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喜歡這套資料就充值下載吧。。。資源目錄里展示的都可在線預覽哦。。。下載后都有，，請放心下載，，文件全都包含在內，，【有疑問咨詢QQ:414951605 或 1304139763】
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英文原文
Injection molding machine
Injection molding machine is plastic machine for short. It uses the thermal physical properties of plastics, the material from the hopper into the barrel, is barreled by heating coil heat, so the material will be melted, which is arranged by the external force under the action of the motor driving the rotation of the screw in the barrel. The material in the screw under the action of the screw groove, along the forward delivery and compaction, dual role the material in the heating and shear under gradually plasticizing, melted and homogenized, when the screw rotates, the material in the screw channel friction and shear force, the molten material is pushed to the screw head. At the same time, the screw with backward in the material, the screw head forming material storage space, completing the plasticizing process, then, screw in the injection cylinder piston thrust under the action of high speed, high pressure, in the material storage chamber, the melt through the nozzle to the mold cavity injection, cavity melt after pressing, cooling, solidification, mold in the mold closing mechanism of action next, open mold, and through the ejection device to finalize the design good products fall from the top die.
Configuration according to the clamping member and the injection component type has horizontal, vertical, angle type three
(1) Horizontal injection molding machine: horizontal injection molding machine is the most common type. Its characteristic is the center line injection assembly and clamping assembly center line of concentric or consistent, also with the parallel to the mounting surface. It has the advantages of low center of gravity, steady work, mold installation, operation and repair, which are convenient, the mold opening big, small occupied space height; but covers an area of large.
(2) Vertical injection molding machine: its characteristic is clamping device and injection device of the axis line arrangement and perpendicular to the ground. It also has the advantages of small occupied area, convenient assembly and disassembly of insert mold, easy installation, since the bucket into the material plasticization is evenly, easy to realize automation and machine automation line management. The disadvantage of it is the top product is not easy to fall off automatically, it often needs manual or other method to take out, and is not easy to realize full automatic operation and large products injection; machine height, feeding, inconvenient repair.
(3) Angle type injection molding machine: injection device and a molding device axis are arranged vertically. According to the injection assembly center lines are vertical, horizontal and relative position of the vertical and horizontal installation, recumbent points: ① horizontal vertical, injection assembly line and plane parallel, and mold assembly center line and the base of vertical and horizontal, vertical; injection assembly center line and the surface vertical, and die assembly center line and the reference surface. The advantages of angle type injection machine has the advantages of both horizontal and vertical injection molding machine, special apply to the mold opening side gate asymmetric geometry products.
At present, the injection device are common cylinder form and double cylinder form, I plant the injection molding machine is double cylinder form, and is directly driven by a hydraulic motor of screw in injection molding. Because of different manufacturers, different types of machine components are not the same; the following will make a concrete analysis of our factory with machine.
The working principle is: the plastic, screw in plastic parts in the drive the main shaft to rotate through the hydraulic motor, spindle end is connected with the screw, and the other end of the hydraulic motor key connection, screw rotation, plasticity and melt classified pushed to the storage chamber cylinder front, at the same time, screw back in the reaction material, and through the thrust bearing the thrust seat back, pulling the piston rod through the nut straight back. To complete the measurement, injection, the injection cylinder rod chamber oil inlet through the bearing to push the piston rod to complete the action, the rod chamber piston oil inlet to push the piston rod and screw and finish the injection.
The work principle of screw plasticizing components: performs, screw rotation, from the material inlet into the screw groove material advancing continuously forward, heating ring through the barrel wall of the heat transfer to the spiral groove material, solid material in the dual role of external heating and screw rotational shear, and through the thermal process functional section of screw, achieving the plasticizing and melting, melting away the check ring around the screw head, front end through the channel into the screw, and generates backpressure, push the screw after the shift measurement complete melt, at the time of injection screw up, piston effect, with rapid advancement, in the cylinder, will melt reservoir material in the chamber through the nozzle into the mold.
Screw plasticizing components generally have the following characteristics:
The screw has two functions of plasticizing and injection;
The screw in plastic, only for the plastic
The plastics in plasticizing process, thermal process through than extrusion;
The screw on the plasticizing and injection were to occur, axial displacement, and screw in working state of intermittent when to stop, thus forming a non - stability of screw plasticizing process.
(1) Screw
Screw is a key component of plastic parts, direct contact with plastic, plastic through the effective length of the screw channel, after the heat for a long time, must go through 3 states (glass, behavior, viscous state) transformation, geometric parameters, geometry, length of functional section of screw will directly affect the transmission efficiency and the plasticizing quality of plastic, will ultimately affect the quality of injection molding cycle and product.
Compared with the extrusion screw, plastic screw has the following characteristics:
The injection screw length-diameter ratio and compression ratio is small;
Screw groove of injection screw is section of the deep;
The injection screws feeding sections is longer, and are short;
The injection screw work, plasticizing capacity and melt temperature will vary with the axial displacement screw and change.
(I) classification, screw
Injection screw according to the plastic adaptability, can be divided into general and special screw, general also called conventional screw, can be processed with low viscosity, most of the thermoplastic, civil plastic crystalline and amorphous and engineering plastics, is the most basic form of the screw, and the corresponding and special screw, is used to process with ordinary screw processing hard plastic; according to the screw structure and geometry characteristics, can be divided into conventional screw and screw, the conventional screw is also known as the three section screw, is the basic form of the screw, screw form has many kinds, such as separation screw, screw, wavy shunt screw, no metering section of screw.
The conventional screw thread effective length is usually divided into feeding sections (conveying), the compression section (Plastics segment), and metering section (averaging period), according to the plastic properties of different, can be divided into gradual, mutation type and general type screw.
The tapered screw: compression long, plasticizing energy transfer for PVC relaxation, poor thermal stability of plastic.
The mutant compression screw: short, plasticizing energy conversion is more acuteness, used for polyolefin, PA crystalline plastics.
The general purpose screw: adaptability is strong, and can be suitable for processing a variety of plastic, avoid frequent replacement of the screw, increase production efficiency.
DS screw diameter, screw diameter directly affect the plasticizing capacity, will directly affect the injection volume, therefore, injection volume of injection molding machine the screw diameter is large.
L/ds - screw length to diameter ratio. L is the effective length of screw thread part of the screw, the ratio of length to diameter is larger, the length of that thread, directly affect the thermal process of material in the screw, the ability to influence the absorption of energy, while the energy source has two parts: one part is the external heating coil to the barrel, and another part is friction thermal and shear heat generated by the rotation of the screw, the external mechanical energy conversion, therefore, L/ds directly affect the melting effect of material and melt, but if L/ds is too large, the transmission torque increase, increased energy consumption.
L1 - feeding length. The feeding section is also called conveying or feed section, in order to improve the transport capacity, screw groove surface must be smooth, the length of the L1 shall ensure that the material conveying length too short enough, because L1 will lead to premature melting material, thus it is difficult to guarantee the transportation conditions of stabilizing pressure, will be difficult to ensure the screw later. Plastic under their own gravity from the hopper to slip into the screw, screw rotation, the thrust surface friction in the barrel and screw groove under the action of the material is compressed into a solid, nut intensive, the relative motion along the direction of the thread, this section, plastic solid state, namely the glass state.
The depth of screw channel H1 - feed section. H1 deep, is receiving materials, improving the feeding quantity and plasticizing capacity, but will affect the shear strength of material plasticization and screw root, general H1 ≈ (0.12 ~ 0.16) ds.
L3 - melting length. Melting section called homogeneous section or the measuring section, melt further homogenization, uniform temperature in the channel of L3 segment, uniform composition, the formation of good quality of melt, the length of L3 is helpful to melt in the screw groove fluctuations, stable pressure, causes the material to feed evenly extruded from the screw head, so it is also called the metering section. L3 short time, help to improve the general screw plasticizing capacity, L3= (4 ~ 5)ds.
H3 - melting section of spiral groove depth, H3 small, shallow groove, improves the plasticizing effect of plastic melt, to melt homogenization, but H3 is too small will lead to higher shear rate, and shear heat is too large, causing degradation of the molecular chain, the effect of melt quality,; conversely, if the H3 is too large, the perform, enhanced flow screw back pressure generated, will reduce the plasticizing capacity.
L2 - plasticizing period (compression) length of thread. The tapered space material continuously under compression, shear and mixing effect, material from the L2 point, molten pool increased, to the point of weld pool has been occupying the entire screw groove, the material from the glass state through viscoelastic state transition to a viscous state, namely this segment, the plastic is state of coexistence in the particles with a molten body. The length of L2 will affect the transformation of the material from the glassy to viscous flow state, is too short will not change, plugging in the terminal segment of the L2 formation of high pressure, torque or axial force of solid material; too long will increase the screw torque and unnecessary consumption, general L2= (6 ~ 8) ds. For the crystalline plastics, material melting point, melting a narrow range, L2 can be shorter, generally (3 ~ 4) ds, for heat-sensitive plastic, this section Kvetching.
S - Pitch, the size effect of helix angle, thus affecting the transport efficiency of screw, general S ≈ ds.
E - Compression ratio. ε =h1/h3, namely the feeding section of spiral groove depth H1 and the melting section of spiral groove depth ratio of h3. E, will enhance the shear effect, but will weaken the plasticizing capacity, generally speaking, ε slightly smaller as well, to help improve the plasticizing capacity and increase the adaptability to raw materials, for crystalline plastics, the compression ratio is 2.6~3.0. For low viscosity and thermal stability of plastic, can choose the high compression ratio and high viscosity; thermal sensitivity plastic, should choose low compression rate.
(2) The screw head
In the injection screw, screw head is: the plastic, can be good plastic melt and releasing to the storage chamber, and in high pressure injection, and can effectively close the melt front screw head, prevent backflow.
The screw head is divided into two categories, with check ring and not the inverse ring with the check, the check ring, a plastic screw, melt homogenizing section will check ring away, through the gap formation and the screw head, into the storage chamber, injection pressure, melt screw the head of the formation of thrust, the non-return valve return channel plugging, prevent backflow.
For some high viscosity materials such as PMMA, PC, AC or poor thermal stability of PVC material, in order to reduce the retention time of shearing and material, can not check ring, but this injection will produce reflux, prolonging holding time.
On the screw head requirements:
The screw head to be flexible smooth;
The check ring and the cylinder to be suitable with the gap, to prevent melt flow, and flexible;
The existing flow section is enough, but also to ensure the check ring face a return force, making fast closed at the time of injection;
The structure should be easy disassembly, convenient cleaning;
The direction of the screw thread screw and screw in screw head instead, prevent a plastic screw head loose.
(3) Cylinder
(I), the barrel structure
Cylinder is an important part of plastic parts; interior screw is arranged outside the heating coil, under complex stress and thermal stress.
(II), the feeding port
Structure feeding port directly affects feed effect and plastic parts of the feeding ability, injection molding machine most by gravity feed material in hopper, simple manufacture, but feed the negative; the feed material and the screw contact angle, contact area is large, can improve the feed efficiency, is not easy in the hopper into bridge hole.
(III), cylinder wall thickness
Cylinder wall thickness is of sufficient strength and stiffness, because the barrel to melt and gas pressure, and the barrel length to diameter ratio, cylinder requires enough heat capacity, so the cylinder walls have a certain thickness, otherwise it is difficult to ensure that the temperature stability; but if it is too thick, barrel bulky, waste material, the thermal inertia of large, slow temperature rise, temperature regulation of delay larger.
(IV), cylinder clearance
Cylinder gap refers to the single gap barrel wall and screw diameter, the gap is too large, plasticizing capacity is reduced, injected back into the discharge increases, injection time, causing material degradation in the process; if it is too small, the thermal expansion effect on the screw and barrel friction, energy consumption increased, even death card, this gap delta = (0.002~0.005) ds.
(V), the material heating and cooling tube
Injection molding machine barrel heating with electric resistance, ceramic heating, cast aluminum heating, should be reasonably arranged according to the application and processing of materials, commonly used has the resistance heating and ceramic heating, to comply with the requirements of injection molding process, the barrel to subsection control, small 3, large machine 5.
Cooling refers to the feeding mouth is cooling, because the feeding mouth if the temperature is too high, the solid in the feeding mouth "bridge", blocking the outlet, thus affecting the transport efficiency of feed section, so the cooling water jacket is arranged in the cooling it. Our factory is through the cooling circulating water cooling of the feed inlet.
(4) Nozzle
(I) function of spray nozzle
The nozzle is an important part of connecting plasticizing device and mold flow; nozzle has a variety of functions:
The perform, establishment of backpressure, degassed, prevent melt salivation, improve plasticizing capability and measurement precision;
The injection mold, forming the contact pressure and the main cast, keep good contact with pouring nozzle sleeve, forming a closed channel, to prevent the plastic melt under high pressure overflow;
injection, establish the melt pressure, shear stress, and the pressure head into the velocity head, the increase of shear rate and temperature, enhance mixing and homogenizing;
Changing the nozzle structure to match the mold and plasticizing device, a new type of flow channel or injection system;
The nozzle also bears the thermostat, thermal insulation and cutting function;
The reducing melts in the import and export of the viscoelastic effect and the eddy loss, in order to stabilize its flow;
The holding pressure, easy to mold products of feeding, and the cooling shaping increased reflow resistance, reduce or prevent the melt in the cavity to return.
(II) The basic form, nozzle
Nozzle can be divided into straight-through nozzle, locking type nozzle, hot runner nozzle and the flow nozzle, the present stage our factory are straight-through nozzle.
Straight-through nozzle is the nozzle is widely applied, its characteristic is the direct and main casting mold nozzle spherical contact, the nozzle radius and the channel than the mold to be small, injection pressure, melt directly through the mold runner system is filled into the cavity, fast speed, low pressure loss, manufacturing and installation are all relatively convenient.
Locking type nozzle is mainly to solve the problem through the nozzle salivation, suitable for low viscosity polymer (such as PA) processing. In the closing the nozzle plastic, prevent melt salivation phenomenon, and when the injection and injection pressure to open, so that melt into the mold cavity.
2 injection cylinder
Its working principle is: the injection cylinder into the oil, the piston drives the piston rod and the bearing is arranged on the thrust seat, drive screw
Push the screw forward or backward. Through the nut piston rod head, can adjust the timing of two parallel to the axial position of the piston rod and the injection screw axial position.
3 thrust bearing
Injection, thrust bearing thrust shaft driven by screw injection; while the plastic, the oil motor drive screw rotation to achieve thrust shaft drives the perform.
4 cylinders
When a moving oil cylinder into the oil, forward seat injection or the back action, and to ensure the injection nozzle and mould the main cast set of circular arc closely contact, the injection pressure can seal the melt.
The 5 part accuracy requirements for injection
After the assembly, the components are arranged on the machine frame, must ensure that the nozzle and mold water sleeve is tightly bonding, in order to prevent overflow, the center line of injection parts requirements and the clamping parts of the center line of concentric; in order to ensure the accuracy of injection screw and barrel inner hole, must ensure that the two injection cylinder bore and the center cylinder hole is parallel with the center line of symmetry; in the horizontal plane, parallelism and symmetry for the center of a moving oil cylinder two guide holes also must ensure that the vertical machine, it must ensure that the two seat moving oil cylinder hole and a cylinder positioning the center hole is parallel with the center line of symmetry. Factors affecting the location accuracy of hole and shaft are associated parts size precision, geometric accuracy, precision and assembly precision.
Each kind of plastic, has an ideal plastic pro