METHOD OF ITEMS MOLDING FROM POWDERY POLYMERS AND DEVICE FOR ITS REALISATION Russian patent published in 2008 - IPC B29C43/52 

FIELD: technological processes.

SUBSTANCE: in method of items molding from powdery polymers powder pressing is carried out during superposition of multiple shift diverse-sign deformation (MSR-deformation) on its whole volume in directions, which are orthogonal to axis of pressing and continuous removal of air exhausted from its volume, at that in the process of pressing the stock is heated, and gradient of temperature in the stock volume does not exceed 10%. Pressing of powder is executed in three stages, in the first of which powder is tightened with imposition of MSR-deformation on it and with continuous increase of pressing pressure up to its maximum permissible values, in the second stage - isobaric exposure of the stock is carried out at the maximum pressure and its heating, and in the third stage MSR-deformation of the stock is carried out at the maximum pressure of pressing, at that in the first stage temperature of powder is maintained at the level that does not exceed 0.3-0.5 from the temperature of polymer melting, and in the second stage it is increased up to 0.8-1.2 of this temperature, at that MSR-deformation in the first and third stages of pressing is completed after cessation of stock tightening at every of these stages. It is possible to carry out MSR-deformation at the first stage of powder pressing after achievement of maximum pressing pressure. Device for molding of items from powdery polymers is equipped with centering laths installed with the possibility of displacement in relation to each other along vertical axis of the press, top, middle and bottom fastening plates, and also top and bottom auxiliary assembly plates, at that centering laths, top fastening, bottom fastening and auxiliary plates are connected to each other with vertical guides, and middle fastening plate is equipped with two pairs of horizontal guides, which are installed in centering laths with the possibility of displacement along the latter in direction that is orthogonal to vertical axis of the press, and auxiliary drive of horizontal displacement installed in one of the pairs of horizontal guides of middle plate. At that die mold of device is arranged in the form of top and bottom molding blocks, every of which consists of rectangular matrix and puncheon, at that matrix of bottom block is fixed in the bottom fastening plate, puncheon of top unit - on the top fastening plate, and matrix of the top unit and puncheon of the bottom unit - on the middle plate. Matrices of every molding units are arranged with the opposite pair of walls installed with the possibility of turn around two axes that coincide with corresponding ribs of end surfaces of matrix and puncheon, and also with the possibility of reciprocal motion in relation to ribs of end surfaces of puncheons. Bottom and top fastening plates are equipped with support rollers that are connected to each other by means of vertical beam, which is fixed in stem of auxiliary drive of horizontal displacement with support on pair of horizontal guides of middle plate and is installed with the possibility of turn around horizontal axis that is orthogonal to axes of horizontal guides of the middle plate, and with the possibility of displacement in relation to rollers along vertical axis of press. One of auxiliary plates is installed on the bottom cross-beam of press, and the second one is equipped with auxiliary drive of vertical displacement connected to the first cross-beam of press and traction rods connected to vertical guides that are installed with the possibility of displacement in relation to vertical axis of press. Side surfaces of every matrix and puncheon, crossings of which with their end surfaces form ribs, in relation to which turn and reciprocal motion of matrix side surfaces are possible, are arranged at the angle of 60-80 degrees to side surfaces of these elements. End surfaces of matrices and puncheons are arranged with corrugated grooves, surfaces of which are orthogonal to axes of horizontal guides of middle plate.

EFFECT: reduction of pressing pressure and higher efficiency of technological process with simultaneous increase of molded items quality.

7 cl, 3 dwg