Apparatus for manufacturing thin-walled bodies of revolution

Abstract

The technical solution relates to the field of processing polymers and can be used in various branches of the national economy for manufacturing hollow articles of the bodies-of-revolution type (tubes), and in particular for manufacturing semifinished biodegradable polymeric stents which are usable in medicine for replacing hollow organs, for example blood vessels. The apparatus for manufacturing thin-walled bodies of revolution comprises a heatable expander which is mounted rotatably about a longitudinal axis, and a feeder for supplying moldable material, said feeder being mounted above the expander so as to be movable therealong, wherein the lower part of the feeder is heatable, the expander is hollow with a reflective internal surface, and the heater of the expander is in the form of a laser, the radiation of which is transported into the expander. The use of the apparatus will make it possible to reduce the thermal action on a polymer when producing semi-finished articles with defined geometrical dimensions from polymeric materials.

Claims

1. An apparatus for manufacturing thin-walled bodies of revolution comprises a heatable expander which is mounted rotatably about a longitudinal axis, and a feeder for supplying mouldable material, said feeder being mounted above the expander so as to be movable therealong, wherein a lower part of the feeder is heatable, the expander is hollow with a reflective internal surface, and a heater of the expander is in the form of a laser, the radiation of which is transported into the expander.

2. The apparatus according to claim 1 further comprising a lens between the laser and an inner cavity of the expander.

3. The apparatus according to claim 1 further comprising a light guide for transporting the radiation of the laser into the expander.

4. The apparatus according to claim 1 further comprising a light guide in an inner cavity of the expander, wherein an end of said light guide is equipped with a lens and an actuator for synchronous movement of the light guide with movement of the feeder, and wherein a localized portion of the reflective internal surface of the expander is absorptive.

5. The apparatus according to claim 3, wherein the light guide is above the expander and further comprising an actuator for synchronous movement of the light guide with movement of the feeder.

6. The apparatus according to claim 1 further comprising an antiadhesive coating on an outer surface of the expander.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) The essence of the claimed apparatus for manufacturing thin-walled bodies of revolution is explained by an example of its implementation and graphical images.

(2) FIG. 1 provides a general schematic diagram of the apparatus for manufacturing thin-walled bodies of revolution.

(3) FIG. 2 provides a schematic diagram of the apparatus for manufacturing thin-walled bodies of revolution using the lens to direct the laser radiation into the expander.

(4) FIG. 3 provides a schematic diagram of the apparatus for manufacturing thin-walled bodies of revolution using the light guide, the end of which is equipped with the lens to input the laser radiation into the expander and the actuator for synchronous movement with the feeder.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(5) The apparatus for manufacturing thin-walled bodies of revolution comprises the heatable expander 1 mounted rotatably about the longitudinal axis and feeder 2 for supplying moldable material, said feeder being mounted above the expander so as to be movable therealong. In its lower part the feeder is equipped with heater 3. The initial biodegradable polymer in the form of rod 4 is placed in the feeder.

(6) The expander is made hollow with a reflective inner surface 5 or with an absorbing inner/outer surface in the case of local heating, and the heater of the expander is in the form of a laser with any wavelength, preferably with a wavelength of 1.06 m or 10.6 m (not shown in the drawings), the radiation of which (conventionally shown in the picture with arrows) is directed inside the expander (directly or through lens 6 (of a mirror or lens type, or a combination thereof) or using the light guide 7 or combination of the light guide 7 with the lens), or is supplied from the outer side of the expander immediately before the lower heated part of the feeder (not shown in the drawings).

(7) The apparatus for manufacturing thin-walled bodies of revolution operates as follows.

(8) The expander 1 is rotated, and the laser radiation is supplied into the expander. When the expander reaches the set temperature, the heater 3 of the lower part of the feeder is switched on. When the required temperature of the heater is reached, the polymer rod 4 is fed in the direction indicated by the vertical arrow at the set speed. The polymer softened at the lower part of the feeder is supplied to the rotating heated expander through a lumen. At the same time, the feeder is moved along the axis of the expander in the direction indicated by the arrow. The lower part of the feeder located at a required gap from the expander smooths the softened polymer over the surface of the expander, forming a tubular semi-finished article of the required thickness. The melt is applied to the expander in a spiral so the lines of the melt overlap. The degree of overlapping is regulated by the ratio of the expander rotation speed, the feeder displacement, and the speed with which the polymer rod is supplied into the feeder. When the end of the expander is reached, the feeder is taken away from the semi-finished article. It is possible to apply several layers of polymer (including polymers with other content and properties to provide the required mechanical and biological characteristics). It is also possible to move the feeder along the axis of the expander in the direction reverse to the direction indicated in FIG. 1. When the semi-finished article is molded, the polymer is no longer supplied into the feeder; the feeder heating is switched off; the feeder is taken away from the expander; and the expander heating laser is switched off. After cooling, the semi-finished article is removed from the expander and sent for further processing.