Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
  • B22D29/00—Removing castings from moulds, not restricted to casting processes covered by a single main group; Removing cores; Handling ingots
  • B22D29/001—Removing cores
  • B22D29/005—Removing cores by vibrating or hammering
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B08—CLEANING
  • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
  • B08B5/00—Cleaning by methods involving the use of air flow or gas flow
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B08—CLEANING
  • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
  • B08B7/00—Cleaning by methods not provided for in a single other subclass or a single group in this subclass
  • B08B7/02—Cleaning by methods not provided for in a single other subclass or a single group in this subclass by distortion, beating, or vibration of the surface to be cleaned
  • B08B7/026—Using sound waves
  • B08B7/028—Using ultrasounds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22C—FOUNDRY MOULDING
  • B22C9/00—Moulds or cores; Moulding processes
  • B22C9/18—Finishing

Definitions

• the present invention relates to a cleaning method for extracting foreign bodies (dust, sand, residue of material ”) and dirt from the interior of rigid rigid enclosures whose complex and sinuous shape does not does not allow easy access to the areas to be cleaned. It aims more particularly a method of cleaning metal parts intended advantageously to the automotive or aeronautical industry, such as for example gearbox casings, cylinder heads, engine blocks, manifolds, pump casings or any other part.
• a known technique consists, for example, in using the method excitation of a part according to the provisions of patent FR-2 755 038, this part having been previously placed in a liquid enclosure.
• the present invention therefore aims to overcome these drawbacks by proposing a industrial process that offers excellent cleaning performance, even within infructuosity of a massive piece of foundry and which aims to take off, to fluidify and extract any conglomerate trapped in the internal conduits of the part to be cleaned such as in particular a part made in foundry from lost kernels or patterns, guaranteeing the undeniable advantages of a dry cleaning.
• the ultrasonic excitation sources are produced from sonotrodes of ⁇ 10 to 60 mm in titanium or steel, tuned to a frequency of 10 to 30 kHz for an amplitude of 40 to 150 ⁇ m peak / peak, fixed on assemblies boosters - piezoelectric or magnetostrictive transducers and animated in movement by ultrasonic frequency generators.
• metal anvils With a small contact surface, in opposition to the impact point of the ultrasonic source and this, with the smallest possible air gap in order to guarantee an excitation punctual while retaining most of the walls, of the room to be made vibrate, free from any vibratory movement.
• these anvils In order not to transmit the vibration to the structure of the machine and in order to maintain this character of freedom of vibration, these anvils must be isolated from the chassis using an element slightly elastic such as a polyurethane part or a pneumatic cylinder, just like the sonotrode / booster / transducer acoustic assembly.
• the sources of low frequency excitation necessary for the cracking of large core masses are made from a pneumatic hammering system of very low frequency of the order of 0.1 to 5 Hz.
• the result in this case essentially depends on the shock wave provided piece by piece which therefore involves defining the conditions of contact between the hammer and workpiece, such as collision speed and mass on-board, this on-board mass being defined in proportion to the clean mass of the part to be cleaned with its core or core residue.
• the hammering can be printed by the piece by at least one of the sonotrodes or by at least one of the anvils supporting said part.
• a judicious realization to generate this movement necessary for cracking is to use the pneumatic assemblies of the ultrasonic sources or their anvil to obtain the desired hammering by alternative control of the pneumatic valve (s) control with adjustment of pressure and flow regulators.
• the source of vibration necessary for the decay of residues to a fluidization allowing the extraction is carried out from a linear vibration of frequency between 100 and 250 Hz, amplitude 1 to 4 mm peak / peak, obtained using a mechanical system tuned to the chosen frequency and alternately excited by two electromagnets through a low generator frequency.
• This linear vibration can be oriented along a horizontal axis or an axis vertical depending on the shape of the part and the flow of the conduits.
• the part must therefore be fixed integrally to the vibrating element from above or by one of the side faces in order to promote flow by gravity, that is to say from below.
• the frequency generator With the sometimes very large mass of the nucleus, especially for sand-based cores, it is essential to provide the frequency generator with automatic frequency control allowing in firstly a tuning of the latter on the mechanical frequency of the vibrating assembly with the mass of the part to be vibrated and, in a second time, to follow in real time the increase in this frequency in proportion to the loss of mass due to the flow of the material gradually released, and this in order to optimize the yield linked to transfer of electromagnetic energy into mechanical energy.
• the material conveying flow of the disintegrated core residues is obtained at using a combined blowing and suction system guaranteeing the type desired flow.
• a central suction ensuring a higher flow speed for example than 20 m / s, and in particular included in the range of 20 to 80 m / s, for a flow corresponding to the sections of the ducts to be cleaned, which will be completed so judicious by a blowing system supplied with compressed air by installing calibrated nozzles at the inlet of each orifice opposite the outlet (s) connected to the suction.
• This supply of compressed air has the role of compensating for the losses of harges linked the sometimes tortuous paths of the conduits and must be checked upstream pressure and cross section in order to be equivalent to the extraction flow rate by suction to avoid backflow.
• suction and blowing systems must be installed as close as possible to duct openings to minimize the intermediate volumes for guarantee a minimum pressure drop and are for example located in a enclosure enveloping the part alone or with the means of vibration, the sources ultrasonic, hammering means, in particular pneumatic or mechanical, the vibrating plate.
• This enclosure maintained under an atmosphere under vacuum, guarantees the evacuation of residues from the workpiece foundry.
• it is necessary to reduce the volume subjected to depression, limiting the passage of the flow to a space of a few millimeters covering the entire three-dimensional external envelope of the room.
• the present invention offers multiple advantages because, by combining phases, ultrasonic excitation, hammering, of vibration and evacuation of residues by a fluid, it guarantees obtaining optimal cleaning or cleaning of the room, while reconciling the imperatives linked to medium and large industrial production series.
• This process is also applicable as a control process allowing to check the quality of cleaning obtained from conventional techniques.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Cleaning In General (AREA)
• Cleaning By Liquid Or Steam (AREA)
• Lubricants (AREA)
• Physical Or Chemical Processes And Apparatus (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=9543537

Family Applications (1)

Country Status (7)

Cited By (1)

Families Citing this family (8)

Citations (4)

Family Cites Families (3)

• 1999
  • 1999-03-23 FR FR9903610A patent/FR2791282B1/fr not_active Expired - Fee Related
• 2000
  • 2000-03-08 DE DE60005729T patent/DE60005729T2/de not_active Expired - Fee Related
  • 2000-03-08 ES ES00400636T patent/ES2211467T3/es not_active Expired - Lifetime
  • 2000-03-08 EP EP00400636A patent/EP1038597B1/de not_active Expired - Lifetime
  • 2000-03-08 AT AT00400636T patent/ATE251506T1/de not_active IP Right Cessation
  • 2000-03-09 CA CA002300504A patent/CA2300504A1/fr not_active Abandoned
  • 2000-03-17 US US09/527,851 patent/US6361610B1/en not_active Expired - Fee Related

Patent Citations (4)

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