The world 's largest injection mold
Mold injection molding is the production of certain parts of the complex parts used in a processing method.Specific principle refers to: the heat of the plastic raw materials from the injection molding machine screw into the high pressure into the plastic mold cavity, after cooling and solidification, Plastic forming products.
The plastic mold is composed of two parts: movable mold and fixed mold. The movable mold is installed on the moving mold of the injection molding machine, and the fixed mold is installed on the fixed template of the injection molding machine.When the injection molding is completed, the movable mold and the mold clamping form the pouring system and Cavity, open mold when the dynamic mode and die separation in order to remove the plastic products.
Although the structure of the mold due to plastic varieties and performance, the shape and structure of plastic products and the type of injection machine may vary, but the basic structure is the same. Die mainly by the casting system, thermostat system, forming parts and structural parts Which is the plastic parts and molded parts are in direct contact with the plastic parts, and with the plastic and products and changes, is the most complex mold, the largest change, requiring processing of the highest degree of finish and precision.
Injection molding is a tool for the production of plastic products; it is also a tool for the complete construction and precise size of plastic products.Place molding is a kind of processing method used in mass production of complex parts of some shapes.Specifically refers to the heat by melting plastic from Injection molding machine high-pressure into the mold cavity, after cooling and curing, to be molded products.
Mold composition
Although the structure of the mold due to plastic varieties and performance, the shape and structure of plastic products and the type of injection machine may vary, but the basic structure is the same. Die mainly by the casting system, thermostat system, forming parts and structural parts Which is the plastic parts and molded parts are in direct contact with the plastic parts, and with the plastic and products and changes, is the most complex mold, the largest change, requiring processing of the highest degree of finish and precision.
The injection mold is composed of two parts: movable mold and fixed mold. The movable mold is installed on the moving mold of the injection molding machine, and the fixed mold is installed on the fixed template of the injection molding machine. When the injection molding is completed, the movable mold and the mold clamping form the pouring system and In order to reduce the heavy mold design and manufacturing workload, injection molds are mostly used in the standard mold base.
When the mold is opened, the movable mold and the mold are separated to remove the plastic parts, and the single part mold is also called the double plate mold, which is the simplest and most basic form of the injection mold. According to the needs can be designed as a single cavity injection mold, can also be designed into multi-cavity injection mold, is the most widely used an injection mold.
There are two sub-types of molds. Compared with the single-part injection molds, the double-part injection molds have been added to the middle plate which can be moved locally Called the activities of the gate plate, which is equipped with gates, runners and mold the other parts and components required), so also called three plates (moving template, the middle plate, set the template) injection mold, which is commonly used for pouring The middle plate in the single-cavity or multi-cavity injection mold, open mode, the middle plate in the fixed-mode guide column and set the template for a distance separation, in order to remove the two templates between the pouring system condensate system. Double parting mold mold structure is complex, high manufacturing costs, parts processing difficulties, generally not for large or large plastic products molding.
Injection molding mold with lateral and core pulling mechanism When the plastic part has side hole or side concave, it is necessary to use the side movement of the core or slider molding. After injection molding, the movement of the first movement down a distance And then the beveled portion of the bending pin fixed to the set plate urges the slider to move outwardly while the plunger of the release mechanism urges the push plate to remove the plastic part from the core.
Injection Molds with Movable Forming Parts Due to some special construction of plastic parts, it is required that the injection mold be provided with movable forming parts such as movable punch, movable die, movable insert, movable thread core or ring , In the stripping with the plastic parts can be moved out of the mold, and then separated from plastic parts.
Automatic thread unloading mold For threaded parts, when the automatic demoulding is required, a screw thread or ring can be set on the mold, a rotary mechanism with a mold opening or an injection molding machine, or a special The drive, driven by a threaded core or threaded ring, is removed from the plastic parts.
No flow channel injection mold No flow channel injection mold refers to the use of the channel for adiabatic heating method, to keep the injection molding machine nozzle between a plastic cavity was molten state, so that the mold out of plastic parts without pouring system condensate. The former said adiabatic flow channel injection mold, the latter said hot runner injection mold.
Right angle injection mold Right angle injection mold is only applicable to angle injection molding machine, and other injection mold is different from the mold in the molding process when the direction of feeding and opening and closing direction perpendicular to his main channel set in the moving The cross-sectional area of the main flow path is different from that of other injection molding machines. In order to prevent the wear and deformation of the injection nozzle and the inlet end of the main flow path , Can be set to replace the flow channel inserts.
Injection Molding Molds on Molded Molds In most injection molds, the stripping devices are mounted on the side of the movable mold, which facilitates the operation of the ejector in the open mold system of the injection molding machine. In actual production , Because some of the plastic parts by the shape of the restrictions, the plastic parts to stay in the mold side of the molding better, which makes the plastic parts from the mold out, it must be set in the mold side of the stripping mechanism.
The injection mold consists of a moving mold and a fixed mold, the moving mold is installed on the moving template of the injection molding machine, the fixed mold is installed on the fixed mold of the injection molding machine, and the movable mold and the fixed mold are closed to form the pouring system during injection molding and Cavities, when the mold is opened, the mold is separated from the mold to remove the plastic products.In order to reduce the heavy mold design and manufacturing workload, most of the injection molds use standard mold bases.
Gating system
Gating system refers to the plastic part of the runner from the nozzle into the cavity, including the main runner, cold material hole, runner and gate.
Gating system, also known as the runner system, is a set of feed channels that direct the plastic melt from the nozzle of the injection machine to the cavity, usually consisting of main runner, runner, gate and cold material hole. It is directly related to the plastic Molding quality and production efficiency of products.
Mainstream Road
It is a part of the mold that connects the nozzle of the injection molding machine to the shunt or cavity. The top of the main flow path is concave to connect with the nozzle. The diameter of the main flow path inlet should be slightly larger than the nozzle diameter (0.8mm) to avoid flash and prevent The two due to the convergence of the closure intercept import diameter according to the size of the product, usually 4-8mm. Mainstream diameter should be expanded inward was 3 ° to 5 ° angle in order to flow demolition mold release.
Cold material hole
It is a hole located at the end of the main flow channel to capture the cold material produced between two injections at the end of the nozzle to prevent blockage of the runner or gate.If the cold material mixes into the cavity once, The resulting product is prone to internal stress.Cold hole diameter of about 8-10mm, a depth of 6mm.In order to facilitate the demolding, the bottom is often borne by the stripping rod stripping the top of the rod should be designed as a meandering hook or Set the sag groove, so that the demoulding can be successfully pulled out the main flow Road. 4 side slider + dynamic mode shrink core, make painstaking efforts die
Shunt
It is a multi-slot mold connected to the main channel and the various cavity of the channel in order to make the melt at equal speed filled with the cavity, the flow path in the mold on the arrangement should be symmetrical and equidistant distribution of the shape of the cross- The size of the plastic melt flow, product stripping and mold manufacturing are difficult to have an impact.
If the flow of the same amount of material, then the circular cross-section of the minimum flow resistance.But the cylindrical flow channel than the small surface, on the diversion of traffickers unfavorable cooling, and this must be opened in two Half mold, both laborious and difficult to align.
Therefore, it is often the case that a runner of trapezoidal or semicircular cross-section is provided on a half mold with a stripper.The runner surface must be polished to reduce the flow resistance and provide a faster filling speed.The size of the runner Depending on the type of plastic, the size and thickness of the product, for most thermoplastics, the cross-sectional width of the shunt is no more than 8 m, extra-large 10-12 m, extra-small 2-3 m. Minimize cross-sectional area to increase shunt weight and extend cooling time.
Gating
It is connected to the main channel (or branch channel) and the cavity of the channel cross-sectional area of the channel can be equal to the main channel (or shunt), but usually are reduced, so it is the entire flow channel cross-sectional area of the smallest Part of the gate shape and size of a great impact on product quality.
The role of the gate is:
A, control the flow rate:
B, in the injection because of this part of the melt premature coagulation and prevent reflux:
C, so that the melt through the strong shear and raise the temperature, thereby reducing the apparent viscosity to improve the mobility:
D, to facilitate the separation of products and runner system gate shape, size and location of the design depends on the nature of the plastic, product size and structure of the general gate cross-section shape is rectangular or circular cross-sectional area should be small and the length should be Short, which is not only based on the above-mentioned role, but also because the small gate becomes bigger and easier, and the big gate is very difficult to narrow the gate position should generally be selected in the product is the thickest and does not affect the appearance of the place.
The design of the gate size should take into account the nature of the plastic melt, which is the space in the mold for molding the plastic product, and the components used to form the cavity are collectively referred to as forming parts.
(Such as holes, grooves, etc.) known as the core or punch (also known as the male model), the shape of the product shape, When designing a molded part, it is first necessary to determine the overall structure of the cavity based on the properties of the plastic, the geometry of the product, the dimensional tolerances and the requirements for use.
The second is based on the selected structure to select the parting surface, the location of the gate and the exhaust hole and the stripping mode.
Finally, according to the size of the control parts of the design and determine the combination of the parts between the plastic melt into the cavity with a high pressure, so the parts to be a reasonable selection and strength and stiffness of the check.
In order to ensure that the surface of plastic products smooth and easy to stripping, where the surface contact with plastic, the roughness Ra> 0.32um, and to corrosion. Molding parts are generally heat treatment to improve the hardness and use of corrosion-resistant steel The
Thermostat system
In order to meet the requirements of the injection process on the mold temperature, the need for a thermostat system to adjust the temperature of the mold.For thermoplastic injection mold, the main design of the cooling system to mold cooling.Meash cooling commonly used method is to set up in the mold cooling water Channel, the use of circulating cooling water to take away the heat of the mold; mold heating in addition to the use of cooling water channel hot water or steam, but also in the mold inside and around the installation of electric heating elements.
Forming parts
Refers to the various parts that make up the shape of the product, including the dynamic mold, the mold and the cavity, the core, the forming rod and the exhaust port, etc. The forming part is composed of the core and the concave mold. The core forms the inner surface of the product, The shape of the outer surface of the mold forming the product The mold core and the cavity form the cavity of the mold.According to the process and manufacturing requirements, sometimes the core and the cavity mold are made up of several pieces, sometimes integrated, only In the easy to damage, difficult to use parts of the inserts.
exhaust vent
It is in the mold to open a slot-shaped air outlet to discharge the original and the melt into the gas into the cavity melt inflow, the air originally stored in the cavity and brought by the melt The gas must be vented to the outside of the die at the end of the stream, otherwise it will cause the product to have blowholes, poor connections, unsatisfactory filling, and even burn the air due to compression and high temperatures.
Under normal circumstances, the exhaust hole can be located in the cavity melt flow at the end, can also be located in the mold parting surface.The latter is in the side of the die set to open deep 0.03-0.2mm, width 1.5- 6mm shallow slot injection, the vent will not have a lot of melt exudation, because the melt will be solidified in the cooling of the channel blockage.Exhaust port opening position against the operator to prevent melting In addition, the ejector rod and ejector hole with the gap, the top block and the stripper and the core of the gap with the exhaust, etc. 88 pieces of mold design commonly used basic knowledge .... Feel new
Structural parts
It refers to the various components that make up the mold structure, including various parts such as guide, demoulding, core pulling and parting, such as front and rear plywood, front and rear clasp mold plates, bearing plates, pressure bearing columns, guide columns, Demolding rod and return rod and so on.
1. Guide parts
In order to ensure that the movable mold and the mold can be accurately aligned in the mold, the mold must be set in the guide parts in the injection mold is usually used in four sets of guide and guide sleeve to form the guide components, and sometimes in the dynamic mode and The mold is set to match each other inside and outside the cone to assist the positioning.
2. Launch organization
In the process of opening the mold, the need for the introduction of plastic products and its in the flow of the condensate out or pull out the introduction of fixed plate and push plate to hold the putter in the putter is generally fixed with a reset lever, When the reset lever is in the dynamic mode, the push plate is reset.
3. Side core pulling mechanism
Some of the plastic products with side or side holes must be lined before they are introduced, and the lateral core can be removed to remove the mold. In this case, the side core pulling mechanism needs to be provided in the mold.
Common defects of injection mold and its adjustment method
