Foam Cushioning Systems
Cushion Materials
| Foam Types |
Density |
Characteristics |
| Polyethylene (PE) |
2#/cubic foot |
Closed cell foam, best for use with heavier/denser equipment, power supplies, communications equipment. Optimum load range .20 to 1.0 lb/sq. in. Resists water pick up, resistant to oils and solvents. Anti Static versions are available. |
| Polyurethane (PU) |
2#/cubic foot |
Open cell multipurpose foam, soft, highly resilient. Best used for lighter weight sensitive equipment, computers, monitors, projectors. Optimum load range .08 to.40 lb/sq. in. Anti Static versions are available. |
| Crosslink PE |
2# to 4# |
Closed cell foam with smooth finish. Loading ranges in line with regular Polyethylene. Resists release of particles. Best used for items like military or commercial optics and medical devices. Different colors and antistatic versions are available |
Cushioning Systems
| Foam Filled |
Case is filled with 1" or 2" layers of PE or PU foam. The foam can be field cut to accept customer's equipment. Each layer can be cut to accept equipment of various sizes. |
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| Foam Lined |
Case is lined with either 1" or 2" thick layers of foam. Allows the case to be used for multiple items or for bulky items with low fragility. |
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| DIY Interiors |
DIY foam, often known as Pick and Pluck foam, is a soft PU foam that is pre-scored in 1/2" x 1/2" cubes that can be individually removed to provide professional looking foam interior. Can be easily and inexpensively replaced if equipment changes. |
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| Fabricated Interiors |
Cases-Cases manufactures custom cavities for simple or complex shaped items. The foam interiors are fabricated from single or multiple foam types. Cases-Cases uses a water jet cutting technology to provide extremely tight tolerances and complex shapes including round or angled cavities. |
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| Die Cut Interiors |
Cases-Cases can provide die cut interiors. Die cuts are popular and cost effective for foam interiors where very small cavities exist or where a high quantity of cases are required. Common applications include sample cases and media cases. |
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| Custom Interiors |
Working with your equipment, specifications or drawings, Cases-Cases can create the optimum case interior, taking into consideration, fragility, spacing, access, storage and usability of the equipment. We have created foam interiors for single and double-entry cases. |
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The type of case, the material of the case shell, and the case fabrication method only defines part of an adequate packaging solution. The cushioning system is equally important to the protection of the payload. Cases-Cases has years of experience in providing complete packaging solutions, including cushioning system design.
There are 4 variables that aid us in determining the appropriate cushion design for your equipment:
- Fragility. The fragility is the level of shock in g's that your equipment can withstand. Often commercial electronic equipment can withstand a shock of approximately 30'gs. Optical equipment and space payloads can withstand shock levels of less than 10g's. Mechanical assemblies are often quite robust and can withstand much higher g inputs. Fragility is often not known and is estimated.
- Drop height. Cases-Cases utilizes drop heights as one of the "available" variables in cushion system design. Many military programs and specifications detail the drop heights of certain items. The MIL-STD 810E details the drop height that a case must pass based on total case and equipment weight as well as container size. If your application is for shipping or use as checked baggage, we design for a 30" drop.
- Sway Space/Cushion Thickness. In a perfect world, Cases-Cases could design containers and cushioning systems and not be limited by available case sizes, case weights, and limitations of how the cases are going to be shipped. Since those and other variables are involved in container design, we often have to compromise between case size and sway space or cushion complexity (cost) vs. case size.
- Density of Equipment. The density of the equipment is the weight divided by the weight bearing surface. The density of the equipment aids us in determining the correct foam type to use as well as the correct amount of bearing surface. Foam cushioning materials have different optimum load ranges, as detailed in the custom case interiors section of Cases-Cases.com.
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The following table is one way the case designers at Cases-Case determine the appropriate cushioning system, case size and foam type for your specific item.
Shock Levels in G's of Fragility
Sway Space (in inches) |
12" |
18" |
24" |
30" |
36" |
| 8.0" |
7 |
8 |
9 |
12 |
15 |
| 7.0" |
8 |
9 |
10 |
14 |
17 |
| 6.0" |
8 |
11 |
12 |
15 |
20 |
| 5.0" |
10 |
13 |
15 |
20 |
25 |
| 4.0" |
12 |
15 |
18 |
25 |
30 |
| 3.5" |
13 |
18 |
20 |
28 |
35 |
| 2.5" |
20 |
25 |
30 |
40 |
50 |
| 2.0" |
25 |
30 |
35 |
50 |
60 |
| 1.5" |
30 |
40 |
50 |
65 |
85 |
| 1.0" |
45 |
60 |
70 |
85 |
105 |
A very simple rule of thumb for "typical" payloads is to use 2" of foam or sway space around all items.
Not all cushioning systems are best done in foam. Additional variables that include sensitivity to particulates, sensitivity to out gassing of foam, and foam's ability to absorb moisture often lead our designers to chose alternate cushioning systems. Let the experts at Cases-Cases solve your most challenging cushioning and packaging problems.
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