010 0. Steven. Fig. อุณหภูมิของพลาสติกเหลวสูงเกินไปจนก๊าซหรือความชื้นแยกตัวออกมาได้. , 47 (2008. This is a video excerpt from our Problems & Solutions Course - Weldlines. In addition, its tensile strength and stiffness will be sharply decreased. Weld lines can. The flow of the material in the injection mould takes place through the gate. They found that the weld line is a zone between 2 and 8 mm wide extending throughout the thickness in whichTo investigate the effect of hot gas heating in injection molding on the weld line appearance, an experiment was conducted with the molding parameters listed in Table 2. Weld-line is a defect that arises in injection molding when two or more flow fronts collide. Weld Line Phenomenon: Surface defect in which the weld, or the part where the flows of melted plastic meet inside the mold, shows up on the surface as a groove or pattern. From Understanding Weld-line Integrity by Sabic Innovative Plastics, p. A weld line is often unavoidable. [ 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. Poor weld line Ⅰ. , 509 (2) (2011), pp. From Understanding Weld-line Integrity by Sabic Innovative Plastics, p. A weld line develops when two or more flow fronts come together but do not meld completely because of partial solidification. 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 are a common issue in injection molding, and occur when two flow fronts meet and fuse together as the material cools and solidifies. Weld lines appear as a result of the flow of molten plastic during the injection molding process. These are preferred over weld lines as they will normally result in improved cosmetics and structure. These are caused by the shot of molten plastic moving at different speeds throughout the injection. and most commonly, thermoplastic polymers are used. The thermo-rheological findings were used to investigate the sources of weld line weakness. Procedia Mater Sci 2014; 3: 2048–2053. 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). T he decreased gloss level at the position of. Change the gate locations. 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. Weld-line yield strength, yield strain, and failure strain of talc-filled polypropylene increase with increasing melt temperature and increasing hold pressure. An injection molding gate is the designed opening in a mold through which molten plastic is introduced into the mold cavity, initiating the process of taking the shape of the desired part. In addition a weld line can be moved to an area where it is less visible. 22 shows how the weld lines are formed when the melt splits around core pins during the injection molding process. org or visit 80-ton Victor injection molding machine, equipped with an accumulator capable of delivering maximum flow rate of 138 cm 3 /s and providing maximum injection pressure of 210 MPa, is utilized for experiments. Plastic Injection Molding Process. 2021年4月23日 / by admin. [8,9] It is capable of. In injection molding, it is often important to maintain consistent color throughout the part. With Ixef® PARA compounds, the strength of a weld line is typically 90 MPa (13,000 psi). ชิ้นงานเกิดเป็นเส้นรอยประสาน Weld line. Weld lines appear as a result of the flow of molten plastic during the injection molding process. In the sense that the weld line is better formed before the resin. + Move gate (to where it is not visible). To explore the formation of weld lines in injection molding, a. Polym. 015 0. Materials Science. 9 – Over Packing. Five injection molding process parameters, including mold temperature, melt temperature, packing pressure, injection. Increase the mold temperature. The effects of these two injection molding process parameters are explained in terms of their influence on the skin-core morphology observed on the fracture surfaces in the weld zone. Meddad and Fisa [3] found that the weld line is a zone between 2 and 8 mm wide extending throughout the thickness in which the fibers are oriented almost. 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. The diameter of the hole is 12 mm. 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). 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. 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. C. Microsyst Technol, 14 (6) (2008), pp. Fig 13:- Detailed view of weld lines. 1007/s00397-003-0339-2 ORIGINAL CONTRIBUTIONCauses and Remedies of Sink Marks In Injection Molding. Weld lines, knit lines, and meld lines are terminologies to describe the imperfections of finished parts in plastic injection molding processing. Weld lines are among the most critical structural defects in parts made by the injection molding of fiber-reinforced thermoplastics, explained Sirmax in a press release. Neat polypropylene retains nearly 90% of its strength on a properly designed and molded weld line. 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. By the reflection method and a high speed camera, the visual system can be used to record and observe the forming process of micro weld lines during the. This occurs mainly in the presence of barriers that divide the melt flow in. We recently had a few pieces (2-3%) crack after assembly, while in storage (not installed, still in the package). Methodology. Weld lines may appear like seams or scratches, but that is not what they are. The following guidelines have. (3-1) Increasing the Resin Temperature at the Weld Line Section. Injection molding is nothing without molds. Weld lines in injection molding are formed when two or more flow fronts of molten plastic material meet and merge during the molding process. We'll show you how. Xie L. Figure 1 below shows the development of a weld line. What Causes Weld Lines in Plastic Injection Molding Parts? I. This happens when the molten plastic is injected into the mold cavity and flows around an obstacle such as a pin, hole, or protrusion, and then comes back together. spelling: injection molding) is a manufacturing process for producing parts by injecting molten material into a mould, or mold. 2. 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. Weld lines are formed when there is an inability of two or more flow fronts to ‘knit’ or ‘weld,’ together during the molding process. Weld Lines and Fibers There are two basic types of weld lines: the stagnant and the flowing [1]. 5. Weld line injection molding troubleshooting. Weld lines occur when melt flow fronts meet during the injection molding of plastic parts. ” Weld Lines in a plastic cover. Adjust the design for the flow pattern to be a single source flow. Shaofei Jiang. Redesign the mold to prevent the weld line. Weld lines can be a weak spot and have therefore to be taken into consideration in part design. Criens, R. (+86) 760 2222 2556 enquiry@starrapid. Figure 1a illustrates how the weld line is produced when two melt streams merge during the final filling process. Weld lines can appear on the components when the molten plastics meet each other as they are flowing from two different parts of the mold. Why You Should Avoid Weld Lines. (1) Flash: Extra plastic material in the shape of films or burrs, which appears on the parting surface, around the runner or in the insert crevice. Weld lines not only affect the appearance and quality of products, but also cause negative influences on the mechanical properties. In. Polymers 2023, 15, 2440 3 of 21. Equipment. Figure 2. The present work focuses on studying the effect of packing pressure on strength of stagnation weld-line. G. In this paper, a weld line factor (W-L factor) was adopted to describe the. Remedies: Raise the temperature of the mold or molten plastic. Table 2-Glass Fiber Glass Fiber Glass Fiber Glass Fiber 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. ”. Minimize the use of release agent. Published 5 July 2019. molding Æ Thermoplastics Æ Weld line Æ Simulation Rheol Acta (2004) 43: 240–245 DOI 10. 000 0. (3-1) Increasing the Resin Temperature at the Weld Line Section. Weld lines can be caused by many reasons, which covers the various aspects of mold, process, raw materials and product design, etc. Materials Science. Double push filling method. 2007; Lotti et al. The edge gate is the most popular and straightforward injection mold gate design. With Ixef® PARA compounds, the strength of a weld line is typically 90 MPa (13,000 psi). Injection molding can be performed with only one of these materials like glass, plastics, etc. To explore the formation of. In injection molded parts, there are 2 types of weld lines: The first type of weld mark is called cold-melt joints and is formed when the melt front enters the cavity with different. 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]. Tekanan. Siemens PLM Software. injection molding. 1. 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. The design of the mold, as well as the part being molded, has a significant impact on the success of the process. 2020-01-1306. 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. The main types of injection molding defects are: 1. Slow down injection speed. ac. How Are They Formed? Molten plastic resin is injected into a mold cavity through an opening known as a gate. When molten plastic flows, it forms a smooth continuous flow until it meets an obstruction. As the weld line can significantly lower the mechanical strength of µIM parts, it is relevant to clarify the position of weld. • Reduce runner dimensions and maintain the same flow rate. 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. th INTRODUCTION Injection molding is one of the most 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 still rather few. This study presents an innovative approach to enhancing weld line strength in advanced polymer injection molding through applying gas-assisted mold. In the first, sequential injection moulding, the lines are displaced to noncritical areas of the moulding. A weld line region is typically filled at the end of an injection stroke or during the pressure phase. Weld Line defect analysis, the most common of many defects in injection moulding products. Another relevant topic in injection molding is the presence of weld lines (WLs) and their properties, which could lead to part weakness through surface disturbances, optical issues and reduced bonding [21, 22]. 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. Weld lines in injection molding occur when two flow fronts meet and create a visible line on the surface of the molded part. Weld-line is a weak area which reduces the strength of the part locally. 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. Usually it’s a straight line, and often to be found radiating away from a hole, inclusion or other such part feature. Failure may result due to the assembly torque, or end-use application loads (temperature, creep). Weld lines form where two or more flow fronts come together and can create a cosmetic or structural problem. Poor weld line quality can lead to short-term or long-term product failures, initiated at the weld line. The weld line in injection molding is created when two melt streams connect, as shown in Figure 1. The occurrence of a weld line means a significant problem both aesthetically and mechanically in the design of injection moulded parts. Increase the mold temperature. Increase the injection speed to reduce the amount of cooling happening in the mold. Known methods to reduce weld-line effects are the optimization of injection molding parameters, enhanced tool temperature, and using special molding tool devices. Consultant @ Effinno Technologies, BSME, MBA - Bridge between Plastics Injection Molding Knowledge and Practice. Remedies: Reduce packing and fill rates by adjusting until the part is properly filled with minimum stresses. For multiple gate and complex part, molding weld-lines are unavoidable, therefore mechanical behavior of the weld-line needs to be predicted. Weld lines occur when melt flow fronts meet during the injection molding of plastic parts. First, an injection mold with triangular inserts was built to study the influence of meeting angles on material properties at the weld line. The effects of filling time, packing time, packing pressure, melt temperature, and mold temperature on the ultimate tensile strength (UTS) and the elongation value of the weld. 2. For multiple gate and complex part, molding weld-lines are unavoidable, therefore mechanical behavior of the weld-line needs to be predicted. This is expected to achieve maximum results while the pressure holding effect will also increase. Stagnant weld lines are formed when melt streams meet head-on. Weld lines often generate mechanically weak areas, because of the unfavorable perpendicular orientation of the macromolecules, fibers and/or other fillers to the direction of the main flow. (1) Flash: Extra plastic material in the shape of films or burrs, which appears on the parting surface, around the runner or in the insert crevice. 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. Burn Marks. ABS is a commonly used plastic in injection molding due to its excellent mechanical properties and chemical resistance. Known also as knit lines and weld marks, weld lines are difficult to eliminate completely, especially if your injection molded part requires holes. A flat product case was considered as an example of a typical aircraft structural element. The. The weld line refers to the process in which the liquid material is divided into two or more flows in the cavity during the injection process and merged together after a period of time [51,77,78,79]. Key words: weld line strength, thermoplastic composites, injection molding, wall thickness, skin and core layers Department of Materials Engineering, Faculty of Engineering, Kasetsart University, Bangkok 10900, Thailand. The microstructure of weld lines is clearly observed from the micrographs. Weld Line defect analysis, the most common of many defects in injection moulding products. Short Shot Short Shot adalah suatu kondisi dimana, plastik leleh yang akan diinjeksikan kedalam cavity tidak mencapai kapasitas yang ideal atau sesuai settingan mesin. reinforcement type and amount in nylon 6/6. Despite injection molding being recognized as a robust process for obtaining parts with high geometry accuracy, one last occurrence remains a challenge in micro-injection molding, especially when junctions are. [1] Kobayashi et al. See moreIncreasing the temperature of the mold or plastic material. Boost time too long Shorten boost time, lower boost pressure, or move transfer to an earlier position . As compared to a weld line, the flow fronts come together at less than 135 degrees. oped which factors the weld lines into the virtual design of chopped-strand-rein-forced thermoplastic parts. The type of resin used during injection molding plays a large role in whether or not a knit line will be present. This gives a clue as to. In this study, the effects of injection temperature, injection pressure, and fiber cont. When two or more strands of molten plastics meet in the mold, a weld line will be produced at the junction [1,2]. In this paper, a weld line factor (W-L factor) was adopted to. If the injection molding speed is too slow, however, there may be an insufficient filling of the mold. 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. 1. Controlling injection molding weld lines with good design and process control. The formation of weld line in the injection molding method is caused by the product and mold design that is one of the common mistakes. The possibility of the functional thin film for. 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. when two or more melt flow fronts contact each other immediately after the cooling process. 666 Azieatul Azrin Dzulkipli and M. Still, it can be seen to varied degrees depending on mold. Flow marks in injection molding are defects that manifest as a line or series of lines forming a pattern different in color from the other parts of the molded material. 8. The second technique, cascade injection moulding, can produce parts free from weld lines. This paper evaluates the shrinkage and strength of weld line using Design of Experiment and Response Surface Methodology in multi-objective optimisation utilising the injection moulding parameters. Our injection molding company is explaining what these imperfections are, why they can compromise. Wavy lines are another feature of weld lines. Let’s review what causes meld and knit line imperfections, how they’re different, and how they affect part durability. Azuddin / Procedia Engineering 184 ( 2017 ) 663 – 672 Fig. Powder injection molding comprises several processing steps, and defects may occur in each step if care is not taken. Weld line formation in the injection molding process occurs. 2) Vents in an injection mold should let the air out, but not the liquid plastic. (1998) for clear photographs. Processing Optimization Reduced frozen skin thickness: High injection speeds also contribute to a thinner frozen skin at the weld line. + Improve vent inside the mold. 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. Effects of cavity surface temperature on mechanical properties of specimens with and without a weld line in rapid heat cycle. 3. Flow lines are off-color lines, streaks, and other patterns that appear on the surface of a part. Weld-line is a defect that arises in injection molding when two or more flow fronts collide. It is important to investigate the weld line because the weld line area can. Threadline gap in-between part due to improper gate location in complex design parts including excess of holes (multipoint. 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. 1. 32–24. When two or more strands of molten plastics meet in the mold, a weld line will be produced at the junction [1,2]. Int J Adv Manuf Technol 52:131–141. 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. But add 30% glass and weld-line strength retention drops to only 34% as high as the compound with no weld. 1% higher than the ones without ultrasonic assistant, which indicates that the weld line strength in micro injection molding can be well reinforced by the ultrasonic oscillation due to the fact that ultrasonic oscillation induces better diffusion among the melting. Here we are looking at most common part defect that can come from injection molding called weld line. Weld lines are among the most critical structural defects in parts made by the injection molding of fiber-reinforced thermoplastics, explained Sirmax in a press release. Insufficient plasticizing ability of injection molding machine. 025 100 120 140 160 180 200 220 240 Mold Temperature (F) LDPE PPEffects of mold temperature and pressure on shrinkage 0. To resolve this issue, rapid heat cycle molding (RHCM) has attracted attention as an innovative PIM technology. (2011) and Fig. 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. A knit line, also called a weld line, occurs when the liquid plastic moves through the mold and hits more melted plastic and they don’t flow or fuse together. C. 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. In order to reduce these weak points, a special ram technique for injection molding, which can be integrated into the mold, was investigated. [1-2] investigated the weld line zone of injection molded glass-fiber-filled polypropylene (PP) composites. In order to prepare the weld line specimen by micro injection molding, a mould integrated with visual system and variotherm system was designed and constructed, shown as Fig. This model provides the necessary information. As such, optimizing mold designs should always be incorporated in your production model. 3 cc/sec, the weld lines are no longer perceivable above 130 C. Some of the approaches include the application of machine learning methods (Chen 2008; Manjunath and Krishna 2012; Kuo et al. Emerging Materials Research. Mold flow analysis is widely employed in mold making industry, utilizing data simulation software, the injection molding process can be simulated and presented on the computer,. • Optimize the design of the runner system. Article Google Scholar Deng YM, Zheng D, Lu XJ (2008) Injection moulding optimization of multi-class design variables using a PSO algorithm. Weld Lines. The next type of injection molding defect is ‘Weld Lines’. Below is one of the examples: !NOTE: if the weld lines is important to the cosmetic surface of your part, please bring this up to your mold maker during quoting phase. The utility model relates to a mold structure capable of eliminating the appearance of weld lines of a hole. At a low volumetric injection flow rate of 33. Strength measurements should be made to. A meld line is defined as the re-merging of two flow fronts. Furthermore, injection molding was applied by filling these pellets into a micro-injection molding machine (C. The graph shows clearly how an increasing cavity temperature correlates with a reduction in the weld lines. Facebook. Weld lines represent the region where two separated melt fronts recombine. These lines can weaken the strength of the part, and they can also be unsightly. Clamping unit berfungsi untuk memegang dan mengatur gerakan mold unit, serta gerakan ejector saat melepas benda dari molding unit, pada clamping unit lah kita bisa mengatur berapa panjang gerakan molding saat dibuka dan seberapa panjang ejector harus bergerak. This remains as a challenge for control engineers. 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 injection molded parts. Designers can easily set up and perform analysis with only a few clicks. The gate location should enable the two flow fronts to merge easily and continue to flow beyond the weld line. Weld line (also known as a knit 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. A new kind of weld line was. 4. We investigate the effects of various heating times and. + Adjust injection speed. 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. As the weld line can significantly lower the mechanical strength of µIM parts, it is relevant to clarify the position of weld. A tensile test specimen mold, which allows cavity thickness varying from 2. This results in a region of a different level of molecular entanglements than the bulk material. Star Rapid offers tips and tricks to improve your prototypes and production parts. 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. Clamping Unit. Flow marks in injection molding can be avoided if adequate measures are taken. Fatigue crack growth (FCG) tests were conducted on SEN specimens prepared from 100 mm. Lugs size is 65 х 24 х 4 mm. The weld line’s strength is reduced when. These flow fronts occur when the molten plastic material encounters obstacles, such as inserts, ribs, or other features within the mold cavity. 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. When two or more strands of molten plastics meet in the mold, a weld line will be produced at the junction [1,2]. These potential causes include: Known methods to reduce weld-line effects are the optimization of injection molding parameters, enhanced tool temperature, and using special molding tool devices. However, even with advanced technologies and precise control, the process is not without its challenges. Its appearance can be improved by adjusting parameters. 9. These lines usually occur around holes or obstructions and cause locally weak areas in the molded part. 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. In this regard, Taguchi orthogonal experimental design is adopted, and five processing parameters, the mold temperature, melt temperature, cooling time, packing. In the RHCM, the mold temperature profile plays a crucial. Avoid knit lines when designing a molded part to improve cosmetic appearance and functionality. Injection pressures too high Reduce pressure . 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]. Set up the process overflow and use it as the place where the weld line is generated, and then cut off and remove it after forming. Melt temperature is 250°C, mold temperature is 110°C. Weld lines. injection molding, (b) weld line and meld line, and (c) injection sample size and shape. Insufficient plasticizing ability of injection molding machine. The definition of weld lines: When multiple plastic flow fronts meet in the cavity after encountering inserts, holes, or areas with inconsistent flow rates or interrupted melt flows, or in the case of gate injection filling, the inability of two or more flow fronts to fully “knit” together will cause the linear weld marks. As the injection process continues, the two separated melt fronts meet again along the longitudinal section of the plate forming a weld line. 000 0. Install an ultrared light inside the hopper. Change the gate locations. The three parameters affecting operation were called injection pressure, injection time, and packing pressure which influence the quality of weld line. These lines can occur at the gate location, where the plastic enters the mold, or anywhere along the flow path. สาเหตุการเกิด weld line คือเมื่อการไหลของพลาสติกมาประสานกันนะจุดใดจุดหนึ่งและจุดนั้นเกิดความแตกต่างของอุณหภูมิในสองทิศทางการไหลจะทำให้เกิด. ). The result is part defects such as weld lines, poor finish, or discoloration. This reduced thickness of the frozen skin further enhances the visual appeal of the. open access Abstract Micro weld lines are the common problem that occurs for plastic molded parts through injection molding process. 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]. สาเหตุรองของการเกิดปัญหาการเกิดประกายเงิน (silver streak) 1. 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. This study presents an innovative approach to enhancing weld line strength in advanced polymer injection molding through applying gas-assisted mold temperature control, significantly increasing mold temperature beyond typical values observed in conventional processes. Mold vents should function the same way. Knit lines, weld lines, mold lines, or flow lines in injection molding are faint lines that become visible on certain plastic parts. Since weldline in plastic injection molding (PIM) has an influence on not only the strength but also the surface appearance of a plastic product, it is preferable to reduce it as much as possible for high product quality. Weld lines in injection molding are frequently unavoidable. Silver Streak. 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. [ 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. A weld or meld line is a weakness or visible flaw created when two or more flow paths meet during the filling process. In the case of PC, the model predicts satisfactorily the weld-line strength as a function of injection temperature. Investigations on WLs in micro injection molded parts were performed in Refs. Compd. Thus, a right gate design raises polymer temperature to prevent the formation of weld lines and flow marks. This study focus on the. examined the relationship between the structural and mechanical qualities in HDPE/PA6 mixture which is molded with weld line and without weld line in plastic injections [6]. For those who are new to the injection molding industry, may be confused about this product. Effects of fillers and/or reinforcements on weld-line strength of nylon 6/6. Here are some reasons why design is important for injection molding. Causes. Weld lines are visually undesirable and a plastic part is structurally weak at weld line positions. 030 0. A weld line is a mark left on the surface of a plastic injected molded part. Injection molding of large/complicated products are usually prepared by multiple compounds, which produces weldlines once the melt fronts are joined by impingement flow. Weld or knit lines are perhaps the most common and difficult injection molding defect to eliminate. 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. This article will introduce you the usage, types, and advantages of the Sequence Injection Timer. Wu CY, Ku CC, Pai HY (2011) Injection molding optimization with weld line design constraint using distributed multi-population genetic algorithm. For this purpose, the width of the weld line calculated by Sigmasoft is. Polym Eng Sci 45(7):1021–1030. They occur when melt flow fronts collide in a mold cavity. In this way critical areas of the interface in regard to the lack of interdiffusion and the inappropriate molecular orientation were found to be placed near. This study examines the impact of injection parameters on the weld line strength of the polyamide 6 and 30% fiberglass (PA6 + 30% FG) composite samples. , Ltd. Flow-induced filler orientation and weld lines are un-avoidable facets of the injection molding process. <Materials> Pre-dry thoroughly. Weld lines in injection molding are a type of cosmetic defect that detracts from a plastic part’s appearance. Zhao, X. In this paper, aiming at the problem of weld line defects in the injec- tion process of a key phone panel, the injection process is optimized by using Moldflow and drop simulation. Voids and bubbles, 6. Proper venting is also required to ensure good weld-line quality. NX Mold Flow Analysis. 2. 5. 809-814. This paper presents the.