SU1496903A1 - Tooling for vacuum moulding - Google Patents

Abstract

The invention relates to foundry, in particular, to vacuum forming. The purpose of the invention is to simplify the design of equipment, improving the quality of castings. The proposed equipment contains water supply means for cooling the castings, made in the form of rigid dosing tanks 1.2, fixed in a flask with a rail 3. Water can be poured both directly in the tank 1.2 and in bags made, for example, from forming film. Dispensers are placed above the heat casting nodes 6. After pouring and thermal destruction of the forming film, the water enters the mold areas adjacent to the heat casting nodes, ensuring its uniform cooling. 2 hp ff, 5 ill.

Description

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31496903

The invention relates to foundry and can be used in the manufacture of casting with the use of vacuum film forming (VPF).

The purpose of the invention is to simplify the design and operation, to improve the quality of castings. ,

FIG. 1 shows the equipment for the manufacture of top ply form, cut; in fig. 2 - flask of the upper half-form, plan; Fig 3 is a bag of a film of water for installation in a container; in fig. 4 - section A-A on 15 of FIG. 2 (an example of the manufacture of a water tank); Fig. 5 is a schematic of the use of the tooling when formed in closed box-shaped (armored) flasks.

Tooling for the manufacture of the mold-20, for example, the method of VPF has in the upper mold half tanks 1 and 2, reinforced, for example, using a rail 3 on the edge 4 flasks), the bottom half-form (not shown) is made 25 in flask without containers 1 and 2. The film on the form is not shown. Capacities can have covers 5, which prevent sand from entering the container when backfilling. The tanks are located above the heat nodes of 30 or in other locations determined by cooling needs -6 (rtlivans obtained in the form, and have a certain volume (volumetric dose-, tori). Water (or other cooler), or pre-filled with bags 7 of a film used, for example, with an SPF, or poured through the necks closed by a lid 5, is placed in a container. The container 40 may have a stopper 8 connected to the shaft 9 with a lid 5 and a handle 10 in the inner part. or has a sand-permeable mesh ( There is no JII bag 7), and serves as a dispenser for fluid flow depending on the total area of its passage openings. The containers 2 and 1 can be mounted on the rib 4 or attached to the flask casing. The containers are made of thin-walled sheet metal so as not to penetrate them. sand during molding. The bag 7 is made according to the shape of the container (FIG. 4) and when placed in the container, the lower end protrudes from it through the lower opening. The bag 7 in the upper part is closed with the clamp 11.

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The rigging works as follows.

Without the use of bags 7, the mold is made by known methods and is cast with metal. After the formation of a hard crust capable of retaining the casting form, the mold is disconnected from the vacuum network (VPF), the top film is removed and the containers 1 and 2 are opened by the handles 10 (mounted at the control level) and filled with water to the top. Water slowly through the metering holes of the grid (or the holes of the tank itself) with a certain speed. It seeps into the molds and moistens the sand surrounding the casting thermal unit. In order to eliminate additional operations for the transport of forms on the conveyor (with large forms) or when using closed flasks (Fig. 5) and other features, water in the tank is loaded before the flasks are installed on the molding table. To do this, it is convenient to use bags 7 of non-heat-resistant film, for example, used for WEF, Bags 7 are made according to the capacitance configuration by welding (for example, with a blade) of a film or using a film lining method with a VPF. A certain dose of water is poured into them and they are closed: by clamping It,

Bag 7 is placed in tank 1 and (2) so that its end protrudes from it and is found at a certain distance, separated by sand, from casting 6. This distance for castings weighing 100 kg is 8-30 mm with that. So that the sand layer is heated by the heat of the casting and by its heat melted a film of the protruding part of the bag from which it begins to exit. This is similar to the case when water is poured directly into the tank, however, the start of the supply is carried out automatically. For castings with a mass of about 100 kg of iron, the crystallization time of the scab is; about 3-15 minutes, after which the vacuum from the mold is turned off and water can be used to control the cooling of the castings.

The penetration of water into the mold occurs under the action of gravity and capillary forces. The water evaporating from the heat of casting spreads deep into the molding sand, condenses, and moist with most of the sand of the mold over time.

When evacuating the lower half, it is possible to intensify the ingress of water into it in the form of steam.

Two layers of film in the mode of both the upper and lower half-molds near the casting undergo thermal decomposition, joining the sand in the perimeter strip where the water passes from the upper half-form to the lower one.

When the wet sand forms are heated, the heat from the casting dries out. The supply of water to the hottest places of the mold above the thermal casting units and the cumulative volume of the dispensers ensure the supply of such a quantity of water that after it evaporates from the mold and during transportation (with inevitable transfer) the sand goes through a cycle of circulation. low humidity, which ensures high sand flow during molding. Dosing of water to the most heated parts of the mold (as opposed to other constructions of the means of humidification) prevents the sand from entering the dry parts of the mold and the formation of high-humidity sand, which requires its subsequent drying. This allows the proposed tooling to be applied in known technological processes, excluding additional operations and equipment. This tooling can be used in conventional molding, but the tooling test was carried out with an HMF, with

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which is low cooling rate of castings.

The equipment offered is simple in design and in terms of maintenance and repair. Its application provides an improvement in the quality of castings by equalizing for differential and adjusting for special castings the cooling rate of their various components, surfaces with the formation of (- B-dimensional or special mechanic and other consumer properties. In the case of a low-intensity heat sink, equipment most promising in application

Claims (3)

1. Equipment for vacuum forming, containing flask and water supply means for): grinding of castings, so that in order to simplify the design and operation, to improve the quality of castings, the water supply means are dispensers installed in the flask. 2. Equipment according to claim 1, in accordance with the fact that the tanks-dispensers are made in the form of bags from non-heat-resistant material placed in a rigid frame. 3. Equipment for PP. 1 and 2, characterized in that the bags are made of a film used for shaping. FIG. 2 fig.Z FIG. Xl-xi FIG. five