For many centuries, the same materials have remained as the base structural support for any structure. These materials include concrete, wood, and steel. However, new research has created the potential for new structural support systems manufactured from fiber-reinforced polymer composites (FRP).
A FRP structure uses a combination of high-performance polymer resins, carbon and glass reinforcement fibers, and a foam core to create a highly stable, yet still flexible structural support system that is inexpensive and highly useful. The structures have been used successfully in the marine, renewable energy, and aerospace markets. FRP has been used in these markets for 40 years with favorable results.
Now, the FRP structures are available for use in architectural and civil structures. There are many benefits to using FRP, including the ability to form unique shapes, the freedom to use structural elements to create design freedom, and a simpler way to create curved forms. FRP is also resistant to structural damage, corrosion, fire, and environmental damage. The cost of FRP is also less than some materials, like steel, and the strength of the material is just as high.
Because of these benefits, the structure requires less maintenance, which cuts down on maintenance time and expenses. Buildings that use the foam structural cores will find that the chances of the structural support catching on fire is much less, and the structure is impervious to flooding. FRP is not invincible, as it can still be damaged by earthquakes and other shifts in the ground. The benefits of the material far outweigh any downsides, however.
Foam fabricating is the manufacturing of a lightweight, versatile, polymer-based material. The material, such as plastic or polyurethane, is frothed up while in a molten state and then cooled, which fills the material with countless little bubbles, giving it an appearance similar to a sponge.
Foam fabricating is a broad term used to describe types of foam, applications and uses of those types and the products that can be formed from foam materials. Foam is simply a substance formed that consists of a number of air bubbles trapped in a liquid or a solid. Foam fabricators classify their product by two categories: open-cell foam and closed-cell foam. Closed-cell foam contains foam cells which are sealed, or "closed" and separate from one another. This foam is very dense and has high compressive strength. Because the cells are not broken in this foam and gas and liquid molecules do not freely travel from cell to cell, the cells expand when exposed to heated gas. The expansion fills the material, making closed cell foam an excellent heat insulator, like spray foam. Open-cell foams are lightweight, spongy, soft foams in which the cell walls or surfaces of the bubbles are broken and air fills all of the spaces in the material. This makes the foam soft and weak; as a result, open-cell foams are commonly used for foam padding and foam cushions. In addition, open cell foams are effective as sound barriers, having about twice the sound resistance as closed cell foam. The medical, construction, automotive, electronics and furniture industries all use foam products.
Foam fabricating services, such as foam cutting, work with many types of foam for numerous applications. The most common foam used is polyurethane foam, which is resilient closed-cell foam that biodegrades in direct and indirect sunlight. Typical applications for urethane foam include surgical scrubbers, x-ray positioning pads, EKG pads, insulation foam, protective foam padding, flexible foam seating and custom insulated containers. Polyethylene foam is a closed-cell, expanded, extruded, flexible plastic foam with predictable shock absorbing qualities. Used mainly as a protective packaging material, polyethylene foam is used to wrap products such as computer components, frozen foods, furniture, signs, sporting goods and clothing. Ethafoam is polyethylene foam that offers excellent shock absorption qualities and is often used for blocking, cushioning and bracing protection in material handling and shipping. Polyether foam is low-cost polyurethane foam that provides good cushioning and has acoustic and packaging properties. PVC foam is closed-cell vinyl foam that is pliable and soft and used in gaskets to prevent water transmission. Expanded polystyrene (EPS) is being used in some surprising applications: as padding foam in bedroom slippers, filter foam in air conditioning units, insulation foam, oil rigs, weather balloons and satellites.
Foam can be made from a variety of materials including plastic, low density elastomers and rubber. Typically formed from polymers, foam is made by mixing a number of chemicals and adding a gassing agent. The addition of the gassing agent causes the material to expand and form a foam strip. The foam is comprised of numerous gas bubbles trapped in the material. After foam is formed, a variety of foam fabricating services can be performed, including several types of foam cutting processes. Die cutting is a common foam fabricating process, in which different shapes are cut out of foam strips, blocks or sheets. Water jet cutting uses a fine stream of water under ultra high pressure to perform the same function as die cutting, but offers extremely close tolerances that die cutting cannot achieve. Hot wire cutting utilizes a heated wire in order to form smooth, straight cuts in the foam. There are also several types of foam forming processes. A popular foam forming process is thermal-forming, in which bulk foam materials are heated in order to produce machining shapes like foam sheets. Another forming process, foam felting, produces denser foam materials by means of compressing and curing thick, soft foam materials.
Foam fabricating services produce a large amount of scrap. The first major source of scrap is produced during foam production as well as foam die cutting processes. Foam scrap is produced as a result of the startup and shutdown of the production line when manufacturing runs are changes over and when foam blocks are cut and shaped into the desired end product. The second major source of foam scrap is foam products that have reached the end of their useful life. Scrap foam is often shredded and rebonded and then used for such products as carpet padding and filler for pillows and furniture. Foam scrap can also be burnt in order to reduce waste bulk; however this was more popular in past decades. Although the burning of foam is considered to be non-toxic by U.S. government agencies, as a result of growing environmental concerns and more stringent carbon dioxide emission regulations, many foam manufacturers have turned to recycling as a waste handling method. Recycling offers manufacturers the ability to recoup return on investment, which would be lost by burning the scrap. Although the use of recyclable foam materials is growing, the process of collecting the foam, separating out the contaminants and then shipping the foam economically can be time consuming and costly to those foam manufacturers wanting to recycle.
Foams in general have a huge assortment of applications, and many of those applications make them valuable across a huge number of industries. It's probably difficult to name an industry or field where fabricated foam isn't found performing some major or minor role. Notable applications include:
Foam fabrication encompasses such a wide selection of fabrication technologies and products, that detailing the history of the various processes' development could easily encompass an entire textbook. The earliest science and fabrication technology of polymeric foams traces back to the 1920s and 1930s, with the development of the Talalay and Dunlop processes for producing latex foam.
From there, the history of foam fabrication shares much in common with the general development of chemicals over the next few decades, as new substances and chemical concepts discovered during the WWI made their way into general industry and technology.
Foamed polystyrene, i.e. Styrofoam, was invented in 1947 by researchers as Dow Chemical Company's industrial labs. Other modern foams trace their history to any number of different researchers and corporations, with each type of foam developing parallel to the others.
Modern foam fabrication thus represents nearly a century of accumulated learning and experimentation from countless researchers and engineers. The scientific principles behind the production of each type of foam, combined with logistical and manufacturing considerations for producing effective products from these foams, continues to evolve even now with the latest breakthroughs in Nano cellular polymer foams.
When discussing fabricated foam, you'll often come across a huge number of descriptors and types. Some of these are differentiated by material, others by production method, still more by post-processing. Even this list fails to encompass every type of foam you may encounter, due to the sheer volume of options available.
There are a few different processes involved in modern foam fabrication. Different types of foam require different production methods, while different applications may require or benefit from various approaches to cutting end products from the foam.
Generally speaking, foam is initially produced through one of the various complex chemical reactions discovered and researched over the century of foam production. From there, foams may be shaped or cast into any number of forms.
In many cases, a simple slab of foam is produced from the initial method. This slab is then cut into various forms via one of several major cutting methods:
Of course, these are only the bare basics of foam fabrication processes and techniques. Dozens of custom cutting and post-processing methods for foam exist, creating nearly as much variation in how a manufactured foam is shaped as there are in the basic materials of the foam.
More advanced foam products may also involve various unique approaches to combining or layering foam via adhesives, heat treatments, lamination, and other joining techniques.
Due to the sheer variability of foam fabrication, it's difficult to detail the machinery likely to be used by any given team. Simple production of two foams such as flexible polyurethane foam or cross-linked polyethylene foam is likely to require significantly different equipment, and either one of those foams may then be shaped, treated, or combined through use of various secondary pieces of equipment.
This makes it particularly important for anyone seeking custom foam fabrication to carefully research their options and discuss their specific needs with each fabricator, as the market is strongly differentiated in capabilities and specialties.
Due to the many different applications of foam across different industries, there are accordingly a wide variation in alternative materials and solutions. For insulation, you might use fiberglass insulation or cellulose boards. For bedding, you might use down or textiles. For shipping purposes, you might alternatively use bubble wrap or cardboard padding.
In many of these fields, foam stands out for its convenience and cost efficiency-but to identify your best option for a given application, you'll need to look closely at your given usage rather than choosing generally between 'foam' and 'not foam'.
It's difficult to describe general benefits of foam fabrication as a process, due to the wide variability of end products. Some foams offer incredible strength, while others are extremely flexible and pliable. Some are brittle but resist pressure, while others are soft but resist tearing. If there's a single overarching benefit to foam fabrication, it's the sheer granularity of options you have in producing your end product.
There are quite a few factors to consider when finding the right manufacturer for your needs. Because foam fabrication encompasses such as wide range of end products and applications, you're best served looking for a fabrication team that matches your specific needs rather than one that's simply 'good' in a generic sense. In particular, you'll want to look for these factors.
- A material utilized to alter the properties,
processing or final use of a base polymer. The quantity of additive is
usually articulated in terms of parts per hundred of the total resin
in the polymer formulation
- The quantity of air that can flow through a two foot by two foot by one foot foam sample with a five inch water pressure differential. Air flow is expressed in cubic feet per minute.
- Voids in molded foam parts that are the result of the entrapment of air pockets occurring during mold fill out. Air traps are characterized by shiny, smooth surfaces.
- Category of compounds that catalyze in polyurethane foam reactions.
- Foam containing electrically conductive material in order to prohibit static electricity buildup or to promote static discharge. Anti-static flexible polyurethane foam is used mainly for packaging electronic components.
- An additive that supplements the main blowing agent water in the production of foam and could create softer or lighter foam.
- A test technique that measures the surface resilience of flexible polyurethane foam by dropping a steel ball of a specified mass from a certain height onto the foam sample. The ball rebound value is the ball rebound height as a percentage of the height of the fall.
- Large, irregular cells found beneath the surface of the skin of a molded foam part.
- The method of foaming flexible polyurethane in production. Blowing happens when toluene diisocyanate and water react to create CO 2.
- The blending of two or more components into a composite. Foam is typically attached to other foam grades or polyester fiber.
- The contouring or shaping of flexible polyurethane foam pieces by the removal of foam with abrasives.
- A section of foam cut from a constantly produced slab stock kind of foam.
- The hollow space left behind in the structure of polyurethane foam encased by polymer membranes or the polymer skeleton after blowing is finished.
- Flexible polyurethane foams produced without using chlorofluorocarbons as auxiliary blowing agents.
- A process in which high-resiliency foam is produced. Pouring is carried out without heat and foam is cured at or near room temperature.
- An additive that will decrease the ability of flexible polyurethane foam to ignite or make it burn more slowly.
- Also known as compression load deflection (CLD), it is a calculation of the load-bearing capability of a foam.
- A process involving special cutting equipment to create a foam sheet with dimples.
- The capability of a flexible polyurethane foam to return to its natural state from the pinched results of die cutting.
- A process in which the mold lid is closed and locked in molded foam production and the foaming mixture is injected through ports in the lid of the mold
- The cutting of foam with a specialized saw into patterns from a foam block, creating a custom foam part.
- The inner area of foam, away from the outer skin.
- A procedure, typically mechanical- or vacuum-assisted, in which the closed cells of a high resilience slab stock or molded foam are opened.
- Foam with low resiliency that does not quickly regain its original shape after deformation.
- A method in which the shape of the foam is altered from its original state through compression or heat.
- The cutting out of parts from foam using a process that is similar to stamping out the part. It is good for long duration runs of cut parts that necessitate uniformity in size.
- The boring of holes into a foam to enhance air flow, provide for greater ease of button application in tufted design and to make the foam feel softer.
- Polymers that, when undergoing deformation, resist and recover in a way similar to that of natural rubber.
- Also called "flame bonding" it is the process of bonding flexible foam to a fabric, film or other material by melting the surface of the foam with a flame source and quickly pressing it to the material before the foam resolidifies.
- A kind of polyurethane foam created with a combination of polymer or graft polyols. This foam is not as uniform in its cell structure in comparison to conventional products, which enhances the comfort, support, resilience and bounce of the foam.
- The cutting of foam using high-temperature wires instead of a saw blade. Hot wire cutting is generally used for cutting intricate parts.
- A quick way to refer to the group of diisocyanates that are one of the two primary ingredients in the chemical process from which polyurethane foam is produced.
- A method of bonding layers of foam together in a simple composite. Laminating could be attained with adhesives or with heat processes, such as flame lamination.
- Method of cutting thin sheets from a foam cylinder.
- The higher-density exterior surface of foam, typically resulting from the foam surface cooling at a higher rate than the core.
- Flexible polyurethane foam produced by the constant pouring of mixed liquids onto a conveyor, which creates a continuous loaf of foam.
- Method a foam cutter uses for cutting sheets from a rectangular foam block.
- Significant hollow spaces that inadvertently form in foam structures. Voids are typically the result of inaccurate mold filling or inadequate moldability.