Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22C—FOUNDRY MOULDING
  • B22C15/00—Moulding machines characterised by the compacting mechanism; Accessories therefor
  • B22C15/23—Compacting by gas pressure or vacuum
  • B22C15/24—Compacting by gas pressure or vacuum involving blowing devices in which the mould material is supplied in the form of loose particles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22C—FOUNDRY MOULDING
  • B22C19/00—Components or accessories for moulding machines
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22C—FOUNDRY MOULDING
  • B22C15/00—Moulding machines characterised by the compacting mechanism; Accessories therefor
  • B22C15/23—Compacting by gas pressure or vacuum
  • B22C15/24—Compacting by gas pressure or vacuum involving blowing devices in which the mould material is supplied in the form of loose particles
  • B22C15/245—Blowing tubes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22C—FOUNDRY MOULDING
  • B22C23/00—Tools; Devices not mentioned before for moulding
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22C—FOUNDRY MOULDING
  • B22C9/00—Moulds or cores; Moulding processes
  • B22C9/12—Treating moulds or cores, e.g. drying, hardening
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22C—FOUNDRY MOULDING
  • B22C9/00—Moulds or cores; Moulding processes
  • B22C9/12—Treating moulds or cores, e.g. drying, hardening
  • B22C9/123—Gas-hardening

Definitions

• the invention relates to a method and a molding machine for producing molded parts, such as casting cores, for casting molds for casting molten metal.
• a molding material which is generally bonded with synthetic resin is filled into the cavity of a mold which determines the final shape of the casting core molded part to be produced.
• the molding tool has a sufficient number of shot openings for uniform filling of the cavity, through which the filling with molding material takes place.
• a "weft nozzle” is inserted into each of these weft openings, through which the molding material is then injected.
• the weft nozzles are usually carried together by a height-adjustable "weft head plate” which ensures that the core box is extended and retracted into the firing position.
• the supply of the shot nozzles usually takes place via a so-called "shot hood", which covers the shot head plate on its side facing away from the molding tool and with molding material is filled.
• shot hood which covers the shot head plate on its side facing away from the molding tool and with molding material is filled.
• the molding material contained in the firing hood is suddenly pressurized with a gas, usually air, uniformly via a firing cylinder, so that it is driven into the mold via the firing nozzles.
• the curing can be initiated by using suitable binders by applying heat.
• suitable binders for applying heat.
• known mold shooters for producing mold cores are equipped with heaters for heating the mold.
• the curing of the molding material is brought about by the supply of heat in the molding tool.
• a molding material is first produced by mixing an inorganic, fire-resistant molding sand with an inorganic binder based on water glass. This molding material is then filled into a temperature-controlled molding tool which is exposed to a negative pressure during filling. The temperature / dwell time of the molding material after the mold is closed is set so that a dimensionally stable and stable edge shell is formed on the core molding. When the core molding has reached this state, the molding tool is opened and the core molding is removed. Immediately afterwards, the core molding is subjected to complete drying under the influence of microwaves. Moisture is thus physically extracted from the molding material formed by the mixture filled into the mold. As a result of this dehumidification process, a solidification of the core molding is achieved in the mold, which at least enables its handling in the further processing steps.
• the object of the invention is to provide a method and a device with which molded parts for casting molds can be produced reliably and with reduced susceptibility to malfunction from a molding material containing an inorganic binder.
• a molding material containing an inorganic binder is filled into a cavity of a molding tool which determines the shape of the molded part to be produced, in a molding machine using filling elements such as shot nozzles and shooting hood,
• the filling elements of the molding machine are kept at a moisture level which prevents the molding material from solidifying.
• the molding tool can be moved relative to the filling elements and / or the filling elements relative to the molding tool from a filling position, in which they are arranged closer together for filling the molding tool, into a waiting position in which they are positioned apart from each other, and
• the molding tool can additionally be moved back and forth between a filling and a removal station.
• a method according to the invention and a mold shooting machine according to the invention for producing casting cores for the casting of light metal melts are particularly suitable, which in practice represent the vast majority of the casting mold parts produced in devices of the type in question here.
• those components which are heated by the heat radiated from the molding tool to a temperature at which the unwanted premature and consequently disruptive curing of the molding material could start are kept moist during the curing of the molding material filled in the heated molding tool.
• the components which are particularly affected by the heating are typically the shot nozzles or the shot hood required for supplying the shot nozzles with the supply plate connected to them or other molding material carrying channels.
• the moistening of the components heated by the heat emitted by the molding tool and consequently endangered with regard to the solidification of the molding material can take place in that at least one of the filling elements is at least temporarily exposed to a moist atmosphere during the curing time.
• This embodiment of the invention is particularly suitable for avoiding hardening of the molding material in the firing hood if a moist atmosphere is specifically maintained in the hood.
• the moisture content of the atmosphere which is preferably formed by air as the carrier gas, can easily be adapted to the respective circumstances. For example, it is conceivable to adjust the humidity of the atmosphere surrounding the waiting nozzles so that condensate forms on the shot nozzles and, as a result, the solidification of molding material contained in or sticking to the shot nozzles is reliably avoided.
• a further, particularly simple to implement and yet effective embodiment of the invention is characterized in that at least one of the co-heated filling elements is brought into contact with a moisture carrier at least temporarily during the curing time.
• This moisture carrier can be an absorbent material impregnated with liquid, in particular water, such as a sponge or a rag. Practical tests have shown that if such a moisture carrier is docked onto the waiting nozzles, the solidification of the molding material contained in the nozzles can be reliably avoided.
• a hot gas preferably heated air
• a hot, dry gas stream is passed through the mold during the time required for the curing of the molding, in addition to the heat introduced via the tool itself. That way on the one hand, the gases generated in the course of curing are removed from the mold.
• additional heat is introduced into the molded part. This heat does not slowly penetrate through the edge shell of the molded part into its interior, but is actively transported by the gas flow into the core interior of the molded part.
• FIG. 1 shows a mold shooting machine for producing casting cores in a first operating position
• Fig. 2 shows the molding machine shown in Fig. 1 in a second operating position.
• the molding machine 1 for producing casting cores K according to the "hot box method" has a mixer 3.
• a molding material F is mixed from an inorganic, refractory molding sand and a water glass-based binder.
• This molding material F is placed in a filling hopper 4 arranged below the mixer 3, from which it is passed into a shooting cylinder 5 positioned below the filling hopper 4.
• the shooting cylinder 5 shoots the filler F into a shooting hood 6 which is connected to it and, starting from the shooting cylinder 5, widens in width and depth and is closed on its underside by a shooting head plate 7.
• a plurality of receptacles are formed in the shot head plate 7, in each of which a shot nozzle 8 is seated.
• the shot nozzles 8 extending in the direction of the upper box 9 of a molding tool 10 are arranged corresponding to the shot holes 11 formed in the upper box 9.
• the shot holes 11 open into a cavity 12 which is formed by corresponding recesses formed in the upper box 9 and the lower box 13 of the molding tool 10. Further elements not shown here can be part of the molding machine 1.
• the shape of the casting core K to be produced is determined by the cavity 12. Vent openings 14 are formed in the lower case 13, via which the air displaced by the filled molding material F escapes when the cavity 12 is filled. If necessary Appropriate ventilation openings, not shown here, are introduced into the upper box.
• the upper box 9 and the lower box 13 of the molding tool 10 can be heated in a controlled manner by means of a heating device 15.
• Actuators are provided to the core box with the shot holes 11 to the shot nozzles
• the molding machine 1 After the molding material F has been shot into the molding tool 10, the molding machine 1 is moved into the waiting position, in which the tips of the shot nozzles
• the shot nozzles 8 maintain this waiting position until the molding material F contained in the cavity 12 of the molding tool 10 has hardened due to the dehumidification to the casting core K which occurs as a result of the heating of the molding material F in the molding tool 10. If no air flow L is passed through the molding tool 10 by means of overpressure or underpressure to improve the curing process, the gases which arise in the course of the curing escape automatically through the shot holes 11 and the ventilation openings 14 from the molding tool 10.
• a humidifying device 16 is connected to the shooting hood 6, via which moist air can be conducted into the interior of the shooting hood 6.
• a Sponge 17 is fastened to a plate 18 which, when the shot nozzles 8 are in the waiting position, can be moved under the shot nozzles 8 and raised so that the sponge 17 presses against the shot nozzles 8 and at least completely surrounds its lower section which has the nozzle opening.
• each of the shot nozzles 8 is assigned a nozzle 19, via which moist air supplied by the humidifying device 16 is blown onto the shot nozzles 8 when the shot nozzles 8 are in the waiting position.
• the moisture content of the moist air introduced into the firing hood 6 in the waiting position and blown against the firing nozzles 8 is adjusted in such a way that there is no dehydration of the molding material. In this way, it is safely prevented that the molding sand F still contained in the waiting position 6 and the shot nozzles 8 in the waiting position solidifies as a result of the heating and the removal of water, which the components in question due to the radiant heat W emitted by the hot molding tool 10 both during the Filling process (Fig. 1) as well as in the longer waiting position (Fig. 2) are exposed.
• the sponge 17 pressed against the shot nozzles 8 in the waiting position additionally ensures in a targeted manner that there is no blockage of the nozzle openings of the shot nozzles 8 as a result of adhesive molding material F.
• the formation of condensate in the area of the shot nozzles 8 can be supported in that the shot nozzles 8 are cooled in the waiting position with the aid of a cooling device, not shown here. This cooling also effectively prevents the Temperature in the interior of the shot nozzles 8 rises to a level critical for the solidification of the molding material F.
• the moistening of the outside of the weft nozzles 8 ensures that solidified molding sand F does not bake on the weft nozzles 8.
• a device 20 which has an air supply connection 21 and a suction connection 22.
• the air supply connection 21 of the device 20 is coupled to the shot holes 11 and the suction connection 22 of the device 20 is connected to ventilation openings 14 of the molding tool 10 (FIG. 2).
• a hot, dry air flow L is continuously conducted into the mold 10 via the air supply connection 21.
• This air flow L flows through the casting core K contained in the molding tool 10 and is in the process of curing and is drawn off via the ventilation openings 14 of the molding tool 10. In this way, the core interior is heated evenly, so that the moisture contained in the casting core K escapes faster overall.
• the air flow L sucked off via the suction connection 22 transports the gases formed in the course of the heating of the casting core K specifically and quickly out of the molding tool 10.
• the more homogeneous heat distribution in the casting core K achieved by the air flow L thus results in a shortened curing time and at the same time improved strength of the casting core K obtained.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Molds, Cores, And Manufacturing Methods Thereof (AREA)
• Moulds For Moulding Plastics Or The Like (AREA)
• Casting Or Compression Moulding Of Plastics Or The Like (AREA)
• Casting Devices For Molds (AREA)

Priority Applications (9)

Applications Claiming Priority (2)

Publications (1)

Family

ID=7698262

Family Applications (1)

Country Status (15)

Cited By (1)

Families Citing this family (8)

Citations (1)

Family Cites Families (6)

• 2001
  • 2001-09-08 DE DE10144193A patent/DE10144193C1/de not_active Expired - Fee Related
• 2002
  • 2002-09-09 ES ES02777041T patent/ES2305307T3/es not_active Expired - Lifetime
  • 2002-09-09 KR KR10-2004-7003461A patent/KR20040063117A/ko not_active Application Discontinuation
  • 2002-09-09 CN CNB028200519A patent/CN1292857C/zh not_active Expired - Fee Related
  • 2002-09-09 WO PCT/EP2002/010079 patent/WO2003022487A1/de active IP Right Grant
  • 2002-09-09 EP EP02777041A patent/EP1444063B1/de not_active Expired - Lifetime
  • 2002-09-09 DE DE50212194T patent/DE50212194D1/de not_active Expired - Lifetime
  • 2002-09-09 HU HU0402386A patent/HUP0402386A2/hu unknown
  • 2002-09-09 RU RU2004110620/02A patent/RU2277453C2/ru not_active IP Right Cessation
  • 2002-09-09 US US10/489,047 patent/US20040250977A1/en not_active Abandoned
  • 2002-09-09 PL PL367721A patent/PL204048B1/pl unknown
  • 2002-09-09 MX MXPA04002068A patent/MXPA04002068A/es active IP Right Grant
  • 2002-09-09 CA CA002459430A patent/CA2459430A1/en not_active Abandoned
  • 2002-09-09 AT AT02777041T patent/ATE393676T1/de not_active IP Right Cessation
  • 2002-09-09 BR BR0212370-3A patent/BR0212370A/pt not_active IP Right Cessation
• 2004
  • 2004-03-04 ZA ZA200401807A patent/ZA200401807B/en unknown

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