The Society of the Plastics Industry [spi] PDF Price. Running the part with the gate sealed (frozen) or unsealed. Valve gate nozzles leave a small witness mark on the part—the same size as the gate diameter. Improve venting and/or relocate to. Ensure Machine Purging: In injection molding, purging refers to cleaning the molding machine of one material or color. At times the part may also shatter. Haze on the one side of the preform. Objectives of the Study. Mixed raw materials or poor thermal stability. This quiz was reviewed by FunTrivia editor crisw before going online. Here is a list of all of the 11 defects covered in the complete molding problems and. Splay happens during the injection molding process due to the presence of gas or vapor within the molten plastic. Preventing Flash in Injection Molded Parts. Randy Kerkstra and business partner Steve Brammer recently launched KB Molding Solutions, which offers training and consulting for the injection molding industry. 7. Plastic decomposition. Using a turnkey manufacturer, who also builds and maintains the mold, can help avoid any costly machining charges or mold replacement. The chart below shows recommended wall thicknesses for common injection molding resins. Gear to shape fittings comprises of a form and an injection molding press. • Visual inspection, trimming, and packing of injection molded plastic products. For specific questions or more information, please email. Injection Molding Know How. Figure 1 is the part before heating. [1] The most common cause of splay is moisture, which is caught in the resin inside the injection molding machine. In addition, mold plumbing should be checked to ensure there are no. Cleaner for Mold; Repair for Mold; Heating Items. 1). Remedies: Raise the mold temperature in increments of 10 degrees F until the bubbles disappear. III. Splay happens during the injection molding process due to the presence of gas or vapor within the molten plastic. Add to Alert. Midstate Mold & Engineering. Znaczenie słowa splay w słowniku w słowniku wraz z przykładami użycia. 1979; pp. Processing issues that lower viscosity also cause flashing in molded parts. Midstate Mold & Engineering. Just like most injection-molding defects, delamination can be caused by one or more of several potential issues. Appearance alone cannot tell you which type of splay is present. Home; Products. Figure 2 is a part tested a few minutes after molding and Fig. To prevent parting line mismatch: Clean off any plastic, dirt, or contaminants that could keep the mold from closing correctly, especially behind slides and inside the leader pin bushings. gas, possibly resulting in inconsistent shot sizes and splay. Injection can be profiled by dividing the shot size by 6, and setting up the position profiles to equal segments. To decide on the likely cause(s), test each to prove/disprove whether it is causing the splay, then take the corrective action. It is indicative of an undesirable turbulence and splitting of the flow front. 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). Moisture and shear are the two primary. If you turn on the spigot to a garden hose, you will hear a hissing sound at the nozzle end for the first few seconds. Scribd is the world's largest social reading and publishing site. Injection Molding Know How. profile extrusion, for example, may require a lower moisture content than. Jetting, also known as jet, worm track, or snake-like pattern, refers to the snake-like curves on a plastic injection molded part along the flow direction from the gate, as shown in Figure 1. First-stage injection fills 92% to 99. 0: l. In some cases, hot manifolds may be. The presence of gloss and/or texture in the tool can make what would otherwise be an exact color match appear very different. It may not necessarily produce visible splay, as the water is consumed in the hydrolysis reaction. 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. Slip agents not only reduce the coefficient of friction (CoF) but also are used to reduce adhesion between the mold and injection molded polymer. The process begins with the mixing and melting of resin pellets. . Ejection temperature is too high. What is Splay? One of the most common injection molding defects is. The root cause of sink marks is a difference in cooling time between the. Paulson’s most advanced injection molding course. 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. Injection molding BrE or Injection molding AmE, is a manufacturing process for producing parts by injecting molten material into a mold. Figure 1 presents the shrinkage of polypropylene versus wall thickness in injection molded parts. The molten material could be metal, glass, rubber, or plastic. Understanding Splay in Injection Molding 1. metal injection moulding 7. 4 sec for WPC compared with 3. Splay is a cosmetic defect that appear in plastic injection moulding, when white instead. The speed in which the plastic is injected into the mold (known as the ram speed) may be too high. 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. Eliminate bubbles and blisters by adding a vent to the mold, making part wall thicknesses more uniform, increasing mold temperature, or increasing injection pressure. Identifying your injection molded part defects is the first line of defense against wasting valuable molding machine time. 8 mm. Focus more on the ejection mechanism in the mold design to reduce or eliminate the dependence on mold release agents. Reposition gates and runners to allow resin to flow around the obstruction from a different direction. Set a higher clamping presure. Appearance alone cannot tell you which type of splay is present. The Troubleshooter’s notebook. He has provided process-engineering expertise to many top companies, including Glock, Honda, Johnson Controls, and. (2-2) Mold temperature is too low. To decide on the likely cause(s), test each to prove/disprove whether it is causing the splay, then take the corrective action. Splay Splay is a cluster of breaks, mars, or marks, visible on a plated part. A cosmetic defect, it is often silvery in color and is sometimes called 'silver streak'. injection moulding machine and components 2. Quick drying Dri-Kote mold release spray is a dry mold release, which has the advantage of being difficult to over apply. 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. इस वीडियो में इंजेक्शन मोल्डिंग से सम्बंधित एक डिफेक्ट silver mark/streaks के बारे में. Transparent Plexiglas DR®, which usually has a slight blue edge color, will develop a slight green edge color if molded beyond the recommended temperature. 4 : 1 and an L/D (length to diameter) ratio between 18 : 1 and 22 : 1 are suggested. In that case, the material particles. He has contributed articles for Plastics Technology and other magazines on multiple topics, such as scientific process development, process. Increase the mold temperature. 12515 NE 95th Street , Vancouver, WA 98682. Smaller gates might require a slower beginning-of-fill speed. , leading to a relatively infusible state. Before his present assignment, Bob managed a molding operation for 25. Content Provider. Specific attention to processing details will enhance quality and productivity . 50,000 Stock items for Same Day Ship Out. Maximum pressure: packing. This approach will assume you have developed a basic understanding of the injection. Heat-related: Check that the melting temperature is. Low Gloss. Fundamentals of Scientific Injection Molding Seminar: Hands-on, Setup, Processing & Troubleshooting (Cleveland) $ 1,595. If the only solution is to use a spray, try our Tuff-Kote and Dri-Kote high-performance mold-release sprays. . A material that will undergo or has undergone a chemical reaction by the action of heat and pressure, catalysts, ultra-violet light, etc. Thin wall injection molding can produce walls as thin as 0. Tool: Single-cavity, cold runner. 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. The molecules bond together as desired and splay is eliminated. Process: (1) Reduce the injection pressure and speed. While small gates may provide a nicer appearance. Bob Hatch is manager of technical service and customer support for Prime Alliance, the Des Moines-based resin distributor. The linear mold shrinkage of injection molded parts will vary from 0. 5. Injection Molding Extrusion Blow Molding Molds & Tooling Manufacturing Recycling Additive Manufacturing Features Thermoforming Compounding Rotomolding. The most common: incompatible materials. To decide on the likely cause(s), test each to prove/disprove whether it is causing the. Expand the gate (*a) 5. Paul Mastro is a plastics engineer with over 30 years of experience in the formulation, injection molding and. Drying is a necessary preparative step to prevent this defect. Smooth out the corners and sharp turns in the mold design to avoid sudden changes in melt flow. Divide the required shot size by 5, creating 5 stages of injection. Splay marking. 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. The Role of Moisture in Injection Molding Splay Defects. Most drying specifications for various resins are at temperatures where the resin will not. Therefore injection mold core and cavity surface finish are as per the specified part drawing. Injection Molding Skills & More. Tel: (60) 3 7890 6399 9am – 6pm (Mon. Flash can be caused by parting line mismatch in the tool. Plastic411 Overview. 2. When the mold temperature is low, the surface layer will be solidified more quickly, making it more. This specification addresses the cosmetic quality of molded plastic parts and related post molding activities. When possible, a plastic injection molding machine with a relatively large barrel can also be used to improve the plasticization of the melt. There have countless "lookalike" defects, and many possible causes of splay, including excessive mold lubrication. If burning or flashing occurs, the injection speed is too high and delamination is being caused by other factors. The presence of gloss and/or texture in the tool can make what would otherwise be an exact color match appear very different. Molding moist polycarbonate can cause splaying, while reducing the polymer’s impact and tensile strength. Adjust improve product quality such as removing blush, splay, flash, short shots and. Try to run the mold on. Faster, and even more accurate, the J-ADS Series assures the highest levels of. splā (splay marks, silver streaking) n. I give you 4 different variables that can cause splay. Preventing Flash in Injection Molded Parts. How You Will Benefit: Splay, blush & peel are very common rigid PVC molding defects. Office: +1. Plastic 411 offers articles, information and training resources to the plastic injection industry. Molten polymer moves through the barrel of the machine and forced in to a steel mold. B. About the Author: Robert Gattshall has more than 22 years’ experience in the injection molding industry and holds multiple certifications in Scientific Injection Molding and the tools of Lean Six Sigma. The molecules bond together as desired and splay is eliminated. Pressure creates heat and eventually the gas reaches a point where it ignites burning the plastic in the mold. The pressures used to inject molten plastic is tremendous. This time we’re going to take a look at Splay. 14 billion, up 12. It's recommended that the minimum L/D used in injection molding be 20:1. As a general rule, the amount of decompression should not exceed 1 ½ times the travel of the. The usual injection of molten plastic is assisted by. spe western sections annual pacific technical conference and technical displays/1979/costa mesa ca; usa; da. 3. There’s a good reason burns are also called gas traps in injection molding: they’re caused by trapped gases. Sliver streaking or yellowing of PET preform. This fault,which appears on a great many mouldings,shows an area, generally near the gate, which has an uneven, lined appearance. Moisture is a major. 508-520-0011 Fax: +1. 2. Welds. com . Teach continue info how to identify and handle splayThese materials tend to generate higher surface resistance during the molding process, creating drag and turbulence that may be reflected in the part appearance—glass fibers, for instance, can add a stringy or sparkly finish to a textured part, while flame retardants might lead to the whitish streaks known to plastic injection molders as splay. Gate size. advantages 8. Jetting can be defined as a "snake-like" pattern on the surface of a molded part, usually emanating from the gate area. This allows the melt to keep enough velocity to ensure proper filing. Splay: This is a common defect that shows up as shiny streaks on the part and. When I tried increasing injection speed, the. 0005''-0. The cure for splash marks is,therefore to eliminate all volatile matter. Plastics Processing || Class - 44 ||🔷 इंजेक्शन मोल्ड़िंग में Silver Streak और Splay Mark Defect क्या होता है?🔷 Silver Streak. This. Moisture and shear are the two primary causes of splay on an injection molded part. Mold vents should function the same way. Molding Defect #1: Splay Molding Defect #2: Peel Molding Defect #3: Blush Troubleshooting Approach Start with Melt Temperature. Remedies: Establish a cushion of at least 1/8'' and not more than 1/4''. Cracking when mold opens • Overpacking • Hot mold • Poor drying • Breakaway too fast • Needs vacuum break • Reduce either packing pressure or time . Please call 814-898-6103 or email [email protected]. 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. The principle of hot/cold molding technology is to raise the mold-cavity surface temperature prior to the polymer entering the cavity, and to subsequently cool the mold cavity once filled, just like in conventional injection molding (see Fig. Barrel and Screw Measurement and Maintenance Programs. When gases get trapped during mold filling, high pressures can cause ignition, which leads to the plastic burning. He has provided process-engineering expertise to many top. Using a turnkey manufacturer, who also builds and maintains the mold, can help avoid any costly machining charges or mold replacement. Splay is. Reduce the screw speed and adjust the backpressure. It usually appears at the gate where the plastic enters the mold. When beginning Purge Programs with customers, I'm often asked how they can eliminate the presence of cloudiness or haze in molded parts. sales@uninko. Custom Plastic Injection Molding - Troubleshooting Techniques - For this part of this series, we will start out with a very basic injection molding problem and some possible ways of solving it. 010 sec or less, switches from velocity to pressure control. Molding Process. Improve the injection speed. D. . , sink marks and voids, and post. 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. CYCLE TIME TOO SHORT. We also share information about the use of the site with our social media, advertising and analytics partners. 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. RESPONSIBILITIES: To run product produced by injection molding presses. JSW, one of the industry's original leading companys, has extensive experience in manufacturing large electric injection molding machines ranging from 550 to 3000 metric tonnes. To decide on the likely cause(s), test each to prove/disprove whether it is causing the splay, then take the corrective action. If the only solution is to use a spray, try our Tuff-Kote and Dri-Kote high-performance mold-release sprays. Step 2 – Properly Document the Process Outputs. Demonstrate high level of understanding of material properties and interactions in the injection molding process. Abstract. Splay can be a costly problem in the production of your molded components. High nozzle temperatures can promote the formation of thermal splay marks from keeping the. The majority of plastics can absorb moister from the air, meaning they are hygroscopic. Valve gate nozzles leave a small witness mark on the part—the same size as the gate diameter. 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. When two materials can’t bond together, it results in separation that very quickly becomes delamination. mold design 4. 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. Dri-Kote works for most injection molding needs. Reduce injection pressure or hold pressure. Contamination can be defined as an imperfection in a molded part caused by the presence of a foreign object or material that is not part of the original molding compound. Injection molding offers numerous advantages when it comes to producing HDPE parts, such as cost-effectiveness, high customization, and high malleability. They usually are a slightly different color than the rest of the piece, and typically occur on more narrow sections of the molded item. Participants are also presented with information and practices on how to best process, document and maintain a reliable scientific injection molding process. When a rust preventative is over-applied, it can cause grease to break down in certain areas of the mold, leading to bleeding. Relative Viscosity = Hydraulic pressure x intensification. As more material enters the mold cavity, it. The main types of injection molding defects are: 1. Add more cooling circuits. . Scars or surface defects on injection molding arising from two main mechanisms. injection molding process was carried out by varying important processing parameters of mold temperature, injection speed, packing pressure and melt. FIG. 1: In a cold-runner mold, the cold slug forms inside the end of the nozzle where it touches the cold mold steel. Well, what this simply implies is that injection polycarbonate molding makes it possible for you to create a wide range of part sizes. The material temperature could also be raised to accomplish the same effect. These are cosmetic blemishes on the part’s surface. Moisture-related splay defects can be traced to a material’s drying state,. There are two kinds of splay: moisture splay and heat splay. The resulting defect, known as splay or silver streaking, is an indicator that the material being molded contains too much moisture. Moisture and shear are the two primary causes of splay on an injection molded part. It is. 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. Often times, the feedthroat is run at too cool a temperature, but it's also important that the feedthroat isn't so hot. «Splay» Meaning of splay in the English dictionary with examples of use. Appearance alone cannot tell you which type of splay is present. A cosmetic defect, it is often silvery in color and is sometimes called ‘silver streak’s. The melt holds enough temperature to maintain a low enough viscosity. 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. 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. Just like most injection-molding defects, delamination can be caused by one or more of several potential issues. 508-520-3222Jan 04, 1999. There is a level of insulation from the plastic layer on the wall. 1. Splay Marks can be defined as a “splash-like” appearance (or spray pattern) on the surface of a molded part. Splay due to moisture usually results in silver streaks on the surface and slight delaminating of a film layer. This article will help to identify various. High nozzle temperatures can promote the formation of thermal splay marks from keeping the. (3) Check if the heater and thermocouple are working properly. Increase injection pressure. Fill pattern animation. As a raw material for injection molding, HDPE is an excellent choice. The moisture and volatile content in the raw material is. PDF. 025 inches per inch, depending on the particular resin, molding conditions, part design, part wall thickness, and direction of flow. Increase the mold temperature and reduce the barrel temperature for injection molding of thin-walled products. Even without any injection molding surface finish or post-processing treatment, molded. 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. Injection Molding. Figure 1 is the part before heating. 00. 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. Material- ABS Barrel Temperature- ~240 Celsius Pre-drying- 80-90 C for 3 hours The streaks do not come over whole part but only at a single location at the end of fill each time. 8 : 1 and 2. An opening in the mold where the injection-molded material enters the mold to create the intended plastic part. Remedies: Reducing the injection speed will allow the plastic flow front to stay together and not form the individual streams that cause the. It is a good practice to place gates and runners in individual inserts so they can be easily replaced and/or reworked. The Role of Moisture in Injection Molding Splay Defects. 2. This position will be based out of our New Automated Injection Molding plant located in Pineville, NC. Tatjana Geminger, Stefan Jarka, in Specialized Injection Molding Techniques, 2016. Injection Molding Flash Occur Causes. Many people think the. 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. The turbulent flow whips air into the polymer, creating micro bubbles. A mold temperature of 330 F for a PEI material is still “cold” compared with the resin’s 750 F melt temperature (Fig. Solution: Ensure the nylon is properly dried; increase dimensions in edge gate, sprue O-diameter, and nozzle orifice; relocate edge gate to the center. 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 Causes & Remedies: Machine Cause. It is because a higher temperature results in prematurely expelling the injection-molded components. The Troubleshooter’s notebook. Cause #2: Material. Reduce the barrel temperature and increase the injection pressure. It causes silvery streaks on the surface of the molded part. A step by step guide to injection molding and the challenges that can arise during manufacturing. Learn more about how to identify and deal splayCalculate melt residence time by formula in molding guides . 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. There are many "lookalike" errors, and many possible causes of splay, including immoderate molding lubrication. Inlet pressure curve. Injection molding Cycle. Injection Molding Processing Guide. (2) Increase the size of the runner system. 4. Most drying specifications for various resins are at temperatures where the resin will not agglomerate,If a balance tool is creating unequal short shots, make sure drops and tips are not contaminated from a previous run. Step 1 – Develop a Scientific Molding Process. Injection Molding Tuesday, June 27, 2006. Our quality software enables us to provide the molders with data on the specific defects and where we are seeing them on the parts so they can make adjustments to their processes and/or modifications to the molds themselves to solve the problems. For example, injection speed may need to be adjusted to counteract splay created by shear stress, which can be caused by the shape of the part. Under normal circumstances, the molten plastic fills the mold cavity in a “fountain flow” manner, as shown in Figure 2, which depicts the “fountain. Run capacity has increased from 1,000-1,500 parts to 24,000 parts before having to reapply, with a 45-second cycle time. Haze develops when PET in either injection or blow stages is heated beyond about 115°C (240°F) and allowed to cool down for even a short time. Find the most up-to-date version of SPI AQ-103 at GlobalSpec. Add vents in local areas that show blush. It is a cosmetic defect typically appearing as an off-color streak, often silver in hue, along the. Remedies: Use an injection screw with the proper compression ratio. Troubleshoot molding machines to bring parts into specifications for size, appearance, flash, splay, cycle time, etc. That degradation creates a gas, which is. Must Have 3 YRS Experience In Plastic Injection Molding & Submit a Resume . Purchase Injection Molding Components now. Injection Molding: How to Set Second. What causes splay in plastic injection molding? Moisture and shear are the two primary causes of splay on an. 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. Splay or Steam typically visible streaks or bubbles in or on the end-product caused by the boiling of the moisture in the pellet that becomes gas/steam. Synonyms for splay and translation of splay to 25 languages. e. Advantages of HDPE as a Material. It uses one of thousands of resins available to. The injection molding of cyclic olefin copolymers (COC) was discussed. Let’s first discuss moisture, as most of the time splay is due to the fact that the resin has not been dried properly. If you were to pour water and molasses at the same time, water would flow much easier than the molasses. Lets discuss moisture, as most of the time splay occurs because the resin has not been properly dried. One of the most common injection molding defects is Splay, also referred to as “silver streaks” or “jetting”. Category: Injection Molding. This three-part series in the Troubleshooter column outlines key signs used to evaluate splay conditions. Flow marks are most commonly caused by resin cooling too quickly or improper gate location. spelling: injection molding) is a process for producing parts by injecting molten material into a mould, or mold. . Through intensive machine time and use of our unique injection molding simulator SimTech™, ProMolder 3 is the most thorough and technically accurate training available. 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. Ada banyak penyebab yang lebih mungkin, tapi perlu informasi lebih lanjut dan benar Cacat jenis sebenarnya injeksi. Flow lines are off-color lines, streaks, and other patterns that appear on the surface of a part. Splay caused by moisture. Now, from the machine’s point of view, as the screw reaches the position of switchover, the controller, in something like 0. fFlow rate. Weld lines are injection molding defects that can be mitigated by a number of tactics that depend on your part design. 2) Vents in an injection mold should let the air out, but not the liquid plastic. It provides a clear, free-flowing path for plastic granules, powders, and liquids (such as liquid color) into the feed section of the screw. e Fill, Pack, Hold & Cooling/Plastication. Splay can be a costly problem in the production of your molded components. That’s the air escaping out of the nozzle until the hose is full of pressurized water. Purchase Injection Molding Components now. Check out the numbers in the table accompanying the graph. Figure 1 presents the shrinkage of polypropylene versus wall thickness in injection molded parts. The maximum weight reduction which can be achieved greatly depends on the individual mold shape. building; 35 molding machines;Injection molding Troubleshooting guide. 4 Injection Speed. They were processing gray rigid polyvinyl chloride (RPVC) with an 80mm 24:1 general purpose screw with a thread-on smear tip in a Demag injection molding machine. 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. The injection molding cycle can be broken down in to 04 phase i. Lower the hold pressure fix the PET preform mold. 2. Mold leaks also can cause moisture-related splay, so check the mold carefully for any signs of damage or leakage. Scientific molding practices optimize gate velocity for bubble-free filling. XIAOLIN Plastic Industry Co. Warping: A deformation where part surfaces or walls twist or bend as the part cools. Repeat Step 3 until the fill time is over 10 sec. 3. This property significantly enhances the rate at which you. Injection molding is a process that utilizes a molten material that is forced into a mold to form a part. This video helps to visually define the different properties of splay. Identifying splay can be challenging, as its appearance may resemble other defects such as surface scratches, scuffs, flow lines, contamination-related delamination, or flaking, all. Remedies: Decreasing the barrel temperature allows the plastic to stay molten without burning or charring. Gas Marks Defined. When the molten material flows from the thin wall to the thick wall, it expands. Machines with fill speed programming capability are recommended. 1).