注塑工艺培训资料
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注塑工艺培训资料
注塑工艺培训教程
成型参数设定要领与优化
注塑成型四大要素
1)塑胶原料
2)注塑模具
3)注塑机
4)成型工艺技术
成型工艺的五种参数:
温度
时间
压力
速度
位置切换
注射工艺参数
, 储料参数;加料量(注射量)、余料量(缓冲垫)、螺杆转速、背压(塑化压力)、倒塑
(松退)。
, 注射参数:注射压力、注射速度(保压压力和时间、分段注射与位置 , 温度
参数:料筒温度、喷嘴温度、模具温度、油液温度。 , 时间参数:注射时间、保压
时间、中间停留时间、储料时间、冷却时间。
level of security personnel on duty, fire security measures taken. 9, post signs----construction site management and workers should wear distinctive markings. 10, security----focus on "safety of Sambo", parts of the construction, road surface protection facilities; implementation of Ministry of construction, "score", regular or not regular inspection, timely scoring, reward. ----11, with coordination between the construction and the total package units, collaboration among the type
of work, comprehensive progress in contradiction to consult each other when dealt with properly. ----12, public relations personnel to abide by social morality, professional ethics, business discipline, properly handle PR around the construction site. Three, civilized construction appraisal, management (a) the construction site "five": lighting, hardening, greening, landscaping and purification. (B) noise emission standards: the day <65dB night <55dB (c) ... Protections: 1 enhancing
the protection of all the construction finished and semi-finished products for education. Often quality education for workers, for moral education of the civilization production and the protection of the finished and semi-finished products. Education staff at the time of construction to respect other people and their work, cherish the completed and partially completed finished or semi-finished products. In front of the project for the corresponding rules
一、储料工艺参数
1)加料量(注射量)
2)余料量(缓冲垫)
3)螺杆转速
4)背压(塑化压力)
5)倒塑(松退)
1.1加料量的设定
螺杆从注射终止位置后退到加料终止位置的距离称为计量行程或储料行程。因此,螺杆端前面部分的塑料容积就是螺杆后退行程的计量容积(即注射量),所以计量行程办是注射行程。
1.2余料量(缓冲垫)
在料量设定时,料筒前端熔料被注射的分量在零位前要预留一段位置作缓冲用,称为“缓冲垫”。此段位置不少于3mm,通常设定10mm。
1.3余料量的调整作用
1)设定缓冲垫可提高注射量的重复精度和稳定塑件成型质量。
2)在保压阶段有一个缓慢推进过程,将剩余的高积存压力继续向模腔及流道传送,使塑件冷却收缩时不断有料补充。
3)可改善塑件密度,使塑件表面光泽度好、颜色均匀、尺寸稳定、内应力小,从而提高塑件的质量。
4)对缓冲垫位置大小的调节(可改普某些工艺上的不足。
5)保护螺杆头如射胶射尽到零位置或预留射终位置过小,在注射惯性或机器控制失准的情况下(容易出现螺杆头卡住料筒头,在预料动作时甚至会拧断螺杆头。 1.4螺杆转速的作用
螺杆转速越高(熔料在螺杆中输出能力和剪切效应越好。调整螺杆转速(n,min)
即是调整塑化效果及加料进行时间。
level of security personnel on duty, fire security measures taken. 9, post signs----construction site management and workers should wear distinctive markings. 10, security----focus on "safety of Sambo", parts of the construction, road surface protection facilities; implementation of Ministry of construction, "score", regular or not regular inspection, timely scoring, reward. ----11, with coordination between the construction and the total package units, collaboration among the type
of work, comprehensive progress in contradiction to consult each other when dealt with properly. ----12, public relations personnel to abide by social morality, professional ethics, business discipline, properly handle PR around the construction site. Three, civilized construction appraisal, management (a) the construction site "five": lighting, hardening, greening, landscaping and purification. (B) noise emission standards: the day <65dB night <55dB (c) ... Protections: 1 enhancing
the protection of all the construction finished and semi-finished products for education. Often quality education for workers, for moral education of the civilization production and the protection of the finished and semi-finished products. Education staff at the time of construction to respect other people and their work, cherish the completed and partially completed finished or semi-finished products. In front of the project for the corresponding rules
一般情况下加料时间的长短是由螺杆转速与背压所决定:螺杆转速越高,背压压力越小,加料时间越短,反之加料时间越长。因此螺杆转速是影响塑化能力、塑化质量和储料时间的主要参数。
1. 1.5螺杆转速的控制要领
调整螺杆转速和背压的参数时,要控制加料时间短于冷却时问。
为了达到料筒温度的准确控制,通常最佳的做法是调整螺杆的旋转速度使加料时间在许可范围内尽量长(相比冷却时间略短1,2s),这样可减少因螺杆旋转磨擦而产生的热量,避免了熔料温度过高。
2. 多段储料的作用
由于螺杆在储料阶段会向后退,即表示塑料从料口处输送到螺杆端部的有效长度并不样,螺杆作用在塑料上剪切力能量也不一样。储料行程越长(塑化作用的有效长度变化越长(产生的不稳定作用亦越大。
为了抵消螺杆塑化有效长度的变化和螺杆越位现象,在不同的螺杆后退位置使用逐渐递增背压和逐渐递减螺杆转速,可达到塑化质量稳定和均一的作用。 3. 多段储料的设定准则
储料开始阶段以合适的背压和螺杆转速完成行程的60,,80,,其后将背后提高和速度减半到储料完成,最后将螺杆后退4~5mm后卸压。
4. 背压的作用
背压对熔体温度的影响是非常明显的,因为背压增加了熔体的内压力,加强了剪切效果,形成剪切热(使大分子热能增加(物料的受热时间增加,从而提高了熔体的温度,塑化质量也得到改善。
5. 背压的产生
在熔料过程中,因螺杆的后退,射胶液压缸内的压力油要排回油箱。若利用液压阀调节液压油的排放量时,射胶液压缸内的压力便会因螺杆后退而上升,背压便
是指这时射胶液压缸内的压力(即背压是用来限制螺杆后退速度而增加塑料在熔胶
过程中所受的压力,又称为塑化压力。
6. 背压的用途
1)可解决塑件混色不良。增加背压后塑料要经过较多次的搅拌才会被推送到螺
杆前端,因此颜色的混和会比没有加背压时更好。
level of security personnel on duty, fire security measures taken. 9, post signs----construction site management and workers should wear distinctive markings. 10, security----focus on "safety of Sambo", parts of the construction, road surface protection facilities; implementation of Ministry of construction, "score", regular or not regular inspection, timely scoring, reward. ----11, with coordination between the construction and the total package units, collaboration among the type
of work, comprehensive progress in contradiction to consult each other when dealt with properly. ----12, public relations personnel to abide by social morality, professional ethics, business discipline, properly handle PR around the construction site. Three, civilized construction appraisal, management (a) the construction site "five": lighting, hardening, greening, landscaping and purification. (B) noise emission standards: the day <65dB night <55dB (c) ... Protections: 1 enhancing
the protection of all the construction finished and semi-finished products for education. Often quality education for workers, for moral education of the civilization production and the protection of the finished and semi-finished products. Education staff at the time of construction to respect other people and their work, cherish the
completed and partially completed finished or semi-finished products. In front of the project for the corresponding rules
2)可解决塑件气纹及气泡。增加背压后,熔化的塑料因压力的上升令密度增加(使塑料含有空气的机会降低,避免了气纹及气泡的产生。
3)可稳定塑件成型质量。增加背压能改善塑化效果(增加熔料的单位密度,避
免了因塑料塑化不良而导致塑件在重量及尺寸上的不稳定。
4)可助快速转换塑料或颜色。增加背压令附于螺杆上的塑料所受压力上升,塑料在承受一定压力搅拌时(附于螺杆表面上的旧料或颜色比较容易地被带走及射出,达到快速转换塑料的目的。
倒塑(松退)定义
当螺杆计量(预塑)到位后,再后退一段距离,使计量室中熔体的比容增加,内压下降,防止熔体通过喷嘴或间隙从计量室向外流出,这个后退动作称为倒塑(又叫松退或防涎量(后退的距离称倒塑量或倒塑行程。
倒塑的作用
1)防喷嘴流涎。
2)在固定加料时,可降低从喷嘴到流道系统的压力(减少内应力并在开模时容
易抽出料杆。
3)稳定计量精度。
倒塑设定准则
螺杆后退速度通常选取最快速度的20,,35,为宜。因为螺杆以较慢的速度向后
退(可使螺杆前端的止逆环可以在每一注塑循环回复到同一位置上(减少了螺杆垫料量的变化。
螺杆后退位置设定必须根据螺杆的直径和止逆环的实际移动范围为目标(典型
的数值是4,10mm。如螺杆后退位置过大,则会形成吸气现象(使塑件产生表面性缺陷。注射工艺参数
1)注射压力
2)注射速度
3)保压压力与时间
4)分段注射
注射压力的定义
在注射过程中为了克服烙料流经喷嘴、流道和模腔等各处的流动阻力,注射螺杆将level of security personnel on duty, fire security measures taken. 9, post signs----construction site management and workers should wear distinctive markings. 10, security----focus on "safety of Sambo", parts of the construction, road surface protection facilities; implementation of Ministry of construction, "score", regular or not regular inspection, timely scoring, reward. ----11, with coordination between the construction and the total package units, collaboration among the type of work, comprehensive progress in contradiction to consult each other when dealt with properly. ----12, public relations personnel to abide by social morality, professional ethics, business discipline, properly handle PR around the construction site. Three, civilized construction appraisal, management (a) the construction site "five": lighting, hardening, greening, landscaping and purification. (B) noise emission standards: the day <65dB night <55dB (c) ... Protections: 1 enhancing the protection of all the construction finished and semi-finished
products for education. Often quality education for workers, for moral education of the civilization production and the protection of the finished and semi-finished products. Education staff at the time of construction to respect other people and their work, cherish the completed and partially completed finished or semi-finished products. In front of the project for the corresponding rules
料筒内的熔融塑料在设定的时间内完全并持续充满温度较低的模腔,就需要有足够的推进力(当推进力达到某个峰值,就称之为注射压力。
影响注射压力的因素
影响所需注射压力的因素有很多,主要有如下三个方面:
1)塑料流动性因素(塑化粘度、注射速度、模具温度)。
2)塑料流动阻力因素(喷嘴形式和射孔尺寸、模具流道系统尺寸、塑件的形状
和尺寸)。
3)塑件尺寸精度或其它品质要求。
注射压力的设定准则
在不会造成塑件粘模及飞边的限度内以稍高的压力注射可使模内熔融体在完全冷凝前始终获得充分的压力和质量补充。
任何塑料所需的注射压力是以塑件刚好欠注,再补充一定的注射压力使产品达到质量要求为准则。
注射速度的定义
注射速度是指螺杆在注射动作时移动的速度,通常用cm,s表示。影响塑料充模流动性的因素
1)原料的流动性(因塑料品级和规格而异)。
2)模腔内料流通道变化大(因塑件结构而异)。
3)充模温差(模具温度与原料塑化温度、模腔各处的温度、型芯与型腔的温度)。
4)充模时差(注射开始到注射结束的时间)。
注射速度与充模流体速度
注射速度是调节充模熔料的流动速率和决定充模时间的必要条件。若想获得质
量满意的塑件,所设置的注射速度必须使熔料在充模过程中得到最佳的连贯性流动要求。注射速度与残余应力
熔体经喷嘴射出的速度对最终的塑胶产品分子排列及残余应力有很大的影响。
由于充模阶段注射速度影响剪切力和剪切速率进而影响产品成型质量。保压压力
的定义
塑件的密度主要决定于封闭浇口时施加压力的大小,而与充模压力无关。当模
腔充满塑料后(还需继续加一定的补充压力,直至浇口完全冷却封闭为止的一段时间,该level of security personnel on duty, fire security measures taken. 9, post signs----construction site management and workers should wear distinctive markings. 10, security----focus on "safety of Sambo", parts of the construction, road surface protection facilities; implementation of Ministry of construction, "score", regular or not regular inspection, timely scoring, reward. ----11, with coordination between the construction and the total package units, collaboration among the type
of work, comprehensive progress in contradiction to consult each other when dealt with properly. ----12, public relations personnel to abide by social morality, professional ethics, business discipline, properly handle PR around the construction site. Three, civilized construction appraisal, management (a) the construction site "five": lighting,
hardening, greening, landscaping and purification. (B) noise emission standards: the day <65dB night <55dB (c) ... Protections: 1 enhancing the protection of all the construction finished and semi-finished products for education. Often quality education for workers, for moral education of the civilization production and the protection of the finished and semi-finished products. Education staff at the time of construction to respect other people and their work, cherish the completed and partially completed finished or semi-finished products. In front of the project for the corresponding rules
压力就是保压压力。
保压压力的作用
保压压力的作用是补充浇口附近的料量至浇口完全硬化封闭(阻止模腔的塑料
受残余压力作用产生倒流,防止塑件的收缩和减少气泡。
保压时问的选择
保压时间的长短与料温、塑件厚薄、浇口大小有直接关系。料温越高、塑件胶壁越厚、浇口越大(保压时间就越长,反之保压时间越短。
保压时间一般根据塑件的重量或可接受的凹痕程度定出最短的保压时间。保
压压力多段的设定
对于份量重、胶壁厚的塑件(保压范围和行程相对要大,必须相应使用多段保压,防止塑件在长时间的保压过程产生分子取向及内应力差异。
多段保压的设定准则
多段的保压压力设定参数是不同的,以压力和时间来划分,通常是逐段递减。
保压时间在确定的偏短时间开始调整,每注塑一次都增加一段保压时间,直到塑件可接受为止,此时保压时间便不再增加。
保压时间的设定准则
设定一个偏短的保压时间,进入半自动注塑,然后测量产品的重量,并以重量为参考点,逐渐增加保压时间。通过一系列的注塑测试和微调保压时间,一直到产品重量不再增加为止,这样就可取得最佳的保压时间。
分段注射的定义
分段注射是指在充模过程中(当螺杆向模腔内推进熔体时?在不同的位置使用不同的注射压力和注射速度。
用分段注射可控制充模流速
采用不分级注射时,由于模腔结构复杂的原因,导致充模熔体流速不恒定。
当采用分级注射后,就可控制充模熔体的流速接近恒定。避免熔体过早凝固和高剪切形成紊流。
注射料量与切换位置
在试注塑和调整注塑缺陷过程中,最关键的工作是要摸准速度切换点。即是根椐成型的结果去估算料量的计量比例与充模流程比例,分别作出位置比较。以判断速度转换level of security personnel on duty, fire security measures taken. 9, post signs----construction site management and workers should wear distinctive markings. 10, security----focus on "safety of Sambo", parts of the construction, road surface protection facilities; implementation of Ministry of construction, "score", regular or not regular inspection, timely scoring, reward. ----11, with coordination between the construction and the total package units, collaboration among the type of work, comprehensive progress in contradiction to consult each other when dealt with properly. ----12, public relations personnel to abide by social morality, professional ethics, business
discipline, properly handle PR around the construction site. Three, civilized construction appraisal, management (a) the construction site "five": lighting, hardening, greening, landscaping and purification. (B) noise emission standards: the day <65dB night <55dB (c) ... Protections: 1 enhancing the protection of all the construction finished and semi-finished products for education. Often quality education for workers,
for moral education of the civilization production and the protection of the finished and semi-finished products. Education staff at the time of construction to respect other people and their work, cherish the completed and partially completed finished or semi-finished products. In front of the project for the corresponding rules
的正确位置。
确定分段段数
在多段注射工艺上,要分多少段注射,一般根据流道的结构、浇口的形式和塑件的几何形状、生产效率和产品质量而定。
分段位置的寻找方法
对各段的注射速度切换点的设定,通常采用欠注法(短射法),可快速和直观地确认到实际所需的位置切换点。
温度参数工艺
1)料筒温度
2)模具温度
3)油液温度
料筒温度
料筒温度是指料筒表面的加热温度。料筒的表面温度,并不是料筒内部熔料
的实际受热温度。因料筒内料粒的真正受热熔融来自于二个不同的热源:一是电热
圈通过金属料筒由外至内的热传递:一是螺杆旋转的磨擦热(即剪切热)直接作用于
料粒。料温设置
料筒各段温度的设置,必须是塑料分解温度以下的成型温度范围通常从进料段
到出料段逐渐递升温度。
模具温度
模具温度足指模腔的表面温度。通常是靠通入的冷却介质来恒定模腔温度,或
靠冷却介质在成型周期内控制热平衡而保持一定的模腔温度,在一定时间内使模腔塑件冷却定型,每一周期内保持恒定的模具温度是保证成型塑件质量稳定的前提条件。模温波动大影响产品质量
假如模温波动较大,对成型塑件的收缩率、变形、尺寸稳定性、机械强度、应
力和表面质量会有所影响。
模温影响产品质量
模具温度主要影响到充模熔体的流动性(其次是塑料的结晶程度。
过低的模温会降低熔体充模流动性(必然要增加注射压力来帮助充模(这样会增
加塑件内应力(降低塑件的机械强度。
level of security personnel on duty, fire security measures taken. 9, post signs----construction site management and workers should wear distinctive markings. 10, security----focus on "safety of Sambo", parts of the construction, road surface protection facilities; implementation of Ministry of construction, "score", regular or not regular inspection, timely scoring, reward. ----11, with coordination between the construction and the total package units, collaboration among the type
of work, comprehensive progress in contradiction to consult each other when dealt with properly. ----12, public relations personnel to abide by social morality, professional ethics, business discipline, properly handle PR around the construction site. Three, civilized construction appraisal, management (a) the construction site "five": lighting, hardening, greening, landscaping and purification. (B) noise emission standards: the day <65dB night <55dB (c) ... Protections: 1 enhancing the protection of all the construction finished and semi-finished products for education. Often quality education for workers, for moral education of the civilization production and the protection of the finished and semi-finished products. Education staff at the time of construction to respect other people and their work, cherish the completed and partially completed finished or semi-finished products. In front of the project for the corresponding rules
模温影响冷却时间
提高的模温,一方面可提高塑料熔体的充模流动性,但另一方面会导致塑件成型收缩率增大和延长了冷却时间,降低了生产效率。
模温影响内应力
合适的模具温度是保持用额定最大的注射压力的80,以下的压力,这样有利于
塑件各部位收缩缓慢、冷却均匀一致,应力便得到充分松驰,避免了塑件因模温不当而产生凹陷缩痕或应力开裂等注塑缺陷。
模温与塑料种类
对非结晶类塑料(由于其成型收缩率较小,因此在生产上使用略高一些的模温
和较短的冷却时间;
对结晶类塑料,由于其成型收缩率较大,因此普遍使用较低的模温及较长的冷
却时间。
模具温度与冷却时间
通常对非结晶类塑料,由于其成型收缩率较小,因此在生产上使用略高一些的
模温和较短的冷却时间;而对结晶类塑料,由于其成型收缩率较大,因此,普遍使
用较低的模温及较长的冷却时间。
模具温度的选取原则
模具温度应该是在熔胶的流动性与模其温度之间作折衷选择。
较低的模具温度可以加速成形周期。故应尽量使用可接受的最低模具温度。
油温
油温是指液压系统的压力油温度。油温的变化影响注射工艺参数,如注射压
力、注射速率等的稳定性。
当油温升高时,液压油的勃度降低(增加了油的泄漏量,导致液压系统压力和
流量的波动,使注射压力和注射速率降低,影响制品的质量和生产效率。因此,在调整注射成型工艺参数时,应注意到油温的变化。
正常的油温应保持在30-50?。
时间工艺参数
1)注射时间
2)保压时间
level of security personnel on duty, fire security measures taken. 9, post signs----construction site management and workers should wear distinctive markings. 10, security----focus on "safety of Sambo", parts of the construction, road surface protection facilities; implementation of Ministry of construction, "score", regular or not regular inspection,
timely scoring, reward. ----11, with coordination between the construction and the total package units, collaboration among the type of work, comprehensive progress in contradiction to consult each other when dealt with properly. ----12, public relations personnel to abide by social morality, professional ethics, business discipline, properly handle PR around the construction site. Three, civilized construction appraisal, management (a) the construction site "five": lighting, hardening, greening, landscaping and purification. (B) noise emission standards: the day <65dB night <55dB (c) ... Protections: 1 enhancing the protection of all the construction finished and semi-finished products for education. Often quality education for workers, for moral education of the civilization production and the protection of the finished and semi-finished products. Education staff at the time of construction to respect other people and their work, cherish the completed and partially completed finished or semi-finished products. In front of the project for the corresponding rules
3)中间停留时间
4)冷却时间
5)储料时间
注射时间
要注满一个塑件,就需要一定的注射时间,而且注射速度越高,注射时间就越短,反之则长。
注射时问与注塑质量
注射时间的长短通常由塑料的塑化粘度、注射速度、注射份量、塑件质量要求
等决定。注射速度越快,充模时间就越短,熔体成型温差小,塑件光泽度好(生产
效率也高。相反注射速度越慢,充模时间就越长,熔体成型密度高及尺寸稳定,但生产效率相对要低。
冷却时间
冷却时间是指塑件在模腔内得到脱模所希望的充分定型所需的时间。因为塑件
在模腔内的定型过程也是个散热过程,理论上模具是一个热交换器,有多少热量注入,就有多少热量随冷却介质带出,要想达到传热平衡和恒定模具温度,只有使用适宜的冷却时间作为控制条件。
冷却时间的选择
冷却时间的长短设定,主要取决定于塑件的厚度、材料的热焓量和结晶程度、
模具温度、以及出模时的硬化程度等。
通常结晶型塑料设定冷却时问长(非结晶型塑料冷却时间短。
冷却时间的设定准则
如设定过长的冷却时间不仅会降低生产效率,而且会增加脱模困难。因此大多
数注塑生产的冷却时间,是以保证塑件出模时不变形为原则,并在此原则下设定最短的冷却时间。
level of security personnel on duty, fire security measures taken. 9, post signs----construction site management and workers should wear distinctive markings. 10, security----focus on "safety of Sambo", parts of the construction, road surface protection facilities; implementation of Ministry of construction, "score", regular or not regular inspection, timely scoring, reward. ----11, with coordination between the construction and the total package units, collaboration among the type
of work, comprehensive progress in contradiction to consult each other when dealt with properly. ----12, public relations personnel to abide by social morality, professional ethics, business discipline, properly handle PR around the construction site. Three, civilized construction appraisal, management (a) the construction site "five": lighting, hardening, greening, landscaping and purification. (B) noise emission standards: the day <65dB night <55dB (c) ... Protections: 1 enhancing the protection of all the construction finished and semi-finished products for education. Often quality education for workers, for moral education of the civilization production and the protection of the finished and semi-finished products. Education staff at the time of construction to respect other people and their work, cherish the completed and partially completed finished or semi-finished products. In front of the project for the corresponding rules