"Molds are the mother of industry" is well known to everyone. The importance of molds is increasingly recognized by people, and mold design and mold manufacturing technology have made great progress.
The innovation of mold processing technology, the wide application of various new mold materials, the standardization and specialization of mold parts, etc., all force us to adapt to the development of molds faster and more accurately in design.
The level of mold design, the quality of processing equipment, the strength of manufacturing power, the quality of molds directly affects the development of many new products and the renewal of old products, and affects the improvement of product quality and economic benefits. Plastic molds refer to molds of plastic parts. Currently, commonly used plastic molds are mainly injection molds. What is an injection mold?
Injection mold: The feeding method is to transport the material into the barrel of the injection machine by manpower or conveying device. The material is heated and melted. Then, under the push of the screw or piston, it enters the cavity through the nozzle and the mold feeding system. After sufficient cooling, the material is hardened and fixed in the cavity. The forming tool required for this forming process is called an injection mold.
Injection Module Model
Injection Module is mainly composed of mold seat, mold kernel, casting system, cooling system, ejection system, guide positioning support mechanism, exhaust system, core extraction mechanism, etc.
injection mold basic structure
1. The injection mold seat can be divided into two-plate mold seats and three-plate mold seats according to the type:
2-plate mold seats form
3-plate mold seats---between the female template and the male template, there is also a movable peeling plate. It is suitable for multi-cavity molds for central feeding, single-cavity molds for central feeding, multi-cavity injection molds for surface feeding, and unbalanced multi-cavity molds for edge feeding.
3 plate mold holder consists of
2. Module:
molded to form
3. Pouring system:
casting system consists of the main channel, the split channel, the gate and the cold material hole. The quality of the runner design has an impact on the accuracy, appearance, production cycle, etc. of the finished product.
Casting system
(1)Casting system icon:
Casting system icon
(2) Selection of flow channel:
The following figure shows the cross-sectional shapes of various flow channels. Generally, the efficiency of the flow channel is represented by the ratio of the cross-sectional area of the flow channel to the perimeter of the flow channel. From the figure, we can see that the efficiency of the circle is the highest, so the circular flow channel is widely used.
Runner type
(3) Cooling system: The injection molding process of
thermoplastic and partial thermosetting plastic is to inject a molten plastic with a higher temperature into a mold with a lower temperature through high pressure, and then cure it after cooling and solidification to obtain the required products. Cooling methods are divided into water cooling, air cooling, frozen water cooling and oil cooling.
No cooling system
Setting up the layout and precautions for cooling waterways:
•When the mold structure and strength allow, the diameter of the water holes should be as large as possible, and the quantity should be as large as possible, so that the cooling will be more uniform;
•The distance between the waterway and the surface of the cavity should be basically the same, and it should not be too close or too far;
•The "O" ring should be set when the waterway passes through two inserts;
•The water hole joint should be set on the side that does not affect the operation, and it is best not to be designed on the side of the world;
• water holes should not be arranged directly above the screw;
•The water hole should not be too close to the pin hole, the inlet hole, the screw hole, etc., generally not less than 3mm;
•Overall water paths should not be set up at the place where the plastic parts are welded to avoid affecting the strength of the product;
•Try to avoid water holes from the molding surface and side walls;
•The water holes should not interfere with any object;
•The cooling should be strengthened near gates and hot runners, and the cooling water can usually be made possible. First pass near the gate;
•The waterway should not be too long, so as to ensure that the inlet and outlet cooling water temperature is generally within 5 degrees Celsius, and the precision parts within 3 degrees Celsius;
•The thicker parts of the product should be specially cooled;
(4) Ejection system:
Product ejection is the last link in the injection molding process. When the product is solidified in the mold, there is an effective way to eject it from the mold. The quality of the ejection will ultimately determine the quality of the product. Therefore, the ejection of the product cannot be ignored, and the product cannot be deformed, whitened, or cracked during ejection. This device is the ejection system. Ejection type: dome needle, flat thimble needle, sleeve thimble, ejection block, disassembly plate, oblique pin, air thimble, etc. The ejection method is divided into one-stage ejection, two-stage ejection, and delayed action ejection.
Thread pin type
(5) Guide positioning support mechanism:
Guide mechanism: Ensure that there is a certain direction and position between the male and female molds when the mold is assembled and adjusted. The guide parts should bear a certain lateral force and play a role in guiding and positioning. The guide mechanism parts include guide columns and guide sleeves GP and GB of male and female formwork. The guide columns and guide sleeves of the ejection plate (top plate guide columns EGP), male and female formwork and ejection plate guide (RP).
Guide mechanism
Positioning mechanism: For molds that require large precision and guide parts to withstand large lateral forces, a positioning device is usually required. The template positioning mechanism is called the positioning mechanism.
template positioning mechanism Template positioning mechanism
mold reticle positioning mechanism Mold reticle positioning mechanism
support mechanism: The injection pressure of the injection molding machine is very large. When the span between the two mold feet is very large and the male template is not strong enough, the male template will deflect. Using support columns (SP) is to form many fulcrums at the bottom of the male formwork to minimize deformation of the male formwork.
Support mechanism diagram
(6) Exhaust system:
gas mainly comes from the air present in the feed system and cavity, the gases generated by the evaporation of moisture contained in plastics, the gases generated by the decomposition of certain additives in plastics, or the gases generated by chemical reactions. The function of exhaust gas is to reduce the wind, burning, etc. of the product. The exhaust methods are divided into exhaust gas using matching gaps, opening exhaust gas tanks on the parting surface, exhaust gas using exhaust plugs, forced exhaust gas, etc.
(7) Core extraction mechanism:
core extraction mechanism is divided into two types: slider mechanism and oblique pin mechanism.
slider mechanism - is a way to deal with the finished product's external inverted hook. It is generally a mechanism for lateral typing, core extraction and resetting with the injection machine's mold opening and closing force. This mechanism is economical, reliable in action, and strong practicality. Commonly used are diagonal support tips and lever core pulling. The figure below is the diagonal support tip core pulling.
oblique support tip core pulling
oblique pin mechanism is used in simple, short core pulling distance and no appearance requirements. It is used in situations where sliders cannot be used.
Basic Structure
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