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GB/T 17037 consists of the following five parts under the general title Plastic - Injection moulding of test specimens of thermoplastic materials: —— Part 1: General principles, and moulding of multipurpose and bar test specimens; —— Part 2: Small tensile bars; —— Part 3: Small plates; —— Part 4: Determination of moulding shrinkage; —— Part 5: Preparation of standard specimens for investigating anisotropy. This is Part 1 of GB/T 17037. This part is drafted in accordance with the rules given in GB/T 1.1- 2009. This part replaces GB/T 17037.1-1997 Injection moulding of test specimens of thermoplastic materials - Part 1: General principles and moulding of multipurpose and bar test specimens. In addition to editorial changes, the following main technical changes have been made with respect to GB/T 17037.1-1997: —— The following terms and definitions are added: mass of moulding (3.22), mass of test specimen (3.23), sink mark ratio (3.24), and cavity pressure (3.25); —— The specimen type code is revised according to GB/T 37426. —— The methods for setting the injection moulding parameters (see Annex D) is added; —— The determination method of hold pressure and hold time (see Annex E) is added; This part has been redrafted and modified in relation to ISO 294-1: 2017 Plastics - Injection moulding of test specimens of thermoplastic materials - Part 1: General principles, and moulding of multipurpose and bar test specimens. The main technical differences with respect to ISO 294-1: 2017 are as follows: —— The adjustments of technical differences are made for the normative references in this standard so as to adapt to the technical conditions of China. The adjustment is mainly reflected in clause 2 "Normative reference", with the specific adjustments as follows: • ISO 179-1 is replaced by GB/T 1043.1 which is identical to the international standard; • ISO 294-4 is replaced by GB/T 17037.4 which is identical to the international standard; • ISO 20753 is replaced by GB/T 37426, which is modified in relation to the international standard; The following editorial changes have been made in this part: —— The web address information of ISO and IEC for maintenance of terminology database in clause 3 Terms and definitions is given in the form of note. Attention is drawn to the possibility that some of the elements of this standard may be the subject of patent rights. The issuing body of this document shall not be held responsible for identifying any or all such patent rights. This part was proposed by China Petroleum and Chemical Industry Association. This part was prepared by the National Technical Committee 15 on Plastic of Standardization Administration of China. The previous edition replaced by this part is as follows: —— GB/T 17037.1-1997. Introduction Many factors in the injection-moulding process influence the properties of moulded specimens and hence the measured values obtained when the specimens are used in a test method. The mechanical properties of such specimens are strongly dependent on the conditions of the moulding process used to prepare the specimens. Exact definition of each of the main parameters of the moulding process is a basic requirement for reproducible and comparable operating conditions. See Bibliography [1], [2], [4], [5] and [6]. It is important in defining moulding conditions to consider any influence the conditions may have on the properties to be determined. Thermoplastics exhibit differences in molecular orientation in crystallization morphology (for crystalline and semicrystalline polymers), in phase morphology (for heterogeneous thermoplastics) as well as in the orientation of anisotropic fillers such as short fibres; see Bibliography [3]. Residual (“frozen-in”) stresses in the moulded specimens and thermal degradation of the polymer during moulding also influence properties. Therefore, these phenomena must be controlled to avoid the fluctuation of the numerical values of the specimen performance. Care has been taken to ensure that the GB/ ISO moulds described can all be fitted in existing injection moulding equipment and have interchangeable cavity plates. Plastics - Injection moulding of test specimens of thermoplastic materials - Part 1: General principles, and moulding of multipurpose and bar test specimens 1 Scope This part of GB/T 17037 gives the general principles to be followed when injection moulding specimens of thermoplastic materials and gives details of mould designs for preparing two types of specimen for use in acquiring reference data, i.e. type A1 and type B1 specimens as specified in GB/T 37426, and provides a basis for establishing reproducible moulding conditions. Its purpose is to provide consistent descriptions of the main parameters of the moulding process and to establish a uniform practice in reporting moulding conditions. The particular conditions required for the reproducible preparation of specimens will vary for each material used and are given in the national standard for the relevant material or are to be agreed upon between the interested parties. This part is applicable to reproducible preparation of multipurpose and bar test specimens by injection moulding of thermoplastic materials. Note: Interlaboratory tests with acrylonitrile/ butadiene/ styrene (ABS), styrene/ butadiene (SB) and poly methyl methacrylate (PMMA) have shown that mould design is an important factor in the reproducible preparation of specimens. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. GB/T 1043.1 Plastics - Determination of charpy impact properties - Part 1: Non-instrumented impact test (GB/T 1043.1-2008, ISO 179-1: 2000, IDT) GB/T 17037.3-2003 Plastics - Injection moulding of test specimens of thermoplastic materials - Part 3: Small plates (ISO 294-3: 2002, IDT) GB/T 17037.4 Plastic - Injection moulding of test specimens of thermoplastic materials - Part 4: Determination of moulding shrinkage (GB/T 17037.4-2003, ISO 294-4: 2001, IDT) GB/T 37426-2019 Plastics - Test specimens (GB/T 37426-2019, ISO 20753: 2018, MOD) ISO 294-2 Plastics - Injection moulding of test specimens of thermoplastic materials - Part 2: Small tensile bars 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. Note: ISO and IEC maintain terminological databases for use in standardization at the following addresses: —— IEC Electropedia: available at http:// www .electropedia .org —— ISO Online browsing platform: available at http://wwwi.so.org/obp 3.1 mould temperature TC average temperature of the mould cavity surfaces measured after the system has attained thermal equilibrium and immediately after opening the mould, ℃ 3.2 melt temperature TM temperature of the molten plastic in a free shot, ℃ 3.3 melt pressure P pressure of the plastic material in front of the screw at any time during the moulding process, MPa 3.4 hold pressure PH melt pressure (3.3) during the hold time (3.9), MPa 3.5 moulding cycle complete sequence of operations in the moulding process required for the production of one set of specimens (see Figure 1) Key: X—— time t; 5—— mould-open time tO; Y—— melt pressure p; 6—— melt pressure p; 1—— cycle time tT; 7—— longitudinal position of screw l; 2—— injection time tI; 8——mould opening; 3—— hold time tH; 9——mould closing 4—— cooling time tC; Note: The melt pressure during the cooling phase is not zero due to back pressure effects. Figure 1 Schematic diagram of an injection-moulding cycle showing the melt pressure (full line) and the longitudinal position of the screw (dashed line) as a function of time 3.6 cycle time tT time required to carry out a complete moulding cycle (3.5), s Note: The cycle time is the sum of the injection time, tI, the cooling time, tC, and the mould open time, tO. 3.7 injection time tI time from the instant the screw starts to move forward until the switchover point between the injection period and the hold period, s 3.8 cooling time tc time from the end of the injection period until the mould starts to open, s 3.9 hold time tH time during which the pressure is maintained at the hold pressure (3.4), s 3.10 mould-open time tO time from the instant the mould starts to open until the mould is closed and exerts the full clamping force (3.19), s Note: It includes the time required to remove the mouldings from the mould. 3.11 cavity part of the hollow space in a mould that produces one specimen 3.12 single-cavity mould mould with one cavity (3.11) only 3.13 multi-cavity mould mould that has two or more identical cavities (3.11) in a parallel-flow arrangement Note: Identical flow-path geometries and symmetrical positioning of the cavities in the mould ensure that all specimens from one shot are equivalent in their properties. 3.14 family mould multi-cavity mould (3.13) containing cavities (3.11) which have different geometries 3.15 GB/ISO mould one of several standard moulds including designated GB/T 37426 type A1, B1, C1, D11 and D12 intended for the reproducible preparation of specimens with comparable properties Note: The moulds have a fixed plate with a central sprue, plus a multi-cavity cavity plate as described in 3.13. Note: Additional details are given in 4.1.1.4. An example of a complete mould is shown in Annex C. 3.16 critical cross-sectional area Ac cross-sectional area of the cavity (3.11) in a single-cavity mould (3.12) or multi-cavity mould (3.13) at the position where the critical portion of the test specimen, i.e. that part on which the measurement will be made, is moulded, mm2 Note: For tensile specimens, for instance, the critical portion of the test specimen is the narrow section which is subjected to the greatest stress during testing. 3.17 moulding volume VM ratio of the mass of the moulding (3.22) to the density of the solid plastic, mm3 3.18 projected area Ap overall profile of the moulding projected on to the parting plane, mm2 3.19 clamping force FM force holding the plates of the mould closed, kN 3.20 injection velocity vI average velocity of the melt as it passes through the critical cross-sectional area (3.16), mm/s 3.21 shot volume max. VS product of the maximum metering stroke of the injection-moulding machine and the cross-sectional area of the screw, mm3 3.22 mass of moulding Wm total mass of the specimens, the runner(s) and the sprue in a single moulding, g 3.23 mass of test specimen Ws mass of a single specimen, excluding the runner(s) and the sprue, g 3.24 sink mark ratio SR indication of the relative depth of a sink mark on the surface of the specimen, dimensionless Note: The measurement of sink mark and the calculation method of sink mark ratio are shown in E.1. 2.1. 3.25 cavity pressure Pc pressure of the melt in the mould cavity, measured with a pressure sensor on the inner surface of the cavity, MPa 4 Apparatus 4.1 Moulds 4.1.1 GB/ISO moulds (multi-cavity) 4.1.1.1 GB/ISO moulds are strongly recommended for producing specimens for the acquisition of data which are intended to be comparable (see GB/T 19467.1, GB/T 19467.2, ISO 11403-1., ISO 11403-2 and ISO 11403-3), as well as for use in the case of disputes involving different standards. 4.1.1.2 Multipurpose test specimen as specified in GB/T 37426 type A1 shall be moulded in a two-cavity mould using a Z- or T-runner (see Annex A). The mould as shown in Figure 2 shall meet the requirements specified in 4.1.1.4. Of the two types of runner, the Z-runner is preferred owing to the more symmetrical closure force obtained. The specimen mouldings produced shall have the dimensions of the type A1 specimen specified in GB/T 37426. 4.1.1.3 Rectangular 80 mm × 10 mm × 4 mm bars (GB/T 37426 type B1) shall be moulded in a four-cavity mould with a double-T runner. The mould shall meet the requirements specified in 4.1.1.4, schematic diagram is shown in Figure 3. The bars produced shall have the same cross-sectional dimensions along their central section as multipurpose specimens (see GB/T 37426) and a length of 80 mm ± 2 mm. 4.1.1.4 The main constructional details of the GB/ISO moulds used for preparing type A1 and type B1 specimens specified in GB/T 37426 are shown in Figures 2 and 3. They shall meet the following requirements: Foreword i Introduction iii 1 Scope 2 Normative references 3 Terms and definitions 4 Apparatus 5 Procedure 6 Report on test-specimen preparation Annex A (Informative) Examples of runner configurations Annex B (Informative) Standards for plastic injection mould components Annex C (Informative) Example of an injection mould Annex D (Informative) Methods for setting the injection moulding parameters Annex E (Informative) Methods of determining the hold pressure and hold time Bibliography 塑料 热塑性塑料材料注塑试样的制备 第1部分:一般原理及多用途试样和长条形试样的制备 1范围 GB/T 17037的本部分给出了热塑性塑料材料注塑试样所遵循的一般原理。给出了用于制备两种试样的模具设计的详细参考数据,例如GB/T 37426规定的A1型和B1型试样,提供了可再现的注塑条件,其口的是提供模塑过程主要参数的一致性描述,并在报告的模塑条件下建立统一的方法。试样的可再现性制备所需的详细条件会随使用材料而有所变化,这些条件在相关材料的国家标准中有规定,或由相关方约定。 本部分适用于热塑性塑料材料注塑制备具有可再现性的多用途试样和长条形试样。 注:对丙烯腈/丁二烯/苯乙烯(ABS)、苯乙烯/丁二烯(SB)和聚甲基丙烯酸甲酯(PMMA)的实验室之间试验表明。模具设计是保证试样的可再现性制备的重要因素之一。 2规范性引用文件 下列文件对于本文件的应用是必不可少的。凡是注日期的引用文件,仅注日期的版本适用于本文件。凡是不注日期的引用文件,其最新版本(包括所有的修改单)适用于本文件。 GB/T 1043.1塑料 简支梁冲击性能的测定 第1部分:非仪器化冲击试验(GB/T 1043.12008.ISO 179-1:2000.IDT) GB/T 17037.32003塑料 热塑性塑料材料注塑试样的制备 第3部分:小方试片(ISO 294-3:2002.IDT) GB/T 17037.4塑料 热塑性塑料材料注塑试样的制备 第4部分:模塑收缩率的测定(GB/T 17037.4—2003,ISO 294-4:2001,IDT) GB/T 37426塑料试样(GB/T 37426—2019,ISO 20753:2018,MOD) ISO 294-2塑料 热塑性塑料材料注塑试样的制备 第2部分:小拉伸试样(Plastics-Injection moulding of test specimens of thermoplastic materials-Part 2:Small tensile bars) 3术语和定义 下列术语和定义适用于本文件。 注:ISO 和IEC用以下网址维护术语数据库: ——IEC世界在线电子技术词汇:http://www.clectropedia.org ISO 在线浏览平台:http://www.iso.org/obp 3.1模具温度 mould temperature TC 模具系统达到热平衡后。打开模具,立即测得的模具型腔表面的平均温度,单位为摄氏度(℃)。 3.2熔体温度 melt temperature TM 对空注射所得的熔融塑料的温度,单位为摄氏度(℃)。 3.3熔体压力melt pressure p 在模塑过程中的任一时刻,螺杆前端处塑料材料的压力,单位为兆帕(MPa)。 3.4保压压力hold pressure PH 在保压时间(3.9)内的熔体压力(3.3),单位为兆帕(MPa)。 3.5模塑周期 moulding cycle 在模塑过程中,制备一模注塑试样所需要的全部操作工序(见图1)。 说明: X——时间t; 5——开模时间tn; Y——熔体压力p; 6——熔体压力p; 1——循环时间tt; 7——螺杆轴间位置l; 2——注射时间t1; 8——模具开模; 3——保压时间tH; 9——模具合模。 4——冷却时间te; 注:由于背压的影响,冷却时间(3.8)内熔体压力不为零。 图1模塑周期示意图——熔体压力(实线)和螺杆轴向位置(虚线)与模塑时间的坐标图 3.6循环时间 cycle time tT 完成一个模塑周期(3.5)所用的时间,单位为秒(s)。 注:循环时间等于注射时间Tr、冷却时间tc和开模时间tn之和。 3.7注射时间 injection time tt 从螺杆向前运动开始,直至从注射转换到保压过程时所需要的时间,单位为秒(s)。 3.8冷却时间 cooling time tc 从注射过程结束,至模具开始打开前所用的时间,单位为秒(s)。 3.9保压时间hold time tH 保压压力(3.4)阶段,维持该压力的时间。单位为秒(s)。 3.10开模时间 mould-open time tO 从模具开始打开的瞬间到再关闭并施加最大锁模力(3.19)时的时间,单位为秒(s)。 注:这段时间包括从模具中移出模塑件的时间。 3.11型腔 cavity 在模具中,用于制备一个试样的空腔部分。 3.12单型腔模具 single-cavity mould 仅有一个型腔(3.11)的模具。 3.13多型腔模具multi-cavity mould 包含两个或多个相同且与流动方向平行排列的型腔(3.11)的模具。 注:相同几何形状的流道和对称的型腔位置能保证一次注塑的所有试样在性能上是相同的。 3.14家族式模具 family mould 包含不同几何形状和尺寸的型腔(3.11)的多型腔模具(3.13)。 3.15GB/ISO 模具GB/ISO mould 用于制备具有可比性和再现性试样的几个标准模具之一,包括制备GB/T 37426中A1型、B1型、C1型、D11型和D12型等试样的标准模具。 注1:标准模具包括一个有中心主流道的定模板和一个有3.13中所描述的多型腔的型腔板。 注2:其他详细情况见4.1.1.4,附录C给出了一套完整模具的部件分解示意图。 3.16关键部位横截面面积 critical cross-sectional area Ac 在一个单型腔模具(3.12)或多型腔模具(3.13)中,成型试样关键部位型腔(3.11)的横截面的面积,亦即测试时试样被测量的部分,单位为平方毫米(mm2)。 注:例如拉伸试样,试样的关键部位为其狭窄部分,试验时该部分承受最大的应力。 3.17模塑体积 moulding volume VM 模塑件质量(3.22)与固体塑料密度的比值,单位为立方毫米(mm3)。 3.18投影面积 projected area Ap 模塑件在分型面上的投影面积,单位为平方毫米(mm2)。 3.19锁模力 clamping force FM 模塑过程中为保持模具闭合而加在模具上的力,单位为千牛(kN)。 3.20注射速率 injection velocity v1 熔体通过关键部位横截面(3.16)时的平均速率,单位为毫米每秒(mm/s)。 3.21最大注射量 shot volume max. VS 注塑机的最大计量行程与螺杆横截面积的乘积,单位为立方毫米(mm3)。 3.22模塑件质量mass of moulding Wm 包括试样、分流道和主流道的模塑件的总质量,单位为克(g)。 3.23试样质量 mass of test specimen Ws 不包括分流道和主流道的单一试样的质量,单位为克(g)。 3.24缩痕比 sink mark ratio SR 试样表面上显示的缩痕的相对深度,无量纲。 注:缩痕的测量以及缩痕比的计算方法见E.1.2.1。 3.25型腔压力 cavity pressure Pc 熔体在型腔内的压力,通过型腔底部表面的压力传感器测量,单位为兆帕(MPa)。 4设备 4.1模具 4.1.1GB/ISO 模具(多型腔模具) 4.1.1.1应采用GB/ISO 模具制备试样.制备的试样不但可获得具有可比性的数据(参见GB/T 19467.1,GB/T 19167.2,ISO 11403-1.ISO 11403-2和ISO 11403-3),而且可解决执行不同标准的争议。 4.1.1.2应使用Z形或T形流道的两型腔模具(参见附录A)制备GB/T 37426规定的A1型多用途试样。模具应满足4.1.1.4中所列的要求,示意图见图2。在两种类型的流道中,推荐使用Z形流道,因其能获得更均衡的合模力。制备试样的尺寸应符合GB/T 37426规定的A1型多用途试样的尺寸。 4.1.1.3应使用双T形流道的四型腔模具制备GB/T 37426规定的B1型80mm×10mm×4mm长条形试样,模具应满足4.1.1.4中所列的要求,示意图见图3。制备的长条形试样应与多用途试样的关键部位横截面尺寸(见GB/T 37426)相同,试样长度为80mm±2mm. 4.1.1.4制备GB/T 37426规定的A1型试样和B1型试样的GB/ISO 模具的主要结构见图2和图3,并应满足下列要求: a)靠近喷嘴侧主流道入口的直径至少应为4mm. b)分流道的宽和高(或直径)至少应为5mm。 c)浇口应设置在型腔的一端,见图2和图3。 d)浇口的高度至少应为型腔高度的2/3,浇口的宽度应和与其相连接的型腔的宽度一致。 e)浇口长度应尽可能短,无论如何不应超过3mm。 f)流道的脱模斜角至少应为10°,但不应超过30°。型腔的脱模斜角不应大于1°,拉伸试样肩部脱模斜角不应大于2°。 g)型腔的尺寸应使制备试样的尺寸符合有关试验方法标准的要求。考虑到各种材料的模塑收缩率不同,型腔尺寸的选择应使制备试样的尺寸在规定的标准值与允许的上限值之间。对于GB/T 37426规定的A1型和B1型试样,标准模具型腔的主要尺寸如下: 1)深度:4.0mm~4.2mm。 2)中间部位宽度:10.0mm~10.2mm。 3)(GB/T 37426规定的B1型试样)长度:80mm~82mm。 h)如使用顶出杆,应设置在试样测试区域之外。例如:GB/T 37426规定的A1型多用途试样(哑铃型试样)和C型小拉伸试样(由ISO 294-2规定的C型模具制备),顶出杆可设置在肩部;GB/T 37426规定的B1型长条形试样,顶出杆可设置在中心区域20mm以外的部分;GB/T 37426规定的D型方板形试样(由ISO 294-3规定的D型模具制备),顶出杆可设置在中心区域直径50mm之外的部分。 i)模板加热/冷却系统的设计,应能保证在操作条件下,型腔表面和任一模板表面上任意两点间的温度差小于5℃。 j)推荐使用可更换式的型腔板和浇口镶件,以便从注塑一种试样转换成注塑另一种试样时,可以迅速更换。通过调整注射量Vs可使转换后注塑条件尽可能保持一致。附录A给出了一个带浇口镶件的可更换式型腔板的示意图。 k)推荐在中心分流道处安装压力传感器,以给出注射期间合适的控制参数(传感器是GB/T 17037.4的强制性要求)。在GB/T 17037.3—2003中图2和4.1中k)给出了使用各种类型的GB/ISO 模具时合适的传感器位置。 1)为确保不同GB/ISO 模具间型腔板可以互换,除了图2和图3以及ISO 294-2和GB/T 17037.3规定的要求外,应注意以下结构细节: 1)制备GB/T 37426规定的A1型多用途试样时,推荐型腔长度为170mm,型腔板之间最大长度180mm; 2)型腔板的宽度取决于连接的加热/冷却流道之间的最小距离。此外,制备GB/T 37426规定的B1型试样的模具,可能需要安装制备GB/T 1043.1缺口试样用的特殊插件,因此需留有一定的空间; 3)为了分离试样与流道,在制备GB/T 37426规定的A1型、B1型和C型(模具见ISO 294-2)试样的模具中可设置切断线。为方便从多用途试样上裁出80mm长的部分,也可再设置一对切断线,也可以用于切割方板形试样(模具见GB/T 17037.3)。 m)为方便确认一个模具注塑的所有试样是否一致,建议在每个型腔中试样有效面积之外[见h)] 做标记。例如,简单地在顶出杆顶面上刻上符号,这样可避免对型腔板表面的任何伤害。 n)有缺陷的表面将影响试验的结果,特别是对力学性能试验的结果。因此,模具型腔表面应高度抛光,抛光方向应与试样在试验中的受荷方向一致。 单位为毫米 说明: Sp—主流道: G——浇口。 注:模塑体积VM≈30000mm3:投影面积Ap≈6300mm2。 图2 GB/T 37426规定的A1型试样两型腔的型腔板示意图 单位为毫米 说明: Sp—主流道: G——浇口。 注:模塑体积VM≈30000mm3:投影面积Ap≈6500mm2。 图3 GB/T 37426规定的B1型试样四型腔的型腔板示意图 4.1.1.5其他标准给出了注塑模具零件的更多信息,参见附录B。 4.1.2单型腔模具 单型腔模具(见图4)的型腔可以是哑铃形、圆形或其他形状。单型腔模具制备试样给出的某种性能测定值通常与GB/ISO 模具制备试样的测定值不同。 注:上述差异的产生可能是由于单型腔模具的型腔体积与模塑体积VM之比和GB/ISO 模具的不同。同时,单型腔模具的注塑体积较小,不符合4.2.2要求的体积比,由此也可能会产生错误的性能测定值。 a)主流道(Sp)垂直于模塑试片 b)主流道(Sp)与分型面平行(带有预防喷射的弯曲流道) 图4单型腔模具示例 4.1.3家族式模具 家族式模具(见图5)可同时制备长条形试样、哑铃形试样和圆形试样等。 当家族式模具制备的试样和GB/ISO 模具制备的试样性能测定结果一致时,才可以使用家族式模具。 注:多数情况下,在不同的注塑条件下连续、同时注满家族式模其中不同形状的型腔是困难的,且同时注满的各型腔内真实的注塑条件存在差异。另外,使用家族式模具时不能精确设定各型腔内的注射速率v1。因此,家族式模具不适用于制备标准试样。 图5家族式模具示例 4.2注塑机 4.2.1总则 为制备具有再现性的试样使测试结果可以比较,仅应使用往复式螺杆注塑机,注塑机应配备带有控制注塑条件的必要器件。 更详细的信息,见参考文献[7]。 4.2.2模塑体积 模塑体积VM与注塑机最大注射量VS之比应在20%~80%,仅当有关材料标准规定或制造商推荐时.才可使用较高的比例。 4.2.3控制系统 注塑机的控制系统应能使操作条件保持在下列允许偏差内: 注射时间t1±0.1s; 保压压力pH±5%; 保压时间tH±5%; 熔体温度TM±3℃; 模具温度Tc±3℃(≤80℃时); ±5℃(>80℃时); 模塑件质量WM±2%。 4.2.4螺杆 螺杆的类型(如长度、直径、螺纹高度和压缩比等)应适于所注塑的材料。推荐使用直径18mm~40mm的螺杆。 4.2.5锁模力 在所有操作条件下注塑机的锁模力FM应足够大以防止材料溢出。 注塑所需的最小锁模力可按式(1)计算: FM≥Ap×pmax×10-3 (1) 式中: FM——锁模力,单位为牛(kN); Ap——投影面积,单位为平方毫米(mm2); pamx——熔体压力的最大值,单位为兆帕(MPa)。 注塑机液压系统产生的熔体压力可根据螺杆的轴向作用力FS用式(2)计算: (2) 式中: p——熔体压力,单位为兆帕(MPa); FS——螺杆的轴向作用力,单位为千牛(kN); D——螺杆直径.单位为平方毫米(mm2)。 对于制备GB/T 37426规定的A1型和B1型试样的GB/ISO 模具,最小锁模力可由FM≥6500×pmax×10-3计算得出,例如当最大熔体压力为80MPa时,最小锁模力为520kN。 带有可更换型腔板的注塑模具系统,需考虑例如制备GB/T 37426规定的D11型和D12型试样用GB/ISO 模具的投影面积Ap≈11000mm2,因更大的投影面积而需要更高的锁模力。 4.2.6温度计 应使用精确至±1℃的带针形探头的温度计测量熔体温度TM。同样,应使用精确至±1℃的表面温度计测量模具型腔表面的温度以给出模具温度TC(见3.1)。 5步骤 5.1材料的状态调节 注塑前,应按有关材料标准的规定对热塑性塑料材料的粒子或颗粒进行状态调节。如尚无相关材料标准,推荐使用生产商提供的条件进行状态调节。 应避免材料在其温度明显低于室温时直接暴露在空气中,以防止湿气在材料上冷凝。 5.2注塑 5.2.1按有关材料标准的规定设定注塑机的操作条件。如尚无相关材料标准,则按相关方约定的条件进行设定。 5.2.2对很多热塑性塑料,当使用制备GB/T 37426规定的A1型试样或B1型试样的模具时,注射速率的适用范围是200mm/s±100mm/s。应注意,对于一个给定的注射速率v1的值,注射时间t1;与模具中型腔数n成反比[见式(3)]。应尽可能减少注射速率的变化。 注:在附录D给出了注塑操作参数的设定方法。 注射速率范围的讨论仅适用于单型腔模具和多型腔模具,并可按式(3)计算注射速率: (3) 式中: v1——注射速率,单位为毫米每秒(mm/s); VM——模塑体积,单位为立方毫米(mm3); t1——注射时间,单位为秒(s); n——模具型腔数,无量纲; AC——关键部位横截面积,单位为平方毫米(mm2)。 5.2.3保压压力pH由材料的结构和性能决定;保压压力应由制备试样的相关性能确定。当使用不同保压压力下制备的无凹痕、无空洞和无其他可见缺陷的试样,可获得相似的性能测定值时,推荐使用低压力作为保压压力。 可采用下列方法之一确定保压压力: a)从模塑件切取试样的试样质量法; b)缩痕比法; c)不产生飞边的最大熔体压力法。 注:附录E给出了上述三种确定保压压力方法的描述。例如,其中方法c)为最大熔体压力法。也可使用其他可比较的方法确定正确的保压压力。 5.2.4确保材料在浇口区域凝固前维持恒定的保压压力,如在保压时间tH内保持恒定的保压压力。可采用下列方法之一确定保压时间: a)测量试样质量的试样质量法; b)测量型腔压力的方法。 注:附录E中E.2给出了上述两种确定保压时间方法的描述。也可使用其他可比较的方法确定正确的保压时间。 5.2.5弃掉注塑机达到稳定状态之前的模塑件。当达到稳定条件后,记录操作条件,开始收集试样。 在注塑过程中,应使用合适的方法,如检查模塑件质量的方法,维持注塑条件的稳定。 5.2.6注塑材料的任何变化,均应彻底清空和清洗注塑机。使用新材料注塑试样时.收集试样前应至少弃去10个模塑件。
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GB/T 17037.1-2019, GB 17037.1-2019, GBT 17037.1-2019, GB/T17037.1-2019, GB/T 17037.1, GB/T17037.1, GB17037.1-2019, GB 17037.1, GB17037.1, GBT17037.1-2019, GBT 17037.1, GBT17037.1 |