Injection mold.Selection of die holder
Basic introduction of die frame
1. National standard of formwork
The standard of mould frame can be generally divided into national standard and enterprise standard. National standard, such as the mould frame standard of plastic injection mould promulgated by China in 1990, enterprise standard, such as LKM of longji group (longji), Futaba of Japan, etc.
The following first to understand the standards of our country:
(1) basic type A1: the fixed die is two templates, the moving die is one template, and the push rod is used to push out the mechanism. Suitable for injection membrane of single parting surface.
(2) basic type A2: both fixed and moving molds are two templates with push rod pushing mechanism. It is suitable for the injection film of direct current channel and inclined guide column core-pulling.
(3) basic A3: the fixed mold is two templates, the moving mold is one template, using the push plate to push out the mechanism.It is suitable for plastic parts with large demoulding force, thin shell plastic parts and plastic parts with no protruding marks on the surface.
(4) basic A4: fixed die and moving die are two templates, using the push plate out mechanism.The fit range is similar to A1.
LKM(longji) die frame of longji group
Currently, the standard formwork used by foreign enterprises are: LKM(dragon), Futaba(Futaba - Japan), DME (USA), HASCO (Germany) and so on.The following to longji group production die to understand the structure of the die:
(1) large nozzle die frame
(2) fine nozzle die frame
(3) simplified thin nozzle die frame
Selection principle of die frame.injection mold
1.the selection of large nozzle die frame principle
(1) the structure of the parts is simple, the appearance requirements are not very strict, the side is allowed to have the gate mark, no other special structure
(2) when large nozzle die frame can be used, thin nozzle die frame is not needed. Large nozzle die frame is used for the mold of primary parting
2. Selection principle of fine nozzle die frame
(1) the projection area of single cavity and molding parts on the parting surface is large, requiring multi-point glue feeding.
(2) multiple cavities of a mold, where individual parts require point feeding or parts must center feeding
(3) multiple cavities of one mold, the size of individual cavity is greatly different, and the bushing of the gate should deviate from the center of the mold when using large nozzle
(4) molds with high precision, small dimensional tolerance and high service life requirements
(5) barrel, shell or box products with large height
(6) gear mold, multi-cavity tire blowing mold, etc
3. the simplified type of fine nozzle selection principle
(1) there are large side pumping mechanism (slide block, oil cylinder) on both sides, and it takes a long time to use the thin nozzle die frame. At this time, the simplified thin nozzle die frame can be used
(2) GAI and GCI series are commonly used in simplified thin nozzle die frame for large nozzle die with slider on the side of female die
4. The selection principle of i-type die and straight-body die
(1) when the width of die frame is less than or equal to 250mm, die frame adopts i-shape;
(2) when the width of die frame is between 250-350mm, the die frame with female die fixed plate (t-type) shall be adopted.
(3) when the width of the die frame is more than 400mm and there is a slider, the die frame with a straight body and a panel (T type) shall be adopted;When there is no slider, use straight formwork without panel (H type).
Mold frame design of plastic parts (case).
1）Basic information of plastic parts
4）Mold kernel design
5）Length and width of die holder
6）Height of die holder
7）Selection of die frame
8）Confirmation of overall structure of formwork
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