Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D17/00—Pressure die casting or injection die casting, i.e. casting in which the metal is forced into a mould under high pressure
  • B22D17/007—Semi-solid pressure die casting
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D15/00—Casting using a mould or core of which a part significant to the process is of high thermal conductivity, e.g. chill casting; Moulds or accessories specially adapted therefor
  • B22D15/005—Casting using a mould or core of which a part significant to the process is of high thermal conductivity, e.g. chill casting; Moulds or accessories specially adapted therefor of rolls, wheels or the like
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/49481—Wheel making
  • Y10T29/49492—Land wheel
  • Y10T29/49524—Rim making
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/4998—Combined manufacture including applying or shaping of fluent material
  • Y10T29/49988—Metal casting

Definitions

• the invention relates to a method for producing die-cast parts, in particular parts made of aluminum or magnesium materials.
• the invention particularly relates to the manufacture of rims or wheels for the automotive industry.
• Rims or wheels for vehicles are now manufactured from aluminum materials using the low-pressure casting process. These are mostly simply controlled low pressure casting machines with a high manual workload. Every machine needs an operator who is exposed to both the high temperatures of the molten metal and the exhaust gases from the casting process. The demolding of the cast parts is complex.
• the manufacturer purchases the required aluminum alloy in ingot form and melts it in melting furnaces next to the low-pressure casting machine, i.e. the quality can also vary from machine to machine.
• a metal block (ingot) of a mass which essentially corresponds to the casting weight is introduced into the gas space above the bath level of the casting machine and before or after Pulling or ejecting the casting is introduced into the bath of the casting machine.
• DE-C-195 38 243 discloses a process for producing a semi-melted thixogiess casting material in which thixogiess material, which has an outer layer section with dendrites around an outer periphery of a main body section, is subjected to a heat treatment in order to to produce molten casting material with solid and liquid phases coexisting therein.
• the dendrites respectively.
• Dendrite fragments are transformed into spherical solid phases by increasing the temperature of the outer layer section with respect to the main body section, and the outer layer section is brought into a semi-melted state.
• the use of skin effects is intended to prevent the main body from heating up too quickly.
• Such a step-by-step method for heating is complex and requires several induction heating steps with different frequencies (powers).
• the invention is therefore based on the object of developing a method for producing die-cast parts, in particular wheels or rims for vehicles, with which the disadvantages of the prior art can be overcome.
• high-quality wheels and the like should be able to be produced with reduced effort.
• the environmental impact should be noticeably reduced in connection with improved working conditions.
• Another object of the invention is to provide a casting device for carrying out the method.
• a die casting cell known as such with supply and heating devices for the casting material, a die casting machine, handling devices and control devices, heating devices are integrated which enable the gradual heating of bolts made of aluminum materials (possibly also magnesium materials), which then come into contact without any significant contact with the ambient air reach the die casting machine.
• the cast parts After die casting or pressure forming, the cast parts are cooled and stored in a special process, and much faster than usual. It is characteristic of the heating process that a high, constant energy input is started and the energy input is then reduced after reaching the thixotropic structure in the metal area.
• Fig. 1 a casting cell.
• Fig. 2 a fixed mold frame in perspective.
• Fig. 3 a mold frame in partial section
• the casting cell contains a die casting machine 1 with a mold, a converter for the heating system 2, a monitor 3, a removal robot 5 for parts removal with a control unit 5, a loading robot 6 for feeding the slug with control unit 7 and a spray robot 8 with control unit 9 Molding temperature control devices 10, cooling stations 11 and 13, electrical, for example inductive heating units 12 for heating slugs (bolts), a device for parts control in front of a conveyor belt 16 for the discharge of non-quality parts and a further conveyor belt 15 for the discharge of the good parts.
• a metal supply is also planned (Sluglager 17), an automatic cleaning station 18 and a manual cleaning station 20 for castings, a scale 19 and a repair area 21.
• the die casting machine 1 is fed directly with slugs or bolts or portions that were previously heated in the heating units 12. They can be transferred directly and with no air into the casting chamber of die casting machine 1.
• the heated slugs in closed containers are fed to the casting chamber of the die casting machine 1 by means of robots 6.
• the containers are closed with a lid, so that the slugs are already heated in them and can be fed from the heating unit 12 to the casting chamber without protective gas when the target temperature is reached.
• the container is provided with a lid which can be lifted off or which is articulated to the container.
• the lid or the bottom of the container can also be provided with an additional and closable opening for pressure or vacuum emptying.
• the container can be rather flat or tall and narrow.
• a complete adaptation of the container to the shape of the material portion is not necessary, although the smallest possible volume of air in the closed container is advantageous. In particular, there should only be a small air gap between the lid and the material surface (portion). A seal that can be achieved through the shape and weight of the lid is usually sufficient.
• the container With semi-solid materials, the container is simply emptied over the edge of the container.
• the bolts can also be fed directly from a heatable supply space / feed channel, which can also be connected directly to the casting chamber, if necessary, the temperature being able to be increased during the transfer if necessary.
• aluminum materials for example, an alloy No.
• A357 (Al-Si7MgO, 6) is preferably used, which allows the cast parts to be quenched and stored in a shorter time (T5 treatment).
• T5 treatment The heating before pouring takes place gradually. This can be divided into three areas.
• a high-performance heating at the beginning a "cooking" after reaching the thixotropic structure in the area of the stud and in a homogenization for the final adjustment of the globulithic structure in the primary material.
• an AI bolt with a diameter of 5 to 6 is first heated with constant high energy to approx. 550 to 570 ° C, whereby the difference in temperature inside the bolt is up to approx. 20 ° C.
• the energy input becomes very high short time drastically reduced, kept very short time ( "cook") and then increased again and held again until a temperature of approximately 585 C C is reached and the temperature difference has dropped to about 2 to 3 degrees.
• the procedure can be simplified to the extent that the step of lowering the energy input can take place more slowly and evenly over a longer period of time.
• the individual bolts can also be “wrapped” in foil before heating, preferably in an aluminum foil, in order to avoid oxide formation etc. Shielding gas can also be used to avoid oxide formation.
• the starting material for the slugs is a homogeneously distributed, fine-grained material, which forms a uniformly distributed, globular microstructure with grain finenesses of approx. 50-100 ⁇ m due to the heating process.
• the latter is for e.g. high-quality wheels or rims, which are to be manufactured using an SSM process, are required.
• the molds and casting tools have a modular structure, so that cost-effective and easily exchangeable mold packages are available for each wheel type. A quick change for the respective shaping part of the forms is possible.
• the shape in the die casting machine 1 is e.g. two-part or three-part and variable use. Since the rim base remains unchanged per wheel dimension, only two mold plates have to be adapted to different front designs. These can still contain inserts that are made of an inexpensive and less high-strength material. The service life of such inserts can thus be adapted to the required number of rounds and only the basic shape has to consist of high-strength material.
• the mold plates can also contain slide inserts that allow adjustable heights and widths in the front design (depending on the tire and rim dimensions) in defined areas, so that an extra shape is not required for each dimension.
• the casting mold for producing a vehicle wheel from, for example, aluminum materials has a fixed molding frame 30 with a mold centering 31 as well as molded parts or slides 32 and cooling spirals.
• the fixed mold frame 30 is connected to the casting chamber 34 in a conventional manner. It also has part-specific core elements for bores in the hub 36 of the wheel 35, which can also serve as ejector elements of the wheel 35. This means that no additional ejectors are required, but functional parts are used that are already required for other tasks (here as the core element).
• the mold is filled from the hub 36 of the wheel 35 and between the hub surface and the gate 37 of the casting chamber 34, a filter or sieve 38 is arranged as an insert on the hub 36, which primarily serves to remove oxide skins of the SSM to be pressed in. Retain Bolzens, resp. to tear open and shred.
• the sieve 38 is a stamped part made of aluminum or steel and perforated as desired according to the hub surface.
• the bolts, not shown, are heated and fed with low O 2 .
• the filling in the mold cavity is largely dry, ie without lubricant. Due to the sieve, there is no need for a shearing knife for the oxide skin of the bolt.
• the casting chamber 34 and the casting piston of the die casting machine 1 preferably consist of a ceramic material in order to be able to dispense with lubricants and spraying agents as far as possible.
• the molded parts or slide 32 are provided with drives and guides (not shown) in order to ensure that the molded parts or slide 32 are retracted and extended.
• surfaces for locking the slide 32 are provided almost perpendicular to the support plane of the fixed mold frame 30. Furthermore, surfaces for locking the slide 32 are provided, which are arranged parallel to the abovementioned support plane on the slide 32 or the molded parts. Also almost perpendicular to the support plane mentioned, further surfaces for combined counter-locking and shape centering are provided.
• Corresponding counter contours are formed in the movable mold frame 33.
• the surfaces for locking the slide 32 are preferably on or in the fixed mold frame 30 and particularly preferably in a line.
• the surfaces for mold centering are circumferential regardless of the number of molded parts or slides 32.
• the forces acting during casting are thus distributed in the fixed mold frame 30 to the surfaces for combined mold centering and counter-locking to the right and left of the slide 32 - force transmission and force transmission are thus approximately in line and are easier to control.
• the molded parts or slides 32 are available for the common range of wheel sizes (for example from 13 "to 22") and can be arranged in only one set of molded frames 30, 33.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Molds, Cores, And Manufacturing Methods Thereof (AREA)
• Moulds For Moulding Plastics Or The Like (AREA)
• Forging (AREA)
• Blow-Moulding Or Thermoforming Of Plastics Or The Like (AREA)

Applications Claiming Priority (5)

Publications (2)

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Family Applications (1)

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• 2002
  • 2002-11-26 WO PCT/CH2002/000639 patent/WO2003045609A2/fr not_active Ceased
  • 2002-11-26 ES ES02776638T patent/ES2248613T3/es not_active Expired - Lifetime
  • 2002-11-26 AT AT02776638T patent/ATE305835T1/de not_active IP Right Cessation
  • 2002-11-26 US US10/495,680 patent/US20050022384A1/en not_active Abandoned
  • 2002-11-26 EP EP02776638A patent/EP1448331B1/fr not_active Expired - Lifetime
  • 2002-11-26 CN CNA028237579A patent/CN1596168A/zh active Pending
  • 2002-11-26 DE DE50204493T patent/DE50204493D1/de not_active Expired - Fee Related
  • 2002-11-26 AU AU2002339288A patent/AU2002339288A1/en not_active Abandoned

Non-Patent Citations (1)

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