Method of manufacturing open-cell bodies and bodies manufactured using said method

Abstract

In a method of manufacturing open-cell bodies, individual parts of an open pore plastic in a size which corresponds to the size of the bodies to be manufactured while taking account of the shrinkage on a sintering or an open pore plastic element having predetermined break points which take account of the size and geometrical design of bodies to be manufactured are/is in filtrated and coated with a suspension in which at least one powdery material is contained. Organic components are expelled after a first heat treatment. Subsequently, a sintering is carried out. Parts of porous plastic provided with the suspension are separated before the first heat treatment or wherein, afterwards the open-cell element which is obtained from the plastic element from the material with which the bodies are formed is cut by forces and thereby separated bodies can be obtained.

Claims

1. A method of manufacturing multiple same-size open-cell bodies comprising the steps of infiltrating and coating a open pore plastic element with a suspension containing a liquid and at least one powdery material with which the bodies are to be manufactured, the open pore plastic element having predetermined break points defining the same size and geometrical design as the open-cell bodies to be manufactured while taking account of shrinkage during sintering, expelling organic components after a first heat treatment, subsequently sintering the infiltrated and coated plastic element, and separating the sintered, infiltrated and coated plastic element into the multiple same-size open-cell bodies by forces acting at the predetermined break points.

2. A method in accordance with claim 1, characterized in that the predetermined break points are formed by stripping an open-pore plastic material or by cutting an open-pore plastic material.

3. A method in accordance with claim 1, characterized in that a web having a thickness of at least 0.5 mm is maintained at the predefined predetermined break points.

4. A method in accordance with claim 1, characterized in that forming the predetermined break points is achieved by cutting, thermally by means of irradiation or by punching.

5. A method in accordance with claim 1, characterized in that the predetermined break points are formed by stripping an open-pore plastic material carried out at a surface of the plastic material.

6. A method in accordance with claim 1, characterized in that a plastic element is used in which predefined predetermined break points are formed with which an annular body or a frame-shaped body of a polygon is formed after the sintering and the cutting of the predetermined break points.

Description

(1) There is shown:

(2) FIG. 1 a perspective representation of a plastic element from a plastic foam having predefined predetermined break points.

(3) A porous plastic element 1 is shown in FIG. 1 in which predetermined break points 2 which are predefined in a surface by a material stripping or in the manufacture of the plastic element 1 have been formed in the form of respective lines aligned perpendicular to one another. The predefined predetermined break points 2 can also have different geometrical designs at the plastic element 1.

EXAMPLE 1

(4) A polyurethane sponge as a porous plastic having a dimension of 200 mm×200 mm, a thickness of 10 mm and a cell size of 1300 μm was cut using a cutting blade into 400 cubes having an edge length of 10 mm×10 mm×10 mm. These 400 cubes were wetted with a metal powder/binder suspension comprising 80 wt. % AISI430 metal powder having a particle size d90<22 μm and 20 wt. % of an 8% aqueous PVA solution and were subsequently led through 2 rollers having a roller spacing of 2 mm several times after one another. A homogeneous coating of the surface of the plastic was thereby achieved in and at the porous plastic element which resulted in a mean weight of the individual cubes of 0.4 g respectively. After a drying, the so-called green cubes were debound in a batch furnace in a hydrogen atmosphere, that is the organic components were removed. Subsequently to this, the cubes were sintered at a temperature of 1260°. The sintered cubes were subsequently separated and deburred in a rotating container. The cubes had a mean density of 0.5 g/cm.sup.3 after the sintering.

EXAMPLE 2

(5) A polyurethane sponge having a dimension of 200 mm×200 mm, a thickness of 10 mm and a cell size of 1900 μm was cut using a cutting blade into 400 cubes having an edge length of 10 mm×10 mm×10 mm. These 400 cubes were wetted with a ceramic powder/binder suspension comprising 60 wt. % Al.sub.2O.sub.3 powder having a particle size d90<1 μm and 40 wt. % of an 10% aqueous PVA solution and were subsequently led through two rollers having a roller spacing of 1 mm several times after one another. A homogeneous coating was thereby achieved which resulted in a mean cube weight of 0.3 g. After a drying, the so-called green cubes were debound in a furnace and sintered as bulk cubes at air at a temperature of 1450°C. The cubes had a mean density of 0.4 g/cm.sup.3 after the sintering.

EXAMPLE 3

(6) In a polyurethane foam as a porous plastic element 1 having a cell size of 900 μm and a thickness of 8 mm gaps were cut out as predefined predetermined break points 2 using a hot wire (electrical resistance heating wire). The gap width amounted to 0.85 mm in this respect. The thickness of the predefined predetermined break point 2 amounted to 1 mm, The dimensions of the remaining structure after the incorporation of the predetermined break points 2 and gaps were selected such that bodies having the dimensions 8 mm×8 mm×6 mm were obtained after the sintering,

(7) The polyurethane sponges thus processed were wettted with a metal powder/binder suspension comprising 95 wt. % AISI316 metal powder having a particle size d.sub.90<22 μm and a 6% aqueous PVA solution and were subsequently led through two rollers having a roller spacing of 1 mm several times after one another. A homogeneous coating was thereby achieved which resulted in a mean density of 0.3 g/cm.sup.3. After a drying, the so-railed cuboid green bodies were debound in a furnace and were sintered in the batch furnace in a hydrogen atmosphere at a temperature of 1260° C., After the sintering, the bodies having the dimensions 8 mm×8 mm×6 mm were broken out of the plate at the predefined predetermined break points. The cuboid bodies had a mean density of 0.5 g/cm.sup.3 after the sintering.

EXAMPLE 4

(8) In a polyurethane foam as a plastic element 1 having a cell size of 1200 μm and a thickness of 10 mm gaps were cut out as predefined predetermined break points 2 using a hot wire. The gap width amounted to 0.85 mm in this respect. The thickness of the predefined predetermined break point 2 amounted to 1.5 mm. The dimensions of the remaining structure after the incorporation of the predetermined break points 2 and gaps were selected such that bodies having the dimensions 10 mm×10 mm×6 mm were obtained after the sintering.

(9) The polyurethane sponge thus processed was wettted with a metal powder/binder suspension comprising 85 wt. % Fe23Cr6Al metal powder having a particle size d.sub.90<22 μm and a 6% aqueous PVA solution and was subsequently led through two rollers having a roller spacing of 1 mm several times after one another. A homogeneous coating was thereby achieved which resulted in a mean density of 0.4 g/cm.sup.3. After a drying, the so-called green cubes were debound in a furnace and sintered in a batch furnace and in a hydrogen atmosphere at a temperature of 1260° C. After the sintering, the bodies having the dimensions 10 mm×10 mm×6 mm were broken out of the plate at the predefined predetermined break points. The cubes had a mean density of 0.5 g/m.sup.3 after the sintering.

EXAMPLE 5

(10) A polyurethane sponge having a dimension of 200 mm×200 mm, a thickness of 10 mm and a cell size of 1000 μm of the open pores was cut using a cutting blade into 400 cubes having an edge length of 10 mm×10 mm×10 mm. These 400 cubes were wetted with a metal powder/binder suspension comprising 80 wt. % Co metal powder having a particle size d90<10 μm and 20 wt. % of an 8% aqueous PVA solution and were subsequently led through 2 rollers having a roller spacing of 1 mm several times after one another. A homogeneous coating of the surface of the plastic was thereby achieved in and at the porous plastic element which resulted in a mean weight of the individual cubes of 0.5 g respectively. After a drying, the so-called green cubes were debound in a batch furnace in a hydrogen atmosphere, that is the organic components were removed. Subsequently to this, the cubes were sintered at a temperature of 1350°. The sintered cubes were subsequently separated in a rotating container. The cubes had a mean density of 0.7 g/cm.sup.3 after the sintering.