MDI Products proudly announces a breakthrough formulation that raises the upper service temperature of our foam. We have subjected the foam to the aggressive enclosed environment of a temperature controlled oven at the constant temperature of 70 C (158F) for over 24 hours. The foam exhibited no deformation from this exposure and a shrinkage factor of less than 1%. This oven test is considered a litmus test for heat resistance of foams.
For those who are familiar with soft flexible foam products, this represents a major accomplishment!
We at MDI Products have continued since our inception in 2001, to push the limits of what can be done with Foam Direct Injection Molding. From the very beginning we sought to bring this technology to soft, flexible foam products that were not originally considered to be candidates for injection molding. We could see applications that covered almost every field.
To this end we have developed a range of proprietary formulations to make use of the unique properties found with this process. We can produce products that are tailored to the highly specific needs of our customers. Just tell us what your product requirements are and we will get busy to supply the correct formulation to match the parameters that are important to you.
Expansion injection molding process as used by MDI for manufacture of technical products is a complex mixture of science and art.
A major challenge is the difficulty of making a quantitative statement of injection molding that becomes clear when one analyses the machinery, material and process.
The factors that affect the process are material temperature, temperature profile, pressure, material velocities in cylinder and mold, mold temperature, viscosity and flow patterns in the mold. These factors are difficult to measure and only intermittently if at all.
The material used as made by compounding is not identical each time, having different heat histories, molecular weights, molecular weight distribution, degrees of polymerization and impurities.
Careful and proper control of these variables are critical for MDI’s manufacture of complex engineering products for a consistent and successful outcome.
Visit MDI’s website where you will find new content and information on injection molding process of polyolefin/EVA materials.
The general (and deprecated) term “foam” applies to a wide variety of cellular polymeric materials, plastics or elastomers. A product, either flexible or rigid, that has been produced by the internal generation or liberation of a gas in a fluid medium that is polymerizing while expanding in volume. The final result is either open or closed-cell product.
The cell geometry i.e. open vs. closed cell size and shape, greatly affect the foam properties. Thus, closed cell foams are most suitable for thermal insulation, while open cell foams are best for acoustical insulation.
Foams may be flexible or rigid, depending upon whether their glass transition temperatures are below or above room temperature, which, in turn, depends upon their chemical composition, degree of crystallainity and degree of cross-linking.
The production of foams can take place by many different techniques. In MDI’s injection molding process foaming is achieved by thermal decomposition of chemical blowing agent as the result of the exothermic heat of reaction during polymerization. (see white paper- MDI Foaming Process)
Cell: (bubble) (pore0- a simple small cavity formed by gaseous displacement in an elastomer and surrounded completely by its walls.
Closed-cell: A cell totally enclosed by its walls and hence not interconnecting with other cells.
Cell count: The number of cells or bubbles per linear inch or centimeter.
Open cell: A cell not totally enclosed by its walls and hence interconnecting with other cells.
I always say I am very lucky because I love what I do. I have to bubble up my excitement most of the time, as we manufacture custom parts and we operate under strict confidentiality to protect the intellectual property of designers and inventors from around the world. All I can say is that I come in contact with some incredibly brilliant people!
Typically people come to us to make an existing product smarter, more durable, more protective, lighter, and more beautiful than what exists in the marketplace. Afterall, we can make parts in any Pantone color you can dream of, with logos and textures and patterns imbedded into the mold, eliminating the need for secondary operations. Did I mention our Polycell is REACH certified? Safety and Protection should go hand in hand...This leads me to my next client, who has given direct consent for me to boast about their clever creation on my site.
I am involved with a company called "mentalKase" that has recently launched on Kickstarter after two years of R&D. The product is based on patents that have sold over 2,000,000 units under license in hand held video game products. The inventors decided to give it an entrepreneurial go in the smartphone/tablet market themselves. The product differentiates in both material construction and design that goes a step beyond the current offering of "ruggedized" cases. mentalKase is the world's first dual layer foam case for iPhone 4/4s and 5. Foam is impact resistant, buoyant and anti-microbial. Please visit the Kickstarter page and watch the video to learn more about mentalkase.
Kickstater is a "crowd funding" platform where creators share all sorts of projects. People interested in the project can "donate" to the project and receive "awards" for their donations. mentalKase has developed award levels where you will receive actual product at a discount to suggested retail. One caveat of Kickstarter is that projects do not receive any funding unless they hit the funding goal. mentalKase's funding goal is $50,000 and is set to expire at the end of February. The funds raised go directly into production of iPhone 4/4s and to tool for iPhone 5 which will put the company in a position to deliver product to initial customers (Kickstarters) while expanding distribution channels for ongoing sales.
Please support mentalKase. The product is great at protecting you and your iPhone and you will help us create a company that will design and develop mentalKases for other devices and form factors.
If you have any questions or comments let me know
I'm mentalkased. Are you? Please share this note and/or the kickstarter link to spread the word!
P.S.- The designer colors are beautiful, and noone but mentalkase is using them in the case industry right now, so make your case stand out in functionality and style.
I was thinking back over my last ten years in the injection molded (EVA and polyolefin foam) business, and wondered which products made with this process are my favorites. It's an extremely hard question because there have been lots and lots of products made. Many products have been made by my company but other companies in our industry have also created incredible designs. If I had to narrow it down to only five, which five would it be?
It was hard to decide, but here's my list. I'm sure, however, that I will need to do another post for the runners up.
Crocs Sandals. The Crocs Sandal is the number one obvious choice. It’s not only because of the incredible (so ugly, it’s beautiful) design but because of the worldwide phenomenon it created. We were lucky enough to manufacture Crocs in our factory and it never ceased to delight me to watch them being made. After they came out of a hot mold, the sandals were cooled on a unit that looked like a ferris wheel, where each level held one cycle of production. Round and round they would go and, at the end of the cycle, they would be removed from the carousel. Straps were attached and "voila" a new pair of Crocs was born, in a rainbow selection of colors.
Backpack Padding. If you’ve owned a backpack, especially a high-end backpack, you probably never noticed the comfort-foam included in the product. Why? Because it was always hidden behind fabric or mesh. The ability to injection mold EVA and polyolefin foam changed all that. Here’s a backpack that is wearing its lumbar and upper back comfort-foam on the outside, as a showpiece. The detail of the injection molded foam process allowed for industrial design to not only deal with the practical, but also the beautiful.
Kayak Seat. Traditionally, kayak seats were made from compression molded foam with a fabric laminate. This product design has always had a limited life. Several years ago a few kayak companies were adventurous enough to recognize the durability and detail benefits that result from the application of the injection molding foam process. They designed kayak seats that were not only very detailed with undercuts and logos but extremely durable.
Carseat Armrest. Check out this really creative foam carseat armrest. The carseat manufacturer designed the armrest foam to be injection molded separately and allowed the foam to "shrink" onto a plastic substrate. The subtrate has ridges on it that create a "grip" relationship between the foam and the plastic. The results ended up utilizing the benefits of EVA/polyolefin foam in an armrest application that needed to be "kid friendly."
Construction Kneeling Unit. I don't know if I like this product more because of its design or because of its function. I'll bet if you just looked at the product on the left you would never know it was used in construction. This clever kneeling pad design allows workers to stay on top of a house during roof construction as they are installing one truss after another. The time savings in crane rental is up to 40%, paying for the product almost the first time it is used. The orange support is made of durable, powder-coated aluminum. The injection molded EVA/polyolefin foam padding provides comfort for knees and legs and stays dry during use.
If you have a favorite, I'd love to hear about it. If you send me a photo, I will be happy to post it. In the meantime, visit our product solutions gallery to see a selection of products we've made over the years
I love this story, even if we didn't make the “One World” soccer ball.
This soccer ball took 5 years to develop. I can believe it. I, absolutely, know how hard this soccer ball was to manufacture. I've worked on lots projects in the injection foam molding process that have required extensive R&D to make the product come out just right.
It all started when a music producer and inventor, Tim Jahnigen, saw how children traumatized by their violent environment “were desperate to play with anything.” It gave him the idea to create an indestructible soccer ball.
After 5 years of development, and some help from Sting, he developed a soccer ball with the injection foam molding process like Crocs sandals.
The soccer ball is indestructible because this soft foam is basically indestructible. How long have you worn your Crocs sandals? The soft foam has its own, extremely durable, skin that is formed during the manufacturing process. Inside the skin is an equally tough, closed cell, foam that won’t absorb liquid.
See how a truck can run over it and still not destroy it.
All of these process and foam benefits mean the kids will be able play with this ball in any environment with no chance of it being flattened, and almost no chance of it ever being damaged. I understand a ball was given to a lion in the Johannesburg zoo. Even he couldn’t destroy it.
People confuse foam density and foam softness all the time. They say to me, “I’m looking for a low density foam.” I always ask “Do you really mean density or do you mean softness?” They (almost always) mean softness.
So, what is the difference? The density of foam is a measurement of the weight of a cubic volume of a material, like 12lbs/ft3. On the other hand, the softness of foam is a measurement of the tension on the surface of the material when it is touched.
Actually, there is not a real direct relationship between foam density and foam softness. You can have foam that is 2lb/ft3 density and is very soft or very hard. It depends on the chemicals used to make the foam.
How, then, is softness measured? It’s measured with an instrument called a durometer. There are three major softness measurement scales: Shore 00 (shown right), Shore A, and Asker C. Shore 00 is the best scale to use when you want to measure something that is very soft as it has the widest scale on the soft end.
So, is there any relationship between softness and density? Not really. However, there is a direct relationship between density and Squishiness (a new term I have created.) Of course, I’ve had to also create the tool for measuring this soft foam specification…the Squishometer (seen below left.)
Take the difference between open cell foam and closed cell foam. Open cell foam scores extremely high on the Squishometer because it has a very low density. (A sponge is an example of open cell foam.) Closed cell foam tends to be denser and, therefore, scores low on the Squishometer.
Hopefully my short post on this (often confused) physical property of soft foam is now clear. The next customer who asks me will be the test of this theory.
For years, product designers and developers have been asking if the injection molded foam process could produce parts in a dual density or dual colors.
Although this foam process was invented several years ago, it wasn't really perfected. There was always some flash bleeding over into one side or the other between the densities or colors which made the parts look sloppy and not of the quality most developers need. Of course, this was most visible when the colors were different.
Finally, after lots of trials, this foam process is now perfected for simple geometry parts. This is huge progress in a growing industry that has no centralized association. It's the hard working inventive people on both the machine manufacturing and molder sides that pushed past all the obstacles that ultimately resulted in this breakthough.
So far, we've only been able create real quality parts when the geometry is simple, like a sandal or a midsole. Look at them. Don't they look fabulous? For example the upper side is one color (and one density) and the bottom side is a second color (and denser for abrasion resistance.)
Obviously, it can't stop here. Those of us in this industry must continue to strive to create the ability to produce more complex geometric parts in dual density/dual color. Hopefully, this will not take several years to perfect like the initial trials.
An adventurous customer, with a vision of their complex part in dual color or dual density, will absolutely help accelerate the development.
Almost any resin can be foamed. The world of foam is made from many different resins yet the injection molded foam process uses EVA, in combination with polyolefin elastomers. Why is that? Because it makes soft foam parts!
Hard or Soft Foam? There are many other polymers like polypropylene, polyethylene, or polystyrene which can easily be foamed creating a lower density, lighter product. However the results will stiff and hard as they are hard and stiff resins to begin with.
EVA produces flexible foam. EVA is a polymer that is similar to an elastomer because it can be made to be soft and flexible. That's the origin of the term flexible foam. This means that when soft EVA is manufactured, the resulting foam will also be even softer and pliable, allowing the production of varied soft foam parts to be used in industries such as juvenile, outdoor, sporting goods, kitchen and bath to name a few.
How does it work? In a simplistic sense, any formula combining EVA and polyolefins will have a linear chemical makeup. Under normal circumstances, having a linear chain creates a harder material. However, because of the specific chemical makeup of EVA it won't crystallize easily, helping it to retain its softness. In addition, EVA foam can be crosslinked, which will both help to stabilize the foam as well as produce soft foam final parts.
Crosslinking creates stable soft foam. Basically crosslinked foams, like EVA foam, are more stable than similar highly expanded un-crosslinked foams. This means it can retain its foam structure at temperatures approaching the melting point of the polymer used and, in some cases, exceed it. One of the additional benefits of parts made from EVA foam, and other crosslinked foams, is the ability to create parts by compression molding methods, including the injection molded foam process.
Why EVA foam is a perfect resin for our injection molding manufacturing process? It produces soft EVA molded parts that are stable, durable, closed cell, and chemically resistant.
5 ways products manufactured by injection molded foam differ from compression molded foam, not counting the obvious...Injection molded foam products are made by a pellet to product process, injecting a melted pellet into a closed mold foaming the formula into a multi-dimensional design. Compression molding foam can't come close to creating the same complex designs. However, when injection molding produces the same, or similar, product to compression molding here's how they differ.
Aesthetic Quality. When it comes to a finished look, the overall appearance of a compression molded (vacuform/thermoform) foam part cannot compare with that of an injection molded foam part. The increased density, and perfect "mold" finish of an injection mold, produces a part with far superior aesthetics. Because the foam used for compression molded parts is outsourced, the quality of the foam is also likely to be variable, affecting the final aesthetics of the part. On the other hand, because the injection molded foam is manufactured in-house with the foam and part made simultaneously, the quality is always consistent.
Specific variables that affect quality in compression parts, but not injection parts, are:
inconsistent cell count within the foam, variable pigmentation and density in the raw materials causing color variation
inconsisent part to part processing time, temperature and degree of compression causing variation in part definition.
Dimension Quality: The ability to produce a consistent dimensional part is based on how well the molding process can be controlled. The pellet to product process means that the manufacturing of the foam, and final part, are one and the same. Most processing conditions can be controlled and duplicated, resulting in minimal part to part variation. Compression molding, however, starts with a bun or sheet of foam that is heated and molded into a different shape, subject to far more variable processing conditions. In addition, the need for final trimming of the compression molded part can also be a major contributor to a low quality image.
Thickness Variation: If the final product has varying height profiles, a compression molded part must start with a sheet (bun) of foam that is the height of the tallest dimension of the part. If the foam chosen for the compression molding process does not come in a thick enough bun, laminating sheets together is required to form thicker buns. This can result in that some parts have a lamination line which can delaminate with time. Injection molded foam parts, however, can be made to any height, not limited by the process, without need for lamination.
Post Mold Stability: Another area where the two processes differ significantly is what happens to the part after it is processed. Injection molded parts are extremely soft and malleable when they finish their molding cycle. During the post molding phase, a cooling fixture may be required to help the part maintain its shape. Unless the part is subjected to external forces that causes it to change shape, the final cooled part will be exactly what was expect. On the other hand, compression molded foam parts can suffer post molding shrinkage and warp, even if cooling fixtures are utilized.
Cost and Value: Compression molded foam parts will almost always cost less than injection molded foam parts. Not only is the tooling and manufacturing equipment less expensive but the parts as well. Because compression molding uses bun stock, low density (inexpensive) foams are often chosen. This results in lower quality products that are great for a give-away or other temporary product. Injection molded foam products, while more expensive, are attractive, with long lasting value.
Both compression molded foam and injection molded foam have their place in the world of manufacturing. Choose the foam process that is best for your product.