基于单片机控制的自动抽放水系统设计说明书带开题
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Discussed digital printer and the numeral printing ink type Along with printing digitization step quickening, the numeral prints cTP and so on the new technology to be like a raging fire. Already becomes prints the irreversible mainstream development technology now. The digital printing printability also has the obvious difference with traditional printing. To the printing equipment printing material, the printing technology set the new request. In order to achieve the good print quality and the high velocity production. The digital printing material, in particular the numeral printing ink research and the development appears importantly. After several years development, the numeral printing ink technology Zhen will be later day mature. But the numeral printing ink high price still was restricts the digital printing development the bottleneck. The principle digital printing image formation To discuss the numeral printing ink, must talk about the digital printer inevitably, because the different factory promotes the digital printer image formation principle is different, to uses the numeral printing ink the composition performance, the character request to be also different. At present uses the digital ElSiJ equipment image formation principle may divide into six big kinds.1.electronic camera called the static electricity image formation, is useing the laser scan method to form the static electricity on the photoconductor to dive the shade to use the charged color powder and the static electricity again dives the shade electric charge function, shifts the color powder phantom to accepts for printing in the thing to complete printing.2.spray imaging printing ink have by certain speed from the tiny spray nozzle selectively spray to accept for printing in the thing to realize the printing ink phantom reappearance. Spurts ink printing to divide into continuously spurts ink printing and according to must spurt ink printing. Spurts the ink system is continuously causes the ink using the pressure to form the continual ink class through the pore. After the high speed under ink changes the tiny bubble causes the bubble charged. The charged ink drop may spray under the electric charge board control to accepts for printing the position which the surface needs to form the printing chart article. The ink drop displacement quantity and accepts for printing an inking position leaves when the pore by the ink drop the charged quantity decisionAccording to must spurt the ink with to spurt the ink differently to lie in affects Yu the Chu ink the pressure is not continuously continual. When is the image formation digital signal control, the need only then has the pressure to affect sprays. According to must spurt the ink because does not have the ink drop displacement, may omit the ink trough and the circulatory system, spurts the ink structure relative simplification ? 203. electricity condensation image formation Electricity condensation image formation is through the electrode between electrochemistry responded causes the printing ink to have the condensation. And adheres firmly in the image formation drum surface forms the image. Has not had the blank region printing ink which the electrochemistry responded still to maintain the liquid state to be possible through the scraper to blow except, but the drum surface from adheres firmly the chart article which the printing ink forms then to shift through the pressure to accepts for printing in the thing, completes printing. Electricity condensation numeral printer representative the type is the EIcorsy Corporations product. The resolving power is 400dpi? 204. magnetic recording image formation Magnetic recording image formation is depends upon the magnetic material the magneton the directional arrangement to form magnetism under the outside magnetic field function to dive the shade. Again dives the shade using magnetism sex-linked colors powder and magnetism to affect mutually under the magnetic field strength completes the development. Shifts by magnetism sex-linked colors powder to accepts for printing in the thing to form the image. This method only uses in black and white printing generally5. Static electricity image formations Static electricity image formations apply the broadest digital printing image formation technology. It is uses the laser scanning method to form the static electricity on the photoconductor to dive the shade. Uses the charged color powder and the static electricity dives the shade electric charge function to form dives the shade, shifts to accepts for printing in the thing namely to complete printing. Develops the way differently to divide into two kinds of one kind uses the electronic printing ink development. Resolving power ? 00dpi, take HPInd go as representative. Another kind is uses the dry color powder development, the resolving power ? 00dpiXeikon, Xerox, Agfa, CanonKodak, ManRoIand and IBM and so on the digital printer all uses this method ? 206. Thermal imagery Thermal imageries are after the material heating the physical performance change on the medium the image formation. Divides into the direct thermal imagery and the hot shift image formation. The direct thermal imagery is the use after processes specially has the special coating to accept for printing the material, after the heating the coating has the color transformation. The hot shift image formation printing ink spreads the cloth on the inked ribbon. Namely shifts to the color membrane or the inked ribbon heating to accepts for printing on the material, the image formation quality may reach the picture levelNumeral printing ink 1. Dried powder digital printing ink Dried powder digital printing ink helps by the pigment granule which forms in the electric charge the pellet electrically charged medicinal preparation and the fusibility resin mix forms. Has the negative charge toner to expose the part adsorption to form the image to transfer in the toner the resin to melt Indias to paper on toner image after the heating, adheres firmly in accepts for printing in the thing to form the image ? 202.Liquid state numeral printing ink Liquid state numeral printing ink commonly used Yu Penmo prints, the printing ink type with spurts an ink structure to concern. Spurts the ink separable thermo-compression type and the piezoelectricity type two big kinds, but the piezoelectricity type has the high accuracy and the low accuracy 2 kind of .EPSON nozzle belongs to high accuracy nozzle Xaar and the Spectra nozzle belongs to the low accuracy nozzle. The high accuracy nozzle uses the river character dye or the pigment printing ink. The latter uses the solvent pigment printing ink majority. And the difference is that the traditional ink, electronic ink in the liquid medium is not dependent on the curing film ink drying time. But encountered high temperature (130. C) immediately curing blanket on the blanket. Fax ink on the blanket and then transfer to 100% of paper or other media.On the other hand. Basic electronic liquid ink is a new resin material, and its micro-polygon shape. Under pressure, unlike the spread of traditional ink, but with the combination of close contact with paper or other media immediately after curing so that the printed image a little more clearly the edge of virtual networks and the proliferation of.Electronic liquid ink into water-based ink and oil-based (solvent-based) ink. Water-based ink by the solvents, coloring agents, surfactants pH modifier, drying agent and add the necessary components. For hot-type ink-jet printing system, the only choice of water-based ink. On-demand ink-jet printing ink is usually water-based ink. Oil (solvent-based) ink solvent by the coloring agent, distributed 3, J n the composition of other regulators.3.solid-state digital printing inkSolid-state digital printing ink jet printing is mainly used in the normal solid-state under the printing ink was heated, the viscosity decreases and the jet after the substrates surface. Solid-state digital printing ink from a coloring agent, charge-Dutch tablets agent, viscosity control agents and carriers and other components.4. Electronic inkElectronic ink is a special coating for the printing film-based materials as a display of a special ink made from microcapsules coated in nano-scale diameter. Microcapsules, there are many positively charged white particles and negatively charged black particles, and micro-capsules in a transparent liquid. When positively charged microcapsules charge, the positively charged particles gather in the direction of the observer side, and appear as white; negative electrical charge, the negatively charged black particles gathered at the observer side, and show the black.Particles showed that the color of the location and control by the electric field to control the electric field from high-resolution display arrays generate floor.5.UV/EB inkThe so-called UV / EB ink is to use UV-curable or electron beam energy curing ink. uv / EB radiation curing type ink-jet printing ink in an increasingly wide range of applications. UV inks in digital printing is the most important feature of good stability, and only in the uV light the advantages of curing can be effectively blocked to prevent the print head to extend the actual print head life. However, inadequacies yes. Using uv / EB printing inks print speed will result in lower, such as ink supply constraints and a large quantity of ink through the print head speed. At present, Xennla new XenJetVivide series uV-curable CMYK pigment-based inks Xaar has adopted the companys certification, and this new printing ink used in Omnidot760 head.Now, the worldwide study of the number of printing ink is in full swing, the digital printing press manufacturers such as Canon, HewIett Packard, EPSONScitexXeikon, HPIndigo and so on according to their characteristics of digital presses and research and development to adapt to the characteristics of their systems the number of printing ink. In addition, other well-known global manufacturer of printing ink. Such as DIC, Sun Chemical, Flint, SakataInxCorp companies have begun to set foot in the digital printing ink development and production. With the widespread use of digital presses, digital printing ink on the research and development will be more in depth. 5a new digital printing ink will continue to emerge.IIThe external condition research of affecting pumps using machinery sealAbstract: Through to pumps with the mechanical seal practical application and the theoretical analysis, proposed the mechanical seal actual seal effect not only with the mechanical seal own performance related, the condition which with other spare parts also which provides the condition as well as the seal servosystem provides to have the important relations, therefore pumps the unit product when the design, must for the mechanical seal use provide a good external condition.Key words: Pumps Mechanical seal MeasuresAt present the mechanical seal in pumps in a kind of product the application extremely widespread, but and will save the energy along with the product technical level enhancement the request, the mechanical seal application prospect is more widespread. The mechanical seal seal effect directly will affect the entire machine movement, in particular in petroleum chemical industry domain, because will exist flammable, explosive, is easy to volatilize, to be violently poisonous and so on the medium. The mechanical seal appears will divulge, seriously will affect the production normally to carry on, is serious also appears the significant security accident. People when analysis quality breakdown reason, often is familiar with in the mechanical seal own aspect searches the reason, for example: Mechanical seal shaping whether appropriate, choice of material whether correct, the packing surface compared to presses whether correctly, rubs the vice- choice is whether reasonable and so on. But is short very much in the mechanical seal external condition aspect searches the reason, for example: Pumps for the mechanical seal creation condition whether appropriate, the servosystem disposition is whether appropriate, but these aspects reasons often are count for much. This article author from pumped has analyzed the reasonable measure with the mechanical seal external condition angle which the influence seal effect several kind of factors and should adopt.1 Principle and request that machinery seals off: The mechanical seal is depends on a pair of relative motion link end surface A (fixed, another revolves together with axis) the mutual fitting forms the small axial play plays the seal role, this kind of equipment is called the mechanical seal. The mechanical seal usually by moves the link, the static link, contracts the part and the seal part is composed. Moves the link and the static link end surface composes a pair to rub, moves the link to depend on in the sealed chamber the liquid pressure to cause its shoulder up on the static link end surface, and produces on two links end surfaces suitable compared to presses and maintains an extremely thin liquid membrane to achieve the seal the goal. Contracts the part pressurize, may cause to pump under the operating condition, also maintains the end surface fitting, guaranteed the seal medium nothing more than leaks, and prevented the impurity enters seals the end surface. Seals the part to play the seal to move the link and axis gap B, the static link and the gland gap C role, simultaneously to the vibration which pumps, attacks the cushioning effect. The mechanical seal in the actual movement is not an isolated part, it is with other spare parts which pumps combines the movement together, simultaneously may see through its basic principle, the mechanical seal normal operation has the condition, for instance: Otherwise fleeing measures a pump spindles being not able to very big, friction subsidiary end face can not form the ratio pressure demanding regularly; The pump spindle that machinery hermetic sealing gets along can not have boundary very big deflection , end face waits a minute otherwise than pressure will be uneven. Besides only when satisfying similar such external condition, fine machinery seals off oneself function, ability reaches ideal hermetic sealing effect.2 Analysis of causes that external condition affects:2.1 Pump spindle axial to fleeing is measured big:The hermetic sealing that machinery seals off needs to have certain ratio pressure face to face, such ability plays arrive at hermetic sealing role, be requiring that spring that machinery seals off needs to have certain compression amounts right now, give a propulsive force sealing off end face, rotating makes hermetic sealing produce the pressure sealing off the what be demanded ratio face to face. For ensuring that this one is compared to pressure, the amounts machinery is sealed off requiring that the pump spindle can not have very big fleeing, need to ensure that within 0.5 mm in general. Design but middle in reality, unreasonable because of design, that sometimes, very big fleeing of pump spindle creation measure , seal off to machinery sigmatism is very disadvantageous. This phenomenon sometimes appears in multi-level centrifugal pump, Especially in the process of pump starting, flee amounts are comparatively big.The automation changes the b balancing a set and balancing the axial gap between the ring when balance plate works , changes the difference balancing the pressure checking front and back two flanks thereby , produces one and comes to balance the axial force axial contrary force direction acting force. The inertia effect moving since the rotator flees and transient pump working condition fluctuation, the rotator moving round will not be motionless in some one axial balance location.Balance the state fleeing all the time in retinue to move. But the amounts balancing axial to fleeing in checking in regular job only have 0105 011 mm , satisfy permission axial to fleeing that machinery seals off measuring 015 mm requests, allowable machinery hermetic sealing axial to fleeing balancing axial to fleeing to measure possibility getting it in gear, when stopping machine , working condition great change in pump making rings round expects that.After pumps passes through the long time movement, the friction balancing a set and balancing a ring wears away , gap b enhances subsequently, the amounts sealing off axial to fleeing increase machinery unceasingly. Effect because of axial force, hermetic sealing compacting soft and floury sucking oblique tones in increases by strenuously , hermetic sealing wears the effect aggravating , sealing up completely until hermetic sealing damages , loses face to face away face to face.The machinery spitting out oblique tones is sealed off , is wear away with balancing plates, rotator component axial to fleeing measures the amounts sealing off axial to fleeing demanding greater than , the force sealing off compacting soft and floury is diminished , cannot reach the effect sealing off a request , making the machinery hermetic sealing on both side of the pump all ultimately losing hermetic sealing.2.2 The axial force is prejudiced big:Machinery hermetic sealing can bear the axial forces in the process of usage, if the effect that existence seals off axial the force , to machinery is grave. Since pump axial the aspect cause such as rational and making , assembling , being put into use that dynamic balance organization designs, brings about the axial force be not balanced away sometimes.Machinery hermetic sealing bears a axial force , the seal gland temperature will be partial to height when moving round, to the medium that polypropylene is similar to, before the high temperature be able to be molten down, the pump starts the queen therefore losing hermetic sealing effect very quickly right away , discontinuous gushing sealing off end face then appearing leaves out phenomenon when the pump is motionless.2.3 pump spindles deflections are slanting big:That machinery hermetic sealing calls end face hermetic sealing, is that one kind of axis of rotation to contact-type moves hermetic sealing , it is under fluid medium and elasticity component effect , two perpendicularities reach hermetic sealing effect thereby in stick the small side door , relative rapid and intense axle centre line hermetic sealing end face revolution, demands to need to accept a force homogeneously between two hermetic sealing therefore.The machinery spitting out oblique tones is sealed off , is wear away with balancing plates, rotator component axial to fleeing measures the amounts sealing off axial to fleeing demanding greater than , the force sealing off compacting soft and floury is diminished , cannot reach the effect sealing off a request , making the machinery hermetic sealing on both side of the pump all ultimately losing hermetic sealing.2.4 not assisting irrigation system or assists irrigation system to interpose block of wood reasonableness: That assisting that machinery seals off washes system is very important , it can protect effects such as sealing off face , getting to the cooling , lubrication , washing away varia effectively. Design that allocation assists irrigation system, to be unable to reach hermetic sealing effect not rationally sometimes;Have foreign substance sometimes although designing that the personnel has designed auxiliary system, since in washing liquid, rate of flow , pressure washing liquid are insufficient , wash mouth location designing that wait for cause unreasonable , also same being unable to reach hermetic sealing effect.2.5 vibration is slanting big:Machinery seals off vibration insisting to lead to big , ultimate losing hermetic sealing effect. That machinery seals off big slanting vibration cause sometimes is not that machinery seals off self cause but , other pump component and part is to produce the origin vibrating , waits for cause if the pump spindle designs that cause , axle bearing accuracy unreasonable , processing are insufficient , shaft coupling degree difference , radial force of equal rank are big.2.6 Cause that the pump vapor erodes:The function is not good , the pump rotation rate is partial to height since device system operation is unreasonable and the pump entrance vapor erodes, that the vapor erodes , the vapor erodes the entry occurrence part in the pump the day afer tomorrow happened , is able to have air bubble in the water, that it may pound machinery on one hand seals off the outside surface soft and floury , makes its surface damage appear on; That another aspect may make fitting that astiring sound is encircled by also contain air bubble in flow soft and floury film, can not form the stable flow film , brings about the trunk friction that fitting that astiring sound is encircled by face , makes machinery seal damage.2.7 Machine work accuracy is insufficient:Machine work accuracy is insufficient , cause has many, the treating accuracy having plenty of machinery sealing self off is insufficient , this aspect cause finds also easy to pay attention to easy to arouse people. But the sometimes is a pump other component treating accuracy lack , this aspect cause, do not pay attention to easy to arouse people. For instance: Cause such as pump spindle , axle sleeve , the pump body , the accuracy lack sealing off enlarging of the cavity body. The hermetic sealing effect that these cause existence seals off to machinery is very disadvantageous.3 responds to the measure adopting:3.1Remove a pump spindle fleeing to measure big measure:Amounts designing that axial force balance is equipped with , removes axial to fleeing rationally. For satisfying this one request,have two to the multi-level centrifugal pump , the comparatively ideal design plan: One is that balance plate adds axial to stopping push axle bearing , balance the axial force from balance plate , carry out axial on the pump spindle from axial to stopping pushing axle bearing position-limit; Another is that the balance drum adds axial to stopping push axle bearing, axial force balancing away major part from the balance drum, axial surplus force bears from stopping pushing axle bearing , axial to stopping pushing axle bearing carries out axial on the pump spindle at the same time position-limit. Second kinds schemes key is to design the balance drum rationally, makes that be able to balance away the most axial force really. Wait for a product to opening a pump in other single stage pump,within amounts range sealing off range demanded by in machinery designing fleeing adopting a few measure guarantee pump spindles now and then.3.2 Remove big axial strenuously prejudiced measure:The organization designing axial dynamic balance rationally, makes that be able to balance away the axial force really sufficiently , being sealed up completely by machinery creates a favorable condition. Must achieve testing detecting and discovering problem and solve a problem before the product , unfinished products leave the factory to importance that fields such as a little electric power plant , petrochemical industry, applies. Some important pumps can design a axial to measuring the force ring on the rotator , monitor at any time to being on the march toward the force size scroll, discover a problem in time solve.3.3 Remove big prejudiced pump spindle deflection measure:Existence is in this phenomenon mostly in multi-level centrifugal pump of horizontal type, adopting the following measure time design: (1) cuts down both ends distance between axle bearing. The pump impeller progression is not very more than , under the general pump lift request is comparatively good situation, try ones best to improve every level impeller lift, cuts down progression;(2) increases the pump spindle diameter. During the period of the diameter designing a pump spindle, consider the size transferring power simplely only, do not but want the inertia factors such as load , radial force thinking that machinery seals off ,the axis deflection, starts method and being connected with. Much one point designing that not sufficient cognition arrives at this; (3) improves pump spindle material grade; (4) pump spindles are designed after being completed, the deflection to the pump spindle asks the checkout carrying out the core of school to secretly scheme against.3.4 Increases by assisting irrigation system: Under the situation that condition allows, system designing auxiliary irrigation to the full. Wash pressure general requirements overtoping 0107 011 MPa sealing off cavity pressure, if transportation medium belongs to easy vaporization, respond to 01175 012 MPa higher than vaporization pressure then. The pressure sealing off a cavity is going to secretly scheme against according to every kind of pump structure during the past factors such as pattern , system pressure.Or when shaft seal accent pressure is very high when pressure uses almost approximation should seal up completely the maximal limit, fever of also may make shaft seal liquid be on the move from the area sealing off a cavity attracting liquid till low pressure, to take away friction. If the irrigation amounts being recommended by administering medicine to bring out the cold be what 1 shows.According to each kind of pump operation condition,deploy the pipeline and accessories rationally. If the chiller , pore plate , filter , valve , rate of flow indicator , piezometer , the temperature wait. Reliability and life-span sealing up completely in fact, depend on the allocation sealing off auxiliary systems to a great extent.3.5 Remove the measure that the pump entrance vapor erodes:(1) The vapor eclipse function raising a pump is horizontal , the vapor satisfying the scene device erodes the function request;(2) Scene tester request needs and the pump vapor erodes function level matching;(3) That scene installation and working condition adjustment need to give a pump creates advantageous condition.3.6 Remove the measure that the pump shakes:(1) The product is hit by a pump in designing process , is is going to analyse the source vibrating sufficiently, to eliminate shaking a source. ;(2) Pump product fabrication assembles process middle , directive rules goes and carrying out , eliminates shaking a source strictly according to the standard and operation;(3) Pump , electric motor , assist equipment to be going to guard the pass , eliminate strictly to shake a source during the period of scene installation such as base , scene pipeline,;(4) Guard the pass , eliminate when producing , handling , keeping a scene in repair , adjusting, strictly to shake a source.3.7 Execute to the letter design criterion:The design sealing off a products asks pump product design and machinery to carry out the pertinent home and abroad standard , design that should carry out a standard carefully in the process of the product design,among deep every strip content concrete significance understanding a standard , the process the standard content request implementation is designed to the product.By now, actual import having many standards designing that not understand that , go and carrying out the new standard, not but being to copy the experience designing according to the set of old drawing sheet and old people blind strictly. That this resorts to magic arts to improving our country product engineering level and entering international market is very disadvantageous. Improve the standardizing cognition , be that machinery industry designs that need the problem solving urgently at present.4 Concluding remark: Pumps when the design with the mechanical seal, not only must consider the mechanical seal itself influence factor, moreover must consider exterior the mechanical seal each kind of influence factor. Must pay attention to following several questions in the practical work:(1) in pumps the product in the design process to have fully to consider pumps other spare parts as well as the scene other equipment to the mechanical seal use effect influence, creates a good external condition for the mechanical seal;(2) increases to the mechanical seal servosystem vital role understanding, provides the consummation as far as possible the mechanical seal servosystem, enhances the seal effect;(3) to importantly pumps the product the mechanical seal, must increase the protective measures, improves the seal quality, reduces the seal quality accident; (4) analyzes the mechanical seal the quality accident reason, must fully consider pumps other spare parts to the mechanical seal movement influence, take the measure unceasingly to enhance the mechanical seal the effect.The bolt pump has because of the person but variable transportation , self attract ability characteristics such as strong , may become worse , being able to transport the liquid containing a solid particle, in sewage treatment factory, be put into use broadly cover in the field of the drug-dip transporting water , wet sludge and flocculant. The bolt pump selects and uses should abide by economy , rational , reliable principle. If doing not think out in the field of the type designing selections, be able to give hereafter sigmatism, to management , be maintained bring about inconvenient , need according to producing reality therefore selecting and using one, now that the rational reliable bolt pump being able to swear to give birth to a child proceeding as planned and without a hitch, reduce mending cost.References: 【1】Dimethylmethane pump design and research Water pump technology, 1999 (1): 9 131;【2】Blade pump design handbook Mechanical industry press, 19731;【3】How improve the function and life-span that the petroleum and chemical pump seals off with machinery Petrochemical industry equipment technology,1994 (6) ：23261。IIIPrecision injection molding technology of progress Abstract: The polymer precision injection molding technology, impact on precision injection molding of factors, including the precision molds, injection molding machine control accuracy, precision injection process control and other computer control technology. These factors were discussed, and give the relevant solutions, finally introduces some advanced molding technology. Key words: precision injection; injection molding machine precision injection technology; Precision Injection Mold In recent years, as electronics, telecommunications, medical, automotive, and other industries of the rapid development of the high-precision plastic products, and high-performance requirements of growing precision molding technology to continue to progress, new technologies continue to emerge. Precision injection molding products not only require high dimensional accuracy, and low warpage, to write good, but there should also be excellent optical properties. Injection molding is the most important one of the plastic molding methods, including plastics plastics, injection, packing, cooling, and some of the basic process, thus affecting the precision injection molding of many factors. 1, precision molds To produce sophisticated products, precision molds is essential. Die Die in general, the accuracy of the temperature control, mold and die design precision manufacturing, use of plastic shrinkage rate impacts. 1.1 Precision Mold temperature control In general precision injection molding of parts, control mold temperature is to increase productivity. However mold temperature control for precision injection molding of great impact, it affects parts of the contraction, shape, crystallization, such as stress, hot and cold circuit design mold temperature distribution at the request reasonable, precise control accuracy, a die temperature of the best and Lengshuiji control. Mold temperature control and cooling time on the products and their impact on performance of the following factors: (1) melt plastic injection molds and a two-cycle time will be produced in the mold temperature difference fluctuations, and should therefore be to minimize the volatility differential peak. (2) the heat transfer Die Die Die heat through the concrete and die in the transfer out of the media, mold is changed, the media control is the key, the general import and export of its cooling water temperature difference is less than 1 Application of theory to calculate the average temperature, which can guarantee the stability of heat transfer. Media flow and heat transfer are interlinked, mould surface temperature can be used to control the media flow sensor to compensate for environmental temperature changes caused by mold temperature changes. (3) To enable stable Die Die by the heat absorption and dissemination of balance, the injection molding machine to melt injection to strictly maintain a stable temperature. Die surrounding temperature on the mold had a great impact on the general will be affected to die within the melt convection coefficient of change, so the best set up in the mold surface temperature sensor, die at any time observation of the surface temperature, and keep it stable. (4) changes in the efficiency of heat exchange with mold after a long time in the cooling water pipes and Youban appears in the scale, then the interface to reduce the thermal conductivity should furring timely clearance. 1.2 Precision Die Design and Manufacture Die design is good or bad is to ensure the dimensional accuracy of plastic parts premise, in order to enhance the accuracy of precision injection mold, in the process of designing a computer-aided analysis is necessary, especially for gating system and the flow of heat-conditioning systems mold temperature distribution the analysis. Applications should be as much as possible the use of simulation software and close to the actual loading conditions to melt in the mold simulation analysis in the pouring, cooling, and other non-steady-state process. Die manufacturing quality assurance plastic parts Size is the key to accuracy, precision die is the main characteristic of the manufacturing and assembly operations in addition to polishing, are no manual processing. Die general machining and manual processing ratio is about 6:4 to 7:3, and the machining precision molds and manual processing ratio of 9:1. Die materials and heat treatment is the protection of precision molds in the molding process, the die temperature in the state, which even the mould parts tempered by low temperature, high temperature melt production and will repeat parts tempering而使lower hardness, Consideration should also be given retained austenite caused by the volume expansion. Therefore general tempering temperature should be at least molding processing, more than double the die temperature and low-temperature processing is carried out properly in order to eliminate residual austenite. On the high-precision products for Molding precision parts, assembly accumulated precision die in the direction of the accuracy of the sub-surface as well as the parallel degree should achieve micron level. Mold should have sufficient strength, stiffness and abrasion resistance, in the injection molding deformation under the pressure of hard wear. To achieve the above processing can be three-dimensional precision machining centers, CNC machine tool and application of CAD / CAM / CAE and other new technologies. 1.3 precision molds design shrinkage rate of use Thermoplastic plastic molding shrinkage volatile, to mold design, identify and control products cavity size dimensional accuracy difficult. Therefore, in plastic mold design should understand the characteristics and contraction caused by the shape of the parts of the difference in the rate of contraction site, and then use the necessary compensation measures. On the high-precision plastic parts can be manufactured in the design before simple mold, measured molding to the various parts of the actual shrinkage rate, this can greatly enhance the dimensional accuracy of parts. 1.4, the design of precision molds gate Gate type, size, location and quantity of all affected parts dimensional accuracy. At the gate of the jet, but the effects of poor feeding, thick-walled parts do not apply. Gate position and the flow of impact melt flow distance, the longer the process of the greater contraction. Multi-gate process can be shortened, but increasing weld marks. Gate parts should be designed in accordance with the size and the choice of materials and the use of software to help finalize practical experience. 2, the best precision injection molding process parameters set Choose the best molding process parameters to reduce plastic shrinkage rate. Plastic is that the contraction of the heat shrinkable plastic, elastic recovery, plastic deformation, contraction after contraction and a comprehensive reflection of aging, usually caused by absorbent material or molecular chain rearrangement caused, the specific performance linear shrinkage rate and volume contraction rate changes in value of common contraction said. Thermoplastic plastic injection molding products shrinkage volatile, particularly for crystalline plastics injection molding products even more obvious, and not only depend on the degree of crystallinity due to the chemical structure, but also by the process of cooling parameters (cooling rate, the melt temperature, mold temperature , product thickness) the impact of the mold cavity size and design determine the size precision control products and difficulties, there is an urgent need to be aware of parameters on the injection molding of plastic shrinkage rate of the impact of the law. Part of the difference in thickness is generally believed that the two factors: First, high-pressure melt the mold cavity caused minor deformation of a die when the elastic modulus material after the expansion. Generally speaking, quality control and accuracy can be very good dimensional accuracy, and at a higher temperature, mold low melt viscosity, viscosity smaller gradient, in a certain screw back pressure, the quality of precision parts can be accurately controlled. But for liquid crystal polymer (LCP), it just needs a lower mold temperature, it is because cold LCP case will be promptly after cooling amorphous. LCP have low melting heat and orderly structure of the state, in the liquid crystalline state to change between crystalline solid, smaller changes, when fully cooling, the liquid - solid transition is almost complete in an instant. Die in the colder, when a cavity, the cavity material and the bulk of gate has been cured, it is very difficult stage compression added melt, thus parts and the size of the cavity size of the deformation is very close. Plastic amorphous than crystalline plastics low shrinkage with a mixture of contraction rate of low-polymer materials, elastomers at the same time as the increase of the content, materials shrinkage rate decrease. The enhanced or plastic filling, heat capacity decrease stiffness increased significantly reduce shrinkage and fiber filler content or higher, the smaller the rate of contraction. Crystalline precision plastic products also affected by pressure. As pressure crystallization of the role of injection pressure (P1), the packing pressure (P2) and the feeding pressure (P3) to speed up the crystallization process, crystallization of the P1, P2, P3, the increase in upward trend. For P1, the pressure to improve the crystallization of the degree of crystallinity, the contraction rate of increase rose P2 and P3, on the one hand because of the degree of crystallinity increased shrinkage rate increase, on the other hand increased to P2 more pressure to melt, the type cavity has been fully compacted plastic; P3-feed increased to increase, and effectively prevent reflux is conducive to reducing shrinkage. Therefore, the plastic parts of the shrinkage rate is the result of both, with the shrinkage of P1, P2, P3, the first increases and then decreases increased. Precision plastic parts requires not only a stable size tolerances, but also requires strict mechanical properties. These characteristics mainly depend on the cooling phase of the melt in the heat - mechanical role of the historical process. Mold temperature and cooling time on the quality of products and have a direct impact on productivity. Study found that, given the die temperature, the dimensional accuracy of products with the cooling time is not the extension has been significantly improved, and only in a certain period of time, after a prominent role. In general cooling process in such a critical point in time there are two cooling, cooling time in the first point although production products also higher accuracy, but it is not the most stable state, and the second point-in-time cooling cooling relatively long time, However, the products enable the most stable state. 3, using precision injection molding machine to replace conventional injection molding machine Precision injection molding machine generally larger injection power, in addition to such injection pressure and injection to meet the requirements in terms of speed, power itself will be on the injection products improve the accuracy of a certain role. Precision injection molding machine control systems generally have high control precision, it is requested by the products themselves. High accuracy can be guaranteed control of injection process parameters has good accuracy, precision products in order to avoid fluctuations due process parameters change. Therefore precision injection molding machine generally of the injection, injection pressure, injection rate and pressure-pressure, back-pressure and screw speed process parameters such as a multi-level feedback control. Precision Injection requirements of its modulus system has sufficient rigidity, accuracy or products will be a model for the elastic deformation decreased. Second-Die-Die of the system must be able to accurately control the size, or too large or too small a model of precision products will have an adverse impact. So in the design, it should be considered Die rigidity, stiffness, as well as a model system in order to accurately control the size of the precision products, especially flat-panel thin-wall products. When Die larger, must-oriented column deflection check. Precision injection molding machine also must be able to work in the hydraulic circuit precise temperature control, work to prevent the oil due to temperature changes caused viscosity and flow changes, further injection process parameters leading to fluctuations而使products would lose their accuracy. 3.1 parts molding cycle time consistency General typical injection molding machine with three modes: manual, semi-automatic and fully automatic. As the influence of various factors, each of the previous two models molding cycle time may be different, it would affect the temperature and materials to die in the Liaodong stay, thereby affecting the accuracy of parts, in precision Molding should try to use the automatic mode. 3.2 precision injection molding machine screw temperature control and the design of new Injection Molding Machine cylinder automatic thermostat on the cycle of opening and customs led to the Liaodong, melting material density and viscosity changes, thereby affecting the quality and dimensional accuracy of parts of the cyclical fluctuations in the injection molding machine nozzle close to Die Therefore, the temperature of the nozzle molded parts also have a significant impact on. Modern injection molding machine equipped with a special process control software to control temperature fluctuation, which is proportional integral differential (P ID) control. At least from the barrel temperature difference galvanic point perspective, the P ID parameter optimization can completely eliminate temperature fluctuations. To the quality and stability of the plastic parts, plastics injection molding machine unit is very important. To the plastics unit is an important standard to judge: injection volume, plastics rate, injection rate, the polymers in the plastics unit at the time. As the quality of plastic parts for the dimensional accuracy error of a very important impact, and it should be precise injection control of the injection molding machine. Improve measurement precision injection molding machine of the most effective ways is to use technology to achieve the smallest screw diameter, especially for the light parts especially. The measurement of the relative screw length and the overall length of screw smaller, in the plastics materials unit at the time also become shorter. Screw thread is similar to widenin
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