Introduction to 7 systems and basic structure of injection mold
Introduction to hot runner mould
Seven systems of injection mold: pouring system, guiding system, molding system, core pulling system, ejection system, cooling system, exhaust system。
1。 Pouring system: main flow channel, shunt channel, gate, cold well。
2. Guide system: guide post, guide sleeve, positioning block, etc.
3。 Molding system: core, insert, etc。
4. Core pulling system: slide block, inclined pin, etc.
5. Ejection system: ejector pin, ejector block, etc.
6. Cooling system: cooling of the mold itself, water cooling.
7. Exhaust system: the fit clearance of each die insert, the fit clearance of thimble, and the additional exhaust slot.
Hot runner mold introduction
Characteristics of hot runner die: why does this hot runner technology appear? What benefits can hot runner technology bring us? Engineers familiar with injection molding know that conventional injection molding often has the following adverse factors:
A. difficult filling; B. easy deformation of large thin-walled parts; C. waste of sprue raw materials; D. different quality of injection parts of multi-mode cavity mold.
The emergence of hot runner technology provides a relatively perfect solution to these problems. Generally speaking, using hot runner has the following advantages:
1。 Shorten the forming cycle of parts
Because there is no limitation of cooling time of sprue system, parts can be ejected in time after forming and curing. Many thin-walled small parts produced by hot runner die have a forming cycle of less than 5 seconds.
2. Saving plastic raw materials
Because there is no cold runner in the full hot runner mold, there is no production cost. Hot runner technology is an effective way to reduce the cost of raw materials.
3. Reduce waste products and improve product quality
In the process of hot runner mold forming, the temperature of plastic melt is accurately controlled in the runner system。 The plastic can flow into each mold cavity in a more uniform state, and the result is the parts with the same quality。 The sprue quality of hot runner parts is good, the residual stress after demoulding is low, and the deformation of parts is small。 Therefore, many high-quality products in the market are produced by hot runner mold。
4. Eliminate the follow-up process to facilitate production automation
The products are finished products after forming by hot runner mould. There is no need to trim the gate and recycle the cold runner, which is conducive to production automation and greatly improves production efficiency.
5. Expand the application scope of injection molding process
Many advanced plastic forming processes are developed on the basis of hot runner technology。 Such as pet pre molding manufacturing, multi-color co injection in the mold, multi material co injection process, stack mold, etc。
6. Mold cost increases
It is not cost-effective because of its high cost ratio. For mold users in many developing countries, the high price of hot runner system is one of the main problems that affect the wide use of hot runner mold.
7. High requirements for manufacturing process equipment of hot runner mould
The hot runner mold needs precision machining machinery to ensure。 The requirements of integration and cooperation between hot runner system and mould are very strict, otherwise many serious problems will appear in the mould production process。
8。 Complex operation and maintenance
Compared with the cold runner die, the operation and maintenance of hot runner die is more complex。 If the operation is improper, it is easy to damage the parts of hot runner, which makes the production impossible and causes huge economic losses。 For new users of hot runner mold, it takes a long time to accumulate experience。
The hot runner can be broadly divided into:
(I) open hot runner system
(II) valve filling hot runner system
I. open hot runner
Due to the simple structure and few related parts, the open hot runner is relatively simple for mold processing, easy to install and maintain, with few problems in general, and relatively low price. Therefore, if the general product appearance requirements are not very strict or very precise, the open hot runner can meet the injection molding process. Therefore, the open type is classified according to different gates: point gate hot runner, large gate hot runner
Disadvantages: easy to wire drawing and leakage, poor surface quality, less application in foreign high-precision mold.
II。 Valve type hot runner system
Valve heating hot runner is also a kind of hot runner system which is widely used by the main hot runner suppliers in the world. This system uses the valve pin to open or close the gate by mechanical movement at a predetermined time under the action of the valve pin control device. This type of hot runner system has many advantages that the hot tip runner system and the sprue runner system cannot have. For example, the gate opening and closing time can be controlled manually, the gate is smooth and flat, and the application field of hot runner technology can be expanded.
Needle valve type hot nozzle: the needle valve type nozzle is more advanced in technology, with the main advantages as follows: (1) there is no residual mark on the product, and the mark at the gate is smooth; (2) the gate with larger diameter can be used to accelerate cavity filling, further reduce injection pressure and reduce product deformation。 (3) it can prevent the phenomenon of wire drawing and salivation when the mold is opened; (4) when the screw of the injection molding machine moves backward, it can effectively prevent the material from being sucked back from the mold cavity; (5) it can cooperate with the sequence control to reduce the product weld mark。
Contact: Mr Lee
Add: Guangdong guangzhou panyu district NaCun Town cloud road prosperous road no。 1