Injection Mold Tooling Options and Quality Reporting. Depends how hard you want to push it. 2 mm. This can enable the manufacturer to increase the molten plastic temperature at the front of each flow and avoid the occurrence of weld lines. 2. 025 inches per inch, depending on the particular resin, molding conditions, part design, part wall thickness, and direction of flow. A special mold provided with a glass window was used in order to directly evaluate the flow progression during the filling phase of the injection molding process in a thin-wall cavity and to. Reduce the injection speed to limit the risk of trapping air inside the mold. Observation on a “trial and error” basis may be required. Wax or ceramic core size or location See Section 3. These knit-lines are well-known as particularly critical regions in the mold when mechanically loaded. Behind the obstruction, the flows try to merge again, but this is made more difficult by a low temperature of the mold surface and a low melt pressure. Also known as weld lines, knit lines. Injection molding a part with Class-A surface finish and ribs or bosses has proven an elusive goal for molders, despite their best efforts with conventional injection or internal gas-assist technology. 0 to 3. Its superior flowability allows for precise and flawless filling of injection molds without the risk of flow marks and knit lines. ; Wood, Philip E. knit lines and parting lines are at the discretion of MIC-ZG. Depending on the resin, resin temperature, mold temperature, and filling. Also discussed are weld and meld lines and their effects on molded. Based on the resin temperature, filling speed, and resin, there is a variation in the knit lines. Knit lines. Let’s review what causes meld and knit line imperfections, how they’re different, and how they affect part durability. Thicker parts require more cooling time and can lead to air becoming trapped in the mold and weld / knit lines to form. Reduce clamping force. 6 Monate. Injection Molding. Depending on the design of the mold and the material being injected, a knit line may: present no problem at all, be a. The specific method is that when the product is just filled and filled in the cavity, the insert is used to cut the soft material melt in. Moisture in the material due to insufficient drying can form at the melt front, forming an interface between the two melt fronts. Injection Molding Process Guidelines The following is given as a potential process starting point. Imagine a river splitting to go around a rock, then meeting up again on the other side. Macromol Symp 1988;21/21: 489-500. Mold Flow Analysis computer. The mold-opening force varies widely depending on the type and size of the molding machine. A poor knit line can cause only cosmetic blemishes or it can significantly weaken the structural integrity of a part. 5. When working with customers, our design guidelines for living hinges are 0. So. Knit Lines: These occur when different flow fronts come together as plastic flows through the part cavities. 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. 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. Thick walls are not recommended because of POM’s high shrinkage rate. Knit lines, also known as weld lines are areas in the molded part where two or more flow fronts converge. As. Injection molding crush ribs are small, protruding features added to molding designs to support and improve the stability of press-fit connections. See UNDERCUT. When assessing issues with injection molded parts, we want to make sure some core aspects of molding are checked. Three terms that often get mixed up in the plastic injection molding industry are weld, meld, and knit lines. Depending on the resin, resin temperature, mold temperature, and filling speed, knit lines can vary from virtually invisible to something that looks like cracks in the plastic. ISO 9001:2015. Factors were ordered. 344. Venting is required to allow the air in the sprue, runner and cavity to leave the tool as the melt flows into the cavity. A meld line occurs when two moving melt fronts converge and flow parallel to each other. Weld and meld lines are generally caused by holes or inserts in the part, multiple gates, variable wall thickness or hesitation and. 5 kN/cm2 (4 T/in2 ) is required. Back to News Page. Knit Lines. We recommend walls to be no less than 40 to 60 percent of adjacent wall thickness, and all should fit within recommended thickness ranges for the selected resin. Knit lines are hard to eliminate for injection molded plastic parts but designers can minimize cosmetic defects. This information is intended to be used only as a guideline for designers and processors of modified thermoplastics for injection molding. Nicolet Plastics LLC. In a weld line, reinforcement fibers. Nicolet Plastics LLC. It’s called sequential valve gating, or SVG. Injection moulding (U. Reducing the size and depth of depressions helps minimize the impact of knit lines. 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. Complex parts can be reproduced with low cost once mold is manufactured. This month, we covered an array of topics including injection mold venting, business strategies and runnerless micro molds. See UNDERCUT. • Holes formed by core pins are, in essence, 360° inside corners and should follow. Legend: a-in. Figure 1: D-shaped through-hole in center of gear part accepts the drive shaft. Injection Molding: How to Set Second. Multiple gates will always cause knit lines. The main causes of Weld Line or Knit lines are: Convergence of two flowing polymer melt streams during injection molding process: This is the most common cause of weld lines, as the two melt streams coming from different runners or gates in the mold meet and do not fully mix, creating a weak point in the finished product. Because injection mold design and processing is complex, a set solution will not solve all problems. Trapped gas is one of the most common causes of part burns, and can also lead to short shots and voids, blemishes and discernible knit lines that weaken the part. Read on to find out more! 800. (If parts are to be molded by Protomold’s rapid injection molding process, our Design Guidelines should be used. The Demo Mold helps those new to injection molding easily visualize the process and is a great teaching device for educators. These include: Symmetrical parts. Plastics Technology article (June 2018): Technical capabilities of the process have advanced to erase former cycle-time penalties, and ongoing developments address creation of a materials database and new applications in hybrid composite injection overmolding. com . In fact, knit line strength will decrease with higher filler content and with longer fibers. Shorten the mold cycle time so that any trapped air and resin don’t have a chance to overheat. These flaws can affect the aesthetic and structural integrity of the. Other common issues associated with thin walls include uneven cooling, warp, cracks, cosmetic texture inconsistencies, and weak knit lines or fracture points. The uneven thickness of the product will make the melt flow resistance larger and smaller, resulting in unstable melt flow. Mold bases, ejector plates, and some cavities (if nickel or chrome plated to prevent rust). Enlarge gas vents and gates to allow trapped air to escape the mold. He said, “Vent cavities at weld lines or junction points where two or more material streams meet and fuse into a solid mass. 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. The tooling engineer in the mold house will be more into venting, sprue pressure, preheating the mold, cycle times, ejector pin scheme, mold flow, getting a gate location to avoid fill issues or knit lines, excessive flash and molding pressures, and the list goes on. Short shots and knit lines are two phenomena that are caused by using highly viscousTherefore, changing the edges and corners of the mold core to make it buffer transition and keep the melt flow stable can prevent the occurrence of wavy lines. As a result of weak coupling along the knit-line, the weld-line strength can be only about 60% of that of an unreinforced resin. Knit lines, holes, part configuration and the talent of your molder all come into play. Plastic injection molding is a complex and highly intricate process. H-13 Good general purpose tool steel. The resin is transferred to the mold cavity under positive. The metal parts, made of steel grade. Specific attention to processing details will enhance quality and productivity . This can dramatically reduce the effects of material changes, according to the injection molding technology company. PAPER ABSTRACT: Desktop injection molding machines and stereolithographic print ed molds make hands-on injection molding production possible in design studio classrooms and labs. The process is extremely versatile, and can produce very complex shaped parts, with the use of multi-sided molds. Let the molten material cool to a solid-state. As. They occur when melt flow fronts collide in a mold cavity. Many of these tips are geared around injection-molded parts, but some apply to machined and 3D-printed parts as well. BACKING PLATE – In mold construction, a plate used as a support for the cavity blocks, guide pins, bushings, etc. As the melted plastic fills the mold, there are locations where the molten plastic flow stream separates and then comes back together. We recommend walls to be no less than 40 to 60 percent of adjacent wall thickness, and all should fit within recommended thickness ranges for the selected resin. 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. 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. Weld lines typically appear in a part when an obstruction of some kind separates the melt flow and prevents it from "knitting" together. Knit lines are a common defect in injection molding that can affect the appearance and performance of plastic parts. Gate design is another critical piece of part function in plastic injection molding. Bubbles are caused by melting flow fronts colliding in a mold cavity. Core Geometry. Operating Conditions • Fast injection fill speeds, supporting short injection times (1–3 s), especially in thin sectionsKnit lines in reaction injection moldings Knit lines in reaction injection moldings Maier, Christian; Hrymak, Andrew N. Proper mold cooling can eliminate warp, decrease cycle times, and increase part quality. Causes: Weld lines are caused by the inadequate bonding of two or more flow fronts when there is partial solidification of the molten plastic. We ensure customers receive accurate, fast, on-time, sufficient support and services. Typically, injection molded parts will be between 0. The most common and one of the most challenging injection molding defects are weld and knit lines. Gates, vents, sliding cams, pick-out inserts, and any other place where the two sides of. 763-755-7575. Any of the above can result in “knit lines” on final products, but mold flow analysis prior to mold machining can keep these issues from cropping up at all in iteration and production. Knit Lines: Holes in the part will always cause knit lines. Fictiv can help you avoid injection mold design and plastic part design for injection molding problems. In. weld line in injection molding. and Titomanlio, G. Commonly seen at the edge of a hole or other cored feature, knit lines are—as a rule—purely cosmetic, but may create a physical failure point if present in an area of the part that receives substantial stress, such as the head of a screw. reduction on the side the part is folding towards. 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. If the plastic has cooled too. (2) Undesired movement of certain materials in a plastic. Main causes of knit lines in injection molding: 1. Get a free des. It can also aid in material selection since fill. RELATED CONTENT. This design aid shows the mechanics of how the A-side and B-side of a tool work together during the injection molding process to create plastic parts. Observation on a “trial and error” basis may be required. Compression molding can also support large part sizes, and it has a tendency to. knit line formation, application of draft angle and design for assembly. 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. A plastic product formed by the injection mold is divided into two parts, and the line separating the product is called the parting line. Mold venting is critical to the quality and consistency of the finished part. Weld line defects – also known as knit lines – is a defect that occurs when the injected plastic meets within a mold. It’s also relatively inexpensive. 012 in. The thickness of the part plays an important role in how difficult the molding process will be. 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. 120 in. This will helpWeld line. It happens when the molten plastic material flows around obstacles, such as inserts or cores, and rejoins on the other side. 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. . The knit lines are the result of poor molding conditions (likely molding at too low of a temperature). Those are knit lines, formed when two opposing flows of material join together in the mold cavity. Typical Tool Steel for Injection Mold Construction Steel Type Steel Properties Mold Component P-20 Pre-hardened, machines well, high carbon, general-purpose steel. Learn about the key characteristics of common injection molding materials, recommended applications, and how common thermoplastics compare to one another. Release of trapped air in those cases will. A machine heats and mixes the plastic until it is in a pliable molten shape, then a screw device turns to force the plastic into an outlet that leads to the mold. Degassing – Degassing is the simple operation of opening and closing an injection mold to allow any trapped air (or gas) to escape. Temperature is another factor that can cause weld or knit lines in injection molding. Also known as weld lines, knit lines. Solution: People. Refers to portion of injection molding part that has some taper to make it easier to remove from the mold. Hartland, WI 53029. 3. Contact Universal Plastic Mold Today. This information is intended to be used only as a guideline for designers and processors of modified thermoplastics for injection molding. Long shapes are produced without multiple drops or hot runner systems, eliminating knit lines and lowering tooling costs. Contact us. BACKING PLATE – In mold construction, a plate used as a support for the cavity blocks, guide pins, bushings, etc. Still, they are almost always a cosmetic issue. Ham Lake, MN 55304. Please read on, stay posted, subscribe, and we welcome you to tell us what you think. 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. Step 1: The injection of molten plastic into the injection mold from Barrel A. One of the most common ways of adding venting is by manually machining it into the mold (Figs. End-of-arm tooling can make or break a program. Injection molding is the most widely used method for mass-producing plastic parts. thickness with a spacing of about 0. As melt temperature, viscosity and abrasiveness rise, tool life will decline. Check the diameter of the ejector pins and the pin hole tolerances, if the tolerance is too wide this could allow. This summary represents a key subset of the detailed molding information found in the remainder of this molding guide . He is currently a tooling manager for a large, multi-plant molding and manufacturing company. Consider adding mold release (can be added to the polymer itself by the polymer vendor) or at machine side Knit lines Weak knit lines Increase melt temperature Mold temperature too cold Increase injection speed Avoid nucleated products if possible Inadequate venting7. 010 inches. 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. "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. Solution: Increase the injection pressure or speed. Inject the molten material into a mold. By altering the part design, it may be possible to just have one flow front, and avoid multiple flow fronts having to come together. Direct experience designing molds and parts for injection molding and producing the molds and parts is valuable, relevant experience for design students. Weld lines create visible marks, but this type of injection molding defect can also reduce a part’s strength and durability. A weld line, also known as a knit line, is a visible line or mark that occurs in an injection-molded part where two or more melt fronts meet and fuse together during the molding process. extend mold service life. Our On-demand. When venting stationary inserts or core pins in rib or part details with venting issues, I recommend no more than 0. The injection molding process is fairly simple, plastic resin is heated to its melting point and forced through the machine and into your mold to produce your plastic parts. Reduce the injection pressure. 2. RJG announced that its injection molding process control system, CoPilot, will begin offering valve gate control technology for hot runners starting in September 2021. injection molding machines using standard industry practices . RELATED CONTENT. Double push filling method. They again get resolidified along the surface. Compression molding is one of the earliest forms of molding. In places where the plastic flows around a solid piece of the mold, from a simple circle to forming complex shapes like rings or squares. The gate is the entry point to the part-forming cavity, where plastic material is injected from the molding machine barrel, through the sprue and runner, into the mold. Knit lines may also be called stitch lines, weld lines, or meld lines. Other materials, like LCP are great for thin wall micro molding but also notorious for having a bad knit line, potentially snapping from excessive torque in later manufacturing processes. When the temperature is not very high, there are chances of premature solidification, which can cause weld lines to form. 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. As the polymer resin is injected into a mold, it flows through all parts of the mold. Knit / Weld Lines. With over 50 years of experience, Universal Plastic Mold can help you avoid (or at least minimize) knit lines in your molded parts. BURN MARKS Burn Marks: burn marks can occur when the design of a plastic part, and the subsequent injection mold design, causes air to be trapped during the injection (or filling stage) of the molding cycle. From Plastic Materials and Processing by A. In the injection molding process, knit lines are a common occurrence when two or more plastic flow fronts collide and solidify, resulting in a visible seam or line on the molded part. Quick Guide to Injection Molding Amodel® polyphthalamide (PPA) equipment Amodel® PPA resins can be processed on conventional injection molding equipment. Because this allows some cooling and thickening of the resin, tab gates require a relatively large opening into the mold cavity. land and using maximum vent depths to get them as close to self-cleaning as possible. 5. He said, “Vent cavities at weld lines or junction points where two or more material streams meet and fuse into a solid mass. When designing for injection molding, consider these steps to prevent knit lines Resin cools as it is injected into a mold. Find out more by calling 573-437-4154 today or email us. Gating. Adjust the design for the flow pattern to be a single source flow. 3. • Estimated clamp tonnage of 5. Weld-lines, also referred to as spider-lines or knit-lines, are regions in the wall of an extruded plastic pipe, running the whole length of the pipe, at which there is a change in dimension and a. An injection mold that produces pieces while the final tool is being built. Services. In a plastic injection-molded component, a knit line occurs when 2 different plastic flows emerge in a mold. Texturing may also hide surface defects such as knit lines and other imperfections. Venting. There needs to be a balance between fit of the halves, function of the part, visual quality expectations, and the cost to produce the mold. Weld and meld lines are generally caused by holes or inserts in the part, multiple gates, variable wall thickness or hesitation and. S. It is typically used for thermoset materials, but can be used with thermoplastics. 030- to 0. Knit Lines and Resins. Also known as knit lines. Most issues occur before entry into the mold. All that considered, for a specific simple part with specific quality requirements. There is high defect rate (surface defects/knit line). Commonly seen at the edge of a hole or other cored feature, knit lines are—as a. Learn how to troubleshoot weld lines in injection molding. POROUS MOLD MATERIALS. Plastic melt and mold temperature. Once the plastic sets, the mold opens to eject the product. 7. 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. Vertical Plastic Injection Molding. When the mold adopts the multi-gate pouring scheme, the plastic melt. 2. This article will discuss the importance of injection molding nozzles and what makes a good nozzle for a molding or injection. 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. 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. A parting-line vent. Resin pellets are loaded into a barrel where. 0 and Table 1). Injection Molding Problems and Solutions (17/17) – Weld or Knit Lines Sep 27, 2022 Injection Molding Problems and Solutions (16/17) – Warpage Sep 15, 2022. Injection molding machines with footprints similar to desktop FDM and SLA 3D printers are now available. Knit lines, also known as weld lines are areas in the. Not always a problem, but can cause serious structural issues. Mold filling simulation software should be used to ensure that waterExpand. 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 adhesiveWeld lines, created in the areas of collision of two flow fronts of plastic in the injection mold cavity, are the reason of lower mechanical properties and a worse surface condition of molded parts. Advantages for your Injection Molding Machine:. Demo Mold. Thin walls often lead to material flow problems, which can cause unformed areas. . Different plastics make different types of knit lines. How weld lines form. Injection Molding Press. N174W21430 Alcan Dr Jackson, WI 53037 262-677-9700; 16685. Obstructions in the part create weld lines or knit lines during injection molding. The knit line is generally opposite the gate in thermoset. These lines. They occur when melt flow fronts collide in a mold cavity. Probable Cause Suggested RemedyI am working on a thin PC/ASA injection moulded component which has a tendency to snap at the Knit-point (the final point of travel at which the…Opening and closing all the valve gates at the same time necessarily limits the degree of control over weld or knit lines, gas traps, localized packing, and unbalanced flow. The recommended minimum production volume for injection molding is 500 units. 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. The difference between a knit and meld line is significant, dramatically impacting the part’s structural integrity. A knit line in a plastic injection-molded part is created when two separate plastic flows meet within the mold and "resolidify" along their interface. opposed to two or more gates. Most failures of injection molded plastic parts are caused by either improper design of the part or improper design of the mold. C. The chart below shows recommended wall thicknesses for common injection molding resins. Redesign the mold: Redesigning the mold to. 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. To learn more about us or to get a quote, click here or call 1. Weld / knit plane forms as flow fronts recombine Weld line and failure due to flow around core. They are very much related but independent disciplines. The comment on melt flow index is correct, but, I've molded straight PC down to . Weld Lines. The mold opens and closes on a vertical axis in the vertical injection molding. Even parts with metal inserts can be produced. For non-reinforced or non-filled nylon, the mechanical performance in the knit lines (planes) areas are approximately equal to the mechanical performance of the resin (polyamide) used. 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. From the start of your project, you can count on The Toolroom to exceed your expectations for all of your plastic injection molding needs. The Troubleshooting Tips below offer common solutions to challenges in IML and IMD. IM: hot or warm knit lines are cause by _____ while cold knit lines are caused by _____. In the plastic injection moulding industry, we work with materials that are by-products of oil refinement and moulds made of metal casting, so our terminology is bound to be at least slightly confusing. . Knit lines are consideredmolding defects, and occur when the mold or/and materialtemperaturesare set too low:. This will help the mold designer to determine the allowable gate and knit line locations. Our prototype injection molding process helps you cut product development cycles by weeks—sometimes months—and bridge to production with injection-molded parts within days. Typically, this fillet radius should be somewhere near 0. Weld line. CNC-Bearbeitung; Spritzgusswerkzeuge und -teile; Stereolithographie (SLA) Selektives. pdf), Text File (. A screw-type plunger forces the material into a heated chambe r,. (1. Give us a call at (425) 339-0288 or email us at info@sealectplastics. The areas in the cavity where such buildup tends to be common are at end-of-fill areas, details that trap gas, and knit lines. Molding is a manufacturing process in which resin in a barrel is heated to a molten state,. RE: Knit Line Affect On Material Strength lorelei5607 (Automotive). Adjust the design for the flow pattern to be a single source flow. Undercuts add cost to tooling and molding, which is recommended to eliminate or minimize as possible. While not always visible, weld lines (aka knit lines) are where two resin flows meet. Knit lines are formed in injection moulding when two flow fronts meet in the middle of a part (a line where two sides of the plastic are “knit” together). Its superior flowability allows for precise and flawless filling of injection molds without the risk of flow marks and knit lines. Knit line / Meld line / Transfer line Discoloured line where two flow fronts meet Mould or material temperatures set too low (the material is cold when they meet, so they don't bond). The temperature might fall at some places like in the mold, runners leading to the mold and injection molding. Change gate locations. Having uniform wall thicknesses between 0. The depth of the texture or letters is somewhat. They are the result of fundamental physical effects taking place inside of the mold. The injection molding process uses a granular plastic that is gravity fed from a hopper. A well-designed injection-molded part will usually have draft, but the same draft that helps eject a part from the. ABOUT THE AUTHOR. 5 : 1 and a L/D (length toMold flow analysis is a software simulation which show how the resin fill in the mold in injection molding process. 5T, where T is your nominal wall thickness. Take these steps to avoid knit lines. TRADITIONAL MACHINES VENTS. In addition, the force of the gas holds the appearance side of the part in contact with. In the 1947 book, Injection Molding of Plastics, the late Dr. This slight depression is a tiny line called the weld line or knit line. Exploring common molding defects and. , 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. Figure 1 presents the shrinkage of polypropylene versus wall thickness in injection molded parts. 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. Meld and knit lines are actually both different types of weld lines. The bottom of your rib must also feature a fillet. Weld lines, also called knit lines, are a defect that occurs with molded parts caused by two different flows of plastic resin that do not adequately join together or weld together correctly during injection molding. Weld lines are formed when there is an inability of two or more flow fronts to ‘knit’ or ‘weld,’ together during the molding process. Figure 1 Flow Lines Knit or Weld Lines Cavity Gates Table 1 Knit line in a multi-injection-point cavity. Injection speed and pressure. The leading edge of the molten material is often the coolest point and the closest to solidifying. Pitfall #1 – Knit Lines. Understand the causes of knit lines in injection molding and explore effective solutions to minimize their impact. Weld Lines-3 Ways for Detecting and Correcting. Services Group. To account for variations in viscosity, nylon injection molding machines need to maintain an appropriate injection pressure. Design with Plastics - for Injection Molding process. 4. Thermoplastic Elastomer Molding Guidelines.