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Draft angle design is an important factor when designing plastic parts. Because of shrinkage of plastic material, injection molded parts have a tendency to shrink onto a core. This creates higher contact pressure on the core surface and increases friction between the core and the part, thus making ejection of the part from the mold difficult.
The cube mold technology is characterized by components that rotate vertically round the axis. The lower section of the mold runs on the machine base and the lower machine tie bars. The top section of the part runs on the upper machine tie bars. In this technology, components are molded within the rotating system at different steps.
A plastic extrusion machine extrudes plastic in a continuous profile. The main machine is usually called the host, and its accompanying equipment are called the plastic auxiliary equipment. Plastic extruders can make plastic film/wrapping, packing tape, corrugated sheets, plastic lumber, pipes, tubes, insulated wire, monofilament and nets.
This projected area is multiplied by a clamp force of from 1.8 to 7.2 tons for each square centimetre of the projected areas. As a rule of thumb, 4 or 5 tons/in 2 can be used for most products. If the plastic material is very stiff, it requires more injection pressure to fill the mould, and thus more clamp tonnage to hold the mould closed.
The micrometre (SI symbol: μm) is a unit of length in the metric system equal to 10 −6 metres ( 1 / 1 000 000 m = 0. 000 001 m). To help compare different orders of magnitude, this section lists some items with lengths between 10 −6 and 10 −5 m (between 1 and 10 micrometers, or μm). ~0.7–300 μm – wavelength of infrared radiation
Resin code for polyethylene terephthalate Polypropylene lid of a Tic Tac box, with a living hinge and the resin identification code, 5, under its flap. The Resin Identification Code (RIC) is a technical standard with a set of symbols appearing on plastic products that identify the plastic resin out of which the product is made. [1]
As the plastic hardens, it may contract slightly. By tapering the sides of the mold by an appropriate "draft angle", for instance 2° (two degrees), the mold will be easier to remove. This is a practice that is used, in applicable cases, when working with fiberglass.
A common post-extrusion process for plastic sheet stock is thermoforming, where the sheet is heated until soft (plastic), and formed via a mold into a new shape. When vacuum is used, this is often described as vacuum forming. Orientation (i.e. ability/ available density of the sheet to be drawn to the mold which can vary in depths from 1 to 36 ...