The advantages of compression molding include more isotropic fiber distribution, dimensional stability, and surface finish. Weld-lines or knit-lines are formed during the mold filling process when the split melt flow fronts meet at the same downstream location. Introduction to Knit Line Injection Molding Knit Line Injection Molding is a process that allows manufacturers to produce parts more quickly, accurately, and at less cost than traditional injection molding. Chris Newmarker | Dec 27, 2013. 010 inches. Specific attention to processing details will enhance quality and productivity . Understanding Knit Lines in Injection Molding: Causes and Solutions. Our plastic injection molding glossary provides key terms. Timing and temperature are significant contributing factors when it comes to flow and knit line defects. After samples have been approved, it’s time to kickoff. Knit lines, also known as weld lines, are fine lines that resemble hairline fractures or cracks. To prevent swirling, perform tests whenever possible and use pre-compounded resin to ensure identical color match across parts. Give us a call at (425) 339-0288 or email us at info@sealectplastics. Over the years, I have developed two separate “5M” systems. We have an elite team that designs for injection molding, rapid prototyping with metal and plastic, and produces world-class products under the same roof. Back to News Page. Reduce. You don't give us much to go on. . Facebook. In the 1947 book, Injection Molding of Plastics, the late Dr. Injection Molding: How to Set Second. ” Depending on the material you use, the knit lines could be invisible or obvious—work with an injection molding company to figure out. By contrast, a slow injection speed will give you a matte finish and a cold mold, such as 50F, will give you a more flexible part. Injection Mold Tooling Options and Quality Reporting. 025 inches per inch, depending on the particular resin, molding conditions, part design, part wall thickness, and direction of flow. Inject the molten material into a mold. Because viscosity is a. 1050 Walnut Ridge Drive. When the temperature is not very high, there are chances of premature solidification, which can cause weld lines to form. Weld lines: Also known as knit lines, these are molding defects that occur when two flow fronts meet without the ability to “weld. Gates that are too small can also cause the uneven flow of material or result in knit lines, blemishes that occur where two resin flows meet. com. A poor knit line can cause only cosmetic blemishes or it can significantly weaken the structural integrity of a part. They occur when melt flow fronts collide in a mold cavity. Our goal of 100% efficiency, zero scrap and repeatable processes can sometimes be hindered by poor setups or changes in the molding process. 7. Submarine gates are another injection molding types of gate that is located below the surface of the part, typically on the underside or back of the part. In this phenomenon, some portions of the mold cavity are filling, while others undergo over. Disadvantage: May rust if improperly stored. Reinforcing ribs play a pivotal role in the strength of a plastic part. Dabei erreichen unsere Produkte zufriedene Käufer in mehr als 30 Ländern. The plastic melt that passes through the gate at high speed directly enters the cavity, then contacts the surface of the cavity to solidify, and then is pushed by the subsequent plastic melt, leaving traces of meandering. Those are knit lines, formed when two opposing flows of material join together in the mold cavity. (1987). mixed manually and quickly stored in the tank of an injection machine just before the start of the resin injection or (2) the components are stored separately in different tanks of an injection machine with a mixing head. While this process is largely efficient and reliable, it's not without its potential issues. By using this method, theMolding analysis study: An example of the low patterns and knit (weld) lines formation (MoldFlow® data) of injection molded round plastic part with a complex shape and with a ring. injection molding machines using standard industry practices . Plastic injection molding has long been an affordable and efficient process for producing custom prototypes and end-use production parts. Understand the causes of knit lines in injection molding and explore effective solutions to minimize their impact. Shear Controlled Orientation Injection Molding of Polymeric Composites with Enhanced Properties. 3D printed molds in the injection molding process to lower costs and lead time. (2) Undesired movement of certain materials in a plastic. This guide to thermoplastics and injection molding material selection is aimed at an engineer who plans to quantitatively analyze a part, determine loads, stresses, strains, and environments and make an optimal material decision based on the analysis. High mold temperatures usually provide less residual stress. Find out more by calling 573-437-4154 today or email us. Our goal of 100% efficiency, zero scrap and repeatable processes can sometimes be hindered by poor setups or changes in the molding process. Let’s review what causes meld and knit line imperfections, how they’re different, and how they affect part durability. 015in wall. Weld lines create visible marks, but this type of injection molding defect can also reduce a part’s strength and durability. 11) The part design must take into account possible knit line locations and work to direct them away from higher stress areas. As the melted plastic fills the mold, there are locations where the molten plastic flow stream separates and then comes back together. Our On-demand. 2. Legend: a-in. Sequential valve gate technology. What causes knit lines? Knit lines are formed when the molten plastic flowing into the mold cavity runs into an obstruction, such as a core pin that forms the through hole on a flange of an enclosure. Knit lines are formed in injection molding when two flow fronts meet in the middle of a part (a line where two sides of the plastic. Plastic melt and mold temperature. Having uniform wall thicknesses between 0. What Are Cosmetic Standards for Plastic Parts?. Nicolet Plastics LLC. Reduce the injection speed to limit the risk of trapping air inside the mold. It is caused by the incomplete joining of the uncured. Based on the resin temperature, filling speed, and resin, there is a variation in the knit lines. Main causes of knit lines in injection molding: 1. A knit line is any line, visible or not, where two resin flows meet. Weld lines typically appear in a part when an obstruction of some kind separates the melt flow and prevents it from "knitting" together. Bubbles are caused by melting flow fronts colliding in a mold cavity. The injection molding process uses a granular plastic that is grav ity fed from a hopper. These lines. Venting. For example, increasing gate size can improve part filling. See full list on fathommfg. All that considered, for a specific simple part with specific quality requirements. Also known as string lines. The parting lines is where the two injection mold halves (A side and B side) meet. Weld or knit lines are perhaps the most common and difficult injection molding defect to eliminate. These flaws can affect the aesthetic and structural integrity of the. 080" – 0. Gating. So. If the plastic has cooled too. Injection Molding Problems and Solutions (17/17) – Weld or Knit Lines Sep 27, 2022injection-molding machine (Arburg allrounder 320C, Germany). ABS. Understanding types of injection molding process can help to avoid some design challenges early in the process. An obstruction such as a core pin or holes will split the material flow and cause a weld line issue to form on the other side. Self-mating parts. To account for variations in viscosity, nylon injection molding machines need to maintain an appropriate injection pressure. 1513 Sam Bass Rd. Unsymmetrical filling makes knit lines in samples, leading to the failure of part, so it must be avoided. A weld or meld line is a weakness or visible. The weld line can either be a minor cosmetic issue. In spite of its cosmetic attributes, a bad knit line can significantly compromise a part. A poor knit line can cause only cosmetic blemishes or it can significantly weaken the structural integrity of a part. Valve gates are most efficiently. injection molding. The injection molding process uses a granular plastic that is gravity fed from a hopper. They again get resolidified along the surface. Call 800-985-6750 or email your inquiry to sales@customgasketmfg. 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. 6 Monate. ABOUT THE AUTHOR. To study the weld line formation of colliding flow fronts the filling of a mold cavity was simulated. Using three test materials, polystyrene (PS), polycarbonate (PC) and polyoxymethylene (POM), the relationship between a design and a processing parameter and the effects of the knit-lines on the tensile properties of injection molded plates. Remedies: Raise the temperature of the mold or molten plastic. Learn how to troubleshoot weld lines in injection molding. 6. Gate locations can be directly behind or on the edge of the graphic. These lines are the result of the molten plastic material recombining after splitting and flowing around an obstacle in the mold cavity. Excessive injection pressure can result in part defects such as overflow or flash. The best we can hope for is to pressurize the knit or meld line better through the combination of melt temperature, mold temperature, flow rates, and holding pressures. One common problem that occurs in injection molding is the formation of knit lines. placed usually in the areas last to fill, near knit lines, as well as on the runner system. A screw-type plunger forces the material into a heated chambe r,. The specimens with a weld line at the center were obtained by double gate molding and the specimens without a weld line wereInjection runner too small Increase runner as needed. ” What else can you do about weld lines—besides redesigning the mold or gate locations or adjust the flow pattern during fill with sequential valve gating? I recently saw a report on this issue from Moldex3D, the maker of molding simulation software. 25T-0. Rapid heat-and-cool molding technologies have attracted increasing. Most issues occur before entry into the mold. When assessing issues with injection molded parts, we want to make sure some core aspects of molding are checked. 060 and 0. It can be determined by a visible line appearing on the surface of the plastic part where two flows of the plastic meet. By understanding material fill, injection mold designers can better position gates, anticipate where knit lines will appear, and locate difficult to fill spots in the mold. As a result, the portion has a faint, perhaps undetectable line. Know about the cause of these lines and the potential solutions. Knit lines form when two or more plastic flow fronts collide and solidify or “knit” during the molding process. suppressed cooling and possibly warp. 0 mm) is crucial to ensuring that parts cool evenly. With over 50 years of experience, Universal Plastic Mold can help you avoid (or at least minimize) knit lines in your molded parts. Weld / knit plane forms as flow fronts recombine Weld line and failure due to flow around core. There are times when porous materials like Porcerax are used in problem or backfill areas. Using three test materials, polystyrene (PS), polycarbonate (PC) and polyoxymethylene (POM), the relationship between a design and a processing parameter. Edge Gates. Weld line. An undercut is any indentation or protrusion that prohibits an ejection of a part from a one-piece mold. These lines usually occur around holes or obstructions and cause locally weak areas in the molded part. Only then can we move on to determining the parting line itself. This type of molding uses a single tool to create both the part's geometry and surface finish in one step. Thermoplastic Elastomer Molding Guidelines. Weld and meld lines are generally caused by holes or inserts in the part, multiple gates, variable wall thickness or hesitation and. 1 Gate Location. From Plastic Materials and Processing by A. Lower the melt and mold temperature to prevent overheating. Find out more by calling 573-437-4154 today or email us. As the polymer resin is injected into a mold, it flows through all parts of the mold. Plasti-Co® Nozzles for Injection Molding Machines. In addition, the force of the gas holds the appearance side of the part in contact with. 4. Factors were ordered. 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. This design tip offers several ways to make your next multipart design less like a root canal and more like a day on the beach. These structures are often small surfaces of about a tenth of an inch in diameter. Learn more about the process by reading this white paper. , Rallis, A. Our glossary of terms provides definitions for a wide range of injection molding terms. 5 : 1 and 3. Understanding Knit Lines in Injection Molding: Causes and Solutions. Weld-lines look like cracks on the appearance of plastic. Solution: Increase the injection pressure or speed. BACKING PLATE – In mold construction, a plate used as a support for the cavity blocks, guide pins, bushings, etc. wall thickness injection molding ribs. com . 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. We all know that injection moulding is great for producing both custom prototypes and end-use production parts, but if you are not careful it can cause some. It’s our responsibility to make sure your design comes out of the mold working properly. While this process is largely efficient and reliable, it's not without its potential issues. This production method is particularly popular when manufacturing in large quantities. Core Geometry. On a hydraulic machine you can program hold pressure: For example, if you set 850 psi (59 bar), you will get 850 psi hold pressure for the time you set on. Increase the injection speed. Setting that Delta P is the secret to consistent fill time. Injection molding is a popular manufacturing process used to fabricate parts in large volumes. Because injection mold design and processing is complex, a set solution will not solve all problems. - You hit on this a little, but dealing with the parting line and ejector pin marks is pretty important, and isn't as simple as it seems at first look. The mold-opening force varies widely depending on the type and size of the molding machine. The goal is to create a uniform thickness and at the smallest (thinnest) level required. "As soon as that part or material is stressed, it can be real conducive to fracture, cracking, breaking, just because of the way it's been molded. Step 1: The injection of molten plastic into the injection mold from Barrel A. 020"). • Standard (general purpose) screws with a compression ratio between 2. Mold venting should be checked and increased if necessary, injection molding service. While not always visible, weld lines (aka knit lines) are where two resin flows meet. holes, multi-point injection. Fortunately, there is a technique that provides almost unlimited control over which parts of a tool fill when and how fast. They again get resolidified along the surface. Except for a few very simple injection molded parts, they occur on most injection molded parts (typically in the form of a line or V-groove), especially large complex items that require use of multi-gate molds and inserts. 08 KICKOFF PRODUCTION. It happens when the molten plastic material flows around obstacles, such as inserts or cores, and rejoins on the other side. In manufacturing, the Weld line or Knit line or Meld line is the line where two flow fronts meet when there is the inability of two or more flow fronts to "knit" together, or "weld", during the molding process. The splay condition can completely cover a part, or it can appear inconsistently in various areas on the part. 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. Even parts with metal inserts can be produced. An option to bluing agents, the long established means of gauging pressure distribution, comes via Pressurex, a thin, flexible, plastic film. Called LS IMM Mexico, the subsidiary is based in Monterrey and led by plastics industry veterans Kevin Kim and Fulvio Menconi. Below is a list of items that should be checked both during normal molding operations and if defects are detected. A thermoset injection molding process may save as much as 50% of machine time per shot with a faster cycle time compared to a thermoset compression molding process, allowing molders to produce high quantities of thermoset components per day in multi-cavity tools. PCS Company, Fraser, Michigan, has launched the Polimold Valve Gate Sequencer, providing injection molders with more precise control of the mold-filling sequence when using valve-gate hot runner systems. Plastic melt and mold temperature. The recommended minimum production volume for injection molding is 500 units. CNC-Bearbeitung; Spritzgusswerkzeuge und -teile; Stereolithographie (SLA) Selektives. Inappropriate temperature. Reducing the size and depth of depressions helps minimize the impact of knit lines. RE: Knit Line Affect On Material Strength lorelei5607 (Automotive). These are caused by the shot of molten plastic moving at different speeds throughout the injection. The depth of the texture or letters is somewhat limited, and extra draftParts were molded at a maximum injection pressure of 235 MPa, a maximum clamping force of 800 kN, a maximum injection speed of 900 mm/s, and a maximum injection stroke of 120 mm. The Difference Between Knit and Meld Lines–and Why It Matters. When injection molding complex parts, often knit-lines are formed during the mold filling stage. Reduce the injection pressure. Knit lines are formed in injection molding when two flow fronts meet in the middle of a part (a line where two sides of the plastic are “knit” together). 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. land and using maximum vent depths to get them as close to self-cleaning as possible. thickness with a spacing of about 0. Injection Molding. Product designers encounter a wide range of challenges when creating and developing molded parts, such as stress factors, warp, and those pesky knit lines. Therefore various injection molding defects can be eliminated. When venting stationary inserts or core pins in rib or part details with venting issues, I recommend no more than 0. ). These flaws can affect the aesthetic and structural integrity of the. The injection molding process offers a vast array of plastic resins to work with. This line does not normally impact the overall shape or dimensions of the item. Learn how material selection, part design,. Reduce the temperature of the mold and plastic being injected. All the while, the material could be the correct material," Hill says. TRADITIONAL MACHINES VENTS. A meld line occurs when two moving melt fronts converge and flow parallel to each other. Step 3: The injection mold undergoes rotation to align in position with injection Barrel B. 5 to 3. Also known as a knit line, this is the point at which two flow formations meet and are unable to connect during injection molding. [8] Bevis, MJ, Reis RL, Cunha AM. 847-952-8088. BACK TAPER – Reverse draft used in mold to prevent molded articles from drawing freely. Thermoplastic Elastomer Molding Guidelines. Knit lines, also known as weld lines are areas in the molded part where two or more flow fronts converge. com Discover why you should avoid knit lines when designing and manufacturing injection moulded parts. Encapsulating the metal insert with plastic creates a single. Injection mold design and custom tooling can make or break the success of a finished plastic product. More about the knit lines in injection molding. Exploring common molding defects and. Molding parts with multiple gates will almost certainly produce a weld line at right-angles to the line joining the two gates which could cause the weld lines to be exceptionally weak (see Figure 1. Some are: Knit lines (discontinuities where two flows merged, creating a weak point)In some situations where a mold has parting line damage, reducing heat can actually improve flash that was a direct result of that damage. When the molten plastic meets an obstruction. The Problems & Solutions course is designed to train injection molding personnel in. 0 to 3. Reduce the injection speed to limit the risk of trapping air inside the mold. 2 mm. The comment on melt flow index is correct, but, I've molded straight PC down to . This defect is caused from excessive lube or oily stock. Knit Lines and Resins. More about the knit lines in injection molding. Reduction of sink can possibly be had by switching to an ABS/PC-blended material. Steven. Wavy lines are another feature of weld lines. 5 mm) is ideal, according to injection molding engineer Jack Rulander of Protolabs in Maple Plain, MN. 1. Bad habits can cause many different problems with injection molding machines, and flow lines are included in that. It has low shrink and high dimensional stability, and it has good resistance to acids and bases. knit lines and parting lines are at the discretion of MIC-ZG. These data were obtained from many andKnit lines in injection molding are common defects of the molded parts. Steven. [8] Bevis, MJ, Reis RL, Cunha AM. Weld line defects – also known as knit lines – is a defect that occurs when the injected plastic meets within a mold. The only parts that count are the ones that meet quality standards, and keeping pressure evenly distributed across a mold’s parting lines is one of the many critical tasks to get those good parts molded. Our Injection Molding Capabilities • Horizontal Injection Molding up to 3300 TONS • Structural Foam Molding + Structural Web • 1oz to 600oz part capacity. Typically, this fillet radius should be somewhere near 0. Mold venting is critical to the quality and consistency of the finished part. Bubbles are caused by melting flow fronts colliding in a mold cavity. Contact Universal Plastic Mold Today. It allows our molders to monitor fill pressure, cosmetic concerns, and the basic quality of the parts. Plastic Injection Molding Part Design Guidelines, Plastic part Design Guidance, Parting Line Draft Undercuts Wall Thickness & Uniformity Bosses Gussets and Ribs Radii and Corners Material Shrinkage Gating. Imagine a river splitting to go around a rock, then meeting up again on the other side. The packing pins are similar in construction to mold ejector pins and may also be mold ejector pins depending on mold configuration. Injection molding can form complex geometries easily, apply single part with multiple functions. Other common issues associated with thin walls include uneven cooling, warp, cracks, cosmetic texture inconsistencies, and weak knit lines or fracture points. 18/06/2021. We wanted to independently assess how a mold would fill and where knit lines would be, instead ofKnit Lines. When designing for injection molding, consider these steps to prevent knit lines Resin cools as it is injected into a mold. Because they can be shut off independently you can control flow fronts and knit-line locations. • Repair parting line • Weld up vent depth Gate blush • Melt Fracture • Adjust injection speed (fast/slow) • Increase melt/mold temperatures • Resize gateFeedstocks for injection molding show two rheological behaviors: Pseudoplastic (shear thinning) and Dilatant (shear thickening) behaviors. In plastic part design for injection molding, it is important to design the injection mold so that the molten plastic fills the mold cavity entirely, cools as evenly and as quickly as possible without warping, and functions as intended. For over four decades, our experienced team and leading edge technology have provided you with tooling solutions from start to finish. When injection molding a part, a knit line may present no problem, or can cause a serious structural problem. (If parts are to be molded by Protomold’s rapid injection molding process, our Design Guidelines should be used. To avoid walls that are too fat or too thin, designing a wall thickness between 0. With over 50 years of experience, Universal Plastic Mold can help you avoid (or at least minimize) knit lines in your molded parts. As these flow fronts come together. While injection molding itself is a straightforward process involving melting. Injection molding is the most cost-competitive technology for manufacturing high volumes of identical plastic parts. Generally all plastic components should be designed with draft where possible. Multiple gates will always. The most common and one of the most challenging injection molding defects are weld and knit lines. In a plastic injection-molded component, a knit line occurs when 2 different plastic flows emerge in a mold. Obstructions in the part create weld lines or knit lines during injection molding. Injection speed and pressure. Use the fewest number of gates possible. Three terms that often get mixed up in injection molding are weld, meld and knit lines. Jabil (formerly Nypro) is uniquely qualified to offer a state-of-the-art curriculum in injection molding and related disciplines, which require highly specialized skills and continuous. Weld lines create visible marks, but this type of injection molding defect can also reduce a part’s strength and durability. With fast accurate, injection-mold simulations, designing injection-molded products, developing injection molds, and shooting parts is more collaborative, accurate, and efficient, saving time and driving down costs. 160"). Mold flow analysis is a software simulation that can show how resin will fill the mold during the injection molding process. Direct experience designing molds and parts for injection molding and producing the molds and parts is valuable, relevant experience for design students. Heat resistance. A weld line, or knit line, occurs when two flows of melted plastic meet and “knit” together. Flow Lines / Knit Lines Flow/Knit Lines 11. The Troubleshooting Tips below offer common solutions to challenges in IML and IMD. While injection molding dies are expensive to produce, each die canHowever, they can also create weld lines or knit lines in the part where the flow fronts meet. Two major moldability pitfalls to avoid are sink and voids. But we can’t talk about the injection molding process without discussing the injection molding machine. Plasti-Co ® manufactures a wide range of injection molding nozzles from standard nozzle tips, extended nozzle tips, nozzle bodies, extended nozzles. The point of meeting creates a weak spot because the edges of the molten plastic, already cooling, don’t mix together very well. Injection moulding (U. Thin wall injection molding can produce walls as thin as 0. Disadvantage: May rust if improperly stored. The plastic in the ‘flow front’ cannot pass through the core pin, so it flows around the core pin splitting into 2 distinct flow fronts. When assessing issues with injection molded parts, we want to make sure some core aspects of molding are checked. The quality of the weld line can be improved through optimized processing conditions, increased mold and melt temperatures, and increased injection speed toWeld Lines. Weld or Knit lines are a plane or section in an injection molding part where the flow of molten plastics meets from different. This, in turn, leaves a large tab to be trimmed, a process that can mar the finished surface. They again get resolidified along the surface. The chart below shows recommended wall thicknesses for common injection molding resins. So what does the 140F mold temperature give us? The molding technician thought the 140F mold water was OK because the data sheet provided by the material supplier suggested mold temperatures from 75 to 180F. Learn about the key characteristics of common injection molding materials, recommended applications, and how common thermoplastics compare to one another. Users will be able to use in-cavity pressure or temperature sensors to control when the valves open or close. Throughout the molding process the press operator visually inspects the molded parts as they come out of the mold for any imperfections such as air trap, knit lines, backrinding, or tearing. 040 and 0. Prevent Flow and Knit Lines During the Injection Molding Process. Typical Tool Steel for Injection Mold Construction Steel Type Steel Properties Mold Component P-20 Pre-hardened, machines well, high carbon, general-purpose steel. Knit line Knit line Start of mold filling. spelling: injection molding) is a process for producing parts by injecting molten material into a mould, or mold. Injection molding a red component, for example, can pose a challenge because at time the component may be too thin for the pigment itself!. The quality of the answer is directly proportional to the information we have to work with. Venting at Weld Lines. The injection molding process is on the surface is fairly simple, plastic resin is heated to its melting point and forced into the cavity of the mold to produce a plastic parts. Most failures occur at what are called “weld lines” or “knit lines”. The mold opens and closes on a vertical axis in the vertical injection molding. These are imperfections in the part where separated flows of cooling material meet and. 763-755-7575. Heat: Too much heat can have an appearance similar to moisture splay. If debossed pattern is indispensable, it should have a depth of no less than 0. Check the diameter of the ejector pins and the pin hole tolerances, if the tolerance is too wide this could allow. Knit lines may also be called stitch lines, weld lines, or meld lines. ISO 9001:2015. One of the most important aspects of hot runner system design is the gate location, which is the point where the molten plastic enters the cavity. Knit lines are hard to eliminate for injection molded plastic parts but designers can minimize cosmetic defects. The temperature might fall at some places like in the mold, runners leading to the mold and injection molding. A mold with too few gates is susceptible to cooling problems, but a mold with too many gates. Mold cooling is one of the most important variables in injection molding. Redesign the mold: Redesigning the mold to. Knit lines. Islyn Thomas summarized the need for a particular vent location better than I ever could. Wax Cold wax Increase wax temperature. This defect is caused when the polymer resin is injected into a mold and flows around a solid piece and forms when the resin collides back together without completely fusing back together. This radius should not be smaller than 0. Knit lines. Different plastics make different types of knit lines. The Bottom Line You might have come across the aforementioned terminology before and did not know what any of the words meant. Knit lines don’t always compromise the structural integrity of plastic parts. Flash: All plastic injection molds contain parting lines, which create the potential for small amounts of molten plastic to escape the mold cavity’s boundaries. ITAR. a specific area on one side lens, a warp line, and a weft line. When injection molding a part, a knit. A wide variety of tool steels are available for injection mold construction. For the metal feedstock, injection and mold-wall temperatures were 130 ºC. Molding is a manufacturing process in which resin in a barrel is heated to a molten state,. Molding Troubleshooting Guide Bond Readout Bond readout is a surface distortion similar to a hump or sink that occurs over a bond line Probable Cause Material Process • Mismatch of compliance between outer panel, inner panel and adhesive • Incompatible thermal expansion coefficients between the SM and the adhesiveIt tells them that you visualized how injection molded parts cool and harden. weld line in injection molding. Once the mold is created and the machine is set up, additional parts can be manufactured very fast and at a very low cost.