The technique<\/p>\n
Rotational moulding is based on the principle of having the material deposited by gravity on the surface of the mould, and not by the effect of centrifugal force.<\/p>\n
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The rotational moulding consists in putting a predetermined quantity of polymer powder, granulated or liquid, inside a hollow shell-shaped mould. Then, the mould is heated and rotated time around two principal axes at the same, in order for the polymer to adhere to the walls of the mould by melting. Still rotating, the mould is cooled, so that the polymer can solidify in the desired shape. When the plastic is hardened enough, the rotation is suspended to permit the extraction of the plastic product from the mould. This process takes place at low rotational speeds, typically at 4-20 rev\/min. The flexibility of this process also means freedom in design.<\/p>\n
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The moulds<\/p>\n
The moulds used in rotational moulding are characterized by a shell-shaped structure.\u00a0 They are usually made up of two half-shells, but more complex pieces may require moulds consisting of three or more parts. Along the coupling lines of the parts, moulds are closed with clamps.<\/p>\n
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The advantages<\/p>\n
Rotational moulding is an atmospheric pressure process allowing producing stress-free pieces. The molten material is not subject to stresses while taking its final shape and this represents one of the biggest pluses of the rotational moulding, if compared to other manufacturing methods of plastic pieces. In addition, since there are no forces acting on the molten plastic during its shaping, the rotational moulds can have thin walls and can be produced at relatively low costs.<\/p>\n
The rotational moulding is also a production technique with a low environmental impact because the fusion of the powders takes place without a direct contact with flames or heat sources.<\/p>\n
Moreover, Niteko\u2019s production system allows additional energy savings by means of a special regenerative unit that makes the reactive energy \u2013 which is produced during the braking phase of the engines through unbalanced operations or quick shutdowns \u2013 available for users on board the machine. At the end of the firing cycle, when the doors of the oven open to change the carts, the sudden shutdown of the ventilation system generates a large amount of reactive energy. Thanks to the energy recovery system, it is possible to shut down the ventilation system in a few seconds, with a drastic reduction of hot air leakage from the oven. The temperature loss is only 30\u00b0-40\u00b0 and the return to the temperature set for the moulding takes place in a very short time, with clear reductions in cycle times and in consumptions.<\/p>\n
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Main pluses of rotational moulding:<\/p>\n
[spb_row element_name=”Row” wrap_type=”full-width-contained” row_bg_type=”color” row_bg_color=”#f4f4f4″ color_row_height=”content-height” bg_type=”cover” parallax_image_height=”content-height” parallax_image_movement=”fixed” parallax_image_speed=”standard” bg_video_loop=”yes” parallax_video_height=”window-height” row_top_style=”none” row_bottom_style=”none” parallax_video_overlay=”none” row_overlay_opacity=”0″ remove_element_spacing=”no” row_col_spacing=”0″ row_col_pos=”default” row_col_equal_heights=”no” row_expanding=”no” row_animation=”none” row_animation_delay=”0″ minimize_row=”no” simplified_controls=”yes” custom_css_percentage=”no” custom_css=”margin-top: 0px;margin-bottom: 0px;” border_styling_global=”default” width=”1\/1″ el_position=”first last”] [spb_blank_spacer height=”60px” width=”1\/1″ el_position=”first last”] [spb_text_block animation=”none” animation_delay=”0″ simplified_controls=”yes” custom_css_percentage=”no” padding_vertical=”0″ padding_horizontal=”0″ margin_vertical=”0″ custom_css=”margin-top: 0px;margin-bottom: 0px;” border_size=”0″ border_styling_global=”default” width=”1\/1″ el_position=”first last”] More about rotational moulding [\/spb_text_block] [spb_blank_spacer […]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-2637","page","type-page","status-publish","hentry"],"yoast_head":"\n