A Continuous Sheet Of Plastic Is Formed

The forming section of a plastics plant puts out a continuous sheet of plastic that is 1 2 m wide and 2 mm thick at a rate of 15 m min.

A continuous sheet of plastic is formed.

Molten plastic in the form of a large droplet called a parison is placed into a two piece clamshell mold. Anything thinner is considered plastic film. Plastic sheets are defined as a continuous form of plastic material thicker than 010 25mm and usually wound on a core but mostly cut into sheets. In the most common method of high volume continuous thermoforming of thin gauge products plastic sheet is fed from a roll or from an extruder into a set of indexing chains that incorporate pins or spikes that pierce the sheet and transport it through an oven for heating to forming temperature.

Plastics extrusion is a high volume manufacturing process in which raw plastic is melted and formed into a continuous profile. There is a huge universe of plastic film materials from those made of a simple single plastic material to complex structures made of different materials and coatings designed to meet the needs of specific applications. Extrusion produces items such as pipe tubing weatherstripping fencing deck railings window frames plastic films and sheeting thermoplastic coatings and wire insulation. Because the walls of the mold are water cooled the plastic quickly solidifies and the bottle can be ejected.

The temperature of the plastic sheet is 90 c when it is exposed to the surrounding air and the sheet is subjected to air flow across the width of the sheet at 30 c and at a velocity of 3 m s. February 5 2015 by jordan katz. You are asked to determine the rate of heat transfer from the plastic sheet to the air.