Vacuum forming process of plastic globe drawing

Abstract

A vacuum forming process of forming a hemisphere from a map-printed PVC plastic planar sheet during the production process of a plastic globe is disclosed. An elliptic heat-resisting sheet is added above the top of the center of a concave vacuum forming mould. Thus, when a vacuum forming machine heats a map film, the core temperature is lower and the thickness of a map film of the hemisphere formed by thermoforming is uniform. Long axis of ellipse of the heat-resisting sheet is corresponding to the extrusion direction during production of the PVC sheet, and short axis is corresponding to the vertical extrusion direction during production of the PVC sheet. The map film of the hemisphere is formed by thermoforming, and deformation of round latitude lines on the surface of the globe is reduced.

Description

technical field [0001] The invention relates to a processing technology of a toy and a teaching instrument, in particular to a vacuum suction forming process of forming a hemispherical PVC plastic flat sheet printed with a map in the production process of a plastic globe. Background technique [0002] The globe is a common tool for imparting geographical knowledge to people, and it is also an indispensable teaching aid for teaching geography and earth knowledge to primary and secondary schools. In the traditional plastic globe technology, the globe is manually embedded on a sphere with 12-petal "boat-shaped" pictures. This kind of globe is difficult to make, time-consuming and laborious. The surface latitude, ground features, annotations, and boundaries of the embedded globe It is easy to dislocate, and the map and the sphere are not bonded firmly, which directly affects the quality of the globe and brings inconvenience to people's learning. [0003] If the map of the south...

AI Technical Summary

Problems solved by technology

However, the production process of PVC plastic sheet heating in vacuum to form a hemispherical shape has a great impact on the quality of the globe: (1) When the PVC plastic sheet is heated, it will be in the extrusion direction of the PVC sheet during production. Elongation and shrinkage in the direction of vertical extrusion. The circular southern and northern hemisphere maps printed on PVC plastic flat sheets are hemispherical after heating and blistering. deviation

(2) PVC plastic flat sheets with maps printed on them, when using a concave mold in vacuum thermoforming, the general blister molding process, the top of the hemispherical shape will be thinned, which will make the thickness of the hemispherical map film uneven, The geographical location will be elongated at the top of the hemisphere, which does not fit the scale of the map; the color map of the northern and southern hemispheres printed on the PVC plastic flat sheet is heated and blistered into a hemispherical map color, and the top becomes lighter and lighter, and the map color of the entire hemisphere Uneven, affecting the colorful quality of the globe