InjectionMoldingDesignGuidelines.doc

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1、Injection Molding Design GuidelinesMuch has been written regarding design guidelines for injection molding. Yet, the design guidelines can be summed up in just a few design rules.1Use uniform wall thicknesses throughout the part. This will minimize sinking, warping, residual stresses, and improve mo

2、ld fill and cycle times. Wall Section Considerations Voids and Shrinkage Warpage2Use generous radius at all corners. The inside corner radius should be a minimum of one material thickness. Radius Limitations3Use the least thickness compliant with the process, material, or product design requirements

3、. Using the least wall thickness for the process ensures rapid cooling, short cycle times, and minimum shot weight. All these result in the least possible part cost.4Design parts to facilitate easy withdrawal from the mold by providing draft (taper) in the direction of mold opening or closing. Draft

4、 and Texture5Use ribs or gussets to improve part stiffness in bending. This avoids the use of thick section to achieve the same, thereby saving on part weight, material costs, and cycle time costs. Rib DesignUniform Walls Parts should be designed with a minimum wall thickness consistent with part fu

5、nction and mold filling considerations. The thinner the wall the faster the part cools, and the cycle times are short, resulting in the lowest possible part costs. Also, thinner parts weight less, which results in smaller amounts of the plastic used per part which also results in lower part costs.零件

6、的设计应以最小壁厚符合部分功能和充填型腔的考虑。越快越细越墙的部分,于是循环冷却的时间很短,导致零件成本最低。同时,较薄的部分,它的结果必然是重量更少的塑料使用少量的每部分也导致了较低的部份成本。The wall thicknesses of an injection-molded part generally range from 2 mm to 4 mm (0.080 inch to 0.160 inch). Thin wall injection molding can produce walls as thin as 0.5 mm (0.020 inch).墙的厚度一般范围从2”塑料部

7、分毫米(0.080英寸到0.160英寸)。薄壁注塑模具可以生产墙壁薄如0.5毫米(0.020英寸)。The need for uniform walls需要统一的壁厚 Thick sections cool slower than thin sections. The thin section first solidifies, and the thick section is still not fully solidified. As the thick section cools, it shrinks and the material for the shrinkage comes o

8、nly from the unsolidified areas, which are connected, to the already solidified thin section. 酷慢于厚壁处薄片。第一次的凝固薄片,浓烈的部分还没有完全凝固。为厚段冷却后,它收缩和材料的收缩是只能从unsolidified区域是相连的,已经凝固薄片。 This builds stresses near the boundary of the thin section to thick section. Since the thin section does not yield because it is

9、 solid, the thick section (which is still liquid) must yield. Often this leads to warping or twisting. If this is severe enough, the part could even crack. 这个建立在边境附近应力的薄壁厚的部分。由于薄壁不屈服,因为它是固体,厚的部分(这仍然是流动的)必须屈服。这常常会导致扭曲或扭曲。如果这是严重的足够的,部分甚至开裂。Uniform wall thicknesses reduce/eliminate this problem. 均匀的壁厚度

10、的减少或消除这一问题。 Uniform walled parts are easier to fill in the mold cavity, since the molten plastic does not face varying restrictions as it fills.坚固的部分是容易制服填写模具型腔,因为熔化塑胶没有面临不同的限制其填充。What if you cannot have uniform walls, (due to design limitations) ?如果你不能拥有统一的墙壁,(由于设计的局限性)? When uniform walls are not

11、possible, then the change in section should be as gradual as possible. 当统一的墙壁是不可能的,那么改变部分应该是作为逐渐越好。 Coring can help in making the wall sections uniform, and eliminate the problems associated with non-uniform walls. 取心能帮助使墙面部分统一和消除非均匀壁相关的问题。 Warping problems can be reduced by building supporting feat

12、ures such as gussets.翘曲的问题可以减少建筑配套功能,如gussets。Voids and Shrinkage孔洞及收缩Shrinkage is caused by intersecting walls of non-uniform wall thickness. Examples of these are ribs, bosses, and other projections of the nominal wall. If these projections have greater wall thicknesses, they will solidify slower.

13、 The region where they are attached to the nominal wall will shrink along with the projection, resulting in a sink in the nominal wall. 摘要缩松缺陷是引起非均匀壁厚壁的相交。其中一个例子是肋骨,老板,和其他预测的命名的墙。如果这些预测有更大的墙厚度不同,他们就会凝固速度较慢。他们的地方被纳入名义墙会收缩随着投影,导致在一个沉名义墙。 Shrink can be minimized by maintaining rib thicknesses to 50 to

14、60% of the walls they are attached to. 收缩可以最小化维持肋厚度的60%至,在墙上。 Bosses located at corners can result in very thick walls causing sinks. Bosses can be isolated using the techniques illustrated. 位于角落老板会导致很厚壁造成下沉。老板会被孤立使用技术做了说明。Warpage翘曲Thick sections cool slower than thin sections. The thin section firs

15、t solidifies, and the thick section is still not fully solidified. As the thick section cools, it shrinks and the material for the shrinkage comes only from the unsolidified areas, which are connected, to the already solidified thin section. 酷慢于厚壁处薄片。第一次的凝固薄片,浓烈的部分还没有完全凝固。为厚段冷却后,它收缩和材料的收缩是只能从unsolid

16、ified区域是相连的,已经凝固薄片。This builds stresses near the boundary of the thin section to thick section. Since the thin section does not yield because it is solid, the thick section (which is still liquid) must yield. Often this leads to warping or twisting. If this is severe enough, the part could even crac

17、k.这个建立在边境附近应力的薄壁厚的部分。由于薄壁不屈服,因为它是固体,厚的部分(这仍然是流动的)必须屈服。这常常会导致扭曲或扭曲。如果这是严重的足够的,部分甚至开裂。Other causes:其他原因: Warping can also be caused due to non-uniform mold temperatures or cooling rates. 翘曲也可以引起模具温度不均匀或冷却率。 Non-uniform packing or pressure in the mold. 包装或非压力模具。 Alignment of polymer molecules and fiber

18、 reinforcing strands during the mold fill results in preferential properties in the part. 校准及纤维增强聚合物分子在模具填充股优惠的性能结果的部分。 Molding process conditions-too high a injection pressure or temperature or improper temperature and cooling of the mold cavity. Generally, it is best to follow the resin manufactur

19、ers guidelines on process conditions and only vary conditions within the limits of the guidelines. 成型工艺条件太高的注射压力或温度或不当的模具温度和冷却腔。通常,最好遵循树脂生产厂家的指南只不同工艺条件和条件的范围内的指导方针。It is not good practice to go beyond the pressure and temperature recommendations to compensate for other defects in the mold. If runner

20、s need to be sized differently to allow for a proper fill, or gate sizes that need to be changed, then those changes need to happen.这并不是一个好实践,超越了压力和温度补偿其他缺陷,建议在模具。如果选手需要大小不同的允许一个恰到好处的填补,或门大小需要改变以后,这些变化一定会发生。Otherwise the finished parts will have too much built in stresses, could crack in service or

21、warp-leading to more severe problems such as customer returns or field service issues.否则制件将有太多可以建在应力、裂缝或warp-leading服务更多的严重问题,例如客户回报或现场服务的问题。Radius半径 Sharp corners greatly increase the stress concentration. This high amount of stress concentration can often lead to failure of plastic parts. 急转弯大大增加的

22、应力集中。这种高数量的应力集中会导致失败的塑料部件。Sharp corners can come about in non-obvious places. Examples of this are a boss attached to a surface, or a strengthening rib. These corners need to be radiused just like all other corners. The stress concentration factor varies with radius, for a given thickness.在棱角能来non-o

23、bvious的地方。 这样的例子是一个老板在一个表面上,或加强肋。这些角落需要就像所有其他各类的角落。应力集中系数随半径,对于一个给定的厚度。As can be seen from the above chart, the stress concentration factor is quite high for R/T values lesss than 0.5. For values of R/T over 0.5 the stress concentration factor gets lower. 可以看出,从上面的图表的应力集中系数比较高,lesss和R / T值达0.5以上。和R

24、/ T为价值超过0.5的应力集中系数得低。The stress concentration factor is a multiplier factor, it increases the stress.Actual Stress = Stress Concentration Factor K x Stress CalculatedThis is why it is recommended that inside radiuses be a minimum of 1 x thickness.应力集中系数是一个乘数因素,它增加了压力。实际应力=应力集中系数K应力计算这就是为什么在各类建议至少1厚度

25、。 In addition to reducing stresses, fillet radiuses provide streamlined flow paths for the molten plastic resulting in easier fills. 除了能减少应力、鱼片各类流线形途径提供容易熔化塑胶导致填充。Typically, at corners, the inside radius is 0.5 x material thickness and the outside radius is 1.5 x material thickness. A bigger radius

26、should be used if part design will allow it. 通常,在街角,里面半径0.5倍的材料厚度和外半径的材料厚度为1.5倍。一个更大的半径应使用部分设计将允许它。The reason for draft草案的原因 Drafts (or taper) in a mold, facilitates part removal from the mold. The amount of draft angle depends on the depth of the part in the mold, and its required end use function.

27、 Drafts (or taper) in a mold, facilitates part removal from the mold. The amount of draft angle depends on the depth of the part in the mold, and its required end use function. The draft is in the offset angle in a direction parallel to the mold opening and closing. 草案在偏置角与边线平行的方向模具开启和关闭。 It is best

28、 to allow for as much draft as possible for easy release from the mold. As a nominal recommendation, it is best to allow 1 to 2 degrees of draft, with an additional 1.5 min. per 0.025 mm (0.001 inch) depth of texture. See below. 最好是让尽可能多的草案易释放从模具。作为一个命名建议,最好是让1至2度的草案,另外有1.5min.每0.025毫米(0.001英寸)的深度的纹

29、理。见下文。 The mold parting line can be relocated to split the draft in order to minimize it. If no draft is acceptable due to design considerations, then a side-action mold (cam-actuated) may be required at a greater expense in tooling.模具分型线可以分裂的草案被安置在为了避免它。如果没有草案由于设计上考虑是可以接受的,那么side-action模具(cam-actua

30、ted)都需要在一个更大的消费在工具。The reason for texture纹理的原因Textures and Letteringcan be molded on the surfaces, as an aesthetic aid or for incorporating identifying information, either for end users or factory. Texturing also helps hide surface defects such as knit lines, and other surface imperfections. The dep

31、th of texture or letters is somewhat limited, and extra draft needs to be provided to allow for mold withdrawal without marring the surface. 纹理和Letteringcan被塑造的表面,作为审美援助或合并身份识别信息,无论是为最终用户或工厂。材质也有助于隐藏表面缺陷如接合线,和其他表面缺陷。深度的纹理或字母是有点有限,需要提供额外的草案,以便模具表面没有嫁给撤军。 Draft for texturing is somewhat dependant on t

32、he mold design and the specific mold texture. Guidelines are readily available from the mold texture suppliers or mold builders. 汇票要贴图是有点依赖于模具设计和具体的模具结构。方针是现成的从模具结构供应商或模具建设者。 As a general guideline, 1.5 min. per 0.025mm (0.001 inch) depth of texture needs to be allowed for in addition to the normal

33、draft. Usually for general office equipment such as lap-top computers a texture depth of 0.025 mm (0.001 inch) is used and the min. draft recommended is 1.5 . More may be needed for heavier textures surfaces such as leather texture (with a depth of 0.125 mm/0.005 inch) that requires a min. draft of

34、7.5.作为一个通用的方法,min. 1.5每0.025毫米(0.001英寸)的深度的纹理需要允许除了正常的汇票。通常一般办公设备如手提电脑一个纹理深度0.025毫米(0.001英寸),是用来和min. 1.5推荐草案。更可能需要重表面如皮革纹理贴图(深度0.125毫米(0.005英寸),要求min. 7.5草案。The use of ribs使用肋骨 Ribs increase the bending stiffness of a part. Without ribs, the thickness has to be increased to increase the bending sti

35、ffness. Adding ribs increases the moment of inertia, which increases the bending stiffness. Bending stiffness = E (Youngs Modulus) x I (Moment of Inertia) 肋骨提高梁的抗弯刚度的一员。无肋,厚度增加而增加抗弯刚度。加肋增加惯性矩的抗弯刚度,增加了。弯曲刚度= E(杨氏模数)I(惯性矩的)The rib thickness should be less than the wall thickness-to keep sinking to a m

36、inimum. The thickness ranges from 40 to 60 % of the material thickness. In addition, the rib should be attached to the base with generous radiusing at the corners. 肋厚度应小于墙thickness-to保持下沉降到最低。厚度范围从60%到的材料厚度。此外,应重视肋慷慨的radiusing底座的四角。 At rib intersections, the resulting thickness will be more than the

37、 thickness of each individual rib. Coring or some other means of removing material should be used to thin down the walls to avoid excessive sinking on the opposite side. 在十字路口,产生肋厚度会超过每一个个体的厚度骨刺。取心或其他方式去除材料应沿着墙壁用来稀释来避免过多的下沉的一侧。The height of the rib should be limited to less than 3 x thickness. It is

38、 better to have multiple ribs to increase the bending stiffness than one high rib. 肋骨的高度应限于厚度小于3倍。最好是有多个肋骨增加抗弯刚度比一个高肋骨。 The rib orientation is based on providing maximum bending stiffness. Depending on orientation of the bending load, with respect to the part geometry, ribs oriented one way increase

39、 stiffness. If oriented the wrong way there is no increase in stiffness. 肋定位是基于最大弯曲刚度提供。根据弯曲载荷的定位,就部分几何方法之一,肋骨导向增加刚性。如果导向错误的方式有不增加结构刚度。 Draft angles for ribs should be minimum of 0.25 to 0.5 degree of draft per side. If the surface is textured, additional 1.0 degree draft per 0.025 mm (0.001 inch) d

40、epth of texture should be provided.草案肋骨应该最小角度0.25至0.5度的每边草案。如果表面是粗糙的,另外1.0度每0.025毫米(草案)深度0.001英寸的质地应提供。Plastic Part DesignTo insure a quality final product, it is necessary to start out with quality components. Injection molded parts can be molded to a high quality standard by focusing on these area

41、s of plastic technology:以确保最终产品质量,有必要对质量与部件出发。注塑件可以被塑造到高质量的标准,将研究集中在这些领域的塑料技术:1) Correct Part Design1)正确的零件设计2) Accurate Selection of Material2)准确选择材料3) Processing Plastic Processing3)加工塑料加工Only by drawing on expertise from these three areas of plastic technology can a product designer create qualit

42、y molded parts that maximize performance and are cost effective. The purpose of this design guide deals with the first of these three issues - part design.只有借鉴从这三个领域的专业塑料技术的产品设计师能制造出质量塑件的性能和成本,最大限度地有效。的目的,这城市设计导则的第一处理这三个问题部分的设计。Correct Part Design Guidelines正确的部分设计准则If there was only one rule for th

43、e injection molding process it would have to beto maintain uniform wall thickness. Here are some examples of problems associatedwith part designs that feature non-uniform wall thicknesses.如果只有一个规律,它将注塑工艺保持均匀的壁厚。以下是一些例子有关的问题这些特点的原料,当与零部件设计非均匀壁厚度。Sink marks due touneven shrinkage凹痕由于不均匀收缩Sink marks re

44、sult from a wall yielding to the still shrinking interior mass.凹痕造成一个墙还是屈服于室内肿块。收缩Stress due touneven shrinkage导致心理压力不均匀收缩A part with non-uniform wall thickness will cool unevenly, resulting in high molded-in stress.与非均匀壁厚部分就会使不均,导致高注入压力。Voids due to unevenshrinkage由于空隙的不均匀收缩The already cooled secti

45、on will not yield to the shrinking action of the cooling interior mass causing voids in the thick portion of the part.已经冷却部分将不能屈服于收缩引起的内部质量的作用导致冷却在茂密的空隙部分的部分。Warpage due touneven shrinkage里面由于不均匀收缩Concentrated stress at the junction of high & low shrinkage area may cause a part to warp.在应力集中交界的高、低收缩

46、可能会导致部分区域移动。Draft 拔模锥度Plastic parts are always designed with a taper or draft in the direction of mold movement to allow part ejection or removal from the mold. Since plastics shrink when cooled, it is common for parts to shrink (or grip tightly) to cores. A good definition for draft would be: the d

47、egree of taper of a side wall or rib needed to allow the molded plastic part to be removed from the metal mold. Without proper draft, plastic parts may be difficult to remove from the mold. A draft angle of 1/2 degrees is regarded as minimum for most applications. Draft angles of 1 1/2 to 2 degrees

48、per side are considered normal for plastic injection molding.塑料件总是圆锥或草案设计模具运动的方向,让产品顶出或脱除模具。当冷却,自塑料收缩是常见的收缩(或控制部分紧)核心。一个好的的定义是:草案的锥度的程度一侧墙或肋骨需要允许注塑塑料零件,除去金属模具。没有适当的草案,塑料部件可能很难被除掉了模具。汇票的1/2度角度被视为最低为大多数应用程序。汇票的角度1又1/2至2度被认为是正常的每边塑料注射成型工艺。Top of pageRibs肋骨Many times the stiffness of a part must increase because of the load applied to the part design. One of the easiest ways to cure this problem is change the part geometry by adding ribs. The use of ribs is a practical way and economical means of increasing the st