The deformation, bending and twisting of deformed products are mainly due to the fact that the shrinkage rate in the flow direction is larger than that in the vertical direction during plastic molding, which causes the parts to be warped due to different shrinkage rates in each direction. It is also due to the white ground when the injection fills the mold. The twists and turns caused by the deformation caused by the non-existent inward inclination of the part are all manifestations of the deformation caused by the high strength. These problems are very difficult, and the final solution must be from the mold design and development direction.
1. Mould:
(1) The history and quality of the parts must be unified.
(2) The design of the cooling system should make the temperature of each part of the mold cavity uniform, and the pouring system should make the material flow rate cause warpage caused by the flow direction and shrinkage, and thicken the runners and main runners that are not easy to form. , Eliminate the distance difference, pressure difference and temperature difference in the cavity.
(3) Modulus conversion and corner of the part thickness should be changed to be smooth and good vision. For example, increase the margin of the mold surface, improve the polishing of the mold surface, and the ejection system must maintain a balance.
(4) The export is better.
(5) Increase the wall thickness of the part or increase the direction of anti-warping, and strengthen the anti-warping ability of the part by reinforcing ribs.
(6) The strength of the material used in the mold is insufficient.
2. In terms of plastics:
Crystalline plastics have more warpage deformation functions than amorphous plastics. In addition, crystalline plastics can use crystallinity to decrease as the cooling rate becomes faster, and the shrinkage rate is bent and deformed along with the crystallization process.
3. Processing aspects:
(1) The injection pressure is too high, the holding time is too long, and the melt temperature is low and the speed is too fast, which will cause the internal increase and warpage deformation.
(2) The mold temperature is too high, and the cooling time is too short, which causes the part to be ejected due to overheating during demolding.
(3) Reduce the limit while maintaining the minimum congestion and reduce the pressure to within the limit to inhibit the production.
(4) When necessary, the parts that are prone to warping and deformation can be soft-shaped or demolded and then returned.
Color bar color line color flower analysis
The emergence of these defects is mainly due to the common problems of plastic parts colored with masterbatch. At the same time, the coloring of the color particles is uniform in the aspects of color migration, color particles, and colorability. The particles attract the plastic and the uniformity of mixing is relatively relatively speaking, and the finished products naturally have regional differences. The main solution:
(1) During this period of time, the temperature of the feeding section is specially added to make the temperature close to or reduce the temperature of a small section, promote the rapid acceleration of the stage temperature, mix with Happy Birthday, and increase the time to mix and mix.
(2) Under a certain pressure, increase the pressure to increase the melt temperature and shear force in the material. (3) Modify the mold, especially the pouring system, such as the mouth overflow, when the feed passes, the release effect is poor, the temperature is not high, so it is uniform, and the ribbon mold cavity should be changed. Summarize the cause analysis of the finished product In the process of causing this situation, the summary of works is a very common phenomenon.
1. For the machine:
(1) The nozzle hole draws and causes the melted material to circulate and shrinks, and it shrinks because of too much resistance and large amount of material.
(2) If the clamping force is insufficient, the flash will also shrink. Check whether there is any problem with the clamping system.
(3) The amount of plasticization is insufficient. The machine with a large amount of plasticization should be used to check the growth and whether the barrel can be vigorous.
Post time: Nov-03-2021