Ceramic injection forming mould
The present invention relates to ceramic, is the production for ceramic, adopts injection moulding to replace artificial moulding by casting, and it is the mould of ceramic injection forming.
Ceramic injection forming is polymer injection moulding method to be combined with ceramic preparation technology and a kind of technique of preparing ceramic part of growing up.It comprises four processes: the preparation of (1) injection feeding: by suitable organic carrier and ceramic powders mixing, dry, granulation at a certain temperature, obtain injecting materials; (2) blank that cooling curing is required form, the then demoulding are injected in metal die at a high speed in injection moulding: the injection compound after mixing is heated and changes toughness melt in injection (mo(u)lding) machine under certain temperature and pressure; (3) degreasing: by heating or its physico-chemical process, the organic matter in injection moulding blank is got rid of; (4) sintering: by the densification sintering at high temperature of the biscuit after degreasing, obtain required face shaping, dimensional accuracy and microstructural ceramic of compact part.In the eighties in last century, the demand of preparing in order to adapt to the high temperature ceramic components such as reseach of engine and whirling, ceramic injection emphasis is the non-oxidized substance refractory ceramics parts such as silicon nitride, carborundum, engine si3n4 particularly, sic turbine rotor, the injection moulding preparation of blade and sliding bearing, the while successfully works out the high-temperature structural ceramics product of many high-performance, complicated shape.At present, ceramic injection forming has been widely used in the moulding of various ceramic powders and various engineering ceramics goods.Prior art, injection moulding key depends on mould, if controlled, improperly will make a lot of defects of product formation, as crackle, banish, hole, weld seam, layering, powder be separated with binding agent, and these defects until de-refer to and sintering after just can be found, control and optimize injection temperature, mold temperature, injection pressure, dwell time molding parameter fluctuate to reducing blank weight, prevent separation and the segregation of each component in injection material, the utilization rate that improves finished product rate and material is most important.And injection process refers to the good feeding melt of preformed in measuring room is injected into the process that mold cavity the inside is gone.Feeding melt process nozzle, runner and cast gate are to the mobile process of die cavity.From technological process, can be divided into 2 stages, injection stage and packing stage, though these two stages all belong to melt flows process, flox condition has larger difference.Injection stage is to advance melt to start till melt is full of die cavity from screw rod.Now, it is injection molding key parameter that the pressure at screw head, melt being set and screw rod advance the speed of melt.At injection stage, must set up enough speed and pressure and just can guarantee that melt is full of die cavity, if injection pressure regulates too low meeting to cause cavity pressure not enough, melt can not be full of die cavity.Otherwise, adjust too highly, can cause goods overflow edge, the bad phenomenon such as mould rise.And packing stage is from melt, to be full of that die cavity starts till cast gate freezes envelope.After injection stage completes, must continue to keep injection pressure, maintain melt external contracting and flow, till being continued until that cast gate freezes envelope.Therefore packing stage is under the effect of dwell pressure, and the melt in die cavity will obtain cooling and feeding and further compression and density, if dwell pressure is not enough, can cause cavity pressure too low.Dwell time can affect the refluence of solution, and the dwell time, shorter cavity pressure reduced sooner, finally made cavity pressure lower.The setting of barrel and nozzle temperature with control injection molding quality also important, barrel temperature refers to the heating-up temperature on barrel surface, plasticizing mechanism according to injection material in barrel is divided 3 sections of heating, one stage: solid input phase, near material mouthful place, temperature is low, has water quench to prevent material bridge formation, guarantees higher Solid Conveying and Melting efficiency; Second stage: compression section, be material in compressive state, and little by little melting, Temperature Setting is than the high 20-25 ℃ of first paragraph; Phase III: metering section is the stage of material full-fusing, when preformed starts, this section, corresponding to screw metering section, forms measuring room and stores the material having plastified after preformed stops.The temperature of charge of phase III is than the high 20-25 ℃ of second stage, to guarantee that material is in molten condition.Degreasing refers to by heating and other physico-chemical process to be got rid of the organic matter of profiled member and produces a small amount of presintering process.It is the most difficult and most important factor in injection moulding, binding agent and skimming processes link together, binding agent is determining degreasing process, injection molding binder amount generally accounts for green part volume more than 43%, thereby the degreasing of binding agent can only be progressive, otherwise will cause the defects such as cracking brews, caves in to produce, and the crackle producing can not make up by sintering with distortion.Skimming processes length consuming time will be spent tens hours as hot degreasing in addition, even several days time.So can degreasing complete smoothly, for guaranteeing blank quality, improve job efficiency, reduce energy consumption most important.The runner of injection member running gate system and cast gate design are upper, and there are the following runner and cast gate in the existing stage according to requirements such as the shape of product, size, tolerances: (1) down gate; (2) diaphragm gate; (3) tab gate; (4) fan gate; (5) side gate; (6) flat cast gate; (7) claw type cast gate.Cast gate is the position of product charging, with a segment distance of runner and product coupling part, because above-mentioned each gate size is large, therefore after ceramic injection forming, cast gate can not be automatically separated in mould with goods part, after the demoulding, running gate system part links together with ceramic member, must adopt manual separation outward at mould, after pottery sclerosis, hardness is very big, difficulty while therefore causing separation, therefore even when separation, cause great damage, the even more serious product that causes breaks completely, makes qualification rate extremely low.Ceramic injection forming Effect Factors for Sythetic Technology is a lot of in a word.And interrelated, mobility as good in powder be strengthen organic binder bond be basis, at the product that workmanship quality is high, could realize, moulding at complicated shape, be mainly dependence experience, without unified standard and stable degreasing, control, although the application that the forming technique of paraffinic base binder system is succeeded, water based adhesive system and defatting technology thereof be development utilization also, but efficiency is not high.The fine powder production cost that is applicable in addition CIM is high, and in the production of product, the product of simple shape is uneconomical again, is subject to the impact of degreasing simultaneously, and it also cannot prepare heavy wall and large shape Complex Parts, so CIM technology is extremely restricted.But ceramic objects is extremely graceful, is subject to liking of countries in the world.In the nearly more than ten years, obtained develop rapidly, so far injection molding technology must occur, it has the incomparable superiority of traditional-handwork manufacturing process, as product injection moulding in batch, product size precision, positional precision are all that traditional handicraft is incomparable, particularly the workpiece of injection moulding complicated shape, cannot complete by hand.Deficiency when overcoming above-mentioned moulding, I am special to providing in the industry following a kind of new technology to improve above-mentioned each difficult problem according to the Design of Dies of two more than ten years and manufacturing experience.
Summary of the invention
The present invention is to provide ceramic injection forming mould, be that moulding by casting material is pottery, mould is steel manufactures, it is a kind of technique of preparing parts that polymer injection moulding is combined with ceramic preparation technology, for overcome after existing injection molding moulding by casting product sprue difficult separated, job efficiency is low, low precision, degreasing difficulty, injecting molding die of the present invention partly takes measures on customs clearance to realize to die casting components of system as directed and mould dynamic model.Die casting components of system as directed is adopted to TOP-TIP, it is the way of utilizing heating, making to play mold cavity entrance from nozzle of injector is that material one section of runner of fastening keeps molten condition always, only need get product, and needn't get the solidifying material of running gate system thereby reach when die sinking.Exhaust and bleed air system are optimized to design, when material melt is filled die cavity, air and the material that must sequentially discharge in die cavity and running gate system are heated or solidify the low molecular weight volatile gas of generation simultaneously.If a variety of causes in die cavity and the gas that produces is not got rid of totally, will on goods, form bubble on the one hand, seam, surface profile is unclear and filling is scarce expects, gas pressurized on the other hand, volume-diminished and produce high temperature and can cause goods partial carbonization or burn (brown speckle), the gas simultaneously accumulating also can produce buffer brake and reduce filling mold speed, therefore for guaranteeing the heat seal strength of the even of mold filling amount and increase material melt meet, the die cavity position being finally filled at material melt is provided with flash groove to hold clout, also can hold a certain amount of gas simultaneously.The air discharge duct of this invention is opened on somatotype, and the overlap producing because establish exhaust on die joint, is also easy to deviate from goods.This mould is opened in die joint die one side, and groove depth is 0.02～0.05mm, and groove width 1.5-6mm determines according to material properties, not produce overlap, is limited.Air discharge duct communicates with atmosphere.Bleed air system design, exhaust is the needs of product molding, and bleed is the needs of the goods demoulding.Goods for some large moldeed depth shell complicated shapes, after injection moulding, type intracavity gas is excluded, and in the original state of pushing out product, its of core outer surface and article inner surface forms vacuum, cause goods demoulding difficulty, if employing forced demoulding, goods certainly will be out of shape or damage, thus this Design of Dies sideshake bleed, it is the occasion of utilizing the exhaust of forming part die joint fit clearance, and its exhaust clearance is the gap of introducing gas.Insert or core, can not be designed to interference fit with other forming part, air cannot be introduced die cavity like this, as excessive in fit clearance, the positional precision of inserting will be affected, so the local location of the present invention in the side of inserting offers bleed groove, its width dimensions is 0.05mm, in order to avoid flash stops up and do not have due effect, the groove of bleed is simultaneously extended to outside mould, and its degree of depth is 0.2～0.8mm.The cavity design of this mould has adopted two-layer, thereby production of articles efficiency is doubled, production cost declines, simultaneously in order to meet the moulding by casting requirement of thin-walled large piece pottery, adopted without the hot flow path running gate system in the solidifying material of runner, adopt the angie type injector moulding vertical with folding mould direction of injection barrel simultaneously, solved the difficult problem that horizontal injection machine arranges running gate system, to two-layer swaging die temperature control one system, with a pair of rack and pinion drive mechanism being arranged on outside mould, realize two-layer die cavity opening and closing mould action.At present, on ejecting mechanism, the present invention utilizes the thrust of spring to make two-layer die cavity ejecting mechanism pushing out product, thereby guarantees the uniformity of product molding quality, after what is more important forming process of ceramics, adopt the promotion of spring to make ejecting mechanism, guaranteed the effect not being damaged after product is released.The invention solves existing ceramic injection mould, running gate system cast gate is difficult to separated problem with goods, has solved the injection mixture material of existing ceramic injection mould after mixing and be difficult to be heated the problem that changes toughness melt in injection (mo(u)lding) machine.The present invention adopts hot flow path running gate system, makes material in die casting system, keep molten condition for a long time, has solved better that melt temperature is too low can not flow, and excess Temperature material is watered burnt phenomenon and occurs.It is pulled and is kept the required fusion temperature of difference of material kind to regulate by the heating in mould all the time, has solved the technical barrier of degreasing.This invention is by after die casting moulding, is pulled to dynamic model one side after product die sinking, and on dynamic model one side's die cavity or core, reaches the object of degreasing.Blank defect when solving sintering, and these defects are until just find during sintering as separated in crackle, flow liner, hole, weld seam, layering, powder and binding agent, directly affect the problem of the production efficiency of goods, therefore electrothermal tube or the heating wire of the present invention's separated and segregation of each component in mould dynamic model one side has designed control mold temperature, injection pressure, dwell time and prevented injection carry out temperature control to mould dynamic model die cavity or core, in mould, reach so in advance the object of degreasing, to be conducive to the qualification rate of finished product and the utilization rate of material.Ceramic injection forming mould is characterized in that: spring (2) is arranged on screw (3), then screw (3) is fastenedly connected with stripper bolt (1), push rod (4) coordinates with heating plate glade plane space, cushion block for its rear end (5) is used screw (6) locking again after compressing, pin (7) is slidably connected with heating plate and heat-insulating shield, sprue bush (8) and retainer ring (9) matched in clearance, sealing ring (10) closely cooperates with water ring (11), secondary nozzle (12) is arranged in cavity plate (32), mold insert (13) coordinates with slip ring (14) glade plane space, fixed block (15) and slip ring (14) matched in clearance, locating ring (18) is arranged in cavity plate (32) with bearing ring (19), dividing plate (21) is flexibly connected with pin, push pedal (22), guide pillar (23), guide pin bushing (24) glade plane space coordinates, screw (25) is communicated with cavity plate (32), it is in aggregates that seat board (27) is fastenedly connected structure by screw (26) and cushion block (28) and core plate (30), guide pillar (31) and cavity plate (32), core plate (30), hole on cushion block (28) becomes glade plane space to coordinate, tooth bar (34) and tooth bar (37) are arranged on respectively on moving clamping plate and fixed clamping plate, and then fit in engagement with gear (35).
Accompanying drawing explanation
Below in conjunction with accompanying drawing, the present invention is further described
Shown in figure:
Sectional side elevation when Fig. 1 is the injection of mould matched moulds
The sectional side elevation of two-layer die cavity when Fig. 2 is the injection of mould matched moulds
Fig. 3 is the top view of mold runner system
Fig. 4 is the enlarged drawing that secondary nozzle is partly constructed
Fig. 5 is mould rack and pinion drive mechanism schematic diagram
In figure, numeral number represents respectively:
1---stripper bolt 2---spring 3---screw
4---push rod 5---cushion block 6---screws
7---pin 8---sprue bush 9---retainer rings
10---sealing ring 11---water ring 12---secondary nozzles
13---mold insert 14---slip ring 15---retainer rings
16---screw 17---runner 18---locating rings
19---bearing ring 20---centring ring 21---dividing plates
22---push pedal 23---guide pillar 24---guide pin bushings
25---screw 26---screw 27---seat boards
28---cushion block 29---guide pin bushing 30---core plate
31---guide pillar 32---cavity plate 34---tooth bars
35---gear 36---gear 37---tooth bars
Concrete implementing measure:
Shown in figure, be ceramic injection forming mould, its specific embodiment is as follows: large and the shallow and large feature of production lot for ceramic structural area, and mould has adopted two-layer mold cavity forming, thereby makes production of articles efficiency improve nearly one, and production cost reduces.The design feature of this mould is: in order to meet the forming requirements of the forming thin-walled large piece of ceramic material and the problem of ceramic member and running gate system separation difficulty, therefore in running gate system, adopt hot flow path running gate system, to reach the qualification rate requirement of goods, adopted the angie type injector moulding vertical with folding mould direction of injection barrel simultaneously, solved the problem that running gate system difficulty is set with horizontal machine, consistent to two-layer swaging die temperature control, employing is arranged on a pair of rack and pinion drive mechanism outside mould and realizes two-layer die cavity and open, mould assembling action is synchronous, utilize the thrust of spring to make two-layer die cavity ejecting mechanism pushing out product simultaneously, thereby guarantee the uniformity of product molding quality.Its operation principle of ceramic injection forming mould is: after the full mold cavity of injection, through pressurize, cooling, dewaxing after, mould active and inactive mold is opened, now at the upper tooth bar (34) of installing of movable model central layer (30), gear (35) engagement in tooth bar (34) and cavity plate (32), and the coaxial gear (36) of gear (35) and be contained in tooth bar (37) engagement on fixed mold plate.At this moment along with the backward movement of dynamic model, rack and pinion drive mechanism transmission, die joint I-I, the II-II face of two-layer die cavity are opened simultaneously, and the ambilateral push pedal of mould (22) is because the effect of drag hook sequential parting mechanism keeps motionless, and now goods are stayed in core plate (30).When die sinking will finish, tapered shaft forces drag hook rotate to break off relations, the elimination that is connected of ejecting mechanism and fixed and moving die holder plate, and therefore, push pedal (22) and push rod (4) advance under the thrust of spring (2), and goods are pushed away from core plate (30).Stripper bolt (1) limits template somatotype distance, plays again reset simultaneously.During matched moulds, after stripper bolt (1) contact dividing plate (21), by push rod ejecting mechanism, resetted.