Slide mould

The design of the multiple nozzle with tips arranged in series (Figure 4.29) means that a set of such nozzles may be used in slide moulds, for example, or where a very small injection point spacing is required (in the manufacture of mouldings for microelectronics). 

Demoulding of parts with local undercuts (slide mould) During opening stroke thrust in direetion of demoulding, ejection with pins, sleeves or stripper plate after release of undercut Mechanical, cam pins, slide mechanism Flat parts with external undercuts (threads)... 

Slides Cars steel-pressing plant car assembly line hand lay-up of GFRP polymer moulding plant. 

Most polymer properties depend on the average DP. Figure 22.2(b, c), for polyethylene, shows two the tensile strength, and the softening temperature. DPs of less than 300 give no strength because the short molecules slide apart too easily. The strength rises with DP, but so does the viscosity it is hard to mould polyethylene if... 

To study reaction kinetics, cement batches of total mass 300 g were prepared using ingredients measured to the nearest 0-1 g. Mixing was carried out for 10 minutes using a kitchen blender, after which specimens were cast in slabs 10 x 10 x 1-2-1-5 cm in polyethylene moulds. When the setting reaction had proceeded to a sufficient extent and viscosity had risen to give a reasonably stiff paste, a small portion was removed, placed on a glass microscope slide and immediately examined by X-ray diffraction. The remainder of the sample was allowed to set. 

Another approach, which has met with wide approval, has been the use of a reed switch/magnet combination. The magnet is moulded into a plastic sliding device that can move up and down, a reed switch that senses the position of the magnet is mounted on a pc board inside the electric toothbrush. In the down po-... 

This paper takes the form of overhead slides which discuss the foaming of polyethylene in rotational moulding. Discussed are the characteristics of PE foam, its applications and processing, physical properties, one-shot foam, and a third generation rotational moulding grades with improved flow properties. 

Thermoplastics consist of long chains of molecules, in the case of PE these are unbranched. Many of these chains together form a tangle which is more difficult to unravel the more branched the chains are. The branches are like hooks which cause the molecules to catch. Under the influence of relatively small external forces chains and parts of chains can slide across each other. PE is for instance used to make containers, chemical tubing and blow-moulded bottles. Some other thermoplastics are polypropylene (crates), polyvinyl chloride PVC (pipes) and polystyrene (foam). 

Figure 5 Three component injection moulding using a mould with a sliding core...

In summarizing, it can be concluded that the microhardness of elongational flow injection moulded PE is influenced by a local double mechanical contribution (a) a plastic deformation of crystal lamellae under the indenter, and (b) an elastic recovery of shish-fibrils parallel to the injection direction after load removal. Further, the Shish-crystals are preferentially formed when high orientation occurs, i.e. at zones near the centre of the mould and at an optimum processing temperature Tp around 145-150 °C. Below this temperature overall orientation decreases due to a wall-sliding mechanism of the mbber-like molten polymer. 

The gel was made by pouring a degassed aqueous solution of monomer, initiator and cross-linker into the mould (MAA 47%w/v, AMPA 0.9%w/v and MBA l.l%w/v). The mould was then placed in an oven at 80 C for 2 hours, before being placed in a water bath and the mould opened underwater. The gel, attached to the glass slides is stored imder water. 

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