Thermoforming trimming

This polymer film composition can be extruded into a polymer film sheet laminated to or co-extruded with a thermoplastic synthetic resin sheet to make a thermoformable inner liner. The ther-moformable inner liner is thermoformed, trimmed, and nested in a spaced relationship within an outer wall element, after which a polymer foam is injected to the space between the inner liner and the outer wall element. 

Figure 7-73. The addition of a single-plastic clamping strip at each side of a coextruded sheet permits scrap reclaim of the thermoformed trim waste.

This Paper explores the use of a CO2 laser to trim thermoformed parts. Traditionally thermoformers trim their parts with saws, router, or die cutting. These methods can be costly and hazardous, particularly for small volume parts. Many accidents occur in factories and other... 

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... 

Acrylate Styrene Acrylonitrile Polymer Acrylic rubber-modified thermoplastic with high weatherability. Acrylate Styrene Acrylonitrile Polymer has good heat and chemical resistance, toughness, rigidity, and antistatic properties. Processed by extrusion, thermoforming, and molding. Used in construction, leisure, and automotive applications such as siding, exterior auto trim, and in outdoor furniture. 

In this process, PLA sheet is heated to soften the polymer, forced either pneumatic and/or mechanically against the mold, allowed to cool, removed from the mold, and then trimmed. The radiant heater of the thermoforming line for PLA must be adjusted to very low temperatures. Preheating is not absolutely necessary however, it has the general advantage that the sheet is homogeneously preheated. 

Thermoforming normally involves trimming of the final product, which leads to a significant amount of recyclable material. This material is reused for the extrusion of semi-finished products. Eor thick sheets it is common to extrude multilayer materials with a core from regrind, while the top layer is virgin in order to obtain a good surface quality. 

Environment — All thermoplastic sheet material can be recycled and extruded to new semi-finished products — High energy consumption for off- line thermoforming — High amounts of waste material fiom trimming to be transported for recycling, except thermoformer has own extrusion facilities... 

Production of flexible packaging begins with extrusion of plastic resin to yield sheet or film. For film, two main processes are used. In the cast-film process, the resin is extruded through a slit-shaped die onto a water-cooled chrome roUer, where it is solidified. After the edges are trimmed off, the film is wound onto a roll. The film may be oriented by stretching it in the machine direction (uniaxi-ally oriented) or in both the machine and cross directions (biaxially oriented) to improve mechanical and barrier properties. This process is also used to produce plastic sheet for thermoforming or other applications. 

Selected ecoprofile information for expandable polystyrene (EPS) and for thermoformed EPS are presented in Table 4.8. In the Ihermoforming operations studied, trim scrap ranged from 25 to 45%, aU of which was recovered and sent... 

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