The moldability validation and flow analysis tools enable you to iden-tify and correct potential injection molding problems as you design the product. So today we are going to take a look at the five most common defects in injection molding and their solutions. 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. 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. 5. Weld line location. The diameter of the hole is 12 mm. They happen when two flow fronts of melted plastic meet and solidify, leaving a visible line on the surface of the part. 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. This principle has been implemented on a complex component in the case of the spring-loaded cogwheel shown in Figure 5, for instance. 2 mm to 1. box, along the region of weld line formation (wc, wm, we and wl) and away from the weld line, in a radial position along the flow direction (R), as shown in Figure 2. Molding with weld line model Moldex3D was used for calculate the molding of lugs (figure 1). In the plastic injection molding industry, we work with materials that are byproducts of oil refinement and molds made of metal casting, so our terminology is bound to be at least slightly confusing. They occur when melt flow fronts collide in a mold cavity. Low mold temperatures are usually employed to decrease cycle molding time and final process costs; however, resulting surface defects include weld lines, sink. 2. G. As compared to a weld line, the flow fronts come together at less than 135 degrees. Install an ultrared light inside the hopper. 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. 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. Injection pressure or. 2007; Lotti et al. That’s the air escaping out of the nozzle until the hose is full of pressurized water. At a low volumetric injection flow rate of 33. The tensile stresses of the weld lines with ultrasonic functions are 8. Tekanan. A meld line occurs when two moving melt fronts converge and flow parallel to each other. In this experiment, several ejector. According to the characteristics. 10(a) (please see Fig. Weld lines in injection molding are formed when two or more flow fronts of molten plastic material meet and merge during the molding process. Neat polypropylene retains nearly 90% of its strength on a properly designed and molded weld line. 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. Polym Eng Sci 45(7. Abstract and Figures. Flash. Why You Should Avoid Weld Lines. Mechanical properties of the weld line defect in micro injection molding for various nano filled polypropylene composites. Wang. 2011; 509 (2):226–233. 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. But add 30% glass and weld-line strength retention drops to only 34% as high as the compound with no weld. Weld-line is a weak area. Sink Marks Cause 2: Low Pack and Hold time. II. This occurs mainly in the presence of barriers that divide the melt flow in. 015 0. 2023年1月3日 / by admin. 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. 0 mm, is designed to conduct the. Materials Science. C. <1> As illustrated in Figure 4, the existence of. Alloys. 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. Install an ultrared light inside the hopper. Just check out some of it on the above lists. + Adjust injection speed. Weld-line is a defect that arises in injection molding when two or more flow fronts collide. 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. When two or more streams of plastic meet and fuse. 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]. Optimization of Injection Molding Process to Minimize Weld-line and Sink. Weld lines, knit lines, and meld lines are terminologies to describe the imperfections of finished parts in plastic injection molding processing. Weld-line is a weak area which reduces the strength of the part locally. Micro injection molded polymeric parts coated with functional thin films/layers show off the promising applications in microsystems area. Injection molding is a complex multi-variable, nonlinear and time-varying unsteady process, which makes it more difficult to optimize the process parameters. Weld-line is a weak area which reduces the strength of the part locally. Effect of geometry and injection-molding parameters on weld-line strength. Again, consult with professionals as to how you could improve mold designs. A poor knit line can cause only cosmetic blemishes or it can significantly weaken the structural integrity of a part. Additionally, you can get our free Design Cube, which will provide a physical aid to help understand how knit lines form as well as other injection molding design considerations. Weld lines are significant defects that affect injection molding quality, causing the poor appearance and low mechanical strength of injection‐molded parts. The weld lines that occur in injection mouldings are critical areas on which depends on the strength of the mouldings. สาเหตุการเกิด weld line คือเมื่อการไหลของพลาสติกมาประสานกันนะจุดใดจุดหนึ่งและจุดนั้นเกิดความแตกต่างของอุณหภูมิในสองทิศทางการไหลจะทำให้เกิด. In our DFM report, we will analyze the possible weld lines. Plastic part design for injection molding – An introduction. 2. 6. You will have to confirm them before tooling. Cited by (41) Effect of mould surface roughness adjustments to increase the flow path length in the injection moulding process. 666 Azieatul Azrin Dzulkipli and M. 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. Controlling injection molding weld lines with good design and process control. Injection molding is nothing without molds. Its properties make it possible to create thin-walled parts having close tolerances in fast cycles over long. A new kind of weld line was. Expand. This gives a clue as to how it was formed. The weld-lines are undesirable from both aesthetic and functional points of view and their effect is different for. This injection molding defect appears as a black discoloration on the surface of the molded part. We have various types and models available. Injection molding is nothing without molds. Weld lines may appear like seams or scratches, but that is not what they are. 2. Fisa et al. These weld lines occur usually around holes or at the material flow joint area in the injeciton molded part, some welding lins is very small, specially if. Kondisi ini juga bisa menandakan bahwa mesin injection. 21: Weld line failure caused by hoop stresses. Flow lines are off-color lines, streaks, and other patterns that appear on the surface of a part. In this regard, the plasticizing ability of the plastic injection moulding machine should be checked. Re-balancing entire manufacturing lines may be required to effectively deliver and sustain SMED excellence. Weld lines not only affect the appearance and quality of products, but also cause negative influences on the mechanical properties. 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. 1. Therefore, the investigation on the developing process of weld line would be a significant issue for improving the quality of micro injection molded parts. Ada berbagai penyebab mengapa weld line bisa muncul pada permukaan produk plastik. Adding vents, using overflows, or using porous metal. As a result this weld line will be a weak point in this part. Moldflow is computer software that is widely used across the plastic injection molding industry to predict and optimize the injection molding process and assist with mold design. 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]. + Improve vent inside the mold. Depending on the resin, resin temperature, mold temperature, and filling speed, knit lines can vary. 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. open access Abstract Micro weld lines are the common problem that occurs for plastic molded parts through injection molding process. 1. We'll show you how. Meld and knit lines are actually both different types of weld lines. 48 applied high-frequency induction heating to eliminate weld lines in an injection-molded plastic part, and experimental observation indicated that weld depth was reduced from 2. (1983). The following guidelines have. (1) make the mold vent larger at location with weld line; (2) Check if the mold vent is blocked or not or use vacuumized forming. Investigate for potential contamination. 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. 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. They. Weld line strength vs. 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. It is not always easy to completely eliminate weld lines by simply adjusting the relevant injection mold design or the molding conditions. In the end, the total amount of time that running a complete Taguchi DOE (L18) to occupy an injection. “I realized weld -line problems are a very common issue for injection molded parts,” Nicholson told Plastics Technology. Part design features may cause a material flow to split and rejoin as it flows around design features in a mold. This paper presents the. Avoid knit lines when designing a molded part to improve cosmetic appearance and functionality. They can affect the strength and appearance of the part, depending on the temperature, pressure, speed, and mold design of the injection molding process. + Increase mold temp, or materials’ temp, or holding pressure. Google Scholar | Crossref | ISI. The optimal process condition is very likely to appear in this second part's fine-tune group. They occur when melt flow fronts collide in a mold cavity. However, research about the computer determination of weld lines in injection molding remains scarce. The injection molding gate generates heat by dissipation. This results in a region of a different level of molecular entanglements than the bulk material. The. This study presents an innovative approach to enhancing weld line strength in advanced polymer injection molding through applying gas-assisted mold. But the unfavorable and unavoidable defect of weld line in micro injection molding part leads to detrimental mechanical and surface properties. One of the factors that determines the quality of injection molded parts is the weld line [50,75,76]. There are several possible causes that need to be investigated to troubleshoot weld lines in injection molding. In this study, epoxy molding compounds (EMC) filled with glass beads were fabricated with a twin-screw-extruder (TSE) and tempered before further processing to generate different degrees of cross-linking (0–15%) in the compounds. Injection moulding (U. – Use generous and even. Weld-line strength for plastics can vary from 20% to nearly 100% of the strength of the plastic itself. 3. This study focuses on the analysis of fill time by optimizing the injection molding parameters to reduce the defects that are always found on the plastics part such as poor weld line and part not. This defect occurs due to the temperature and pressure not being high enough, causing premature solidification. When two or more strands of molten plastics meet in the mold, a weld line will be produced at the junction [1,2]. Ozcelik studied the influence of the injection parameters and weld line on the mechanical properties of polypropylene (PP) during IM process via the design of experiment (DOE). 2-1. Int J Adv Manuf Technol:1–11In addition to the weld line, the exposure of fibers on the molded product surface results in a rough surface, which degrades the appearance of the product. Avoid knit lines when designing a molded part to improve cosmetic appearance and functionality. Causes. 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]. Remember, by avoiding weld lines, you can lessen operations cost. These flow fronts occur when the molten plastic material encounters obstacles, such as inserts, ribs, or other features within the mold cavity. 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. If so, look for an alternative resin. Fig. 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. They can affect the strength and. 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. This may require higher melt temperature or lower injection speed . This study focuses on the effect of melt temperature on. Insufficient plasticizing ability of injection molding machine. Article Google Scholar Deng YM, Zheng D, Lu XJ (2008) Injection moulding optimization of multi-class design variables using a PSO algorithm. 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. Wu CH, Liang WJ (2005) Effects of geometry and injection-molding parameters on weld-line strength. The graph shows clearly how an increasing cavity temperature correlates with a reduction in the weld lines. These lines can occur at the gate location, where the plastic enters the mold, or anywhere along the flow path. In injection molding, it is often important to maintain consistent color throughout the part. Injection molded plastic parts have comparatively less strength in the weld line section and they also have an impact on product aesthetics. Meld and knit lines are actually both different types of weld lines. Weld line Weld line dikatakan ketika dua atau lebih aliran lelehan depan. Complexities in the design and intricate pathways in the mold can also create flash in injection molded parts. Stagnant weld lines are formed when melt streams meet head-on. Injection molding can be performed with only one of these materials like glass, plastics, etc. Weld line formation in the injection molding process occurs. From: Polylactic Acid (Second Edition), 2019. 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. In an injection molding process, a weld-line forms when two flow fronts meet each other. For multiple gate and complex part, molding weld-lines are unavoidable, therefore mechanical behavior of the weld-line needs to be predicted. Weld lines create visible marks, but this type of injection molding defect can also reduce a part’s strength and durability. Maintain a holding pressure that is no more than 1/2 the. How to Reduce Weld Line in Injection Molding? Weld lines are a common issue that occurs in injection molding. 1. In this study, the effects of injection temperature, injection pressure, and fiber cont. In this paper, two different injection molding tests were completed. , 47 (2008. Plastic part design for injection molding – An introduction. A weld line is a visible seam where two areas of the molten plastic meet. 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. Since it is often impossible to avoid weld lines as well as a limited possibility to increase the weld line strength by adjusting the injection molding parameters, a method to predict the weld line strength in the product development process is shown below. Conclusion The formation of weld lines in micro injection molding of plastic depends on different parameters such as melt temperature, injection pressure and fabrication method. Three terms that often get mixed up in the plastic injection molding industry are weld, meld, and knit 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. Tekanan yang kurang mampu untuk mendorong aliran dan kembali pada posisi semula dapat menimbulkan weld line. For multiple gate and complex part. (3-1) Increasing the Resin Temperature at the Weld Line Section. , a post that forms a hole) and then rejoins, or when polymer melt fronts meet, from multiple injection points. Physics. [8,9] It is capable of. 2-1. Many researchers had emerged with several. In some cases, a weld line can also cause a loss of strength and impact resistance. Thus, it is important to understand (i). 1. Fracture Toughness of Weld Lines in Thermoplastic Injection Molding, Polymer Engineering and Science, 33(15): 996-1001. 2. DescriptionThis insertion ensures the separation of the melt flow. For this purpose, the width of the weld line calculated by Sigmasoft is. 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. This month, in our FREE SimTech™ series of webinars, we will explore weld lines and how they develop. 2. วัตถุดิบ พลาสติก PMPA ( อะคริลิก ) เกรด A. If not, the speed will drop, and it could create weld lines. Fig 13:- Detailed view of weld lines. In addition a weld line can be moved to an area where it is less visible. The utility model relates to a mold structure capable of eliminating the appearance of weld lines of a hole. Sink marks are a common type of injection molding defect. Information about PA6/PA66 (Nylon) Injection Molding. Nozzle – The nozzle is at the end of the barrel and contacts the injection mold. Sequential valve gate technology. In the sense that the weld line is better formed before the resin. When two or more strands of molten plastics meet in the mold, a weld line will be produced at the junction [1,2]. Wavy lines are another feature of weld lines. [ 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. But none of the current packages can predict weld lines’ properties qualitatively. 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. [23, 24]. Consequently, weld regions have been observed to have inferior mechanical properties compared to the bulk. 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. In addition, its tensile strength and stiffness will be sharply decreased. The thermo-rheological findings were used to investigate the sources of weld line weakness. Weld line is formed when two different melt flows converge, as illustrated in Fig. Because of the ever-increasing requirements for parts performance, lots of researchers have perf. 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. In this regard, the plasticizing ability of the plastic injection moulding machine should be checked. Weld line, 5. 2. Weld lines can be caused by many reasons, which covers the various aspects of mold, process, raw materials and product design, etc. ac. Weld lines not only affect the appearance and quality of products, but also cause negative influences on the mechanical properties. In this case the two flow fronts will meet and there will be very little molecular orientation across the weld. 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. Amongst weld line. One solution is to prevent the weld lines from forming in regions that are. 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. ac. Insufficient plasticizing ability of injection molding machine. Fracture behavior of weld lines in injection molded components loaded under real operating conditions. Weld lines can lower the integrity of the 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. Microsyst Technol. For thick-walled parts, slow injection rates result in more uniform polymer distribution . Article Google Scholar Deng YM, Zheng D, Lu XJ (2008) Injection moulding optimization of multi-class design variables using a PSO algorithm. Joe Henz is a chemical engineer with 30 years of experience in the plastics industry, primarily with GE. Computer simulation packages of injection molding have had success in predicting filling behavior in extremely complicated geometries, capable of predicting weld lines’ location exactly. Ideally, the resin flow will split into two flow fronts to pass around the obstruction and then recombine into a single flow front. [1] Kobayashi et al. Slow down injection speed. 2. From Understanding Weld-line Integrity by Sabic Innovative Plastics, p. Rapid heat and cool injection molding is an example of a measure to prevent the generation of weld lines. Try to gradually raise the mold temperature and barrel temperature. Figure 1 below shows the development of a weld line. To explore the formation of weld lines in injection molding, a. Alloys. These lines can weaken the strength of the part, and they can also be unsightly. Weld lines appear as a result of the flow of molten plastic during the injection molding process. In this case the two flow fronts will meet and there will be very little molecular orientation across the weld. Here are some reasons why design is important for injection molding. 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. 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. Munich, Germany: Carl Hanser Verlag, 1994. On the other hand, the mechanical strength at the weld line area of an injection molding part is always a concern. Berikut beberapa di antaranya: 1. Miron MC, Major Z, Adachi T. 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. 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. 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. Weld Lines. Fracture behavior of weld lines in injection molded components loaded under real operating conditions. Increase the injection speed to reduce the amount of cooling happening in the mold. (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. Therefore, it is recommended to do a moldflow study prior to the mold being built. First, an injection mold with triangular inserts was built to study the influence of meeting angles on material properties at the weld line. The injection molding simulation software used offers a method for the detection of weld lines that has shown to be only reliable for the detection of stagnating weld lines. 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. Email him at jhenz@polymer-center. The main types of injection molding defects are: 1. and Mosle, H. Known methods to reduce weld-line effects are the optimization of injection molding parameters, enhanced tool temperature, and using special molding tool devices. Threadline gap in-between part due to improper gate location in complex design parts including excess of holes (multipoint. In. With Ixef® PARA compounds, the strength of a weld line is typically 90 MPa (13,000 psi). The parts are molded flat and are slightly stressed once installed in an arced position, but not excessively. Weld Lines are formed when two or more molten polymer flows meet during the injection molding process. 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. Weld lines are injection molding defects that can be mitigated by a number of tactics that depend on your part design. Weld lines represent the region where two separated melt fronts recombine. To resolve this issue, rapid heat cycle molding (RHCM) has attracted attention as an innovative PIM technology. Short Shot Short Shot adalah suatu kondisi dimana, plastik leleh yang akan diinjeksikan kedalam cavity tidak mencapai kapasitas yang ideal atau sesuai settingan mesin. 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. It can be determined by a visible line appearing on the surface of the plastic part where two flows of the plastic meet. Plastics manufactured by injection molding are meant to be durable and reliable, able to hold up to heavy use, high temperatures, or adverse conditions. Known methods to reduce weld-line effects are the optimization of injection molding parameters, enhanced tool temperature, and using special molding tool devices. 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 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. Gate position in injection mold. 2. Investigate for potential contamination. 025 100 120 140 160 180 200 220 240 Mold Temperature (F) LDPE PPAbstract. To position weld-line to avoid critical areas for the sake of aesthetics or mechanical strength is the key to the success of bi-injection molding. 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 or Knit lines are a plane or section in an injection molding part where the flow of molten plastics meets from different directions. 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. This study describes how the weld line was formed on the part. Poor weld line quality can lead to short-term or long-term product failures, initiated at the weld line. 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,. In this study, we apply the technique of SAW to explore the acoustic properties near injection-weld lines by comparing the velocity of. The following are the conclusion drawn from the present research: 1. 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]. Fellahi et al. The gate location should enable the two flow fronts to merge easily and continue to flow beyond the weld line. 2) Vents in an injection mold should let the air out, but not the liquid plastic. 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. In the present study, Moldflow® software is applied to simulate the injection molding of automobile instrument light guide bracket and optimize the injection gate position. 3 cc/sec, the weld lines decrease over temperatures up to 150 C, while at higher volumetric injection flow rates of 43. As these flow fronts come together on the. Weld lines may appear like seams or scratches, but that is not what they are. Processing Optimization Reduced frozen skin thickness: High injection speeds also contribute to a thinner frozen skin at the weld line. Weld lines form where two or more flow fronts come together and can create a cosmetic or structural problem. 3. Injection molding of large/complicated products are usually prepared by multiple compounds, which produces weldlines once the melt fronts are joined by impingement flow. 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. Injection Molding Glossary; Weld Lines; Weld Lines. Zhao, X. Wolfgang Homes, head of the applications department of Eurotool, a manufacturer of hot runner systems, clarified the two methods for IMI, noting that. Munich, Germany: Carl Hanser Verlag, 1994. 298 µm and the weld line on the heated region was almost eliminated with the aid of induction heating. The injection pressure is too lowEffect of the processing conditions on the variations of the bulk temperature, T b , at the end of mold filling at the two locations: in (left) and away (right) from the weld-line (T w , T inj. Insufficient injection pressure and speed can cause weld lines. The line where two resin flows “knit” or “weld” together during injection molding is called a weld or knit line. Adjust the position of the gate and include a venting slot. 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.