Mixing Nozzles, Standard Nozzles, Insulated and Standard Heater Bands, Thermocouples, etc. Haziness or cloudiness in molded parts is one of the most common injection molding defects. e. A desiccant drier should be used to dry the polycarbonate products to less than 0. This allows the melt to keep enough velocity to ensure proper filing. Inconsistencies in the injection molding or extrusion process caused by the fluctuations in viscosity of the resin which is a major factor in injection molding / extrusion. This cosmetic defect occurs in plastic injection molding, when silver or white str. Allows you to accommodate a variety of part sizes. It will also profile key analysis. January-October 2022, exports of plastic products amounted to $89. In reality, to ensure that every product comes out of the process a success takes a lot of skill and knowledge. The most common: incompatible materials. A cosmetic defect, it is often silvery in color and is sometimes called 'silver streak'. Splay is a cosmetic defect that occurs in plastic injection molding, sometimes we also call it “silver streaks” because of the appearance of silvery scratches across the surface of the. Splay is defined here to include any defects that appear as smeared material or bubbles on the part surface, usually oriented in the flow direction. See Product Details. Located in the heart of Silicon Valley since 1974, we understand the performance expectations of cutting-edge companies delivering innovative technologies. Practical Injection Molding. elimination of splay in injection molding by cavity pressurization author lord ha western electric co. Splay: A layer/ streak of a unwanted gaseous byproduct from the melt or moisture in the material comes in between the melt flow and the cavity walls preventing the texture from being picked up and in addition eventually leaving a residue: Dry plastic to suggested moisture levels; Decrease injection speeds; Decrease melt temperatureWith ABS injection molding, you get the collective benefits and properties of three monomers. Splay 1 3 – 2 – 5 – 4 – Short shots. Just like most injection-molding defects, delamination can be caused by one or more of several potential issues. . Plastics processors are responsible for making process corrections when defects affect their scrap rate. Learn what appearance the purge puddle should have to identify that the material is ready for injection. Injection Molding Extrusion Blow Molding Molds & Tooling Manufacturing Recycling Additive Manufacturing Features Thermoforming Compounding Rotomolding. Air flow may become erratic due to moisture in the molding system and this can be a source of trouble. The melt holds enough temperature to maintain a low enough viscosity. The majority of plastics can absorb moister from the air, meaning they are hygroscopic. It is because a higher temperature results in prematurely expelling the injection-molded components. With injection molding, the pack/hold phase may push the mold’s parting line apart. Splay (also called chicken tracks, tails, and hooks) is usually caused by a gas, usually water (steam), but can be caused by unmelt, dirt, chips, or flakes from three-plate molds, cold slugs, excessive volatile additives, air, and/or decompression. MISUMI | Your Time, Our Priority. ,princeton nj,usa source pactec '79. He has provided process-engineering expertise to many top companies, including Glock, Honda, Johnson Controls, and. Injection Molding Processing Guide. Troubleshoot and correct issues with all Molding equipment. With the same gate diameter and injection speed, the higher the viscosity of the resin (the lower the fluidity ), the. Gloss should be considered in relation to both the mold and resin being processed, since some materials naturally have higher gloss. SPLAY in Injection Molding. Splay or streaking is often a silver color and may look like mica. Paulson’s most advanced injection molding course. This cosmetic defect occurs in plastic injection molding, when silver or white str. Step 2 – Properly Document the Process Outputs. Mis makan dapat menyebabkan materi dalam sekrup/barrel menjadi terlalu panas dan menjebak gas seperti yang didorong melalui zona kompresi yang akan menunjukkan di bagian sebagai lapisan perak/splay. 2. Bernie A. That’s the air escaping out of the nozzle until the hose is full of pressurized water. Ai-powered technology is ideal for cosmetic visual inspection of subcomponent assemblies. That degradation creates a gas, which is. Thicker mold walls enhance the formation of foam. Leading the growth and advancement of technology and innovation in plastics machinery for over 50 years, JSW provides a full line of all-electric injection molding machines, ranging from 30-3000 metric tonnes and offers ease of operation, safety, and environment-friendly improvements such as energy and space-saving features. 3) Friction and mold wall friction overheating. Splay is a defect similar to blisters that is caused by escaping gas or water and which affects the surface of. Solution: Ensure the nylon is properly dried; increase dimensions in edge gate, sprue O-diameter, and nozzle orifice; relocate edge gate to the center. Cause #2: Material. However, you can make small changes to your injection equipment and processes to help you decrease the number of flaws that result from the injection molding process. Our medical molding operations provide class 7 cleanrooms with horizontal and vertical medical injection molding machines to support cost-effect, tight tolerance parts to market in a timely manner. The best way to avoid these part defects is to work with a plastic injection molder that has a great deal of experience with various resins and their applications. Plastic injection defects can lead to large scrap events and lost profits, and splay is one of the more frequent defects a processor must correct. Injection Molding The process of forming a material by forcing it from a heated cylinder, under pressure, through a spruce into a cavity of a confined mold. The raw materials do not satisfy the use criteria. Control injection speed to avoid material shearing and splay. Ejection temperature is too high. This video helps to visually define the different properties of splay. There are many "lookalike" defects, and many possible causes is splay, included excessive mold lubrication. A gas mark is a fault that grows in the direction that melt plastic flows on a product's surface resulting from gas interference during the filling process. High-quality mold should be used in injection molding to avoid molding splay. Injection molding can be a real challenge if you don’t follow the “Five M’s”: Man, Mold, Machine, Material and Method. Remedies: Mold design: (1) Add an exhaust system to a place where the exhaust gas is easily generated. The Troubleshooter’s notebook. Lower melt temperature; The mold gate is too small, injection speed is too fast. Explore our injection molding troubleshooting guide! Web here are 11 common needle mold defects, what the. Splay caused by moisture. Problem: Shear-sensitive material; gate land length much too long; and barrel temperatures, in an effort to eliminate gate blush, were raised too high. Category: Injection Molding. First-stage injection fills 92% to 99. It usually appears at the gate where the plastic enters the mold. March 3, 2017 Leave a comment. Jetting can be defined as a "snake-like" pattern on the surface of a molded part, usually emanating from the gate area. Simplified diagram of the process. Injection moulding process explained with key elements. Figure 2 shows the part after testing, and you can now see a depression or sink. Cleaner for Mold; Repair for Mold; Heating Items. It combines the strength and rigidity of acrylonitrile and styrene polymers with the toughness of polybutadiene to deliver superior hardness and toughness. Must Have 3 YRS Experience In Plastic Injection Molding & Submit a Resume . Thick sections take longer to cool than thin ones. Understanding Splay in Injection Molding 1. The molecules bond together as desired and splay is eliminated. Garrett MacKenzie | Mar 12, 2023 In the injection molding process, the. Warping: A deformation where part surfaces or walls twist or bend as the part cools. Splay is. • Estimated clamp tonnage of 5. Many defects can occur in injection molding. Garrett MacKenzie is the owner/editor of plastic411. Splay is sometimes also called “silver streaks” because of the appearance of silvery scratches across the surface of the injection molded part. Set a higher clamping presure. , Ltd(XIAOLIN) has 18 years of manufacturing experience, we are an experienced manufacturer for custom rapid prototyping, mold, a. 4 Injection Speed. Splay Marks. Usually oblong, silvery surface streaks which are open in the shapre of a U counter to the direction of flow. 07% can cause cosmetic problems on a part surface if the material is exposed to the temperatures of melt processing. Over Applying Rust Preventative. It can be difficult to. Focus more on the ejection mechanism in the mold design to reduce or eliminate the dependence on mold release agents. Gas trapping/ poor venting. To decide on the likely cause(s), test each to prove/disprove. In the process of injection. Thermoplastic resins fall into two distinct categories, each with their own advantages and disadvantages. The best way to avoid these part defects is to work with a plastic injection molder that has a great deal of experience with various resins and their applications. He is a well-known columnist for magazines covering this area. Symptoms/problem: Swirls and gloss on the part’s surface. It may be reminiscent of the grooves on a gramophone record or it may appear simply as an irregular pattern of lines，roughly in a half-circle round the gate. These data were obtained from many and Splay can be a costly problem in the production of your molded components. Date: October 23, 2019. gas, possibly resulting in inconsistent shot sizes and splay. com and a consultant/trainer in plastic injection molding. Splay is one cosmetic defect that occurs in plastic injection molding, although silver oder white streaks appear on the outside of the part. At times the part may also shatter. If you have ever looked closely at a plastic object, you may have noticed a faint line running around its circumference. Since the cavity is more than 90% full, not much more plastic is needed. 020"). See moreSplay is a common defect in plastic injection molding that can be caused by moisture, shear and heat. fFlow rate. Splay is one of the more common — and sometimes baffling — defects in plastic injection molded products. Figure 2 is a part tested a few minutes after molding and Fig. The process begins with the mixing and melting of resin pellets. Using a turnkey manufacturer, who also builds and maintains the mold, can help avoid any costly machining charges or mold replacement. Though it is only visible once plated, it is caused my molding issues; trapped moisture in the plastic can come to the surface during. The turbulent flow whips air into the polymer, creating micro bubbles. R4:The position of the take-up plate is not correct. Medical & Pharma Injection Molding. 002'') pathways on the shutoff area of the cavity blocks. 3 is a part tested 16 hr after molding. Injection molding continues to be a complex manufacturing process that requires perfect harmony of part design, mold design, material selection, and the molding process itself. 2. If you were to pour water and molasses at the same time, water would flow much easier than the molasses. One of the most common defects in plastic injection is splay. It owns the name silver streak because of the appearance of silvery scratches on the injection-molded part's surface. Cracking when mold opens • Overpacking • Hot mold • Poor drying • Breakaway too fast • Needs vacuum break • Reduce either packing pressure or time . When purchasing plastic injection molded parts. Purge the barrel amply, to allow the barrel time to heat soak. Where are many "lookalike" bugs, and many possibly drives about splay, including exorbitant mold lubrication. This type of injection plastic defect occurs as small depressions or recesses. Heat splay, caused by degradation or hang- up, looks similar but is often accompanied by black specks or yellowness. cgnx_pdf Download Consumer Products Solutions Guide. , flash and short shots, packing and cooling related defects i. Moisture can get into the plastic in many ways. In any case, you’d prefer to create polycarbonate parts of different sizes; then this is the best technique that you need to use. 008 to 0. Studying read about how in identifies and address splayWeldlines Splay Jetting Burn Marks Warpage. , sink marks and voids, and post. Moisture. 1. Injection molding moisture steak. These injection mold coatings are applied either in your tool room or on the press and give exceptional release characteristics to the part in the mold, allowing it to eject without sticking and thereby eliminating any pin push marks. Ada banyak penyebab yang lebih mungkin, tapi perlu informasi lebih lanjut dan benar Cacat jenis sebenarnya injeksi. Therefore injection mold core and cavity surface finish are as per the specified part drawing. XIAOLIN Plastic Industry Co. These features occur on flat and consistent surfaces of molded parts. The wet material can cause the formation of steam, creating pockets of trapped gas. Improve venting and/or relocate to. The faster the injection speed, the worse the jetting. Material Drying 101. 3. 5 kN/cm2 (4 T/in2) is required. The defect detection tool then identifies any anomalous parts, detecting both functional and cosmetic defects. Splay is defined here to include any defects that appear as smeared material or bubbles on the part surface, usually oriented in the flow direction. Michael Sepe is our analyst and author. Figure 1 is the part before heating. Many companies worldwide continue to purchase China injection molding services; some are placing large orders, and some even set up their own sourcing office in China. The mold leaks oil, water, and air into the mold cavity, which easily causes silver streaks on the part surface. Molding moist polycarbonate can cause splaying, while reducing the polymer’s impact and tensile strength. Valve gate nozzles eliminate the need for melt decompression because the seal is robust even if the hot runner manifold remains pressurized. These injection mold coatings are applied either in your tool room or on the press and give exceptional release characteristics to the part in the mold, allowing it to eject without sticking and thereby eliminating any pin push marks. C. When in the hands of inadequate expertise, a lot can go wrong. Read our blog post here. Particularly in injection molding, a typical method of forming plastic, care must be. Splay is a term used in the manufacture of injection molded plastics to refer to off-colored streaking along the surface of a molded part. Moisture Content in the Resin. In addition, it is important to note that nylon is not only affected by poor drying/ moisture conditions. The injection molding companies must avoid any extra-thick bits of significant disparities in the thickness of the plastic component when constructing the mold. Adjust the thickness (1t-2t) 6. Inadequate support for the sprue bushing can transfer pressure to the parting line, too. The speed in which the plastic is injected into the mold (known as the ram speed) may be too high. Plastic decomposition. The molecules bond together as desired and splay is eliminated. 3. Learn how to identify and fix splay with Nanoplas products and troubleshooting guide. Symptoms/problem: Swirls and gloss on the part’s surface. Setting too high a temperature can prevent the gate from sealing properly and on time. The plastic pellets are heated until they are liquid. Remedies: Use an injection screw with the proper compression ratio. The product is lasting weekly, as opposed to daily. Learn more about how up identify furthermore address splaySplay can be a costly problem in the production of your molded components. The material pumped out of the cylinder is foamed and shows blisters on the injection molding parts surface. Splay be ampere cosmetic flaw that occurs in plastic injection molding, when silver or white streaks seem on the surface concerning aforementioned part. The injection molding cycle can be broken down in to 04 phase i. 7. Increase the mold temperature. A cosmetic defect caused by moisture in the resin or injection molding machine screw rotation or the movement of. Specific attention to processing details will enhance quality and productivity . Source: Google. At times the part may also shatter. Controlling the switchover from first to. The splay that normally appears when wet polycarbonate is molded was. If the only solution is to use a spray, try our Tuff-Kote and Dri-Kote high-performance mold-release sprays. FIG. SPLAY Splay: Moisture is the primary causes of splay on an injection molded part. Ensure Machine Purging: In injection molding, purging refers to cleaning the molding machine of one material or color. 56 years of injection molding expertise results in a robust, consistent, and precise top tier machine that you can depend on to keep your business in operation. Reduce the barrel temperature and increase the injection pressure. Home; Products. e. Troubleshooting is the art and science of remedying defects after the process has demonstrated the ability to produce acceptable production parts. Here are a few of the most common defects that may occur in plastic injection molding — and how product teams can avoid them. This is an excerpt from Lesson #6 in Paulson's Injection Molded Part Problems and Solutions training progam - Splay (or Silver Streaks) and how to fix them. They. This can result in bubbles or splay in the molded part. The application of chemical foaming agents in injection molding mainly aims at weight reduction in the molded parts thus saving material and money. This property significantly enhances the rate at which you. A compression ratio between 1. Gloss should be considered in relation to both the mold and resin being processed, since some materials naturally have higher gloss. This process is fast, cheap, and helps create vast volumes of identical objects. Increase size of the vents. Air, water vapor, and decomposition gas are all components of gas, and the presence of gas is the primary cause of this mark. CRC Press, Mar 14, 2001 - Technology & Engineering - 232 pages. Over drying can also lead to multiple defect conditions. Use care when reducing barrel temperature, while maintaining proper shear to provide proper melt and mixing. Previous Posts . 508-520-3222Jan 04, 1999. Some molds need to be textured. Slip agents not only reduce the coefficient of friction (CoF) but also are used to reduce adhesion between the mold and injection molded polymer. 6 sec instead of the typical 7 sec for ABS/PC. Remedies: Decreasing the barrel temperature allows the plastic to stay molten without burning or charring. So I came across this defect which looks like splay. If it’s a bubble, the wall stock will swell due to the gas inside expanding. 0005''-0. Reposition gates and runners to allow resin to flow around the obstruction from a different direction. • Visual inspection, trimming, and packing of injection molded plastic products. Steve Brammer is Molding Technical Manager at Lacks Trim Systems. 4. These materials have been developed to meet specific requirements for strength, high temperature and chemical resistance, abrasion resistance and low friction. 508-520-0011 Fax: +1. Take a good look at part design. Too high hold pressure eccentric gate. If the grease breaks down on the slides and lifters, it could become tacky, causing them. View my complete profile. pdf - Free download as PDF File (. Except for large parts, you are usually dealing with only a few extra grams. Its primary function—as the name suggests—is to act as a trap, or “well,” for the cold slug. Haze on the one side of the preform. To decide on the likely cause(s), test each to prove/disprove whether it is causing the splay, then take the corrective action. To create an injection-molded product, manufacturers perform the following steps: The completed mold is placed in the injection molding machine. There only needs to be a very tiny amount of water in the material for steam to form during molding. com. COLD SLUG WELL – Space provided directly opposite the sprue opening in an injection mold to trap the cold slug. The material temperature could also be raised to accomplish the same effect. Appearance alone cannot tell you which type of splay is present. Brittleness can be defined as the tendency of a molded plastic part to break or crack under conditions in which it would not normally do so. The mold maker may think that some minor defects are acceptable, or they may not even consider them from the beginning, which can cause problems when the injection mold is being manufactured. Splay – visible gray or silver streaks on the finished product caused by excess moisture in the material;Injection-molded plastic parts replicate the Injection mold surface finish (Refer to SPI Surface Finish Chart). If the material contains moisture，it should be dried; if decomposition or depolymerization are causing the volatiles, the cylinder temperature should be lowered, and if moisture in the mould is to blame, its temperature should be. Injection Molding Polypropylene: Polypropylene is a very useful plastic for injection molding and is typically available for this purpose in the form of pellets. It is made from stainless steel. Increase the mold temperature and reduce the barrel temperature for injection molding of thin-walled products. The revolutionary low constant pressure injection molding platform works with virtually any plastic injection machine, material, and mold. This cosmetic defect occurs in plastic injection molding, when silver or white streaks appear on the surface of the part face due to air, contamination, heat, moisture, or shear issues. Injection molding BrE or Injection molding AmE, is a manufacturing process for producing parts by injecting molten material into a mold. One is the injection of a high-velocity stream of molten material into the mold ahead of the general flow front. There’s a good reason burns are also called gas traps in injection molding: they’re caused by trapped gases. Splay can be a costly problem in the production of your molded components. Valve gate nozzles leave a small witness mark on the part—the same size as the gate diameter. The special version of its J100ADS has optional integrated magnetic platens and powder-coated surfaces for medical molding. इस वीडियो में इंजेक्शन मोल्डिंग से सम्बंधित एक डिफेक्ट silver mark/streaks के बारे में. Injection molding Cycle. Excessive injection speed causes turbulent, non-laminar melt flow into the cavity. Gate size. Some basic plastic injection molding surface defect identification causes and troubleshooting| Types of defects in injection molding-Let's begin by listing some of the common defects, their possible causes, and some things we might be able. injection molding process was carried out by varying important processing parameters of mold temperature, injection speed, packing pressure and melt. • Standard (general purpose) screws with a compression ratio between 1. Injection molding process explained. This extra effort ensures that their injection molding process is smooth and free of splay defects, resulting in high-quality finished parts. With the machine on cycle, retract the injection unit, Purge. This line is known as the partingSplay is a cosmetic defect that occurs to plastic injection molding, for silver or white smears appear over the surface of the part. Start the fill at a very. Smaller gates might require a slower beginning-of-fill speed. Splay is a cosmetic defect that occurs in plastic injection molding, sometimes we also call it “silver streaks” because of the appearance of silvery scratches across the surface of the. applications. This causes splay, which is a visual defect, but also creates a weak part due to brittleness. This cosmetic defect occurs in plastic injection molding, when silver or white streaks appear on the surface of the part face due to air, contamination, heat, moisture, or shear issues. Injection molding problems MOISTURE RELATED DEFECTS Splay Irregular Moldings Brittleness Bubbles Sink Marks There are several methods for drying resins which utilize industrial drying systems prior to injection molding. 21 Splay Three types of splay are often encountered in injection molding. 3. com . This cosmetic defect occurs in plastic injection molding, when silver or white streaks appear on the surface of the part face due to air, contamination, heat, moisture, or shear issues. The injection speed has a great impact on the degree of molecular orientation in the component and therefore influences the shrinkage and the development of a joint line. This manual, A Guide to Polyolefin Injection Molding, contains general information concerning materials, methods and equipment for producing high quality, injection molded, polyolefin products at optimum production rates. John Bozzelli is the founder of Injection Molding Solutions (Scientific Molding) in Midland, Mich. Reduce injection velocity and record the fill time and pressure at transfer. First, let’s define the purpose of the feed throat: 1. It owns the name silver streak. There are two kinds of splay: moisture splay and heat splay. This quiz was reviewed by FunTrivia editor crisw before going online. Too cold in the rearInjection Molding of Multimaterial Systems. While small gates may provide a nicer appearance. Splay is sometimes called "silver streaks". Increase the venting: Ventilation supplies better flow in the mold. [1] The most common cause of splay is moisture, which is caught in the resin inside the injection molding machine. III. This standard provides a thorough procedure to help develop a robust and stable injection molding process that has minimal variation and produces a high-quality plastic part. The three main causes of splay are heat, moisture, and shear. When gases get trapped during mold filling, high pressures can cause ignition, which leads to the plastic burning. The gate restricts flow as the part fills. COC retain mechanical properties over multiple regrind cycles. Here is a list of all of the 11 defects covered in the complete molding problems and. Using a turnkey manufacturer, who also builds and maintains the mold, can help avoid any costly machining charges or mold replacement. Splay is a cosmetic defect that appear in plastic injection moulding, when white instead white streaks appear on an surface of the part. 2. These are cosmetic blemishes on the part’s surface. Depending on the material,. 50,000 Stock items for Same Day Ship Out. A gas mark is a fault that grows in the direction that melt plastic flows on a product's surface resulting from gas interference during the filling process. Those who look for splay to check for moisture will be fooled. Plastic injection molders – whether lacking the experience, adept knowledge or proper equipment – can produce defective products that don’t stand up to industry regulations, appearance requirements, and/or general client. Increase gate size; 2. Mold vents should function the same way. Injection molding Troubleshooting guide Eastman copolyesters. Injection speed can also influence dimensional. Unfortunately, fixing this injection molding defect often requires mold reformatting. Plastic injection molded parts can be surface finished from matte to highly polished. Appearance alone cannot tell you which type of splay is present. 3. Injection Molding: How Backpressure Adjustments Influence Shot Size Raising backpressure results in increasing shot size, which can cause a host of other problems. Splay happens during the injection molding process due to the presence of gas or vapor within the molten plastic. and T se-Hsi Chen [12. Primarily, moisture and shear. Flow lines are off-color lines, streaks, and other patterns that appear on the surface of a part. All manufacturing. Injection Molding Problems and Solutions (14/17) – Splay Marks. Tel: (60) 3 7890 6399 9am – 6pm (Mon. Several other defects, like scuffs, flow lines, surface scratches, delamination from contamination and flaking, can resemble splay, so it’s important to determine the cause of the streaks as the first step in troubleshooting. 3. Splay injection molding occurs when the melted plastic material is not flowing uniformly, and it causes streaks or lines on the surface of the plastic part. 3. 4% year-on. plastics technology-recent developments and trends. He has provided process-engineering expertise to many top. spe western sections annual pacific technical conference and technical displays/1979/costa mesa ca; usa; da. However, the outsourcing injection molding within China has grown consistently. Hold time. ContaminationBrentwood offers a manufacturing environment of over 30,000 square feet to support our medical device customers. The optimum fill time was 2. e Fill, Pack, Hold & Cooling/Plastication. Warping. . Increase the mold temperatures: Cold mold walls prevent material flow. Cleaner for Mold; Repair for Mold; Heating Items. Here are some common fixes for injection molding splay: Moisture. Splay adjustments can be a simple fix, or several hours of babysitting a press and head scratching. Black specks, splay, color swirls, brown streaks are all molding issues that can often be attributed to poor purging. The product may be locally pressed on the side wall, so it is easy to scratch the product side surface during mold ejection. 4. The inject speed needs to be reduced on the molding machine. There are many "lookalike" errors, and many possible causes of splay, including immoderate molding lubrication. What is Splay? Silver or white streaks appearing on the surface of the part often indicate splay in injection molding. Injection molding moisture steaks or splay marks solution. Splay is a term used in the manufacture of injection molded plastics to refer to off-colored streaking that occurs when moisture is caught in the material feed, or if the material degrades during processing. Flash can be caused by parting line mismatch in the tool. Most often this problem occurs when parts are being made with colored, semi-transparent resins, or have. This article continues our series of troubleshooting reports from one of the leading on-the-spot problem solvers in the molding industry. The chart below shows recommended wall thicknesses for common injection molding resins. “Splay,” which refers to a specific flaw that emerges on the surface of molded objects, is. The maximum weight reduction which can be achieved greatly depends on the individual mold shape. Transparent Plexiglas DR®, which usually has a slight blue edge color, will develop a slight green edge color if molded beyond the recommended temperature. FOW only uses high-quality metal steel for. The web page provides tips on drying, temperature, pressure, speed and mold details for different types of splay. What's SPLAY in molding & how to fix it. Flow marks can be caused by any or all of the following factors: Slow melt injection speed. txt) or read online for free. 3. Moisture and shear are the two primary. Here are 11 common injection molding defects, what the causes are and how you can avoid them. Increase the venting: Ventilation supplies better flow in the mold. Learn more about how to identify and address splayPrecision Thermoplastic Injection Molding in Class 8 Clean RoomThe Role of Moisture in Injection Molding Splay Defects. Splay Defects in Plastic Injection. 5: l. Gate blush is a molding defects commonly caused at the gate location of molded part, It shows as rings or ripples in the mold cavity surrounding the gate area. For a more uniform polymer melt and mixing, screw I-JD (length to diameter) ratio should be at least 20:1 with a compression ratio of at least 2. Splay is a term used in the manufacture of injection molded plastics to refer to off. Injection molding offers numerous advantages when it comes to producing HDPE parts, such as cost-effectiveness, high customization, and high malleability. The pressures used to inject molten plastic is tremendous.