Posted by Nancy Grossbart
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.
You can learn more about it in an article in the San Francisco Chronicle.
Posted by Nancy Grossbart
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.
Any takers??
Posted by Nancy Grossbart
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.
Posted by Nancy Grossbart
When a gas is captured inside another material or resin, you get foam. Because the resin is filled with gas, it makes it expand like a balloon filled with air. This creates many beneficial characteristics such as being lightweight and, sometimes, soft with cushioning capacity. Foams that are made from a plastic resin, start as a solid and then are turned into foam by creating a "gas phase" with a foaming (blowing) agent.
The foaming process begins by creating thousands and thousands of gas bubbles in the melted plastic resin. These thousands of bubbles cause the cubic volume of the base plastic resin to expand as the bubbles increase in size and number. The resulting foam can be open cell foam or closed cell foam.
The next step is for the plastic resin to begin the process of hardening, fixing the shape and size of the bubbles. Foams may be soft and flexible (flexible foam) or hard and rigid, depending on the base resin that is used to make the foam.
When a foam shell wall forms from a rigid material like most metals, plastics, or ceramics, it acts like a tiny ping-pong ball providing lighter weight material. In other words, it has a higher volume-to-weight relationship (lower density) than the same material without a foam shell. This lower density is an important property that plays a key role in many industrial applications such as floatation and insulation, which currently are substantial markets. However, when a shell wall forms from flexible material like rubber or elastomer, it acts like party balloons and provides extra cushioning or softness to the material as well as more volume-to-weight ratio. It can be used in the athletic and furniture industries. Other industries also benefited by the usage of flexible polymeric foams are automotive interiors, seals and gaskets, footwear, medical aid devices and packaging.
You can foam almost anything, if you can find an application that needs it: metal foam, polymeric foam, paper foam, wood foam, and ceramic foam have been developed and used in a variety of products for unique advantages to enrich our lives or to explore the mysterious universe.
In terms of practical perspective, foams can be viewed in three categories; properties, technologies and ingredients.
In general, foam properties can be defined by dimensions, density, softness, cell size, number of cells per cubic volume, shape, and other properties such as surface appearance.
As for technology, it is basically classified as three types of manufacturing: soluble foaming, reactive foaming and melt/solution quenching.
When producing flexible molded foams you will find huge benefits in using some ingredients like polyolefin elastomers (POE). They are known for their flexible characteristics with benefits such as:
- High Durability and Abrasion/Scratch Resistant:
- Chemical Resistance
- High Weathering and UV Stability
Flexible foam can be created in sheet form or by an injection foam molding process. The main difference is that the injection foam molding process produces a "finished part" at the end of the foaming process. The foam molding process that produces a sheet still needs a secondary "fabricating" process to turn it into a usable part.
Learn more about "Understanding Injection Molded Flexible Foam". Download our 8-page white paper.