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Making a case for fabricated flexible foam

C.H. Ellis, maker of custom cases for industrial, military, medical and electronic applications, uses custom foam inserts to protect valuable products inside the case.

The photos in this article illustrate how two different thicknesses and colors of foam are heat-bonded together with cavities custom cut to contain individual instruments, tools, devices, etc.
The photos in this article illustrate how two different thicknesses and colors of foam are heat-bonded together with cavities custom cut to contain individual instruments, tools, devices, etc.

The majority of stories in Packaging World focus on how products are protected on the outside by packaging. But this article reports on flexible foam that’s used inside a custom-made carrying case to protect valuable contents. Each carrying case is subsequently packed in an outer corrugated shipper for distribution.


The packager in this instance is C.H. Ellis Co., an Indianapolis-based maker of stock and custom carrying cases for instruments or measuring devices for the military; for field service and repair industries; for medical devices and test instruments; and for government agencies. Made of plastic or aluminum, these custom cases typically measure 24 x 20 in. x up to 6 in. deep. Cases can carry products or instrumentation often worth up to $10,000. To protect these valuable products, C.H. Ellis works closely with HSM, a global manufacturer of integrated solutions and components to the transportation, furniture, bedding, and a growing number of diversified markets; and its Hi-Tech Foam product brand of foam components for automotive, appliance, medical, aviation, police and military applications.


The two companies have partnered for years, with their more recent collaborations focusing on “shadow boxing” and the use of cross-linked polyolefin foam manufactured by Zotefoams plc.


Think of shadow boxing as an Oreo cookie without one of its outside cookie layers. If you cut through the white filling you would see the dark cookie at the bottom. For the foam used in the C.H. Ellis cases, two different thicknesses and colors of foam are heat-bonded together, with cavities custom cut to contain individual products, tools, devices, etc. When you look at the top of that foam you see one color, like the white cookie filling. Underneath, however, there is a different color, so if the C.H. Ellis customer notices this color, it indicates that the product, tool, device, etc. is missing from the case.


Bob Able, president of C.H. Ellis, explains, “We do a lot of government jobs that involve the use of materials for identification and bond purposes. They need the material to be anti-static or conductive. So we may have a pink-colored foam with a black-colored foam on top. When we lay the customer’s instruments into the foam, they go into a drawer, or in a workstation. When they pull the drawer open there is this foam with all the instruments in it. Because of the color differences, they can tell if there are any instruments missing, which is a big problem because a lot of them are very expensive. With the foam, the customer can take inventory quickly and know if they’ve left one instrument out in the work area, and can go get it and place it back in there. Then they can close the workstation and lock it up for the evening.”


This application refers to Foreign Object Debris, or FOD, whereby the C.H. Ellis customer needs to prevent expensive objects from being left out, lost, or pilfered. That’s why the two different-colored foams, or “shadow boxing” becomes so important.


Zotefoams, explains HSM’s John Metaxas, is a manufacturer of cross-linked polyolefin foams widely used in packaging. “They are unique because they expand their foams using pure nitrogen in a unique autoclave expansion process, whereas most expanded foams use a simple chemical reaction. For instance, a polyethylene foam would use butane to help the foam expand. Over time, that chemical will escape from the foam. Zotefoams, with pure nitrogen, has a very consistent cell structure, so the surface of the foam is uniform, even when you cut it. It gives the end user a nice, aesthetic appeal. But on top of that, when you are dealing with electronic, military, or medical devices, Zotefoams is preferred because the use of only nitrogen offers engineers a level of comfort knowing that there won’t be any chemical reaction or possible outgassing of unreacted chemical agents to affect their product. For instance, there are many foam products that come from overseas, and it may be difficult to get a technical data sheet that lists exactly what type of chemical and how much is being used to produce those foams. Zotefoams is extruded in slab form in England, then shipped to their manufacturing plant in Florence, Kentucky for final expansion,” he says. HSM is an authorized fabricator and distributor of Zotefoams, fabricating the foam to specific sizes and shapes required by C.H. Ellis.

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