CN1048995A - Pure ice-film cold sand molding method and device - Google Patents

Abstract

The pure ice-film cold sand molding genealogy of law refers to the molding sand that contains 3-7% water is poured in the puddle mixer that is equipped with cold drawing and low temperature copper pipe, by the low temperature copper pipe with the liquid nitrogen spray in the liquid nitrogen memory in molding sand, can mix the pure ice-film cold sand of making below-50 ℃ through stirring.Pure ice-film cold sand is put in the moulding machine template sandbox pressurization 12kg/cm ²Below promptly plastic, utilize the back heating effect of ice sheet fragility and template etc. directly to pull out film.This molding is saved the raw material in molding sand, and the system of mixing is simplified, without sand preparation equipment, without remover, the old sand direct reuse, no dust, productivity ratio can reach the 60-120 case/hour, cold sand preparation time 2-3 branch/time, guarantor's type 2-3 hour.

Description

Pure ice-film cold sand molding method and device

The invention belongs to a kind of cold sand molding method and device, particularly belong to a kind of pure ice-film cold sand molding method and device.

By retrieval, the cold sand that state's external cooling sand molding adopts belongs to extraordinary cold sand, is to have added technical measures such as certain additives and employing cold drawing in cold sand, also has a segment distance from production application.

The objective of the invention is to provide pure ice-film cold sand molding method and device.

The present invention is achieved in that cold sand molding method of the present invention is only to add 3～7% water in molding sand, mixes through special installation and makes graininess pure ice-film cold sand, it is added to carry out moulding in the sandbox then.Its technical process is: will add the molding sand of 3～7% water, and pour in the special puddle mixer, and behind startup puddle mixer and the refrigeration plant, open liquid nitrogen memory or nitrogen making machine switch again, puddle mixer is made up of the cold end, cold leg and adiabatic cover plate etc.Provide low-temperature receiver by refrigeration plant.By being fixed on the low temperature copper pipe that has aperture on the puddle mixer inner tube wall, with the liquid nitrogen spray in the liquid nitrogen memory in molding sand, stir and to mix the pure ice-film cold sand of making below-50 ℃ in 1.5～2.5 minutes, draw back the puddle mixer bottom and leak the sand dividing plate, cold hourglass is gone out, and the adiabatic sandbox that the cold sand that spills is put into template exceeds more than the 50mm.Start moulding machine, generally be pressurized to 12kg/cm ²Below promptly plastic (also available blow-moulding machine moulding＜core 〉).Can add on pressure head that for all pressing thick rubber evenly fills up (also can not place because of cold sand good fluidity, itself just can play all pressure effects).Directly utilize the back heating effect of ice sheet fragility and template etc. directly to pull out film.Puddle mixer of the present invention is that the low temperature copper pipe is housed on the inner tube wall of the puddle mixer that is used for production and sales, aperture is arranged on the pipe, aperture D=0.5～1.0mm is equipped with cold drawing on bottom in the puddle mixer and the inner tube wall, and the bottom of puddle mixer and mixing component thereof all are equipped with heat insulation layer.Moulding machine and refrigeration machine are the typing sell goods.

The basic principle of pure ice-film cold sand molding is that deep cooling ice-film cold sand is under high pressure or air pressure compacted under＜core 〉.Deep cooling makes the not conglomeration of ice-film cold sand, Hui Rong not, the energy moisture absorption, make the back molding sand that shakes out be the loose granule state by the ash look that bleaches, pressure or air pressure make that the freezing point of its cold sand surface ice sheet descends, move mutually between sand grains and produce frictional heat, at the surface production thawing water of frost zone, but wherein freeze owing to adhering mutually between heat conduction sand grains.The viscosity of promptly utilizing cold conditions forms freezing casting mold with together freezing mutually between sand grains.The melting point of ice descends to some extent along with the increase of pressure, every increase 1atn, and melting point reduces by 0.075 ℃, and for the cold sand mixture that contains certain impurity, melting point descends more so.This be because: 1, ice produces micro-silica gel with silica sand surface contact.2, water contacts with silica sand and contains certain impurity.3, be dissolved with about 29.18 milliliters/liter of gas in the water.4, mutually move the frictional heat that produced etc. between cold sand.Pure ice-film cold sand molding process is cooling rapidly under the profound hypothermia, can make frozen coating thickness uniformity, because deep cooling makes the ice rete form unformed bloom, loose thickness improves, and easily is graininess.Pressure or air-pressure forming＜core〉are one steps of key of making cold mould, according to cold sand temperature decision moulding pressure, are generally 12kg/cm ²More than.Can place thick rubber evenly fill up (also can not place, because of cold sand good fluidity, itself just can play all pressure effects) on pressure head for all pressing, with assurance cold mould pressure basically identical everywhere, air-pressure forming pressure is 5～6 atmospheric pressure.Pressure forming easily produces the high pressure rebound phenomenon, but to cold mould, because intensity is big, the case hardness height can significantly reduce rebound phenomenon and take place.Dial the anti-pressurization that film mainly utilizes ice sheet fragility and template etc.General easy type do not need the special process measure.But the moulding of seeking quickness, fast skinning can strengthen the temperature difference like this, can prevent the Hui Rong with the cold sand in Metal Contact place again.The tooling device that various and cold sand contacts should be adiabatic.As sand bin, cold sand running sand plate, supporting plate, top box cover plate, so that prolong the holding time of cold mould, pressing case iron not want directly is pressed on the cold mould, should place adiabatic cover plate on it with air-vent, to prevent that cold mould from crossing that snap back is melted, cold mould is deposited except that above-mentioned measure, also can adopt following manner: 1, freezing passage is preserved.2, regularly in cold mould, lead to liquid nitrogen.3, in sandbox, place refrigeration piping, feed refrigerant, but,, otherwise become thermal source so the temperature of refrigerant should be lower than cold sand temperature owing to adopt the deep cooling shell coated sand.Answer mould assembling to deposit after cold mould is carried out, can prolong the resting period greatly like this, should be steady during cast, comparable common sand mold is shake out early, helps cold sand reuse, and temperature is low can save refrigerant consumption.

Employing pure ice-film cold sand molding method can be saved clay and the raw material such as various bonding agent, anti-scab material, coal dust, coating and dressing in the molding sand.The molding sand system of mixing is simplified, and prescription is simple, without mulling, " fluffing of moulding sand is mixed well ".Control cancellation in the middle of the molding sand, the cold sand that mixes after making can use immediately, and sand preparation equipment is simple, saves the molding sand test event, only checks water content, freezing temperature.Save remover in the moulding, boost productivity, sandfalling cleaning equipment is simple.Old sand is reuse immediately, without reclaim equiment.No dust, poison gas, smog pollution, the investment of saving sanitation equipment.Improve working conditions castability height, consistent size.Labor productivity can reach 60～120 casees/hour.Cold sand preparation time 2～3 minutes/time, guarantor's type 2～3 hours has realized the once real great change of casting technique, has great economic benefit and social benefit.

Fig. 1 is pure ice-film cold sand molding method and device schematic diagram.

1 describe pure ice-film cold sand molding method and device thereof in detail in conjunction with the accompanying drawings: pure ice-film cold sand molding method is to pour the molding sand that adds 5% water into puddle mixer 1, start puddle mixer 1, open liquid nitrogen memory 5 switches, by being fixed on the aperture D=1mm that has on puddle mixer 1 inner tube wall, inside radius R=500mm, the low temperature copper pipe 2 of outer radius R=550mm, with the liquid nitrogen spray in the liquid nitrogen memory in mulling, the pure ice-film cold sand that the system of mixing can obtain below-50 ℃ in 2 minutes, draw back puddle mixer 1 bottom and leak sand dividing plate 6, hourglass is gone out, the adiabatic sandbox that the sand that spills is put on the moulding machine 7 exceeds more than the 50mm, starts moulding machine 7, is pressurized to 12kg/cm ²Promptly plastic.Can on pressure head, place thick rubber and evenly fill up for all pressing.Utilize the back heating effect of ice sheet fragility and template etc. directly to pull out film after the moulding of pure ice-film cold sand.

Puddle mixer 1 of the present invention is the outer radius R=550mm that loads onto aperture D=1mm on the inner tube wall of the puddle mixer that is used for production and sales, and the low temperature copper pipe of inside radius R=500mm is equipped with cold drawing 11, heat-insulating shield 3 on the bottom of puddle mixer 1 and the inner tube wall.Mixing component 4 is arranged in the puddle mixer 1, leak sand dividing plate 6.The puddle mixer upper top is equipped with heat-insulating cover 10, covered and add sand mouth 9.Refrigeration machine 8, base 12, scraper plate 13.

Claims (2)

1, pure ice-film cold sand molding method, it is characterized in that the molding sand that will contain 3～7% water pours the puddle mixer that refrigeration plant is housed into, open liquid nitrogen memory (or system ammonia equipment) switch, by being fixed on the foraminate low temperature copper pipe on the puddle mixer inner tube wall that refrigeration plant is housed, with the liquid nitrogen spray of liquid nitrogen memory in mulling, can mix the pure ice-film cold sand of making below-50 ℃ through mulling, the sand dividing plate is leaked in the bottom of drawing back puddle mixer, cold hourglass is gone out, the cold sand that spills is put into the template sandbox on the moulding machine, starts moulding machine and is pressurized to 12～20kg/cm ²Promptly plastic, utilize the back heating effect of ice sheet fragility and template etc. directly to pull out film.

2, the used device of pure ice-film cold sand molding method is characterized in that: cold drawing and low temperature copper pipe are housed on the inner tube wall of puddle mixer, and the bottom and the mixing component thereof of puddle mixer are equipped with heat insulation layer, and the top of puddle mixer is equipped with heat-insulating cover, adds the sand mouth.