a number of forms that they can fill out, including a support form that goes to our engineering department.
They can describe their application and what they’re trying to do and an engineer will get back to them. We also have a sample request form where people can request samples of our material to test. And we have a general question and answer form where people can just ask a question about Sorbothane that we will respond to. This is typically how engineers and entrepreneurs will reach out to us and contact us to find out more about our material.
DW: It’s my understanding that Sorbothane is manufactured locally in the U.S. Have you found many advantages to domestic production, and do you also cater overseas?
DC: Yeah, we find especially over last year, being that we’re U.S. manufacturers that it’s to our advantage. And especially now as everybody knows about the shortages of materials that are being made offshore, plus the long delivery times that it takes for materials to show up over the last six months. It’s been a real positive for us.
But even before that, we felt that being American made, gave us an advantage of shorter lead times. We were able to communicate with people here in the United States on the same time zone. It gave us a bit of an upper hand for many of our customers. Internationally, we’ve been over the years establishing international distributors. So, we have a distributor in England and now we also have one in Austria, and we are working with one in Korea. We’re expanding and having stocking distributors throughout the world is important because the demand for Sorbothane has been increasing — not just in the United States but across the whole world,
DW: Thanks so much for this information, David. You must quite enjoy your role with Sorbothane.
DC: I enjoy the role at Sorbothane because it’s a unique material and it’s a really creative environment. You’re assisting people and creating a solution. You know, it’s not the same part every day. In our manufacturing plant, we’re not making the same parts every day.
On a daily basis, we make 50 or 60 different parts that are used for isolating shock or vibration. These parts cannot all be the same because the loads are different, and the applications are different. So, it also has its challenge because there’s a lot of switch-over in that. But on the creative side and the engineering side and then the sales side, it’s a lot of fun because we’re able to work with entrepreneurs to develop an isolator for a tennis racket. We’ve had another gentleman develop a whole series of isolators for high-end speakers for speaker stands. So, like I said, it’s just a wide range of applications and it requires an ability to be creative. This company allows whoever works here to do just that.
DW: Each day is novel! We’re nearing the end of our available time today. Is there anything else you’d like to touch on before we end our discussion, David?
DC: I think we covered a whole lot about Sorbothane. You know, how it works, how the material works, the versatility of the material. One thing I could touch on is that we offer a wide range of colors. Sorbothane can be blended and made into custom colors. We also offer a range of blues, oranges, reds, greens, yellows, and the colors can be custom blended to match one that’s needed.
DW: And can you mention your website or how to best get in touch?
DC: The best thing is to visit our website, which is Sorbothane.com… very simple. We also have Facebook and all of the other social media if you’d like to use that to come and contact us through there.
DW: Excellent. Thanks again for joining us, David, and providing such great insight.
DC: Thank you, Michelle. It’s been my pleasure. We look forward to working with your company in the future.
DW: Sounds great! To learn more about us, please visit Design World website at designworldonline.com, and be sure to subscribe and share this wherever you listen to your podcast. Thank you listeners for your time and attention. I hope you all have a productive day!
Filed Under: PODCASTS, Shocks + vibration control • gas springs