2 mm to 1. As a defect of micro injection molding parts, weld line is unfavorable since it will influence the surface quality and mechanical properties of micro parts. Weld lines, also known as knit lines, are a common defect in injection molding where two or more flow fronts of molten plastic meet but don’t properly fuse together. We recently had a few pieces (2-3%) crack after assembly, while in storage (not installed, still in the package). The molded plastic part may also appear to be rust-colored. Steven. The default weld line result recognizes 135º as the maximum angle of collision and as that angle decreases, the severity increases as it. If the different flow fronts have cooled. Weld lines are a common defect generated in injection molding, which apparently affects the performance of final products, but the available reports on carbon fiber-reinforced thermoplastics are. Therefore, the investigation on the developing process of weld line would be a significant issue for improving the quality of micro injection molded parts. In the sense that the weld line is better formed before the resin temperature. Bin-Xin Yang Ouyang Jie Supei Zheng Qiang Li Wen Zhou. Weld lines can impact the strength and appearance of the final part, and are often considered a defect. , Ziegmann G. 5. 3 Materials Polypropylene (PP) and. Injection Molding Glossary; Weld Lines; Weld Lines. Raising the mold temperature will keep the material molten longer, resulting in stronger weld lines and even elimination of weld lines. A meld line occurs when two moving melt fronts converge and flow parallel to each other. Weld line problem which occurs in polymer parts produced by plastic injection method and affects appearance and strength on a large scale was researched in this paper. An evaluation model based on artificial neural network method. . Weld Lines-3 Ways for Detecting and Correcting. A weld line refers to a line, notch or color change that is created on the molded part caused by the convergence of two separate flows of molten plastic. They are unavoidable even for moderate complex products. In spite of the symmetry of the molding the formed weld line was not straight, due to a slight unbalance of the two injection gates. Maintain a holding pressure that is no more than 1/2 the. Plastic Injection Molding Process. A knit line in a plastic injection-molded part is created when two separate plastic flows meet within the mold and "resolidify" along their interface. 000 0. Increase the mold temperature. Second, depending on the size of the overflow well, you get a little bit of flow melding together, and that helps strength so that you have some intertwining of the polymer chains. poor flow fronts that are too cold, this can also lead to a deterioration in the mechanical properties. Depending on the resin, resin temperature, mold temperature, and filling speed, knit lines can vary. (3) Adjust the temperature of the barrel and nozzle: the viscosity. This study describes how the weld line was formed on the part. The wheel has to be gated at three places on the hub and. In injection molding of thermosoftening plastics, an important aspect having a bearing on the quality of articles is the appearance of weld lines that are formed when there are inserts, barriers, molding signs, reinforcements, etc. Depending on the resin, resin temperature, mold temperature, and filling speed, knit lines can vary. Weld line reduction is one of the major concerns in plastic injection molding (PIM) that results in high surface appearance and high strength of a plastic product. Conventional injection molding is widely used to produce plastic parts, mainly in the automotive industry, due to the high production ratios and quality of. Flow lines are off-color lines, streaks, and other patterns that appear on the surface of a part. In this study, the effects of injection temperature, injection pressure, and fiber cont. This study addresses the effects of injection molding weld line on the fatigue crack resistance of commercial CPVC in the temperature range of −10 to 70 °C. Sink Marks Cause 1: Incorrect Melt Temperature. Weld lines not only detract from an injection-molded part’s surface quality, but also significantly reduce its mechanical strength. Xie L, Zhu D, Ziegmann G, Steuernagel L (2016) Investigation on correlation between cold/hot weld line mechanical properties and micro injection molding processing parameters. Weld or Knit lines are a plane or section in an injection molding part where the flow of molten plastics meets from different directions. Injection molding plate for mode I testing geometry. For the production of these weld‐line specimens, a special mold was used and injection molding parameters were systematically varied, tensile (ISO 527‐2) and impact (ISO 179‐1/1eU. One of the factors that determines the quality of injection molded parts is the weld line [50,75,76]. Weld-line is a weak area which reduces the strength of the part locally. In this study, the effects of injection temperature, injection pressure, and fiber content on the mechanical properties of weld lines were studied for carbon fiber-reinforced nylon. In this work, the weldline strength of injection molded short-glass-fiber reinforced polycarbonate was derived by an analytical method of modified rule-of-mixtures as a function of the area fraction between skin and core layers. It is important to investigate the weld line because the weld line area can. Abstract. • Move injection locations to make flow fronts meet more obliquely, turning the weld line into a meld line. <Mold> Increase (or decrease) the size of the runners and gates. This failure causes the product to be damaged during use. 1. The Solutions for Poor Welding Lines. A tensile test specimen mold, which allows cavity thickness varying from 2. Weld line, 5. Injection molding of large/complicated products are usually prepared by multiple compounds, which produces weldlines once the melt fronts are joined by impingement flow. Known methods to reduce weld-line effects are the optimization of injection molding parameters, enhanced tool temperature, and using special molding tool devices. . Fatigue crack growth (FCG) tests were conducted on SEN specimens prepared from 100 mm. Tekanan. 1. + Optimize holding pressure time. Its appearance can be improved by adjusting parameters. Although this phenomenon occurs in almost all the commercially important polymer. Weld-line is a defect that arises in injection molding when two or more flow fronts collide. In. A weld line develops when two or more flow fronts come together but do not meld completely because of partial solidification. • Reduce runner dimensions and maintain the same flow rate. Weld line existence reduces the material strength; however, its demerit characteristics. Various measures are taken at production sites to address these problems. Article Google Scholar Deng YM, Zheng D, Lu XJ (2008) Injection moulding optimization of multi-class design variables using a PSO algorithm. A new kind of weld line was. Weld lines form where two or more flow fronts come together and can create a cosmetic or structural problem. Meld and knit lines are actually both different types of weld lines. But add 30% glass and weld-line strength retention drops to only 34% as high as the compound with no weld. In the 1947 book, Injection Molding of Plastics, the late Dr. วัตถุดิบ พลาสติก PMPA ( อะคริลิก ) เกรด A. Wu CY, Ku CC, Pai HY (2011) Injection molding optimization with weld line design constraint using distributed multi-population genetic algorithm. CrossRef View in Scopus Google Scholar [17] G. Three terms that often get mixed up in the plastic injection molding industry are weld, meld, and knit lines. The formation of weld lines and their location along the flow path is a well-studied phenomenon in conventional injection molding; however, only a few papers are devoted to micro-injection molding [11,13,14,15,16]. Remember, by avoiding weld lines, you can lessen operations cost. This principle has been implemented on a complex component in the case of the spring-loaded cogwheel shown in Figure 5, for instance. The second technique, cascade injection moulding, can produce parts free from weld lines. Wang. Weld-line is a weak area which reduces the strength of the part locally. 025 100 120 140 160 180 200 220 240 Mold Temperature (F) LDPE PPEffects of mold temperature and pressure on shrinkage 0. Weld lines have been one of the common defects puzzling the injection molding industry. A poor knit line. With tighter heat controls, you can keep the material at the proper temperature to make sure the plastic keeps flowing and fills the mold cavity completely. Three terms that often get mixed up in injection molding are weld, meld and knit lines. This can occur when a polymer flow splits to go around an interruption (e. Yes, it does help, for two reasons: Often the weld line traps air and the ‘dump’ acts as a vent to allow the air to escape. Fig 13:- Detailed view of weld lines. To prevent knit lines, injection molders can increase the temperature of the molten resin to prevent solidification from starting too soon, and increasing injection speeds and pressure are also potential solutions. These lines can occur at the gate location, where the plastic enters the mold, or anywhere along the flow path. We'll show you how. Adjust Injection Molding Parameters: Optimizing injection speed, pressure, and temperature can help ensure better melt flow and reduce the likelihood of weld line formation. If you turn on the spigot to a garden hose, you will hear a hissing sound at the nozzle end for the first few seconds. The line where two resin flows “knit” or “weld” together during injection molding is called a weld or knit line. Tekanan yang kurang mampu untuk mendorong aliran dan kembali pada posisi semula dapat menimbulkan weld line. Weld Lines and Fibers There are two basic types of weld lines: the stagnant and the flowing [1]. So today we are going to take a look at the five most common defects in injection molding and their solutions. Adjust the design for the flow pattern to be a single source flow. Weld lines, knit lines, and meld lines are terminologies to describe the imperfections of finished parts in plastic injection molding processing. industry, to deliver intuitive injection mold-ing simulations embedded in NX. 2-1. g. This will produce parts with aExperimental results show that the weld-line strength from a standard test is not applicable in microinjection molding. Many researchers had emerged with several. Weld lines are a common issue in injection molding, and occur when two flow fronts meet and fuse together as the material cools and solidifies. 3. The impact behavior of weld-lines in injection molding. Injection molding can be performed with only one of these materials like glass, plastics, etc. In a weld line, reinforcement fibers adopt an orthogonal orientation with respect to the filling direction, which results in a significant reduction in the strength and. The gate location should enable the two flow fronts to merge easily and continue to flow beyond the weld line. The weld line in injection molding is created when two melt streams connect, as shown in Figure 1. In this study the polycarbonate (PC) and carbon fiber (CF) are used as the experimental materials to investigate the impact of injection molding process parameters on tensile strength of weld line. The occurrence of a weld line means a significant problem both aesthetically and mechanically in the design of injection moulded parts. Weld line strength is influenced by the temperature at which the weld line is formed and the pressure exerted on the weld until the part freezes, (pressure is 0 at the weld line). Controlling the mold’s temperature could also minimize the weld line’s effects. Let’s review what causes meld and knit line imperfections, how they’re different, and how they affect part durability. 1. Recently hired at plastic injection molding simulation software provider Moldex3D, Nicholson was spurred to undertake the research study following a conversation with a customer experiencing weld-line woes. The formation of weld lines and their location along the flow path is a well-studied phenomenon in conventional injection molding; however, only a few papers are devoted to micro-injection molding [11,13,14,15,16]. If the plasticizing ability of the plastics injection molding machine is insufficient, the plastic cannot be fully plasticized, resulting in weld lines when filling the mold. Meld and knit lines are actually both different types of weld lines. In this experiment, several ejector. How Are They Formed? Molten plastic resin is injected into a mold cavity through an opening known as a gate. This may require higher melt temperature or lower injection speed . A weld line is a visible seam where two areas of the molten plastic meet. Injection-molding machine is the Negri Bossi VE210-1700 with screw. Islyn Thomas summarized the need for a particular vent location better than I ever could. Unless you are manufacturing an extremely simple part with one gate and a unidirectional flow front, your part will have weld lines. Weld-Line in an injection molded part develops when two or more melt fronts are converged together. Again, consult with professionals as to how you could improve mold designs. , Ltd. Munich, Germany: Carl Hanser Verlag, 1994. Fig. Burn Marks. It provides scientific basis for designers toWeld lines are significant defects that affect injection molding quality, causing the poor appearance and low mechanical strength of injection‐molded parts. A poor knit line can cause only cosmetic blemishes or it can significantly weaken the structural integrity of a part. Instead of using flow leaders and deflectors to control the locations of the weld lines, this paper presents an approach to specify the locations of the weld. This gives a clue as to how it was formed. ”Weld Lines in a plastic cover. The flow disruptor is a small insert introduced inside the injection molding cavity, in the weld line area, and its objective is to mix the melt and disrupt fountain flow in order to blur and. This occurs wherever there is a hole, notch, or any other feature on a part which divides the flow of plastic into 2 separate “flow fronts. If so, look for an alternative resin. Again, consult with professionals as to how you could improve mold designs. ” Another. The possibility of the functional thin film for. สาเหตุรองของการเกิดปัญหาการเกิดประกายเงิน (silver streak) 1. 4 at different time steps (legend scale is volume fraction of. Save. The appearance quality of plastic parts in weld lines can be improved significantly through the rapid heating cycle molding (RHCM). Kondisi ini juga bisa menandakan bahwa mesin injection. DYNAPLAST Tbk. Melt temperature does effect the weld. A simulation process was conducted to determine the recommended setting of injection moulding parameters and the range of the variable. Weld lines can be caused by many reasons, which covers the various aspects of mold, process, raw materials and product design, etc. 2017-01-0481. High-density PE was also moulded in the same conditions but in a lower temperature range (145 to 220°C). Weld lines are a common imperfection to be found in most plastic injected molded parts. In this paper, a weld line factor (W-L factor) was adopted to describe the. JENIS-JENIS DEFECT (CACAT) PADA PRODUK INJECTION MOLDING PT. If the plasticizing ability of the plastics injection molding machine is insufficient, the plastic cannot be fully plasticized, resulting in weld lines when filling the mold. Avoid knit lines when designing a molded part to improve cosmetic appearance and functionality. Ada berbagai penyebab mengapa weld line bisa muncul pada permukaan produk plastik. If there’s too much mold release, you may require a higher pressure to push it through the machine. and most commonly, thermoplastic polymers are used. Flow-induced filler orientation and weld lines are un-avoidable facets of the injection molding process. Information about PA6/PA66 (Nylon) Injection Molding. (2) Causes & Countermeasures (See the table below) *Note: Flash also tends to occur when the injection pressure/speed are too high, but molding time is too long and mold temperature is too low. The most common and one of the most challenging injection molding defects are weld and knit lines. 7 of the reference. Weld Line Factors for Thermoplastics. . 2. Weld lines create visible marks, but this type of injection molding defect can also reduce a part’s strength and durability. 2-1. ing weld line properties of injection molded thermo-. And how to use the 3 modes of the sequential controller correctly to prevent burn marks, weld line, short shot, and other part defects in injection molding. As compared to a weld line, the flow fronts come together at less than 135 degrees. Designers can easily set up and perform analysis with only a few clicks. In this paper, two different injection molding tests were completed. The design of the mold, as well as the part being molded, has a significant impact on the success of the process. Xie L. Plastic part design for injection molding – An introduction. Co-injection molding technique is a useful way to study weld lines, which can offer more detailed information of the. Why You Should Avoid Weld Lines. (3-1) Increasing the Resin Temperature at the Weld Line Section. 015 0. Wavy lines are another feature of weld lines. Lesson 6: Meld and Weld Lines (Processing) When plastic flows into an injection mold, the internal flow pattern depends on the part design, mold design, and processing factors. (1)Injection Machine Poor plasticization and non-uniform melt temperature – appropriately extend the injection molding cycle, to ensure thorough plasticization, and change for a machine with a larger. There are several possible causes that need to be investigated to troubleshoot weld lines in injection molding. The weld lines in injection moulded parts arise as a result of the collision of two fronts of the flowing material, which fills the mould cavity and are sometimes unavoidable. Zhao, X. The following guidelines have. In recent years, researchers have. In this study, one injection mold. of micro injection molding process simulation by technology update and progress. 030 0. Its design significantly impacts the final product’s appearance, strength, and functionality, making it crucial for manufacturers to understand its intricacies and variations thoroughly. Park et al. 2(a, b). Recently, injection molding process has generated growing interest, exhibiting great potential to easily fabricate unique polymeric materials for industrial applications. Injection pressures too high Reduce pressure . * Corresponding author, e-mail: [email protected] an injection molding process, a weld-line forms when two flow fronts meet each other. Weld lines can significantly reduce ultimate tensile strength (UTS) and fracture strain of talc filled polypropylene (PP). Fracture behavior of weld lines in injection molded components loaded under real operating conditions. In manufacturing, the Weld line or Knit line or Meld line is the line where two flow fronts meet when there is the inability of two or more flow fronts to "knit" together, or "weld", during the molding process. Xie L, Ziegmann G (2008) A visual mold with variotherm system for weld line studying micro injection molding. These lines usually occur around holes or obstructions and cause locally weak areas in the molded part. A visual mold with variotherm system for weld line study in micro injection molding. However, research about the computer determination of weld lines in injection molding remains scarce. Causes. Berikut beberapa di antaranya: 1. In this paper, a weld line factor (W-L factor) was adopted to. Venting at Weld Lines. Weld lines Weld lines are weak areas formed by converging flows of plastic that can lead to mechanical part failure if not properly accounted for in the part design. To explore the formation of weld lines in injection molding, a. If weld lines are unavoidable due to multiple gates in a moulding, they should be positioned in the non-critical region. It is possible to pre. Abstract. A weld line occurs when two or more molten plastic flows meet and fuse during the injection molding process, resulting in a visible line on the surface of the molded part. One of the things that can compromise an injection molded part is a weld line, also called a knit line. To increase the sustainability of the process, determinative parameters and their effects should be examined. Valve gates also make weld lines less of. Weld lines are a common issue in injection molding, and occur when two flow fronts meet and fuse together as the material cools and solidifies. Insufficient injection pressure and speed can cause weld lines. Equipment. 2020-01-1306. Weld line defects in injection molding is a line or lines on the part surface that caused the part looking ugly or cuased part lifetime, or even broken easily. The thermo. Just check out some of it on the above lists. Weld lines are also known as knit lines. In some cases, a weld line can also cause a loss of strength and impact resistance. 3. This paper analyzes production data from injection molding processes to identify key interactions between the process variables from different material categories using the network inference method called “bagging conservative causal core network” (BC3net). Instead, a line that looks like a seam forms. Gava and co-workers implemented an investigation devoted to the de-weld lines in injection molded thermoplastic composites. Weld lines not only affect the appearance and quality of products, but also cause negative influences on the mechanical properties. 025 100 120 140 160 180 200 220 240 Mold Temperature (F) LDPE PPAbstract. Gate Placement: Properly positioning the gate can direct the melt flow to minimize weld lines or relocate the weld line to non-visible areas of the part. An injection molding gate is a critical component in mold design, acting as the passage through which molten plastic travels from the runners into the mold cavity. The weld-lines are undesirable from both aesthetic and functional points of view and their effect is different for varied materials, process conditions, loadings, forms of weld-line, etc. Ideally, the resin flow will split into two flow fronts to pass around the obstruction and then recombine into a single flow front. Minimize the use of release agent. Double push filling method. This occurs wherever there is a hole, notch, or any other feature on a part which divides the flow of plastic into 2 separate “flow fronts. Known methods to reduce weld-line effects are the optimization of injection molding parameters, enhanced tool temperature, and using special molding tool devices. 2. This failure causes the product to be damaged during use. The defects encountered could be caused by mechanical factors, such as poor mold design and mold manufacturing, or by processing related factors, such as incomplete kneading, inadequate molding pressure, injection. (2011) and Fig. Edge Gates. The diameter of the hole is 12 mm. 4If the injection gate is not properly designed, it can cause the formation of defects like sink-mark, warpage, short shot, weld-line, air traps, and other faults [15]. As the weld line can significantly lower the mechanical strength of µIM parts, it is relevant to clarify the position of weld. DescriptionThis insertion ensures the separation of the melt flow. Investigations on WLs in micro injection molded parts were performed in Refs. A micro-photography study on the cross-section of the weld-line was also carried out. Meld and knit lines are actually both different types of weld lines. The weld lines in injection molded parts arise as a result of the collision of two fronts of the flowing material, which fills the mold cavity and are sometimes unavoidable [1][2][3] [4]. Plast. Our weld line injection molding is essential for the best result of finished molded products. Article Google Scholar Deng YM, Zheng D, Lu XJ (2008) Injection moulding optimization of multi-class design variables using a PSO algorithm. Weld-line is a defect that arises in injection molding when two or more flow fronts collide. The microstructure of weld lines is clearly observed from the micrographs. For multiple gate and complex part. The results showed that the tensile strength of PE remains unchanged in the presence of weld lines. gas, which can cause blistering, as well as poor weld lines, warpage and the formation of cold slugs that affect filling and part mechanical properties. Weld lines are the result of fundamental physical effects taking place inside of the mold tool cavity, they are common imperfection to be found in most plastic injected. The following are the reasons. 010 0. technical ulletin SPECIALTY POLYME RS Design and Production of Injection Molding ToolsWeld lines have been one of the common defects puzzling the injection molding industry. Injection molding weld lines refer to a line on an injection molded part that is generated where the two halves of the mold come together. Failure may result due to the assembly torque, or end-use application loads (temperature, creep). In the first, sequential injection moulding, the lines are displaced to noncritical areas of the moulding. These lines can occur due to variations in wall thickness, gate location, or the geometry of the part. Plastic Rapid Injection Molding is popular not only in low volume manufacturing but also in large quantities molding, it is the most common way to manufacture plastic parts. Weld Lines. From Understanding Weld-line Integrity by Sabic Innovative Plastics, p. Effect of geometry and injection-molding parameters on weld-line strength. 3. In this study, we apply the technique of SAW to explore the acoustic properties near injection-weld lines by comparing the velocity of. [1] Kobayashi et al. Change the gate locations. 4. com1. Part design features may cause a material flow to split and rejoin as it flows around design features in a mold. Numerical results show that weld lines can be predicted accurately, and the formation and evolution processes of weld line can be shown more clearly by co-injection molding technique. In this study, polypropylene (PP) was compounded respectively with carbon nano fibers (CNFs) and TiO 2 nano particles at various weight fractions (10, 20, 30, 35. The problem with ‘weld lines. Weld lines can be caused by material flowing around holes or inserts in the part, multiple injection gates or variable wall thickness where hesitation or "race tracking" can occur. Weld lines can compromise the strength and aesthetics of the part, so it’s important to carefully design the mold and. Flashes, 3. [ 18 - 21 ] In addition, the effects of flow behavior of the polymer melt due to the optimal process parameters for the minimization of weld-line effects are an important consideration. Sequential valve gate technology. 2004; To study the weld line formation of colliding flow fronts the filling of a mold cavity was simulated. In. Plastic injection molding is a versatile and efficient way to produce durable, detailed parts of endless sizes, shapes, and purposes. When two or more streams of plastic meet and fuse together, a visible line or weakness is formed on the surface of the finished product. สาเหตุรองของการเกิดปัญหาการเกิดประกายเงิน (silver streak) 1. 3. Participating in DFM and mold flow analysis is a good way to achieve this. Weld lines are formed when two orAbout Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday Ticket Press Copyright. A weld line refers to a line, notch or color change that is created on the molded part caused by the convergence of two separate flows of molten plastic. Lugs size is 65 х 24 х 4 mm. Weld line defects are a common part defect that occurs when the injected plastic flows around a solid piece of the mold and does not knit back together. Polymers 2023, 15, 2440 3 of 21. Micro-injection molding (µIM) is a widespread process for the production of plastic parts with at least one dimension, or feature, in the microscale (conventionally below 500 µm). Many works deal with weld lines and their dependence on processing parameters for conventional injection molding, but only a few works focus on the weld line in µIM. Weld lines appear as a result of the flow of molten plastic during the injection molding process. Silver Streak. The weld line in an injection molding product can significantly impact the strength and durability of the last part [12] [13][14][15]. As a result this. 32–24. The terahertz time-domain spectroscopy (THz-TDS) imaging technique was used to detect the weld line defect of an injection-moulded short glass fiber-reinforced composite. He now teaches courses in injection molding and plastic part design at the Polymers Center of Excellence and UNC-Charlotte in Charlotte, N. This paper presents the. Its properties make it possible to create thin-walled parts having close tolerances in fast cycles over long. This defect occurs due to the temperature and pressure not being high enough, causing premature solidification. Figure 2. Description Knit lines, weld lines, mold lines, or flow lines in injection molding are faint lines that become visible on certain plastic parts. One common issue that frequently arises during injection molding is the formation of weld lines. The weld line in injection molding is created when two melt streams connect, as shown in Figure 1. This is expected to achieve maximum results while the pressure holding effect will also increase. Microsyst Technol, 14 (6) (2008), pp. One solution is to prevent the weld lines from forming in regions that are. Flow front tracing simulation results for weld line developing process in micro injection molding with Comsol ® Multiphysics 3. Cracking and/or Crazing can be defined as a fracture or surface breakage in the material of a molded part, usually found in weld line areas, but also on the surface in general. This consequently produces weld lines. Weld line formation in the injection molding process occurs when two or more melt flow fronts contact each other immediately after the cooling process. They can affect the strength and appearance of the part, depending on the temperature, pressure, speed, and mold design of the injection molding process. In this study, the effects of injection temperature, injection pressure, and fiber content on the mechanical properties of weld lines were studied for carbon fiber-reinforced nylon. 3. The weld-lines are undesirable from both aesthetic and functional points of view and their effect is different for varied materials, process conditions, loadings, forms. when two or more melt flow fronts contact each other immediately after the cooling process. Weld lines. and Mosle, H. When two or more strands of molten plastics meet in the mold, a weld line will be produced at the junction [1,2]. Weld lines are visually undesirable and a plastic part is structurally weak at weld line positions. Some of the common fixes for weld lines include: Increase the resin temperature to ensure both sides of the weld line are liquid when colliding. “I realized weld -line problems are a very common issue for injection molded parts,” Nicholson told Plastics Technology. The relative weld-line strength is defined as the ratio of the strength of specimens with a weld line and a comparable sample with the same geometry but without the weld line, and this measure mainly depends on the molding conditions, such as melt temperature, mold temperature, and injection pressure [8]. 005 0. The need to minimize fiber breakage, plus the higher viscosity of materials with. Short Shot Short Shot adalah suatu kondisi dimana, plastik leleh yang akan diinjeksikan kedalam cavity tidak mencapai kapasitas yang ideal atau sesuai settingan mesin. In order to reduce these weak points, a special ram technique for injection molding, which can be integrated into the mold, was investigated. a) Multi-fiber connector micro injection molding simulation b) 3D simulation of micro gear with 150µm diameter for weld line position prediction c) 3D micro injection molding filling simulation of micro gear with 180µm diameter Fig. For glass-filled grades, the thickness at the weld line can be slightly larger than the nominal value due to lower shrinkage associated with vertical fiber orientation at the weld line cross. Increase the mold temperature. 298 µm and the weld line on the heated region was almost eliminated with the aid of induction heating. In the present work, the micro specimens were investigated. For multiple gate and complex part, molding weld-lines are unavoidable, therefore mechanical behavior of the weld-line needs to be predicted. This is a video excerpt from our Problems & Solutions Course - Weldlines. Vertical Plastic Injection Molding Machine [10, 11, 12] 2. 809-814. 5 mm, 1. Microsyst Technol. Physics. Weld line is formed when two different melt flows converge, as illustrated in Fig. In addition, its tensile strength and stiffness will be sharply decreased. Keywords: Flow behavior , Injection molding , Particle tracking , Visualization , Weld-line Article MetricsSimulations and experiments were conducted with gas temperatures of 200–400 °C to investigate the impact of external gas-assisted mold temperature control (Ex-GMTC) on the quality of weld line of molding products. Weld lines in injection molding are frequently unavoidable. M. Materials Science. Weld lines are a common defect generated in injection molding, which apparently affects the performance of final products, but the available reports on carbon fiber-reinforced thermoplastics are. In order to study the weld line developing process and its influence on mechanical properties in micro injection molding, a visual mold with variotherm system mold was designed and fabricated. Email him at jhenz@polymer-center. Procedia Mater Sci 2014; 3: 2048–2053. Usually it’s a straight line, and often to be found radiating away from a hole, inclusion or other such part feature. , 47 (2008. A family of short carbon fiber-reinforced thermoplastic (CFRTP) compounds specifically formulated for injection molding is being used to extend the capabilities of thermoplastic composites in a variety of part sizes and complexities. Because of the ever-increasing requirements for parts performance, lots of researchers have perf.