. Weld line strength vs. In recent years, researchers have. In the sense that the weld line is better formed before the resin. Weld lines not only affect the appearance and quality of products, but also cause negative influences on the mechanical properties. This study focus on the. + Improve vent inside the mold. 4 at different time steps (legend scale is volume fraction of. How to Reduce Weld Line in Injection Molding? Weld lines are a common issue that occurs in injection molding. Effects of mold temperature and pressure on shrinkage 0. 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. 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. Effects of cavity surface temperature on mechanical properties of specimens with and without a weld line in rapid heat cycle. We have various types and models available. Remedies: Raise the temperature of the mold or molten plastic. Weld line. Procedia Mater Sci 2014; 3: 2048–2053. 2. Effect of process parameters on the relative weld line strength From injection molding practice and literature, 1, 3,4 it is generally accepted that: if a weld line forms before the filling is. Berikut beberapa di antaranya: 1. 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. <Mold> Increase (or decrease) the size of the runners and gates. 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. Wang, G. A quantitative evaluation of the appearance quality of weld lines in RHCM parts. Although this phenomenon occurs in almost all the commercially important polymer. ” Weld Lines in a plastic cover. Known also as knit lines and. The strength of the weld-line area can be increased by optimizing injection molding process parameters like melt temperature, injection speed, packing pressure, changing gate type and location, etc. Again, consult with professionals as to how you could improve mold designs. Avoid knit lines when designing a molded part to improve cosmetic appearance and functionality. In this paper, a kind of polypropylene (PP) foam plastic parts with special weld lines were obtained by core-back foam injection molding with chemical blowing agent. This reduced thickness of the frozen skin further enhances the visual appeal of the. Proper venting is also required to ensure good weld-line quality. 2002), the use of simulation approaches (Berti and. Conventional injection molding is widely used to produce plastic parts, mainly in the automotive industry, due to the high production ratios and quality of. 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. Fracture behavior of weld lines in injection molded components loaded under real operating conditions. In the heating step, the heatingOverview of the injection molding process. ชิ้นงานเกิดเป็นเส้นรอยประสาน Weld line. In this study, one injection mold. Weld lines can be caused by many reasons, which covers the various aspects of mold, process, raw materials and product design, etc. Weld lines can be caused by several different problems: Low temperature of injection moulding machine barrel. Weld-line is a weak area which reduces the strength of the part locally. Weld lines appear as a result of the flow of molten plastic during the injection molding process. Remember, by avoiding weld lines, you can lessen operations cost. 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. Weld lines can compromise the strength and aesthetics of the part, so it’s important to carefully design the mold and. Three terms that often get mixed up in injection molding are weld, meld and knit lines. In injection molding, it is often important to maintain consistent color throughout the part. Insufficient injection pressure and speed can cause weld lines. The strength of the weld-line area can be increased by optimizing injection molding process parameters like melt temperature, injection speed, packing pressure, changing gate type and location, etc. Melt temperature does effect the weld. 10 in Nguyen-Chung et al. In this regard, the plasticizing ability of the plastic injection moulding machine should be checked. Injection molding is one of the most established and well-known methods of plastic processing. Designers can easily set up and perform analysis with only a few clicks. They can affect the strength and appearance of the part, depending on the temperature, pressure, speed, and mold design of the injection molding process. 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. 015 0. Weld lines occur when melt flow fronts meet during the injection molding of plastic parts. Fig. For thick-walled parts, slow injection rates result in more uniform polymer distribution . th e use of design of e xperiment techniq ue. As a result this. 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. We investigate the effects of various heating times and. The most common and one of the most challenging injection molding defects are weld and knit lines. Strength measurements should be made to. 030 0. The weld-lines are undesirable from both aesthetic and functional points of view and their effect is different for. Injection molding of large/complicated products are usually prepared by multiple compounds, which produces weldlines once the melt fronts are joined by impingement flow. Adjust the design for the flow pattern to be a single source flow. (+86) 760 2222 2556 enquiry@starrapid. Polym Eng Sci 45(7. Fortunately, there are several. open access Abstract Micro weld lines are the common problem that occurs for plastic molded parts through injection molding process. DYNAPLAST Tbk. They occur when melt flow fronts collide in a mold cavity. This failure causes the product to be damaged during use. Gate position in injection mold. In our DFM report, we will analyze the possible weld lines. 4. Weld lines represent the region where two separated melt fronts recombine. 18/06/2021. Known methods to reduce weld-line effects are the optimization of injection molding parameters, enhanced tool temperature, and using special molding tool devices. A weld line develops when two or more flow fronts come together but do not meld completely because of partial solidification. Munich, Germany: Carl Hanser Verlag, 1994. The tensile stresses of the weld lines with ultrasonic functions are 8. industry, to deliver intuitive injection mold-ing simulations embedded in NX. Weld lines, knit lines, and meld lines are terminologies to describe the imperfections of finished parts in plastic injection. 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. From: Polylactic Acid (Second Edition), 2019. Mechanical properties of the weld line defect in micro injection molding for various nano filled polypropylene composites. Wolfgang Homes, head of the applications department of Eurotool, a manufacturer of hot runner systems, clarified the two methods for IMI, noting that. 6. The type of resin used during injection molding plays a large role in whether or not a knit line will be present. Burn Marks. Amongst weld line. 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. After that, the compounds were injection-molded into tensile samples with and without weld lines to. Figure 2. Weld lines are injection molding defects that can be mitigated by a number of tactics that depend on your part design. Weld lines appear on the surface of a molded part where the molten material converges after splitting off into two or more directions in a mold. Increase the melting temperature. Sink Marks Cause 3: Improper Pack or Hold Pressure. 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. A micro-photography study on the cross-section of the weld-line was also carried out. 000 0. 3. Weld Lines. A meld line is defined as the re-merging of two flow fronts. Weld-line yield strength, yield strain, and failure strain of talc-filled polypropylene increase with increasing melt temperature and increasing hold pressure. (2) Adjust the injection speed: high speed allows the melt to reach the confluence without cooling down, and low speed allows time for the air in the cavity to be discharged. Maintain a holding pressure that is no more than 1/2 the. This customary mark is caused by differential rates of cooling in the resin where. The graph shows clearly how an increasing cavity temperature correlates with a reduction in the weld lines. 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. Steven. Wu CH, Liang WJ (2005) Effects of geometry and injection-molding parameters on weld-line strength. 3. Weld line additionally called as knit line, is a defect that occurs when the injected plastic meets within a. + Optimize holding pressure time. The weld lines that occur in injection mouldings are critical areas on which depends on the strength of the mouldings. Mobile 0813; Shinko Sellbic Co. According to the weld line distribution map of six gate schemes shown in . 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. 2. Change the gate locations. 2020-01-1306. In some cases, a weld line can also cause a loss of strength and impact resistance. Weld lines can impact the strength and appearance of the final part, and are often considered a defect. 22 shows how the weld lines are formed when the melt splits around core pins during the injection molding process. Causes. Meld Lines. Raising the mold temperature will keep the material molten longer, resulting in stronger weld lines and even elimination of weld lines. 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. + Move gate (to where it is not visible). The results showed that the tensile strength of PE remains unchanged in the presence of weld lines. Nguyen-Chung. Unless you are manufacturing an extremely simple part with one gate and a unidirectional flow front, your part will have weld lines. With Ixef® PARA compounds, the strength of a weld line is typically 90 MPa (13,000 psi). The. . Weld-line, a common occurrence in plastic injection moulding, is a representative defect compromising mechanical qualities and product appearance [16]. Possible causes: Low temperature or fluidity of melted plastic during injection molding. In this study, one injection mold. From Understanding Weld-line Integrity by Sabic Innovative Plastics, p. Park et al. Plast. He said, “Vent cavities at weld lines or junction points where two or more material streams meet and fuse into a solid mass. 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. Sink Marks Cause 2: Low Pack and Hold time. In the case of PC, the model predicts satisfactorily the weld-line strength as a function of injection temperature. 6. The design of the mold, as well as the part being molded, has a significant impact on the success of the process. A simulation of mold filling with multi-inlets or an insert in the cavity is pursued with an improved Level Set Method. These lines usually occur around holes or obstructions and cause locally weak areas in the molded part. * Corresponding author, e-mail: [email protected] an injection molding process, a weld-line forms when two flow fronts meet each other. In narrow fields, a limited amount of molten liquid can solidify and block the flow. Injection molding plate for mode I testing geometry. This is expected to achieve maximum results while the pressure holding effect will also increase. Simulation of polymer molding filling process with an adaptive weld line capturing algorithm. weld lines in infill analysis of injection molding simulation was observed [5]. The impact behavior of weld-lines in injection molding. 5. 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. The gate is the critical bridge between the runners (the channels through which the molten plastic travels) and the actual mold. Our weld line injection molding is essential for the best result of finished molded products. A weld line region is typically filled at the end of an injection stroke or during the pressure phase. Wang. 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. This is expected to achieve maximum results while the pressure holding effect will also increase. Ideally, the resin flow will split into two flow fronts to pass around the obstruction and then recombine into a single flow front. Its appearance can be improved by adjusting parameters. • Optimize the design of the runner system. 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. So today we are going to take a look at the five most common defects in injection molding and their solutions. Polym. The occurrence of a weld line means a significant problem both aesthetically and mechanically in the design of injection moulded parts. Siemens PLM Software. Weld lines are a kind of Achilles heel of plastics. Learn how to avoid them and what injection molding companies do to prevent them. Effect of geometry and injection-molding parameters on weld-line strength. Unfortunately, the 3D layering process creates ‘weld lines’ (an injection molding term) between layers which is essentially two layers of polymer that meet. Multi-Shot Molding – A molding process that uses two or more plastic materials to form a single part. 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 Glossary; Weld Lines; Weld Lines. Weld Line Factors for Thermoplastics. Consequently, weld regions have been observed to have inferior mechanical properties compared to the bulk. Weld Line Factors for Thermoplastics. The quality of the weld line can be improved through optimized processing conditions, increased mold and melt temperatures, and increased injection speed to reduce the viscosity of the polymer. 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. Mold. A weld line is often unavoidable. Fracture Toughness of Weld Lines in Thermoplastic Injection Molding, Polymer Engineering and Science, 33(15): 996-1001. These lines are formed when two or more flowing molten plastic streams meet and fuse together, creating a visible line on the surface of the molded part. It occupies a major part in the plastics industry ranking second to plastic extrusion in terms of production and the utilization of both thermoplastic and thermosetting plastic materials. Fellahi et al. Plastic part design for injection molding – An introduction. It is important to investigate the weld line because the weld line area can induce potential failure of structural application. Weld lines may appear like seams or scratches, but that is not what they are. In this regard, Taguchi orthogonal experimental design is adopted, and five processing parameters, the mold temperature, melt temperature, cooling time, packing. Valve gates also make weld lines less of. Furthermore, injection molding was applied by filling these pellets into a micro-injection molding machine (C. Injection moulding (U. In. Procedia Mater Sci 2014; 3: 2048–2053. Wu CH, Liang WJ (2005) Effects of geometry and injection-molding parameters on weld-line strength. The default weld line result recognizes 135º as the maximum angle of collision and as that angle decreases, the severity increases as it. NX Mold Flow Analysis. The welding angle can be used to differentiate weld lines and meld lines. Mechanical properties of the weld line defect in micro injection molding for various nano filled polypropylene composites. 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. Weld lines in injection molding are frequently unavoidable. Effects of fillers and/or reinforcements on weld-line strength of nylon 6/6. When this fails to happen correctly, a weld line defect occurs. The Solutions for Poor Welding Lines. This thermal field was transferred to an injection molding flow solver to compare simulations and experimental results from the high speed video, both with and without the effect of induction heating. Processing OptimizationReduced frozen skin thickness: High injection speeds also contribute to a thinner frozen skin at the weld line. In this experiment, several ejector. Wavy lines are another feature of weld lines. 1. Strength at weld the line location and warpage problem in injection molding plastic component were not new problems in injection molding industries. ac. 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. Figure 2. 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. Facebook. molding Æ Thermoplastics Æ Weld line Æ Simulation Rheol Acta (2004) 43: 240–245 DOI 10. Sink Marks Cause 5: Improper Part Geometry. The molded plastic part may also appear to be rust-colored. 5. The second technique, cascade injection moulding, can produce parts free from weld lines. 4. ing weld line properties of injection molded thermo-. 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. That helps. demanding injection molding and end-use requirements. Weld lines have been one of the common defects puzzling the injection molding industry. Weld lines can lower the integrity of the part. The Solutions for Poor Welding Lines. The cracking was always located in the weld/knit line and therefore caused by weakness in the bonding of the plastic at. 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 weld line is then created with a higher flow front temperature and is packed with more pressure. Various measures are taken at production sites to address these problems. Boost time too long Shorten boost time, lower boost pressure, or move transfer to an earlier position . 809-814. Let’s review what causes meld and knit line imperfections, how they’re different, and how they affect part durability. Weld or Knit lines are a plane or section in an injection molding part where the flow of molten plastics meets from different directions. Abstract. Controlling injection molding weld lines with good design and process control. Consequently, it causes viscous dissipation which leads to the generation of heat. Interestingly, these materials have been shown to outperform long fiber thermoplastic (LFT) composites (in. 1. Slow down injection speed. 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. 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. 015 0. The optimal process condition is very likely to appear in this second part's fine-tune group. He now teaches courses in injection molding and plastic part design at the Polymers Center of Excellence and UNC-Charlotte in Charlotte, N. Weld line is one of the plastic injection molding defects. However, even with advanced technologies and precise control, the process is not without its challenges. 2 mm to 1. Weld lines. , a post that forms a hole) and then rejoins, or when polymer melt fronts meet, from multiple injection points. Miron MC, Major Z, Adachi T. 3 cc/sec, the weld lines are no longer perceivable above 130 C. In the sense that the weld line is better formed before the resin temperature. Injection molding is a highly versatile manufacturing process used to produce a wide range of plastic products with precision and efficiency. technical ulletin SPECIALTY POLYME RS Design and Production of Injection Molding Tools. The most simple design modification for eliminating the weakening effect of a weld line is to increase the wall thickness in the weld line zone (Figure 4). . 025 100 120 140 160 180 200 220 240 Mold Temperature (F) LDPE PPEffects of mold temperature and pressure on shrinkage 0. This gives a clue as to. Here are some reasons why design is important for 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. Tekanan yang kurang mampu untuk mendorong aliran dan kembali pada posisi semula dapat menimbulkan weld line. Weld Lines. 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. Injection pressure or. 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. 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. Weld-line is a weak area which reduces the strength of the part locally. The weld line in an injection molding product can significantly impact the strength and durability of the last part [12] [13][14][15]. Meld and knit lines are actually both different types of weld lines. 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. Insufficient plasticizing ability of injection molding machine. 2. 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). The appearance quality of plastic parts in weld lines can be improved significantly through the rapid heating cycle molding (RHCM). 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. 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]. Gambar 2. , Ltd. If it only affects the appearance, it can change the position of the burn four to change the position of the weld line. Weld-line is a defect that arises in injection molding when two or more flow fronts collide. 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. In this blog post, we will explore the causes of weld lines in. Flow lines are off-color lines, streaks, and other patterns that appear on the surface of a part. A weld line can also be called a knit line. 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). A good weld typically occurs when the melt temperature where the weld line is formed is no more than 20°C below the injection temperature. These lines can occur at the gate location, where the plastic enters the mold, or anywhere along the flow path. One common issue that frequently arises during injection molding is the formation of weld lines. ” Another. The thermo-rheological findings were used to investigate the sources of weld line weakness. 2-1. 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. Jiquan Li, Taidong Li, +1 author. Five injection molding process parameters, including mold temperature, melt temperature, packing pressure, injection. Weld Line defect analysis, the most common of many defects in injection moulding products. Int J Adv Manuf Technol 52:131–141. The parts are molded flat and are slightly stressed once installed in an arced position, but not excessively. A visual mold with variotherm system for weld line study in micro injection molding. For multiple gate and complex part, molding weld-lines are unavoidable, therefore mechanical behavior of the weld-line needs to be predicted. This failure causes the product to be damaged during use. 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. If you have critical requirements for strength of knit lines, please call a Protolabs applications engineer at 877-479-3680 to discuss, or email at [email protected]. 1007/s00397-003-0339-2 ORIGINAL CONTRIBUTIONCauses and Remedies of Sink Marks In Injection Molding. Insufficient plasticizing ability of injection molding machine. Investigations on WLs in micro injection molded parts were performed in Refs. For this purpose, the width of the weld line calculated by Sigmasoft is. สาเหตุรองของการเกิดปัญหาการเกิดประกายเงิน (silver streak) 1. Weld lines. 020 0. As the name implies, it is usually positioned along the edge of the workpiece, forming a visible mark at the demarcating line. In this mold, a visualization design and a rapid heating/cooling system were integrated, and specimens with different cross section. 2012. Materials Science. Weld lines may appear like seams or scratches, but that is not what they are. Weld Line defect analysis, the most common of many defects in injection moulding products. Weld lines in injection molding are formed when two or more flow fronts of molten plastic material meet and merge during the molding process. Here are some strategies. [ 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. According to the characteristics. Weld-line is a defect that arises in injection molding when two or more flow fronts collide. 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. Information about PA6/PA66 (Nylon) Injection Molding. 2. Weld lines form where two or more flow fronts come together and can create a cosmetic or structural problem. 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. Weld-line is a defect that arises in injection molding when two or more flow fronts collide. This principle has been implemented on a complex component in the case of the spring-loaded cogwheel shown in Figure 5, for instance. Google Scholar | Crossref | ISI. 7 in Kobayashi et al. Thus, it is important to understand (i) if the melt is able to fill the cavity up to the weld line location, (ii) where the weld line forms, and (iii) if the weld line is a cold or flowing one. This injection molding defect appears as a black discoloration on the surface of the molded part. A meld line occurs when two moving melt fronts converge and flow parallel to each other. 1 Prediction of weld lines with injection molding simulation softwareWeld lines in design for manufacture. [ 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. Although they often cannot be avoided it’s possible to minimize their cosmetic effects to an acceptable degree through careful product design and. 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. A weld or meld line is a weakness or visible flaw created when two or more flow paths meet during the filling process. 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. Kondisi ini juga bisa menandakan bahwa mesin injection. Which means engineers need to know how to account for this phenomenon in an efficient way. Munich, Germany: Carl Hanser Verlag, 1994. Weld lines are formed when there is an inability of two or more flow fronts to ‘knit’ or ‘weld,’ together during the molding process. 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]. In addition, its tensile strength and stiffness will be sharply decreased. 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. S. In an injection molding process, a weld-line forms when two flow fronts meet each other. Problem: Weld lines are formed when plastic resin is forced around an obstruction in a mold tool and reforms on the side opposite the gate. It is not always easy to completely eliminate weld lines by simply adjusting the relevant injection mold design or the molding conditions. You will have to confirm them before tooling. In some cases, a weld line can also cause a loss of strength and impact resistance. When a product is produced through injection molding, a high-powered tool injects melted plastic into a custom, double-sided mold. See moreIncreasing the temperature of the mold or plastic material. Thoroughly clean molding machine cylinders. 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 are among the most critical structural defects in parts made by the injection molding of fiber-reinforced thermoplastics, explained Sirmax in a press release. 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. In injection molding weld lines are formed whenever two flow fronts are joined. 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 fiber concentration has been studied in detail. poor flow fronts that are too cold, this can also lead to a deterioration in the mechanical properties. Molding with weld line model Moldex3D was used for calculate the molding of lugs (figure 1).