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1. die structure
There are many kinds of moulds. Because of the similarity of functions, the parts that make up the moulds often have the same structural characteristics in different moulds. Taking typical injection moulds and stamping moulds as examples, the processing rules of the parts can be found.
Basic structure of injection mold
The basic structure of injection mold is divided into forming parts, pouring system, guiding mechanism, ejection device, lateral parting and core pulling mechanism, cooling and heating system and exhaust system.
(1) Formed parts refer to the parts that constitute the die cavity, mainly including punch, concave die, core, forming rod, forming ring and insert.
The runner system refers to the plastic flow passage from the nozzle of the injection molding machine to the mold cavity. The common gating system is made up of the main flow channel, the diversion channel, the gate and the cold material hole.
(3) The guiding mechanism mainly has the function of positioning, guiding and bearing certain side pressure in the plastic mould, so as to ensure the accurate closing of the moving and fixing moulds. The clamping guide mechanism is composed of a guide, a guide sleeve or a guide hole (directly opened on the template), a positioning cone, etc.
The ejection device mainly plays the role of ejecting the parts from the die, which consists of ejector rod or pipe jacking or pushing plate, ejector plate, ejector rod fixing plate, reset rod and pulling rod.
The function of the lateral parting and core pulling machine is to separate the lateral punch or pull out the lateral core, which usually includes inclined guide pillar, bending pin, inclined guide groove, wedge block, inclined slide block, inclined groove, gear rack and other parts.
The function of cooling and heating system is to adjust the technological temperature of die, which is composed of cooling system (cooling water hole, cooling water tank, copper pipe) or heating system.
The function of the exhaust system is to remove the gas in the cavity, which is mainly composed of the exhaust groove and the matching clearance.
The basic structure of the 2. die
The basic structure of punching die can be divided into process parts and auxiliary parts. Process parts include working parts, positioning parts, unloading and ejecting parts. Auxiliary parts include guiding parts, supporting and clamping parts and fastening parts and other parts.
The working parts are mainly composed of punch, concave die, punch die and edge insert.
2. Positioning parts consist of positioning pin, retaining pin, guide pin, guide plate and fixed distance side blade.
3. The unloading and ejecting parts are made up of pressing plate, unloading plate, ejector, top pin and push plate.
4. The guide parts are mainly composed of guide posts, guide sleeves, guide plates and guide pipes.
_Supporting and clamping parts are composed of upper and lower formwork, die handle, punch and concave die fixing plate, cushion plate and limiter, etc.
Fastening parts and other components include screws, pins, springs, lifting handles and brackets.
3. classification of mold parts
Although there are many parts which make up the die structure, and their functions, shapes and application requirements are different, they can be roughly divided into four categories according to the analysis of the processing characteristics of the structure.
(1) shaft sleeve parts include guide pillar, guide sleeve, gate sleeve, mold handle, positioning ring and so on.
(2) rod parts include ejector pin, reset lever, push rod, drawing rod and so on.
(3) plate parts include formwork, backing plate, unloading plate, push plate, cushion block and so on.
(4) molding parts include punch, die, core, cavity, etc.
4. the composition of the mold parts.
Although the shapes of the parts are different, the basic surfaces of each part can be summarized into 3 types.
(1) the outer surface, inner surface and conical surface of the revolving part.
(2) the surface of the flat plate and the end face of the shaft.
(3) two dimensional curved surface and three-dimensional surface of curved surface forming parts.
The essence of mold parts forming is to solve these 3 basic surface processing problems. For the rotary surface and plane, traditional cutting can be used to form. Different processing schemes can be selected according to different accuracy requirements and different materials of the parts surface.
5. selection of blank for mold parts
The blanks used in die parts mainly include forgings, castings, weldments, various profiles and sheets. When choosing the blank, the main factors to be considered are: the stipulation of the die drawing; the structural shape and geometric size of the die parts; the production batch; the material of the die parts and the requirement of the material structure and mechanical properties, etc. Round bars or forgings are commonly used in the blanks of axle and sleeve parts. Hot-rolled or cold-rolled round bars are mostly used in smooth axles, sleeves and stepped axles or sleeves with little difference in diameter, and forgings are mostly used in axles, sleeves and stepped axles or sleeves with high mechanical properties and wide difference in diameter. The commonly used blanks for rod parts are similar to those of shafts and sleeves, and non-circular bars can also be made of non-circular bars. Plate parts such as ejector plate and unloading plate adopt the blank cut by steel plate, and forgings are used when the precision is high and the force is large. Forming parts such as punch and die are required to adopt forging die blank.
