澆口剝離困難
Difficult gate stripping
注塑過程中,澆口粘在澆口套內,不易脫出。開模時,產品有裂紋損壞。此外,操作人員在脫模前必須將銅棒的從噴嘴中敲出以使其松動,這嚴重影響了生產效率。
During injection molding, the gate is stuck in the gate sleeve and is not easy to come out. During mold opening, the product is cracked and damaged. In addition, the operator must knock the tip of the copper bar out of the nozzle to loosen it before demoulding, which seriously affects the production efficiency.
造成這種故障的主要原因是澆口錐孔光潔度差,內孔圓周方向有刀痕。二是材料太軟,使用一段時間后錐孔小端變形或損壞,水口球面弧度太小,導致澆口材料在這里產生鉚頭。澆口套錐孔加工難度大,應盡量采用標準件。如果需要自己加工,還應制作或購買專用鉸刀。錐孔需要磨削到Ra0.4以下。此外,還必須提供澆口拉桿或澆口彈出機構。
The main reason for this failure is the poor finish of the gate taper hole and the knife marks on the circumference of the inner hole. Second, the material is too soft, the small end of the taper hole is deformed or damaged after a period of use, and the spherical radian of the nozzle is too small, resulting in the rivet head of the gate material here. It is difficult to process the taper hole of sprue sleeve, so standard parts should be used as much as possible. If you need to process by yourself, you should also make or purchase a special reamer. The taper hole needs to be ground below Ra0.4. In addition, a gate pull rod or gate ejection mechanism must be provided.
動、定模偏移
Dynamic and fixed mode offset
對于大型模具,由于各個方向的填充率不同,以及安裝模具時模具自身重量的影響,會出現動模和定模偏移。
For large molds, due to the different filling rates in all directions and the influence of the weight of the mold itself when installing the mold, the moving mold and the fixed mold will shift.
在這些情況下,注射時導柱會受到橫向偏移力,開模時導柱表面會粗糙和損壞。
In these cases, the guide post will be subjected to lateral offset force during injection, and the surface of the guide post will be rough and damaged during mold opening.
為了上述問題,在模具分型面的四個側面各增加一個高強度定位鍵。使用圓柱鍵既簡單又有效。導孔與分型面的垂直度非常重要。
In order to solve the above problems, a high-strength positioning key is added to each of the four sides of the parting surface of the die. Using cylindrical keys is simple and effective. The perpendicularity between the guide hole and the parting surface is very important.
在處理中,使用了移動。定模對位并裝夾后,鏜床一次完成,可保證動、定模孔的同心度,垂直度誤差小。此外,導柱和導套的熱處理硬度必須符合設計要求。
In processing, movement is used. After the fixed mold is aligned and clamped, the boring machine is completed at one time, which can ensure the concentricity of the moving and fixed mold holes and small Perpendicularity Error. In addition, the heat treatment hardness of guide post and guide sleeve must meet the design requirements.
移動模板彎曲
Moving formwork bending
模具注射時,模腔內的熔融塑料產生巨大的背壓,一般為600~1000kg/cm2。模具制造商有時不注意這個問題,經常改變原來的設計尺寸,或者用低強度的鋼板代替動模板。在帶頂桿頂桿的模具中,由于兩側座之間的跨度大,注射時模板向下彎曲。
During mold injection, the molten plastic in the mold cavity produces a huge back pressure, which is generally 600~1000kg/cm2. Mold manufacturers sometimes do not pay attention to this problem, often change the original design size, or use low-strength steel plate to replace the movable formwork. In the mold with ejector pin ejector pin, due to the large span between the seats on both sides, the template is bent downward during injection.
因此,
山東模具制造廠家認為動模板必須采用鋼材,并有足夠的厚度。不得使用A3等低強度鋼板。必要時可在動模板下設置支撐柱或支撐塊,以減少模板厚度,提高承載能力。
Therefore, Shandong mold manufacturers believe that the movable formwork must be made of high-quality steel with sufficient thickness. Low strength steel plates such as A3 shall not be used. If necessary, support columns or blocks can be set under the movable formwork to reduce the thickness of the formwork and improve the bearing capacity.
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