CN105618680A - Full mold casting technique for diesel engine cylinder body - Google Patents

Abstract

The invention relates to casting methods, in particular to a full mold casting technique for a diesel engine cylinder body. The full mold casting technique for the diesel engine cylinder body comprises the following steps that a, prefoaming is conducted; b, curing is conducted; c, foam forming is conducted; d, models are combined into a cluster; e, the models are coated; f, a mold bed is prepared; g, a full mold model is placed; h, sand filling is conducted; i, sealing and shaping are conducted; j, pouring and displacing are conducted; and k, cooling and cleaning are conducted. The full mold casting technique for the diesel engine cylinder body has the beneficial effects that firstly, excellent foam plastic beads are used for further reducing the amount of residual carbon; secondly, the reasonable bead prefoaming density is effectively controlled, so that the situation that a white mold deforms and even breaks due to the fact that the strength of the white mold is insufficient is avoided, and the defects, such as pores and carbon defects, of castings are also avoided; and thirdly, the problem that the quality of the castings is low is solved, and thus volume production of diesel engine cylinder bodies is achieved.

Description

The lost foam casting process of diesel engine cylinder block

Technical field

One casting method of the present invention, the lost foam casting process of especially a kind of diesel engine cylinder block.

Background technology

Diesel engine cylinder block is a kind of more complicated foundry goods, domestic main employing clay sand mold casting, minority enterprise adopts cold-box or hot box casting, but these casting method ubiquity labor intensity are big, environmental pollution serious, molding sand reuse is few, antiquated sand cannot process, raw materials consumption is heavy, casting weight is laid particular stress on, casting quality cannot ensure series of problems such as (mould shift, sand holes, slag inclusion, pores etc.). The appearance of lost foam casting thoroughly solves tradition sand casting often along with defects such as mould shift, sand holes, slag inclusion, pore, rough surface, and the foundry goods that lost foam casting process produces, can effectively control casting defect, fineness is also improved significantly, and lost foam casting adopts the dry sand of certain order number, dry sand can recycle, reclamation rate up to 99.5%, energy-conserving and environment-protective.

Existing lost foam casting process puts into due to equipment cost, and the technology such as Foam Pattern mould (Bai Mo) manufacture, coating process, pouring technology exists the problem that cannot overcome: 1. needing to manufacture white mould in lost foam casting process, Bai Mo is easily deformed (density is little, Bai Mo is subject to the External Force Actings such as hydraulic pressure when the demoulding and deforms as: polystyrene bead pre-sends out) in the fabrication process; 2. the coating being coated with on white mould is uneven, is not coated with complete and shows money or valuables one carries unintentionally, can scab during casting; 3. there is back-up sand blind area in white mould; 4. when casting, the cylinder head of white mould generally can be faced up placements by a., so can reduce blind area, but there is carbon slag in the cylinder head face obtained of casting; B. the temperature distortion of cast gate place is also susceptible to the situation of scab, these all can affect the quality of foundry goods, and utilize at home at present lost foam casting process produce in enormous quantities diesel engine, cylinder of petrol engine enterprise almost without, most also in looking around experimental stage.

Summary of the invention

The technical problem to be solved in the present invention is: based on the problems referred to above, the present invention provides the lost foam casting process of a kind of diesel engine cylinder block, to solve equipment cost input height, and the problem that cannot overcome existed in the technology such as white molding is made, coating process, pouring technology, it is achieved utilize lost foam casting process to produce the one-tenth article batch of diesel engine, cylinder of petrol engine.

The technical solution adopted for the present invention to solve the technical problems is: provides the lost foam casting process of a kind of diesel engine cylinder block, comprises the steps:

A. prefoam: select expandability methymethacrylate and styrene copolymerized resin beadlet, and the particle diameter of its original beadlet less than or equal to foundry goods minimum wall thickness (MINI W.) 1/9��1/10, expandability methymethacrylate is injected intermittent steam pre-foaming machine with styrene copolymerized resin beadlet by a 1kg, adopt the time relay, temperature controller Synchronization Control, advance time is 25��45s, temperature is 80��100 DEG C, and meanwhile, controlling pre-density of sending out is 18��25g/l;

B. ripening: be placed in feed bin dry, that ventilate ripening 7��18 hours through expandability methymethacrylate and the styrene copolymerized resin beadlet of prefoam;

C. foaming: the expandability methymethacrylate of ripening and styrene copolymerized resin beadlet are filled in the die cavity of metal die, heating, beadlet is made to reexpand, fill up the space between beadlet, and make mutually to merge between beadlet, form smooth surface, namely form bubble moulding model and dead head model;

D. model group composite variety: being bonded together with the combination of dead head model by the bubble moulding model processed, form model cluster, binding material is rubber latex, resin solvent, PUR and adhesive tape;

E. mould coatings: take paint specially for disappearing cast mold and add water in mould wash mixer stirring, container put into by coating after stirring, model group it is coated with successively by the method for leaching, brush, pouring and spray, repeat twice, coating layer thickness is 0.5��2mm, coating is dried at 40��50 DEG C, forms casting mold inner shell, i.e. lost foam pattern;

F. prepared by casting bed: put on a vibration table by the sandbox with aspirating chamber, and clamping, and the thickness bed load at 50��100mm, vibration ramming are put in bottom, and sandbox is one side opening, is provided with aspirating chamber or the sandbox of exhaust tube, lifting or walking mechanism;

G. placing lost foam pattern: after jolt ramming, put into lost foam pattern in sandbox, and train sand and fix, cast gate exceeds molding sand plane 3.5cm, and molding sand is binder free, without dosing thing, water-free drystone sand;

H. back-up sand: adding drystone sand, impose three-dimensional vibrating simultaneously, time of vibration is 35��55 seconds, makes molding sand be full of each position of model, and makes the bulk density of molding sand increase;

I. sealing sizing: sandbox surface plastic sheeting seals, and is pumped into certain vacuum with vacuum pump by sandbox, by atmospheric pressure and the difference of pressure in casting mold by together with sand grains " bonding ", maintenance casting-up process does not collapse scattered;

J. displacement is poured into a mould: during cavityless casting cast, under the heat effect of liquid metals, lost foam pattern generation pyrolytic gasification, produce a large amount of gas, constantly outwards discharged by coating molding sand, certain air pressure is formed in casting mold, model and metal gap, liquid metals constantly occupies lost foam pattern position, push ahead, the replacement process of liquid metals and lost foam pattern occurs, and the final result of displacement is to form foundry goods, adopts cast continuously during cast, watering termination of pumping after rear casting mold vacuum maintains 3��5 minutes, pouring temperature is 650��730 DEG C;

K. cooling down cleaning: after cooling, sandbox tilts to hang out foundry goods or directly hangs out foundry goods, foundry goods and dry sand natural separation from sandbox, isolated dry sand is reused after processing.

The invention has the beneficial effects as follows: 1. select preferably bubble to mould beadlet, reduce the carbon of residual further; 2. effectively control beadlet and reasonably send out density in advance, do not result in white mould insufficient strength and be deformed, even rupture, without producing casting defect, such as pore, carbon defects etc., 3. solve the problem that casting quality is low, thus realizing the mass production of single cylinder diesel cylinder body.

Detailed description of the invention

Presently in connection with specific embodiment, the invention will be further described, and following example are intended to illustrate the present invention rather than limitation of the invention further.

A kind of lost foam casting process of diesel engine cylinder block, comprise the steps: to select expandability methymethacrylate and styrene copolymerized resin beadlet, and the particle diameter of its original beadlet equal to foundry goods minimum wall thickness (MINI W.) 1/10, expandability methymethacrylate is injected intermittent steam pre-foaming machine with styrene copolymerized resin beadlet by a 1kg, adopting the time relay, temperature controller Synchronization Control, advance time is 35s, and temperature is 95 DEG C, meanwhile, controlling pre-density of sending out is 23g/l; It is placed in feed bin dry, that ventilate ripening 12 hours through expandability methymethacrylate and the styrene copolymerized resin beadlet of prefoam; The expandability methymethacrylate of ripening and styrene copolymerized resin beadlet are filled in the die cavity of metal die, heating, make beadlet reexpand, fill up the space between beadlet, and make mutually to merge between beadlet, form smooth surface, namely form bubble moulding model and dead head model;

Being bonded together with the combination of dead head model by the bubble moulding model processed, form model cluster, binding material is rubber latex, resin solvent, PUR and adhesive tape; Taking paint specially for disappearing cast mold to add water in mould wash mixer stirring, container put into by the coating after stirring, with leaching, brush, drenches and the method for spray is coated with model group successively, repeating twice, coating layer thickness is 1mm, and coating is dried at 43 DEG C, form casting mold inner shell, i.e. lost foam pattern;

Sandbox with aspirating chamber is put on a vibration table, and clamping, the thickness bed load at 60mm, vibration ramming are put in bottom, and sandbox is one side opening, is provided with aspirating chamber or the sandbox of exhaust tube, lifting or walking mechanism; After jolt ramming, putting into lost foam pattern in sandbox, and train sand and fix, cast gate exceeds molding sand plane 3.5cm, and molding sand is binder free, without dosing thing, water-free drystone sand; Adding drystone sand, impose three-dimensional vibrating simultaneously, time of vibration is 43 seconds, makes molding sand be full of each position of model, and makes the bulk density of molding sand increase; Sandbox surface plastic sheeting seals, and is pumped into certain vacuum with vacuum pump by sandbox, and by atmospheric pressure and the difference of pressure in casting mold by together with sand grains " bonding ", maintenance casting-up process does not collapse scattered;

During cavityless casting cast, under the heat effect of liquid metals, lost foam pattern generation pyrolytic gasification, produce a large amount of gas, constantly outwards discharged by coating molding sand, certain air pressure is formed in casting mold, model and metal gap, liquid metals constantly occupies lost foam pattern position, push ahead, the replacement process of liquid metals and lost foam pattern occurs, and the final result of displacement is to form foundry goods, adopts cast continuously during cast, watering termination of pumping after rear casting mold vacuum maintains 4 minutes, pouring temperature is 648 DEG C;

After cooling, sandbox tilting to hang out foundry goods or directly hangs out foundry goods, foundry goods and dry sand natural separation from sandbox, isolated dry sand is reused after processing.

With the above-mentioned desirable embodiment according to the present invention for enlightenment, by above-mentioned description, relevant staff in the scope not necessarily departing from this invention technological thought, can carry out various change and amendment completely. The technical scope of this invention is not limited to the content in description, it is necessary to determine its technical scope according to right.

Claims (1)

1. the lost foam casting process of a diesel engine cylinder block, it is characterised in that: comprise the steps:

A. prefoam: select expandability methymethacrylate and styrene copolymerized resin beadlet, and the particle diameter of its original beadlet less than or equal to foundry goods minimum wall thickness (MINI W.) 1/9��1/10, expandability methymethacrylate is injected intermittent steam pre-foaming machine with styrene copolymerized resin beadlet by a 1kg, adopt the time relay, temperature controller Synchronization Control, advance time is 25��45s, temperature is 80��100 DEG C, and meanwhile, controlling pre-density of sending out is 18��25g/l;

B. ripening: be placed in feed bin dry, that ventilate ripening 7��18 hours through expandability methymethacrylate and the styrene copolymerized resin beadlet of prefoam;

C. foaming: the expandability methymethacrylate of ripening and styrene copolymerized resin beadlet are filled in the die cavity of metal die, heating, beadlet is made to reexpand, fill up the space between beadlet, and make mutually to merge between beadlet, form smooth surface, namely form bubble moulding model and dead head model;

D. model group composite variety: being bonded together with the combination of dead head model by the bubble moulding model processed, form model cluster, binding material is rubber latex, resin solvent, PUR and adhesive tape;

E. mould coatings: take paint specially for disappearing cast mold and add water in mould wash mixer stirring, container put into by coating after stirring, model group it is coated with successively by the method for leaching, brush, pouring and spray, repeat twice, coating layer thickness is 0.5��2mm, coating is dried at 40��50 DEG C, forms casting mold inner shell, i.e. lost foam pattern;

F. prepared by casting bed: put on a vibration table by the sandbox with aspirating chamber, and clamping, and the thickness bed load at 50��100mm, vibration ramming are put in bottom, and sandbox is one side opening, is provided with aspirating chamber or the sandbox of exhaust tube, lifting or walking mechanism;

G. placing lost foam pattern: after jolt ramming, put into lost foam pattern in sandbox, and train sand and fix, cast gate exceeds molding sand plane 3.5cm, and molding sand is binder free, without dosing thing, water-free drystone sand;

H. back-up sand: adding drystone sand, impose three-dimensional vibrating simultaneously, time of vibration is 35��55 seconds, makes molding sand be full of each position of model, and makes the bulk density of molding sand increase;

I. sealing sizing: sandbox surface plastic sheeting seals, and is pumped into certain vacuum with vacuum pump by sandbox, by atmospheric pressure and the difference of pressure in casting mold by together with sand grains " bonding ", maintenance casting-up process does not collapse scattered;

J. displacement is poured into a mould: during cavityless casting cast, under the heat effect of liquid metals, lost foam pattern generation pyrolytic gasification, produce a large amount of gas, constantly outwards discharged by coating molding sand, certain air pressure is formed in casting mold, model and metal gap, liquid metals constantly occupies lost foam pattern position, push ahead, the replacement process of liquid metals and lost foam pattern occurs, and the final result of displacement is to form foundry goods, adopts cast continuously during cast, watering termination of pumping after rear casting mold vacuum maintains 3��5 minutes, pouring temperature is 650��730 DEG C;

K. cooling down cleaning: after cooling, sandbox tilts to hang out foundry goods or directly hangs out foundry goods, foundry goods and dry sand natural separation from sandbox, isolated dry sand is reused after processing.