The mould that is used for a mould two cave transparent injection-molded parts advances to water the runner of system
Technical field
The utility model relates to a kind of mould that is used for a mould two cave transparent injection-molded parts and advances to water the runner of system.
Background technology
For the injecting products of PMMA transparent material,, make it in later stage use or temperature shock and cold cycling testing experiment, cracking phenomena often occur because there is internal stress in product after the injection moulding.Processing mode for the injecting products internal stress much is to carry out the secondary baking destressing, and this very easily causes bad orders such as scuffing, dust pollution to clear glass outward appearance part.The product in one mould, two caves, injection moulding filling balance also is most important to the quality and the homogeneity of two cave products.
Summary of the invention
The purpose of this utility model provides a kind of runner that can improve a mould two cave transparent injection-molded parts internal stress.
In order to achieve the above object, the technical solution of the utility model has provided a kind of mould that is used for a mould two cave transparent injection-molded parts and has advanced to water the runner of system, comprises the runner body, has a cast gate in the both sides of runner body, and it is characterized in that: the runner body is S-shaped.
Further, described cast gate center is offset h in opposite directions, 0.8≤h≤1.2mm.
The diameter of described runner body is 6-10mm.
The utility model has the advantages that: significantly reduce near the internal stress of annotating part of cast gate; Reach the harmony of a mould two cave fillings, improve the homogeneity of two cave product qualities.
Summary of the invention
Fig. 1 advances to water the runner of system for a kind of mould that is used for a mould two cave transparent injection-molded parts that the utility model provides.
The specific embodiment
Specify the utility model below in conjunction with embodiment.
Embodiment
As shown in Figure 1, a kind of mould that is used for a mould two cave transparent injection-molded parts that provides for the utility model advances to water the runner of system, comprises runner body 1, has a cast gate 2 in the both sides of runner body 1, and runner body 1 is S-shaped.
Existing stress to concentrate the most tangible basic reason near the cast gate is that the PMMA macromolecule is injecting the die cavity process, because the gate area comparative resistance is big, under pressure, at this regional relative velocity height, the macromolecule long-chain is in the state of being straightened, keep high relatively packing density again under the dwell pressure effect, the long strand that is straightened has little time to shrink the release physical elastic energy, thereby causes near the internal stress that produces of notes spare cast gate of depanning.
The utility model is designed to S shape with runner body 1, is beneficial to the buffering injection pressure, makes filling more steady, can improve surperficial swash and envelope weld bond defective.Cast gate 2 centers are offset h in opposite directions simultaneously, and h=1mm can effectively improve the balance of two cave fillings, annotate part quality homogeneity thereby improve two caves.Runner body 1 diameter design 8mm, the gate shape design is full, and resistance is little, helps reducing filling and dwell pressure.
By above design optimization, cast gate annex problem of stress concentration significantly improves, and makes to annotate part smoothly by temperature shock and cold cycling test, does not ftracture.