SU476739A3 - Method for the production of hollow plastic rods - Google Patents

Description

one

The invention will be adapted to the technique of making hollow handle bars by extruding a thermoplastic.

A known method for the production of hollow plastic rods made of individual sectors, separated by radial capillary channels, pushes the molten material through an extrusion die with a star-shaped core. The rods manufactured in a known manner, do not have sufficiently good capillary.

To eliminate this drawback, the rod is cooled to a temperature lower than the melting temperature of the material at the exit from the extrusion die, after which the rod is subjected to mechanical stretching, reducing the diameter of the rod to such an extent that at least Sectors come into contact with one another. In order to ensure symmetric alignment of the sectors, the rod is subjected to mechanical stretching, reducing its diameter to such a value that the tops of at least one lara opposite the other sectors decrease the central axis of the rod so that the sectors come into contact with the said Pair of sectors along their side walls. Rod diameter

reduce pa 50% of its original size. In order to simplify the operation of mechanical stretching, the rod is subjected to a dragging operation before cooling, reducing its diameter to a value at which the sectors do not come into contact with one another, while reducing the diameter of the rod by 60% of the original size. After mechanical stretching, the sterol is re-cooled, rolled between the rollers, and the secondary is subjected to mechanical stretching followed by cooling. Furthermore, the method includes the step of annealing the rod at a temperature lower than the melting temperature of the material carried out after cooling the rod before the first stage of its mechanical expansion.

The drawings show one of the examples of the implementation of the proposed method.

FIG. 1 shows a handle (longitudinal section) having a core made of a thermoplastic material; FIG. 2 is a transverse section of the rod at the exit of the extrusion feeder (in an enlarged scale); in fig. 3 is a cross-section wiped out after its diameter has been reduced to a predetermined size as a result of mechanical stretching; in fig. 4 is a cross-section of the rod (on an enlarged scale) in its co-no-co-pointed part, which in FIG.

3 wade of circumference; on

 Block scheme technological

nrotsesa, illustrating the proposed

way to.

The first step in the production process of hollow plastic plastics is to force melted material through a star-shaped extrusion die. A rod 1 is thus produced, consisting of separate sectors 2, 3 and 4, separated by radial channels 5, having parallel walls 6, and extending from the central cavity 7. The sectors have different lengths. The longer sectors 2 and 3 alternate with the shorter sectors 4. The top 8 of the short sector 4 is located at a greater distance from the central axis 9 of the rod than the top 10 of the longer sectors 2 and 3. Of the cejcTopoiB 2 and 3, the longer sectors are 3 located opposite one another.

The rod shown in FIG. 2 has 12 channels arranged symmetrically about the axis 9 of the rod 1. Obviously, an increase in the number of channels will lead to an improvement in ink distribution in the rod. After extrusion, the channels 5 have parallel side walls, and after mechanical expansion of the rod 1, the channels take a conical shape and converge to the central axis. If the primary diameter of the rod is 10 mm, then after the dragging operation it is 4 mm, and after mechanical stretching, the diameter of the rod is 2 mm.

Before mechanical stretching, the bail is cooled, thus avoiding the melting of the tops of the sectors and the fusion of the sectors among themselves. After mechanically stretching, the tops of the short sectors 4 are at a certain distance from the central axis of the rod, and the tops of the sectors 2 reach the axis, while the tops of the longest sectors 3 are in contact with each other and pass through the central axis 9.

Thus, the central cavity 7 is filled.

Sectors 3 are intended to ensure the same bending of all sectors and their symmetrical arrangement after mechanical stretching, which causes a reduction in the cross section of the rod. The tops of the short sectors 4, while not reaching the central axis, are in contact with the lateral sides of sectors 2 and 3. In the case that the rods with a diameter of 10 mm are stretched to obtain a final diameter of 2 mm, the long sectors 3 are longer than the sectors 2 by 0 2 mm.

The channels 5 are not isolated from each other, they can be interconnected by means of capillary holes at the points of contact between sectors 2, 3 and 4. Thus.

if the channels are plugged, ink flows into these blocked channels from other channels below the point of clogging, so that the flow of ink is distributed symmetrically with respect to the central axis.

The sequence of technological technological operations for the manufacture of hollow rods is schematically shown in FIG. 5. From an extruder 11, a rod with a diameter of about 10 mm is directed for cooling into a tank 12 filled with cold water, with the result that the temperature of the rod becomes lower than the melting point of the material used for

rods.

The cooled rod, with the aid of an extension system 13, is subjected to preliminary drawing, while the diameter decreases from 10 to 4 mm, then passes through the subheater 14 (electric furnace), where it is heated to a temperature slightly below the melting point of the material, but sufficient for heating. stress and annealing the material in order to reduce

brittleness due to previous cooling.

Next, the rod is subjected to mechanical stretching, carried out by means of a device 15, representing a set of die planks with round holes, the diameter of which is gradually reduced to a predetermined value, for example 2 mm. From the device 15, the rod is directed to the second cooling tank 16, where heat evolved as a result of the mechanical stretching operation is removed, then the rod is rolled into the device 17 consisting of four pairs of rollers, resulting in the rod acquiring a regular cylindrical shape. The rod is then subjected to subsequent mechanical stretching with the REM device of device 18, similar to device 15. Here the rod is slightly stretched to exactly the specified diameter within the tolerance, after which it is cooled in the vessel 19 to the temperature required to cut the rod into short sections using cutting device 20. Next sharpen both ends of the rod.

The rod thus manufactured is placed in the handle body 21 (see FIG. 1), which may be made of plastic. Thanks to the sharpening of the rod on both sides

it can be inserted into the housing at any end. Part of the housing 21 is filled with absorption material 22, propped with ink or a special composition. Core 1 is in contact with the ethn: m material,

as a result, the ink enters the rod under the action of a thermal pressure transmitted through the element 23 from the piston 24.

The rod manufactured by the proposed method provides raviomernuyu

n quality graphic

ink supply image.

Subject invention

Claims (7)

1. A method for producing new plastic mass rods made from separate sectors separated by radial capillary channels by extrusion of the molten material through an extrusion: about a die with a star-shaped core, characterized in that, with an improved capillary rod, out of the extrusion core the spinnerets the rod is cooled to a temperature lower than the melting point of the material, after which the rod is subjected to mechanical stretching, reducing the diameter of the rod to such an extent that wherein at least a portion of sectors nrihodit into contact with one another. 2. A method according to claim 1, characterized in that the rod is subjected to mechanical stretching, reducing its diameter to such a value that the tops of at least one pair of oppositely located sectors pass the central axis of the rod so that the other sectors contact with said pair of quadres along their side steioc. 3. Software method pi. 1 and 2, characterized in that the diameter of the rod is reduced by 50% of its original size. 4. Method according to | nn. 1, 2 and 3, that is, in order to simplify the mechanical stretching operation, the rod is subjected to dragging operations before cooling, reducing its diameter to the value at which the sectors are not yet in contact one with the other. 5. A method according to claim 4, characterized in that the diameter of the rod} 1 is reduced by 60% from the original size. 6. Software method paragraphs. 1, 2, 3, 4 n 5, different; and with the fact that after mechanical stretching the rod is cooled again, rolled between the rollers and the secondary is subjected to mechanical stretching followed by cooling. 7. Method according to paragraphs. 1-6, that is, so that the op includes the operation of annealing the rod at a temperature lower than the melting point of the material, carried out after cooling the rod before the first stage of its mechanical stretching. -24 Fig.) Fig-2