RU191248U1 - Active thermal insulation system for the fusion zone of the additive machine - Google Patents

Abstract

The system of active thermal insulation of the working zone of the fusion of the additive machine is aimed at increasing the efficiency of thermal insulation and is made in the form of a protective box (5) of the additive machine. The box (5) is a thin-walled sleeve, inside of which vertical channels (8) are placed along the annular perimeter of the wall for circulation of the coolant. Channels (8) are interconnected in pairs in the upper and lower parts by rhombic transitions (9). The points of inlet (10) and outlet (11) connected to the vertical channels (8) are made in the lower end of the sleeve of the box (5). The channels (8) are preferably made with a rectangular cross section; In this case, selective laser fusion technology can be used. 2 s.p. f-ly, 2 ill.

Description

The claimed technical solution relates to the field of additive technologies, in particular to intermediate devices using methods of selective layer-by-layer fusion of powders and more specifically to means of heat transfer, thermal insulation and cooling of the working space when creating three-dimensional printing objects.

In the process of manufacturing a three-dimensional object by the technologies of three-dimensional printing by the method of selective laser fusion, the surface of the desktop is heated to a high temperature above 200 ° C.

Such a high temperature should be maintained only above the surface of the table, and the space around the table and below it should have an ambient temperature.

Usually, a thermal insulation is provided under the heating element, which acts as a restraining factor and temporarily prevents the temperature increase in the space under the table.

A device for manufacturing a three-dimensional object [DE 19939616 A1]. In this device according to the prior art, the building space is usually heated to a temperature of 100-150 ° C during the laser fusion process.

A disadvantage of the device for manufacturing a three-dimensional object is that external heating to higher temperatures is impossible due to the large thermal load.

The technical problem, the solution that the utility model is aimed at, is to exclude the spread of excess heat from the working zone of the fusion of metal powder inside the box, in which the working table with the heated plate for building the product moves into the surrounding space and provide active thermal insulation of the working table moving mechanism.

The technical result consists in increasing the efficiency of thermal insulation of the surrounding space of the additive machine when creating objects of three-dimensional printing and, in particular, the mechanism for moving the desktop.

The technical result is achieved by the fact that the inventive enclosing box is a thin-walled sleeve, inside of which vertical channels of rectangular section are placed along the annular perimeter of the wall for the circulation of coolant, pairwise interconnected in the upper and lower parts by rhombic transitions. The inlet and outlet points connected to the vertical channels of a rectangular cross-section of the coolant are made in the lower end of the duct sleeve.

Moreover, the cooling channels can be made using selective laser fusion technology, which allows to reduce the complexity and cost of the product, to improve its quality.

The channels are preferably rectangular in shape to provide the largest contact area and thus increase the heat sink efficiency.

The essence of the proposed solution is illustrated by drawings, which depict:

- in FIG. 1 - enclosure box additive machine in the context, where

         1 - product construction platform;

         2 - heating element;

         3 - desktop;

         4 - temperature sensor;

         5 - enclosing box;

         6 - countertop additive installation;

         7 - working area of construction;

- in FIG. 2 is a diagram of a heat sink from a working space of an enclosing box of an additive machine, where

         8 - channel for coolant;

         9 - rhombic transition;

       10 - point of introduction of coolant;

       11 - point of removal of coolant;

       12 - hole for cleaning the internal channels from the powder.

To confirm the feasibility of realizing our purpose with a useful model and achieving the claimed technical result, we consider an embodiment of the system.

The table top (6) of the additive machine is a rectangular plate, which serves to install on it the gas supply and exhaust manifolds. The enclosing box (5) is used to place and move the desktop (4) in it with the fixed platform (1) for constructing the product, installed in the hole of the countertop (6) and fixed with bolts. The work table (3) is used to install the heating element (2) of the construction platform (1), temperature sensor (4), thermal insulator, as well as cooling. A thermal sensor (4) provides temperature control of the platform (1) of product construction. The heating element (2) serves to pre-heat the platform (1) build for better fusion of the part with the platform (1) build.

The active thermal insulation system of the fusion zone of the additive machine is made in the form of a guard box (5) of the additive machine. The box (5) is a thin-walled sleeve, inside of which along the annular perimeter of the wall there are vertical channels (8) for the circulation of coolant (for example, water cooling), pairwise interconnected in the upper and lower parts by rhombic transitions (9). The points of inlet (10) and outlet (11) connected to the vertical channels (8) are made in the lower end of the sleeve of the box (5), which is due to the need to ensure comfortable operation of the thermal insulation system as part of the device as a whole, by the relative position of the machine nodes. Rhombic transitions are necessary so that at the highest and lowest points of the bend of the inner channel during the manufacturing by the additive method, supports that overlap the inner channel at the upper and lower points are not built. To do this, the surface should be at an angle of 30-45 degrees to the plane of the plate.

The channels (8) are preferably made with a rectangular cross section, which provides the largest contact area of the coolant with the heated surface and thereby increases the efficiency of heat removal.

The size of the internal channels (8) of the enclosing box (5) is selected based on the overall parameters of the box (5), the design of the working table (4), the speed and pressure of the coolant. For effective selection of heat generated inside the duct (5), the contact area of the coolant with the inner surface of the duct (5) should be the largest, thus, the thickness of the jumpers between the channels (8). The thickness of the metal layer from the inner and outer surfaces of the duct sleeve (5) and from the surfaces of the upper and lower ends of the duct (5) to the walls of the channels (8) for the circulation of the coolant should be the smallest, using the manufacturing method used.

The heat sink system from the working space of the enclosing box (5) works as follows.

When the surface of the heating element (2) is heated to a predetermined temperature, the temperature sensor (4) gives a command to turn on the cooling system pump, which delivers coolant (for example, water) through the point (10) of entry into the vertical channels (8). The liquid, passing through the channels (8) connected in pairs by rhombic transitions (9), removes excess heat from the interior of the box (5), in which the working table (4) moves with the platform (1) for constructing the product, heated to a temperature of 120 - 300 ° C, and goes through the point (11) of the outlet to the liquid cooling system (standard chiller).

The manufacture of the enclosing box (5) with many internal vertical channels (8), pairwise connected with a rhombic transition (9) for the passage of coolant throughout the entire inner contour of the sleeve of the box (5), mechanically, according to the existing classical technology, is very difficult, time-consuming and expensive . Such a construction may be made of at least three parts. The inner part is a sleeve with channels (8) in the form of deep-hole drilling (20-25 hole diameters), with milling transitions of paired channels. The upper and lower parts of the duct (5) are plates that must tightly close all channels (8) from coolant leaks. In addition, to connect all three parts into a single design, the presence of fasteners with their reliable fixation from an arbitrary turn is required.

Based on the foregoing, it is proposed to manufacture the enclosing box (5) using additive technology, since this technology allows alloying products with internal channels (8). As a result, we get the design of the enclosing box (5) made of solid metal that does not have connectors, which does not require additional seals and fasteners. And the transition channels (9) of the rhombic shape contribute to better heat transfer and are the most technologically advanced for additive technology.

To manufacture the proposed utility model, a digital (CAD) three-dimensional model of the enclosing box (5) is created, which is transferred to an additive machine for subsequent fusion of the structure from selected metal powder.

An example implementation of a utility model.

The additive machine operator sets the technological modes of fusion of the enclosing box structure (5), in particular:

- thickness of the alloyed powder layer;

- power of the laser radiation source;

- the magnitude of the focal spot of the laser source on the surface of the powder;

- speed and trajectory of the laser beam;

- the temperature of the platform heating the product.

After which, the operator starts the program of manufacturing the enclosure (5).

At the end of production, the operator cleans the product from the remains of the powder: the external surfaces and all internal channels are cleaned through the side holes in the lower belt of the box sleeve. After this, the necessary machining of all working surfaces is performed, the thread is cut in the inlet and outlet openings of the coolant inlets and the thread in the side holes in the lower shell liner. Threaded plugs are screwed into the side openings and sealed against leakage of the coolant.

Claims (3)

1. The enclosure box of the working zone of the alloying of the additive machine, made in the form of a thin-walled sleeve, inside which along the annular perimeter of the wall there are vertical channels for the circulation of coolant, pairwise interconnected in the upper and lower parts by rhombic transitions, while the points of supply and removal of coolant connected to the channels are made in the lower end of the sleeve of the box. 2. The enclosure according to claim 1, characterized in that the channels for circulating the coolant are made by selective laser fusion. 3. The enclosing box according to claim 1, characterized in that the channels for circulating the coolant are made of rectangular cross-section.

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