Thermoformed products

Fig. 3-40 Recommended method for holding metal fittings in thermoformed products.

Tolerance Thermoformed products lack the dimensional accuracy of processes such as injection and compression molded products. 

Fig. 3-41 Example for stacking thermoformed products to avoid jamming.

Thermoformed products are used in various outdoor and commercial applications which require tough products that have a large surface area. Typically, these products do not have close dimensional tolerances. Such applications include ornamental pool liners, dumpster lids, panels for portable sanitation facilities, and agricultural feed troughs. These products, which are not required in very large numbers, could not be produced economically by other molding processes,... 

If a thermoformed product is placed in an oven set to a temperature just above the softening point of the polymer, the product returns to the form of a flat sheet. Why does this happen ... 

Blow moulded and sheet thermoformed products for food, personal care, health, medical and lab ware applications, household chemicals and beauty aid products. .. 

Glazing applications, shatter-resistant glazing for aircraft, boats, protective glazing. .. Transparent thermoformed products... 

Transparent thermoformed products, store fixtures and displays. .. 

The majority of thermoforming production is by roll fed machines. Sheet fed machines are used for the smaller volume applications. Larger production units have in house sheet extrusion equipment. Because of the complexities in synchronising sheet extrusion equipment and the thermoforming machines, the two processes can be carried out independently of each other, the extruded sheet being produced in advance of production schedules. 

Where a clear, thermoformed product is desired, many fabricators use OPS. Because of the low elongation of general-purpose polystyrene, it is necessary to orient the sheet biaxially to obtain the required physical properties for satisfactory part trimming and end use. If there is insufficient elongation in the... 

Novamont www.novamont.com/ Materbi Thermoplastic starch polymer blends biodegradable mulch films and bags, thermoformed products, injection molded items, and packaging foam... 

A common way to increase the bending stiffness of products from melt-inflation processes is to use corrugations. It is not possible to create ribbed shapes, described in the next section, because there is no independent control of the shape of the inner surface of the melt. Corrugations are seen on thermoformed products, blow-moulded bottles and extruded pipes. 

One example of an innovative thermoformed product is the application of new semi-finished products to the thermoforming process, like an interior panel with ambient light for automotive or aviation applications (Fig. 2). The semi-finished product is made of polycarbonate with an electroluminescence layer on the back. In order to protect the electroluminescence layer, the panel is partly back injection molded with PC/ABS. 

Thermoforming as a discontinuous process is often used for Form Fill Seal (FFS) applications. New machine developments allow a continuous output of thermoformed products which can ease the production control of inline FFS machines. 

Thermoforming is an open process, which means the process is sensitive to environmental changes and therefore sometimes unstable and difficult to control. Because of its instability, the thermoforming process has developed more like an art than a science [9]. The settings of process parameters and the development of new thermoformed products is only based on experience [10]. Little attention has been paid to thermoforming in terms of scientific imderstanding, which makes the process critical for complex applications compared to injection molding. 

In-line thermoforming production lines, particularly those being fed directly from an extruder, have to be completely synchronized, or inferior parts result, and/or the cost of the operation goes up. For example, if the trimmer operation has to be slowed down, the extruder output has to be reduced. In fact, a slowdown can result in a shutdown if the extruder cannot operate at the slower speed required. All functions and stations have to be properly interrelated. 

British Petroleum, In the late 1960s, introduced Amlon, a thermoformable product that could be extruded into fibers, without cost of associated solvent recovery. 

Styrene-butadiene copolymers are used in toys, housewares, and medical applications.Thermoformed products include disposable food packaging such as cups, bowls, clam shells, deli containers, and lids. Bhster packs and other display packaging also use styrene-butadiene copolymers. Other packaging apphcations include shrink wrap and vegetable wrap. ... 

Some applications are the same t)rpical for LDPE transparent blown films, mulch films for agriculture, films for package and bags, and also blown bottles, filaments, injection moulded and thermoformed products [69]. 

Thermoforming results in characteristic thickness distributions of the part s walls. Once the sheet contacts the mold surface, it sticks and locally cools. The wall thickness distributions are due to hindering and stretching of the hot sheet material. Thermoformed sheet once formed as product is cooled below its softening to freeze is normally performed by conduction via the mold surface. The mold is kept at a constant temperature by cooling or heating. Finally, the thermoformed product is demolded and cut out or trimmed by various means around the formed regions. 

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