DE202021001848U1 - Device for pressure-assisted vertical gravity casting (DVSG) of metallic materials - Google Patents

Abstract

A device for the production of metallic components, preferably for the lightweight materials aluminum and magnesium, is to be protected, which is characterized by:
1. the use of an upwardly open sand, precision or steel casting mold in combination with a heatable / coolable metallic stamp - according to claim 1, 2, 3.
2. The use of a temperature-controlled (heatable / coolable), metallic stamp, which can be lowered from above into the open, horizontal parting planes of the sand, precision or steel casting mold to the initial dimension (~ component thickness) using a hydraulic / mechanical press - according to claim 2, 3.
3. the slow filling of the sand, precision or steel casting mold, either manually or by means of a dosing device, in order to avoid turbulence. The laminar filling ensures that the melt absorbs less gas and thus improves the quality of the component—according to claim 4.
4. The possibility of controlling the heat balance of the entire system via the metallic die => (1) The additional introduction of heat across the entire component makes it possible to produce alloys that are difficult to cast or very complex component geometries. (2) By cooling the entire component, a fine-grained structure is produced due to rapid solidification of the melt - according to claim 5, 6.
5. the reduction / avoidance of porosity of the component due to the volume shrinkage during the transition from liquid <=> solid, through targeted lowering of the stamp and application of a defined pressure until the cast component has completely solidified - according to claim 7, 8.
6. the possibility of producing complex, thin-walled lightweight components (including undercuts) with, for example, a sand-cast structure - according to claim 1, 2.
7. the possibility of producing (1) thinner/lightweight, (2) almost pore-free/pressure-tight, (3) weldable and (4) dimensionally stable cast components - according to claim 2, 3, 8.
8. the possibility of filling several molds at the same time and the associated production of several cast components with one stroke - according to claim 9.
9. Ability to eject the parts from the mold through the use of a top stripper ring and ejector when using presses with an air table.
10. the possibility of structuring visible surfaces of the component as design elements => considerable advantages for styling applications.

Description

State of the art:

The shortest way from the raw metal to the finished product is with the help of casting. A distinction is made between processes that work with "lost moulds" (moulds that are destroyed after each casting => e.g. sand casting) and with permanent molds with which a large number of castings can be produced (=> e.g permanent mold, low or high pressure die casting).

What all casting processes have in common is that a mold that reflects the shape of the component must be produced, into which the metal is poured and in which it solidifies.

sand casting (=> lost form)

Sand casting is one of the oldest manufacturing techniques and has been used to manufacture metal components for centuries. Sand casting is a manual casting process that involves pouring molten metal into the cavity of a sand mold. Sand casting is the simplest type of casting and is normally used for the production of prototypes and small series - for large series production, fully automatic systems such as cold or hot chamber die casting, low pressure or gravity die casting are usually preferred. In connection with cores, the sand casting process offers very extensive design possibilities.

In sand casting, a molding sand and binder mixture is filled into a molding box and then compacted. Compaction can be done by hand (hand molding) or by machine (machine molding). By putting two mold halves together, a cavity is created into which liquid metal can be poured under gravity (laminar filling), which then solidifies under normal pressure. The sand can be processed (3-5x) and recycled in a cycle process.

Gravity die casting (=> permanent mold)

In chill casting, liquid metal is poured under gravity into a reusable two-piece metal mold where it solidifies under normal pressure. Due to the higher thermal conductivity of the metal mold, more heat can be dissipated in the same period of time compared to sand casting, which usually results in a denser and finer-grained structure, which in turn enables higher strength values.

In the case of smaller quantities, the components are manufactured using permanent mold casting by hand; in the case of larger quantities, this can also be done automatically.

The slow filling of the sand mold or mold under low pressure ensures a laminar flow with connected flow fronts. This allows a homogeneous structure to be achieved with fewer air or release agent inclusions. The result is almost pore-free, pressure-tight and weldable cast components with significantly improved mechanical properties (strength / elongation at break).

Description:

The present invention describes a device for producing metallic cast components, preferably from the light metals aluminum and magnesium, based on a combination of gravity casting and pressing - hereinafter referred to as "pressure-assisted vertical gravity casting (DVSG).

In contrast to conventional sand / permanent mold casting with two-part (sand-sand or metal-metal) molds, the "DVSG" device described here is based on a sand, precision or steel casting mold (sand mold matrix - Fig. [1.1] ; pick-up matrix - Fig.[1.2]) as well as a lowerable, temperature-controlled, metallic stamp - Fig.[2].

The heatable or coolable metallic stamp - Fig.[2] is made using a hydraulic or mechanical press - Fig.[3.1] ; Fig.[3.2] Lowered from above into the open, horizontal parting planes of the sand, precision or steel casting mold to the initial dimension (~ component thickness). This allows in situ different wall thicknesses of the final component - Fig.[4] set.

The sand, precision or steel casting mold is filled either manually or slowly using a dosing device (sprue - Fig.[1.3]). The laminar filling ensures that the melt absorbs less gas.

The metallic stamp - Fig.[2] can be heated for alloys that are difficult to cast or very complex component geometries and thus bring additional heat into the system over the entire component.

The overall system can also be given defined heat via a cooled stamp - Fig.[2] be withdrawn, which leads to faster solidification, a finer grain structure and thus to an improved quality of the final component - Fig.[4] leads.

The completely filled cast component can be reduced in volume shrinkage until it has completely solidified by further lowering the stamp - Fig.[2] be compressed. This results in less shrinkage and thus more precise dimensional accuracy of the final component.

Compared to the conventional sand casting process, the "DVSG" device described here can be used to: (1) significantly thinner / lighter, (2) almost pore-free / pressure-tight, (3) weldable and (4) more dimensionally stable cast components - Fig.[4 ] realize.

With the help of the "DVSG" device described here, several molds can be filled / compressed at the same time with one "stroke".

Claims (1)

A device for the production of metallic components, preferably for the lightweight materials aluminum and magnesium, is to be protected, which is characterized by: 1. the use of a sand, precision or steel casting mold open at the top in combination with a heatable / coolable metallic stamp - according to claim 1 , 2, 3. 2. the use of a temperature-controlled (heatable / coolable), metallic stamp, which, using a hydraulic / mechanical press, is pressed from above into the open, horizontal parting planes of the sand, precision or steel casting mold to the initial dimensions (~ component thickness ) can be lowered - according to claim 2, 3. 3. the slow, manual or metering-controlled filling of the sand, investment or cast steel mold to avoid turbulence. The laminar filling ensures a lower gas absorption of the melt and thus improved quality of the component - according to claim 4. 4. the possibility of controlling the heat balance of the entire system via the metallic stamp => (1) through the additional introduction of heat via the entire Components that are difficult to cast alloys or very complex component geometries can be realized. (2) By cooling the entire component, a fine-grained structure is produced due to rapid solidification of the melt - according to claim 5, 6. 5. the reduction / avoidance of porosity in the component due to volume shrinkage at the transition from liquid <=> solid, through targeted lowering of the Stamp and application of a defined pressure until complete solidification of the cast component - according to claim 7, 8. 6. the possibility of producing complex, thin-walled lightweight components (including undercuts) with, for example, a sand cast structure - after claim 1 , 2. 7. the possibility of producing (1) thinner/light, (2) almost pore-free/pressure-tight, (3) weldable and (4) dimensionally stable cast components - according to claims 2, 3, 8. 8. the possibility of simultaneous filling several molds and the associated production of several cast components with one stroke - according to claim 9. 9. the possibility of ejecting the components from the mold by using a stripper ring at the top and ejector when using presses with a bottom air table. 10. the possibility of structuring visible surfaces of the component as design elements => considerable advantages for styling applications.

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