1澆口脫料困難在注塑過程中,澆口粘在澆口套內,不易脫出。開模時,制品出現(xiàn)裂紋損傷。此外,操作者必須用銅棒從噴嘴處敲出,使之松動后方可脫模,嚴重影響生產(chǎn)效率。
1. It is difficult to take off the gate. In the process of injection molding, the gate is stuck in the gate sleeve and is not easy to take off. When opening the mold, the product is cracked and damaged. In addition, the operator must knock out the tip of the copper rod from the nozzle to loosen it before demoulding, which seriously affects the production efficiency.
故障主要原因澆口錐孔光潔度差,內孔圓周方向有刀痕。其次是材料太軟,使用一段時間后錐孔小端變形或損傷,以及噴嘴球面弧度太小,致使?jié)部诹显诖颂幃a(chǎn)生鉚頭。澆口套的錐孔較難加工,應盡量采用標準件,如需自行加工,也應自制或購買專用鉸刀。錐孔需經(jīng)過研磨Ra0.4以上。此外,必須設置澆口拉料桿或者澆口頂出。
The main cause of the failure is the poor finish of the gate taper hole and the knife mark in the circumferential direction of the inner hole. Secondly, the material is too soft, the small end of the conical hole is deformed or damaged after use for a period of time, and the spherical radian of the nozzle is too small, resulting in the rivet head of the gate material here. The taper hole of gate sleeve is difficult to process, so standard parts shall be used as far as possible. If it needs to be processed by ourselves, special reamers shall also be made or purchased. The taper hole shall be ground to above Ra0.4. In addition, a gate pull rod or gate ejection must be set.
2大型模具動定模偏移大型模具因各向充料速率不同,以及在裝模時受模具自重的影響產(chǎn)生動、定模偏移。在上述幾種情況下,注射時側向偏移力將加在導柱上,開模時導柱表面拉毛、損傷,嚴重時導柱彎曲或切斷,甚無法開模。
2 large mold dynamic and fixed mold offset large molds have dynamic and fixed mold offset due to different anisotropic filling rates and the influence of mold self weight during mold loading. In the above cases, the lateral offset force will be added to the guide column during injection, and the surface of the guide column will be roughened and damaged during mold opening. In serious cases, the guide column will be bent or cut off, or even unable to open the mold.
方法為了以上問題,在模具分型面上增設高強度的定位鍵四面各一個,簡便有效的是采用圓柱鍵。導柱孔與分模面的垂直度關重要,在加工時是采用動、定模對準 位置夾緊后,在鏜床上一次鏜完,這樣可保證動、定??椎耐亩龋⑹勾怪倍日`差小。此外,導柱及導套的熱處理硬度務必達到設計要求。
Solution in order to solve the above problems, a high-strength positioning key is added on the parting surface of the die, one on each side, and the most simple and effective is to use the cylindrical key. The perpendicularity between the guide pillar hole and the parting surface is very important. During processing, the moving and fixed mold are aligned and clamped, and then boring is completed on the boring machine at one time, so as to ensure the concentricity of the moving and fixed mold holes and minimize the perpendicularity error. In addition, the heat treatment hardness of guide post and guide sleeve must meet the design requirements.
3導柱損傷導柱在模具中主要起導向作用,以保證型芯和型腔的成型面在任何情況下互不相碰,不能以導柱作為受力件或定位件用。
3. The guide post is damaged. The guide post mainly plays a guiding role in the die to ensure that the forming surfaces of the core and cavity do not collide with each other under any circumstances. The guide post cannot be used as a stress part or positioning part.
故障主要原因在幾種情況下,注射時動、定模將產(chǎn)生巨大的側向偏移力。塑件壁厚要求不均勻時,料流通過厚壁處速率大,在此處產(chǎn)生較大的壓力;塑件側面不對稱,如階梯形分型面的模具相對的兩側面所受的反壓力不相等。
The main reason for the failure is that in several cases, the moving and fixed mold will produce huge lateral offset force during injection. When the wall thickness of plastic parts is required to be uneven, the rate of material flow passing through the thick wall is large, resulting in large pressure here; The side of the plastic part is asymmetric, such as the back pressure on the opposite sides of the die of the stepped parting surface is not equal.
4動模板彎曲模具在注射時,模腔內熔融塑料產(chǎn)生巨大的反壓力,一般在600~1000公斤/厘米。模具制造者有時不重視此問題,往往改變原設計尺寸,或者把動模板用低強度鋼板代替,在用頂桿頂料的模具中,由于兩側座跨距大,造成注射時模板下彎。
4. When the movable template bending mold is injected, the molten plastic in the mold cavity produces a huge back pressure, generally 600 ~ 1000 kg / cm. Sometimes mold manufacturers do not pay attention to this problem, often change the original design size, or replace the moving template with low-strength steel plate. In the mold with ejector rod, the template is bent down during injection due to the large span of seats on both sides.
方法故動模板必須選用鋼材,要有足夠厚度,切不可用A3等低強度鋼板,在必要時,應在動模板下方設置支撐柱或支撐塊,以減小模板厚度,提高承載能力。
Solution: therefore, the moving formwork must be made of high-quality steel with sufficient thickness. A3 and other low-strength steel plates shall not be used. If necessary, support columns or blocks shall be set under the moving formwork to reduce the thickness of the formwork and improve the bearing capacity.
5頂桿彎曲,斷裂或者漏料自制的頂桿質量較好,就是加工成本太高,現(xiàn)在一般都用標準件,質量要差一些。頂桿與孔的間隙如果太大,則出現(xiàn)漏料,但如果間隙太小,在注射時由于模溫升高,頂桿膨脹而卡死。
5 the ejector rod is bent, broken or leaked. The self-made ejector rod is of good quality, but the processing cost is too high. Now standard parts are generally used, and the quality is worse. If the gap between the ejector rod and the hole is too large, there will be material leakage, but if the gap is too small, the ejector rod will expand and jam due to the increase of mold temperature during injection.
更危險的是,有時頂桿被頂出一般距離就頂不動而折斷,結果在下一次合模時這段露出的頂桿不能復位而撞壞凹模。
What's more dangerous is that sometimes the ejector rod can't move and break when it is pushed out for a general distance. As a result, the exposed ejector rod can't be reset at the next mold closing, and the die is damaged.
方法為了這個問題,頂桿重新修磨,在頂桿前端保留10~15毫米的配合段,中間部分磨小0.2毫米。所有頂桿在裝配后,都必須嚴格檢查配合間隙,一般在0.05~0.08毫米內,要保證整個頂出機構能進退自如。
Solution: in order to solve this problem, the ejector rod shall be reground, the matching section of 10 ~ 15mm shall be reserved at the front end of the ejector rod, and the middle part shall be ground smaller by 0.2mm. After all ejector rods are assembled, the fit clearance must be strictly checked, generally within 0.05 ~ 0.08mm, to ensure that the whole ejector mechanism can move forward and backward freely.
6冷卻不良或水道漏水模具的冷卻效果直接影響制品的質量和生產(chǎn)效率,如冷卻不良,制品收縮大,或收縮不均勻而出現(xiàn)翹面變形等缺陷。另一方面模整體或局部過熱,使模具不能正常成型而停產(chǎn),嚴重者使頂桿等活動件熱脹卡死而損壞。
6 poor cooling or water leakage, the cooling effect of the mold directly affects the quality and production efficiency of the product, such as poor cooling, large shrinkage of the product, or uneven shrinkage and warping deformation. On the other hand, the overall or local overheating of the die makes the die unable to form normally and stop production. In serious cases, the movable parts such as the ejector rod are blocked by thermal expansion and damaged.
故障主要原因冷卻系統(tǒng)的設計,加工以產(chǎn)品形狀而定,不要因為模具結構復雜或加工困難而省去這個系統(tǒng),特別是大中型模具一定要充分考慮冷卻問題。
The main reason for the failure is that the design and processing of the cooling system depend on the product shape. Do not omit this system because of the complex die structure or difficult processing. In particular, the cooling problem must be fully considered for large and medium-sized dies.
7滑塊傾斜,復位不順有些模具因受模板面積限制,導槽長度太小,滑塊在抽芯動作完畢后露出導槽外面,這樣在抽芯后階段和合模復位初階段都容易造成滑塊傾斜,特別是在合模時,滑塊復位不順,使滑塊損傷,甚壓彎破壞。
7. The slide block is inclined and the reset is not smooth. Due to the limitation of the template area, the length of the guide groove is too small, and the slide block is exposed outside the guide groove after the core pulling action is completed. In this way, the slide block is easy to be inclined in the post core pulling stage and the initial stage of mold closing reset, especially in the mold closing, the slide block is not reset smoothly, resulting in damage to the slide block or even bending damage.
方法根據(jù)經(jīng)驗,滑塊完成抽芯動作后,留在滑槽內的長度不應小于導槽全長的2/3。
Solution according to experience, after the slider completes the core pulling action, the length left in the chute shall not be less than 2 / 3 of the total length of the guide groove.
8定距拉緊機構失靈擺鉤、搭扣之類的定距拉緊機構一般用于定模抽芯或一些二次脫模的模具中,因這類機構在模具的兩側面成對設置,其動作要求必須同步,即合模同時搭扣,開模到一 定位置同時脫鉤。一旦失去同步,勢必造成被拉模具的模板歪斜而損壞,這些機構的零件要有較高的剛度和耐磨性,調整也很困難,機構壽命較短,盡量避免使用, 可以改用其他機構。
8. Fixed distance tensioning mechanism fails. Fixed distance tensioning mechanisms such as swing hook and buckle are generally used in fixed mold core pulling or some secondary demoulding molds. Because these mechanisms are set in pairs on both sides of the mold, their actions must be synchronized, that is, the mold is buckled at the same time, and the mold is decoupled at the same time when it is opened to a certain position. Once the synchronization is lost, it is bound to cause the formwork of the drawn die to be skewed and damaged. The parts of these mechanisms should have high stiffness and wear resistance. It is also difficult to adjust. The service life of the mechanism is short. Try to avoid using it and use other mechanisms instead.
故障主要原因斜銷滑塊式抽芯機構損壞這種較常出現(xiàn)的毛病大多是加工上不到位以及用料太小,主要有以下問題:
The main cause of the failure is the damage of the inclined pin sliding block core pulling mechanism. Most of the common problems are that the processing is not in place and the material is too small. The main problems are as follows:
斜銷傾角A大,優(yōu)點是可以在較短的開模行程內產(chǎn)生較大抽芯距。但是采取過大的傾角A,當抽拔力F為一定值時,在抽芯過程中斜銷受到的彎曲力 P=F/COSA,也越大,易出現(xiàn)斜銷變形和斜孔磨損。同時,斜銷對滑塊產(chǎn)生向上的推力N=FTGA也越大,此力使滑塊對導槽內導向面的正壓力增大,從而 增加了滑塊滑動時的摩擦阻力。易造成滑動不順,導槽磨損。根據(jù)經(jīng)驗,傾角A不應大于25。
The inclination angle a of the inclined pin is large, which has the advantage that it can produce a large core pulling distance in a short mold opening stroke. However, if the inclination angle a is too large, when the pulling force F is a certain value, the bending force P = f / cosa of the inclined pin in the core pulling process is also larger, which is prone to deformation of the inclined pin and wear of the inclined hole. At the same time, the upward thrust n = ftga generated by the inclined pin on the slider is also greater, which increases the positive pressure of the slider on the guide surface in the guide groove, thus increasing the friction resistance when the slider slides. It is easy to cause unsmooth sliding and wear of guide groove. According to experience, the inclination A shall not be greater than 25.
方法在抽心力比較小的情況下可采用彈簧推出定模的方法,在抽芯力比較大的情況下可采用動模后退時型芯滑動,先完成抽芯動作后再分模的結構,在大型模具上可采用液壓油缸抽芯。
Solution: when the core pulling force is relatively small, the method of spring pushing out the fixed mold can be adopted. When the core pulling force is relatively large, the structure of core sliding when the moving mold retreats, first completing the core pulling action and then dividing the mold can be adopted. The core pulling of hydraulic cylinder can be adopted on large molds.
9注塑模具中排氣不暢注塑模具中常常有氣體產(chǎn)生,這是由什么產(chǎn)生的?
9. The exhaust in the injection mold is not smooth, and there is often gas in the injection mold. What is the reason for this?
故障主要原因澆注系統(tǒng)與模具型腔中存有的空氣,有些原料含有沒有被干燥排除的水分,它們在高溫下會氣化成水蒸氣,由于在注塑時溫度太高,某些性質不穩(wěn)定的塑料會發(fā)生分解而產(chǎn)生氣體;塑料原料中的某些添加劑揮發(fā)或者相互化學反應生成的氣體。
The main reason for the failure is the air in the gating system and mold cavity. Some raw materials contain moisture that has not been dried out. They will be gasified into steam at high temperature. Due to the high temperature during injection molding, some unstable plastics will decompose and produce gas; Gases generated by volatilization or mutual chemical reaction of some additives in plastic raw materials.
同時排氣不良不暢的緣由,也需要盡快找出來。注塑模的排氣不良將會給塑件的質量等諸多方面帶來一系列的危害,主要表現(xiàn):在注塑過程中熔體將取代型腔中的氣體,如果氣體排出不及時將會造成熔體充填困難,導致注射量不足而不能充滿型腔;排除不暢的氣體會在型腔中形成高壓,并且在一定的壓縮程度下滲入塑料的內部,造成空洞、氣孔、組織疏和銀紋等質量缺陷。
At the same time, the cause of poor exhaust also needs to be found out as soon as possible. Poor exhaust of injection mold will bring a series of hazards to the quality of plastic parts and many other aspects, mainly as follows: in the injection process, the melt will replace the gas in the mold cavity. If the gas is not discharged in time, it will make it difficult to fill the melt, resulting in insufficient injection volume and unable to fill the mold cavity; Poor gas removal will form high pressure in the mold cavity and penetrate into the interior of the plastic under a certain degree of compression, resulting in quality defects such as cavities, pores, sparse tissue and crazing.
由于氣體被高度壓縮,使得型腔內溫度急劇上升,進而引起周圍熔體分解、燒灼,使塑件出現(xiàn)局部碳化和燒焦現(xiàn)象。它主要出現(xiàn)在兩股熔體的合流處,澆口凸緣處;氣體的排除不暢,使得進入各型腔的熔體速度不同,因此易形成流動痕和熔合痕,并使塑件的力學性能降低。由于型腔中氣體的阻礙,會降低充模速度,影響成型周期,降低征稅效率。
Because the gas is highly compressed, the temperature in the mold cavity rises sharply, which leads to the decomposition and burning of the surrounding melt, resulting in local carbonization and charring of the plastic parts. It mainly appears at the confluence of two melts, at the gate flange; The poor removal of gas makes the melt velocity entering each cavity different, so it is easy to form flow marks and fusion marks, and reduce the mechanical properties of plastic parts. Due to the obstruction of gas in the cavity, it will reduce the mold filling speed, affect the molding cycle and reduce the molding efficiency.
塑件中氣泡的分布,模腔中積存空氣所產(chǎn)生的氣泡,常分布在與澆口相對的部位上;塑料原料中分解或化學反應產(chǎn)生的氣泡則沿塑件的厚度分布;塑料原料中殘存水氣化產(chǎn)生的氣泡,則不規(guī)則地分布在整個塑件上。
The distribution of bubbles in plastic parts. The bubbles generated by the accumulation of air in the mold cavity are often distributed on the part opposite to the gate; Bubbles produced by decomposition or chemical reaction in plastic raw materials are distributed along the thickness of plastic parts; The bubbles generated by residual water gasification in plastic raw materials are irregularly distributed on the whole plastic part.
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