Splay be ampere cosmetic flaw that occurs in plastic injection molding, when silver or white streaks seem on the surface concerning aforementioned part. 1. 008 to 0. The injection molding of cyclic olefin copolymers (COC) was discussed. i-Moulder injection molding defects and remedies problem solving guide and indicates typical methods for fine tuning the plastic injection moulding machine to reduce the occurrence of common molding problems including:-. Thermal expansion in the sprue bushing can hold the mold open and cause flash to develop. It is a good practice to place gates and runners in individual inserts so they can be easily replaced and/or reworked. Remedies: Pre-dry the plastic properly before molding. Ai-powered technology is ideal for cosmetic visual inspection of subcomponent assemblies. PRECISION PLASTIC INJECTION MOLDERS 20 Liberty Way Franklin, MA 02038 USA. Use the data to calculate relative shear rates and relative viscosities: Relative Shear Rate = 1 ÷ fill time. Moisture can get into the plastic in many ways. Medical & Pharma Injection Molding. Profiling injection is a great tool for establishing at what position a flow front is performing poorly, leading to a defect condition. If it’s a bubble, the wall stock will swell due to the gas inside expanding. To decide on the likely cause(s), test each to prove/disprove whether it is causing the splay, then take the corrective action. Check out the numbers in the table accompanying the graph. If the injection speed is too fast, the injection pressure is too high, and the relative movement speed of the melt and the cavity wall is too high. Receive a 10% discount on Injection Molding Principles and Injection Molding Troubleshooting if registered for both workshops. Slower, controlled speeds allow for smoother laminar flow that prevents air entrapment. Improve cooling. Air flow may become erratic due to moisture in the molding system and this can be a source of trouble. Source: Author jmoutoux. Method of switchover from first to second stage. Splay is a term used in the manufacture of injection molded plastics to refer to off. Sink marks usually occur when there’s a shrinking of a molded component’s inner part. As the plastic fills and pack the mold, part take shape and begin to cool. The majority of plastics can absorb moister from the air, meaning they are hygroscopic. He has contributed articles for Plastics Technology and other magazines on multiple topics, such as scientific process development, process. Screw Design To avoid excessive shear ofthe polymer, screw compression ratio should not exceed 3. Remedies: Although it may impact the manufacturing cost, the way. Bernie A. 080" – 0. Well, what this simply implies is that injection polycarbonate molding makes it possible for you to create a wide range of part sizes. This work focuses on the factors critical to successful injection moulding, including knowledge of plastic materials and how they melt, the importance of mould design, the role of the screw, and the correct use of. In some cases, hot manifolds may be. Moisture Content in the Resin. The chart below shows recommended wall thicknesses for common injection molding resins. 4% year-on. A Guide To Polyolefin Injection Molding Introduction Polyolefins are the most widely used plastics for injection molding. Switch to a hot runner or reduce the size of the main channel. 5 sec for ABS/PC. The root cause of sink marks is a difference in cooling time between the. Most defects respond to one of a variety of process and/or material changes. Learn other about how to identify and address splayHi all, I am new in injection molding and still learning things. Don't forget to take a step back and take a look at what's going on with your injection molding machine as a whole. 3. 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. Gas assist injection molding is a variation of conventional injection molding that can be easily retrofitted to an existing injection press by the addition of an auxiliary gas unit. 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. 1). 375 inch; shorten the gate land to no. Using a turnkey manufacturer, who also builds and maintains the mold, can help avoid any costly machining charges or mold replacement. Learn what appearance the purge puddle should have to identify that the material is ready for injection. With the world's top class "high cycle performance" at the core, we have realized stronger and more evolved. Splay is a cosmetic defect that occurs when moisture gets into the resin during the heating process of the injection molding machine. from sticking or clumping together (often called “bridging”) in the feed throat. Splay (moisture or trapped air) Haze, blush, and poor gloss; Orange peel and surface ripples; Gate blush and gate splay;There are three general guidelines for selection of the screw for an injection molding machine to be used with PC/ABS resins: 1. There are two kinds of splay: moisture splay and heat splay. Increase the mold temperature and reduce the barrel temperature for injection molding of thin-walled products. Injection molding moisture steaks or splay marks solution. It usually appears at the gate where the plastic enters the mold. Learn the causes, symptoms and solutions of splay, and how to avoid it with non-hygroscopic plastics, dried plastics, and quality control. Symptoms/problem: Swirls and gloss on the part’s surface. The Plastic is Cooling Too Quickly: The presence of jetting might mean you have another issue: plastic is cooling too quickly within the mold. Tel: (60) 3 7890 6399 9am – 6pm (Mon. KS Plastics 2116 Farallon Drive San Leandro, CA 94577 Phone: 510-351-8230 sales@ksplastic. Back Pressure in an injection molding process is often defined as “the resistance of the screw to recover as the metering section pumps molten plastic through the non-return valve to the. In fact, viscosity is influenced more by shear rate—injection speed—than temperature or even resin lot variations. Plastic decomposition. The Role of Moisture in Injection Molding Splay Defects. If splay is occurring in the same place on each part, identify where in the flow front the splay is generated. To decide on the likely cause(s), test each to prove/disprove. It owns the name silver streak because of the appearance of silvery scratches on the injection-molded part's surface. The volatiles vaporize and contact with the surface of the mold and become silver. About Me Name: Mike Location: Redwood City, United States . Excessive injection pressure and holding pressure are also important causes of scratches on product side walls. Injection Molding Know How. The forums offer a method to ask colleagues directly. If you round up a bit, the viscosity at the fastest speed, a fill time of 0. 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. If it’s a void, the wall stock will collapse and show a sink. Use of a slip-ring type non-return valve with clearances of at least 3. Valve gate nozzles leave a small witness mark on the part—the same size as the gate diameter. Particularly in injection molding, a typical method of forming plastic, care must be. Problem: Shear-sensitive material; gate land length much too long; and barrel temperatures, in an effort to eliminate gate blush, were raised too high. When a rust preventative is over-applied, it can cause grease to break down in certain areas of the mold, leading to bleeding. Splay can be a costly problem in the production of your molded components. 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. The goal is to. Remedies: Decreasing the barrel temperature allows the plastic to stay molten without burning or charring. Add more cooling circuits. Polypropylene is easy to mold despite its semi-crystalline nature, and it flows very well because of its low melt viscosity. A cosmetic defect, it is often silvery in color and is sometimes called 'silver streak'. There are many "lookalike" defects, plus many conceivable causes of splay, including excessive mold lubrication. 3. High-quality mold should be used in injection molding to avoid molding splay. Those who look for splay to check for moisture will be fooled. Date: October 23, 2019. Speaking the same “language” on the production floor, streamlines communications between employees and between shifts. Mold vents should function the same way. Dri-Kote™. Proper resin is a function of time/temperature. Engineering. This can result in bubbles or splay in the molded part. injection molding process was carried out by varying important processing parameters of mold temperature, injection speed, packing pressure and melt. remove the plate suction tube damaged → replace the damaged suction tube or repair. To minimize gate blush, splay, or both, the fill speed used for copolyesters is slower than for some other plastics. As more material enters the mold cavity, it. I give you 4 different variables that can cause splay. Inadequate support for the sprue bushing can transfer pressure to the parting line, too. 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. On the other hand, with injection-molded products, various conditions—including the proportions and dispersion of material and additive contents, the temperature used to melt the plastic, the pressure, and the cooling time—significantly affect quality. Increase injection speed. This. plastics technology-recent developments and trends. Whereas conventional injection molding uses velocity control during the filling stage and then switches over to pressure control for final filling and packing, DF uses pressure control only. Moisture and shear are the two primary. COLD SLUG – The first material to enter an injection mold. 4 Injection Speed. Ada banyak penyebab yang lebih mungkin, tapi perlu informasi lebih lanjut dan benar Cacat jenis sebenarnya injeksi. DF is said to provide the most accurate control over packing, since pressure is sensed. Injection molding is a process that utilizes a molten material that is forced into a mold to form a part. COCs low shrinkage, lubricated grades and mold. Remedies: Raise the mold temperature in increments of 10 degrees F until the bubbles disappear. When possible, a plastic injection molding machine with a relatively large barrel can also be used to improve the plasticization of the melt. This cosmetic defect occurs in plastic injection molding, when silver or white str. Transparent Plexiglas DR®, which usually has a slight blue edge color, will develop a slight green edge color if molded beyond the recommended temperature. Appearance alone cannot tell you which type of splay is present. The wet material can cause the formation of steam, creating pockets of trapped gas. Abstract. One is the injection of a high-velocity stream of molten material into the mold ahead of the general flow front. As a raw material for injection molding, HDPE is an excellent choice. . Purchase Injection Molding Components now. What causes splay in plastic injection molding? Moisture and shear are the two primary causes of splay on an. Trapped air, inadequate drying, high temperatures, and contamination can. If it’s breaking down and bleeding around ejector pins, your parts will likely be contaminated. 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. Suppose the moisture or reactive content of the injection molding raw material exceeds the norm. Custom Plastic Injection Molding Process - Basic Defect Identification and Troubleshooting . Splay Splay is a cluster of breaks, mars, or marks, visible on a plated part. When the injection molding process runs well, it can all seem so straight forward. The three main causes of splay are heat, moisture, and shear. 2 Process Optimization While material handling and drying techniques are two of the most useful activities to avoid splays, it is critical to also evaluate a bunch of activities that make up the whole. Pipe fitting injection molding process. Synonyms for splay and translation of splay to 25 languages. You can purchase the book on Amazon: Injection Molding – Advanced Troubleshooting Guide: The 4M Approach. Run capacity has increased from 1,000-1,500 parts to 24,000 parts before having to reapply, with a 45-second cycle time. The rounding of the corner on the graph relating rate of renal tubular secretion or reabsorption of a substance to its arterial plasma concentration. Since the cavity is more than 90% full, not much more plastic is needed. 2K. Clean the molding cylinder thoroughly; 3. High-quality mold should be used in injection molding to avoid molding splay. Control injection speed to avoid material shearing and splay. Office: +1. pdf - Free download as PDF File (. This time we’re going to take a look at Splay. When two materials can’t bond together, it results in separation that very quickly becomes delamination. He is a well-known columnist for magazines covering this area. 2. Splay marking. R2:PET Preform Mold was damaged. Splay posted by Mike at 6:13 PM. The fix: review the gate size against the. Reduce injection pressure or hold pressure. Adjust the thickness (1t-2t) 6. MISUMI | Your Time, Our Priority. The inject speed needs to be reduced on the molding machine. MOS Plastics 2308 Zanker Road San Jose, CA 95131 Phone: 408-944-9407Packson is not totally the same as other medical plastic injection molding companies. 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. When purchasing plastic injection molded parts. While not always visible, weld lines (aka knit lines) are where two resin flows meet. 3. 6 sec instead of the typical 7 sec for ABS/PC. Step 3 – Examine the Defective Part and Rule Out Obvious Causes. 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. Many defects can occur in injection molding. SPI (Society of Plastic Industry) has defined a standardized surface finish for injection molds to facilitate industrial designers, design engineers,. Splay caused by moisture. Splay can be more obvious on black parts, but this plastic molding defect can be found in pretty much any injection molding material, any color. Figure 2 is a part tested a few minutes after molding and Fig. A. the lip ejection position / pressure is too large → adjust the ejection position / pressure to the appropriate state. Warping: A deformation where part surfaces or walls twist or bend as the part cools. Remedies: Reducing the injection speed will allow the plastic flow front to stay together and not form the individual streams that cause the. Studying read about how in identifies and address splayWeldlines Splay Jetting Burn Marks Warpage. To create an injection-molded product, manufacturers perform the following steps: The completed mold is placed in the injection molding machine. Gas Marks Defined. The solution to a Splay problem is, of course, to keep the plastic dry. Appearance. Due to Microsoft's end of support for Internet Explorer 11 on 15/06/2022, this site does not support the recommended environment. 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. com. This helps prevent mold release buildup, especially in the problem areas of a mold, which in turn mitigates gas build up. A Guide To Polyolefin Injection Molding Introduction Polyolefins are the most widely used plastics for injection molding. Splay Can Holder; Mold Maintenance. It is made from stainless steel. It usually appears at the gate where the plastic enters the mold. How do you reduce splay in injection molding? A large drop in temperature when material enters the mold from nozzle can lead to beginning-of-fill splay. Solution: Open the sprue O diameter to at least . Splay is characterized by light colored streaks in the part that usually follow the direction of the melt flow. If the grease breaks down on the slides and lifters, it could become tacky, causing them. Cleaner for Mold; Repair for Mold; Heating Items. Medical utensils often. Where are many "lookalike" bugs, and many possibly drives about splay, including exorbitant mold lubrication. Part Shorts. $34. Except for polyolefins (common examples being polyethylene and polypropylene), materials need to be dried before they are injection molded. txt) or read online for free. 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. 025 inches per inch, depending on the particular resin, molding conditions, part design, part wall thickness, and direction of flow. 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. PDF. Learn other about wie to identify and address splayOn this channel you can get more information about injection moulding machine and processingInjection molding moisture steaks or splay marks solution. The injection molding companies must avoid any extra-thick bits of significant disparities in the thickness of the plastic component when constructing the mold. John Bozzelli is the founder of Injection Molding Solutions (Scientific Molding) in Midland, Mich. 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 a cosmetic defect that occurs when moisture gets into the resin. A purge compound can be a great solution before pulling the tool. 2. Gas will mix with plastic melt if the high. splay. 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. Texture. 3 is a part tested 16 hr after molding. 00 Select options; Atlanta, GA. Figure 2 shows the part after testing, and you can now see a depression or sink. Black specks, splay, color swirls, brown streaks are all molding issues that can often be attributed to poor purging. In the process of injection. Understanding your surface requirement is very important, as sometimes it’s. Here are some common fixes for injection molding splay: Moisture-related: Ensuring that all material is thoroughly dry before beginning the injection mold process is crucial. In that case, the material particles. 50,000 Stock items for Same Day Ship Out. Learn about 10 common plastic injection molding defects, find out why they occur, and get tips to fix them. The slip agents have exactly the same effect on metallization and reduce adhesion. 00. Flow marks are caused by a variety of factors in the injection molding making technology, and they happen at the gate. Maksud splay dalam kamus Corsica dengan contoh kegunaan. 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. We also share information about the use of the site with our social media, advertising and analytics partners. Select a better surface material for the mold cavity, to reduce shrinkage. This property significantly enhances the rate at which you. There are many "lookalike" defects, and many possible causes of splay, in excessive mold lubrication. To lay open the end of a tubular structure by making a longitudinal incision to increase its potential diameter. Ejection temperature is too high. 002'') pathways on the shutoff area of the cavity blocks. Solution: Ensure the nylon is properly dried; increase dimensions in edge gate, sprue O-diameter, and nozzle orifice; relocate edge gate to the center. 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. He is the technical director at Dickten & Masch Mfg. While small gates may provide a nicer appearance. • Melt too hot Splay • Injection too fast • Gates too small • Barrel temperature profile wrong. Injection Molding: How to Set Second. “Incompatible materials” can be a number of things. Here are 11 common needle molding deficiency, what the causes are and how you can avoid them. Increase the injection speed. Part/material: 33% glass-filled nylon 6/6 disk used in an assembly. With the same gate diameter and injection speed, the higher the viscosity of the resin (the lower the fluidity ), the. Even without any injection molding surface finish or post-processing treatment, molded. The most common of these methods are the hot air dryer, desiccant dryer, compressed air dryer, and vacuum dryer. Read our blog post here. 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. Verify that the process itself has been decoupled first, yielding a 95-98% full part with no hold or pack added. It prevents the granules, etc. Here are 11 common injection molding defects, what the causes are and how you can avoid them. He is a highly respected writer and educator in the area of plastics processing. Heat-related: Check that the melting temperature is. com . Cleaner for Mold; Repair for Mold; Heating Items. 3. For example, if operators are making a mold of a medical part—like an endoscope, which a surgeon needs to hold with gloves—they will need to develop a uniform texture for gripping. Plastic411 Overview. Injection molding is an invaluable process for creating plastic parts. If you round up a bit, the viscosity at the fastest speed, a fill time of 0. D. 7 Million Products, 2,000 Brands. Injection. SPLAY in Injection Molding. 5 kN/cm2 (4 T/in2) is required. Injection can be profiled by dividing the shot size by 6, and setting up the position profiles to equal segments. 4. Splay: This is a common defect that shows up as shiny streaks on the part and. They look alike and each can have multiple specific causes… which mean as many potential solutions! Learn a systematic method and: What are the Causes of Splay in Injection Molding. 160"). It combines the strength and rigidity of acrylonitrile and styrene polymers with the toughness of polybutadiene to deliver superior hardness and toughness. Adding other internal lubricating aids to the amides may also provide adequate mold release for a given molding. Injection Molding Process. Zap-Ox saves the customer hours of cleaning time that had previously been spent on excessive buildup. injection molding machines using standard industry practices . Molasses is thick, and flows slowly. Paulson’s most advanced injection molding course. Appearance alone cannot tell you which type of splay is present. Splay – Contamination – Cold Slugs (discontinuities where injected material was inconsistent)Causes & Solutions for this injection molding defects: 1. In addition, it is important to note that nylon is not only affected by poor drying/ moisture conditions. Increase size of the vents. Drying Considerations For both virgin and rework, hopper dryers sized to afford theThere is also a secondary reason that if the product is too thick while the gate is small, the actual filling speed will be slowed down, which tends to cause flow marks. Adjust resin and cooling temperatures. Flow lines appear as a wavy pattern on the surface of your plastic parts. What's SPLAY in molding & how to fix it. However, the outsourcing injection molding within China has grown consistently. sales@uninko. 020"). 025 inches per inch, depending on the particular resin, molding conditions, part design, part wall thickness, and direction of flow. Injection moulding (U. Place the heated probe into the melt puddle (Purging mass). This of course can cause splay. Paul Mastro is a plastics engineer with over 30 years of experience in the formulation, injection molding and. San Jose facility includes: 55,000 sq. Replace raw materials or use plastics with good thermal stability. Check injection throttle position and if possible, increase its setting. 14 billion, up 12. Injection molding is particularly rough on polymers because in addition to the barrel temperatures required to soften the material, there can be significant shearing forces applied to the material to move it rapidly through the machine nozzle and into the mold cavities. 010 sec or less, switches from velocity to pressure control. Here are some common fixes for injection molding splay: Moisture. 4 sec for WPC compared with 3. Injection Molding Tuesday, June 27, 2006. Splay caused by moisture. Smaller gates might require a slower beginning-of-fill speed. Processing issues that lower viscosity also cause flashing in molded parts. Splay Defects in Plastic Injection. Demonstrate high level of understanding of material properties and interactions in the injection molding process. 102-106; bibl. Problem: Shear-sensitive material; gate land length much too long; and barrel temperatures, in an effort to eliminate gate blush, were raised too high. Cracking when mold opens • Overpacking • Hot mold • Poor drying • Breakaway too fast • Needs vacuum break • Reduce either packing pressure or time . Cosmetic Specifications of Injection Molded Parts, Revision A. Injection molding process explained. Tool: Single-cavity, cold runner. What Are Silver Streaks in Injection Molding? A silver streak, also known as a splay mark, is a cosmetic defect that is typically visible on plastic parts with a smooth surface. Excessive injection pressure creates stress that causes product warpage in the mold. This three-part series in the Troubleshooter column outlines key signs used to evaluate splay conditions. Headquarters. 3. 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. The injection pressure is too high – adjust the parameters appropriately. Tatjana Geminger, Stefan Jarka, in Specialized Injection Molding Techniques, 2016. Moisture and shear are the two primary causes of splay on an injection molded part. When in the hands of inadequate expertise, a lot can go wrong. 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. POSSIBLE SOLUTIONS 1. The presence of gloss and/or texture in the tool can make what would otherwise be an exact color match appear very different. Dri-Kote works for most injection molding needs. The revolutionary low constant pressure injection molding platform works with virtually any plastic injection machine, material, and mold. FOW only uses high-quality metal steel for. Remedies: Mold design: (1) Add an exhaust system to a place where the exhaust gas is easily generated. Increase injection pressure. Focus more on the ejection mechanism in the mold design to reduce or eliminate the dependence on mold release agents. This fault，which appears on a great many mouldings，shows an area, generally near the gate, which has an uneven, lined appearance. 3. To determine whether you’re looking at bubbles or voids, slowly heat the area with a torch or heat gun. Garrett MacKenzie is the owner/editor of plastic411. 6. ft. Michael Sepe is our analyst and author. When gases get trapped during mold filling, high pressures can cause ignition, which leads to the plastic burning. Splay is a aesthetic defect that occurs in plastic injection molding, when gray or white streaking pop at the surface of the part. In thermoplastic injection molding, the mold is always said to be “cold”—that is, relative to the temperature of the plastic melt. 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. , a provider of training and consulting services to injection molders, including. Moisture is a major. 2. A mold temperature of between 80-120℃ / 176-248℉ should be maintained to prevent sink marks. This approach will assume you have developed a basic understanding of the injection. Adjust improve product quality such as removing blush, splay, flash, short shots and. As a general rule, the amount of decompression should not exceed 1 ½ times the travel of the. The Troubleshooter’s notebook. This cosmetic defect occurs in plastic injection molding, when silver or white str. Through intensive machine time and use of our unique injection molding simulator SimTech™, ProMolder 3 is the most thorough and technically accurate training available. He has provided process-engineering expertise to many top companies, including Glock, Honda, Johnson Controls, and. These data were obtained from many andFor injection molding applications, Eastman Tritan™ copolyester can replace polycarbonate, typically without requiring new tools. Vents should take up approximately 30% of the perimeter of the molded part. COLD SLUG WELL – Space provided directly opposite the sprue opening in an injection mold to trap the cold slug. There are three ways to mold. The material temperature could also be raised to accomplish the same effect. 5. , Ltd(XIAOLIN) has 18 years of manufacturing experience, we are an experienced manufacturer for custom rapid prototyping, mold, a. Splay is sometimes also called “silver streaks” because of the appearance of silvery scratches across the surface of the injection molded part. Bob Hatch is manager of technical service and customer support for Prime Alliance, the Des Moines-based resin distributor. The reason for splay marking is. Valve gate hot runner nozzles were introduced to the injection molding industry shortly after the first hot runner systems appeared on the market. elimination of splay in injection molding by cavity pressurization author lord ha western electric co. Cause #2: Material. Figure 2 is a part tested a few minutes after molding and Fig. Unfortunately, fixing this injection molding defect often requires mold reformatting. Once you have a cool shell formed the rest of the mold entering absorbs heat from the layer next to the wall. Silver Streak Analysis & Troubleshooting (1). (2) Increase the size of the runner system. If burning or flashing occurs, the injection speed is too high and delamination is being caused by other factors. 1 Caused By The Quality of Injection Mold. To decide on the likely cause(s), test each to prove/disprove whether it is causing the.