{"id":7633,"date":"2026-10-27T06:50:10","date_gmt":"2026-10-27T06:50:10","guid":{"rendered":"https:\/\/uplastech.com\/packaging-tube-extrusion-defects\/"},"modified":"2026-10-27T06:50:10","modified_gmt":"2026-10-27T06:50:10","slug":"packaging-tube-extrusion-defects","status":"publish","type":"post","link":"https:\/\/uplastech.com\/tr\/packaging-tube-extrusion-defects\/","title":{"rendered":"Tube Extrusion Defects: Gels, Die Lines and Weld Lines"},"content":{"rendered":"<style>\n.upl-blog{font-size:17px;line-height:1.78;color:#1f2937}\n.upl-blog p{margin:0 0 18px}\n.upl-blog h2{font-size:26px;line-height:1.3;color:#0b2b33;margin:46px 0 14px;font-weight:700;letter-spacing:-.015em}\n.upl-blog h3{font-size:19.5px;color:#0d3b47;margin:28px 0 10px;font-weight:700}\n.upl-blog ul,.upl-blog ol{margin:0 0 20px;padding-left:22px}\n.upl-blog li{margin:0 0 9px}\n.upl-blog figure{margin:0 0 34px}\n.upl-blog figure img{width:100%;height:auto;display:block;border-radius:10px}\n.upl-blog figcaption{font-size:13px;color:#6b7280;margin-top:10px;line-height:1.5}\n.upl-blog .toc{background:none;border:0;border-radius:0;padding:0;margin:0 0 34px}\n.upl-blog .toc .lwptoc{margin:0}\n.upl-blog .toc h4{margin:0 0 10px;font-size:13px;letter-spacing:.1em;text-transform:uppercase;color:#0d5563}\n.upl-blog .toc ol{margin:0;padding-left:18px;font-size:14.5px}\n.upl-blog .toc li{margin-bottom:6px}\n.upl-blog table{width:100%;border-collapse:collapse;font-size:14.5px;margin:0 0 10px}\n.upl-blog th{background:#0d3b47;color:#fff;text-align:left;padding:11px 13px;font-weight:600;font-size:13.5px;border:0}\n.upl-blog td{padding:11px 13px;border:0;border-bottom:1px solid #e8ebed;vertical-align:top}\n.upl-blog tbody tr:nth-child(even){background:#fafbfc}\n.upl-blog .tablecap{font-size:12.5px;color:#6b7280;margin:0 0 30px}\n.upl-blog .myth{background:#fff8ef;border:1px solid #f6ddbd;border-radius:8px;padding:16px 20px;margin:0 0 26px;font-size:15.5px}\n.upl-blog .myth b{color:#a85c10}\n.upl-blog .callout{background:#f2f8f9;border-radius:8px;padding:18px 22px;margin:0 0 26px;font-size:15.5px;border-left:3px solid #14707f}\n.upl-blog .faq h3{border-top:1px solid #eceff1;padding-top:22px;margin-top:0;font-size:18px}\n.upl-blog .faq h3:first-of-type{border-top:0;padding-top:0}\n.upl-blog .cta{background:linear-gradient(135deg,#0b2b33,#0d5563);color:#fff;border-radius:12px;padding:34px;margin:48px 0 30px}\n.upl-blog .cta h2,.upl-blog .cta .cta-h{color:#fff;margin:0 0 10px;font-size:24px;font-weight:700;line-height:1.3}\n.upl-blog .cta p{color:#c9dee3;margin:0 0 20px;font-size:16px}\n.upl-blog .btn{display:inline-block;background:#e07a1f;color:#fff;text-decoration:none;font-weight:700;padding:13px 26px;border-radius:8px;font-size:15.5px}\n.upl-blog .rel{border-top:1px solid #e8ebed;margin-top:40px;padding-top:26px}\n.upl-blog .rel h4{font-size:13px;letter-spacing:.1em;text-transform:uppercase;color:#6b7280;margin:0 0 14px}\n.upl-blog .rel ul{list-style:none;padding:0;margin:0}\n.upl-blog .rel li{padding:11px 0;border-bottom:1px dashed #e8ebed}\n.upl-blog .rel a{text-decoration:none;font-weight:600;font-size:15.5px}\n@media(max-width:640px){.upl-blog h2{font-size:22px}.upl-blog table{font-size:13px}.upl-blog .cta{padding:24px}}\n\/* \u5355\u7bc7\u9875\u9690\u85cf WhatsApp \u81ea\u52a8\u5c55\u5f00\u7684\u95ee\u5019\u5361\uff0c\u53ea\u4fdd\u7559\u5706\u5f62\u6c14\u6ce1\uff0c\u907f\u514d\u906e\u6321\u4fa7\u680f\u8be2\u76d8\u63d0\u4ea4\u6309\u94ae *\/\nbody.single-post .ht_ctc_chat_greetings_box{display:none !important}\n<\/style>\n<div class=\"upl-blog\">\n<figure>\n<img fetchpriority=\"high\" decoding=\"async\" src=\"https:\/\/uplastech.com\/wp-content\/uploads\/2026\/10\/pkg-tube-defects.jpg\" alt=\"Five white plastic squeeze tubes laid side by side showing surface defects such as die lines and gel specks\" width=\"1536\" height=\"909\"><figcaption>Five tubes from the same line, under raking light. Only one of them is acceptable. The defects here are all surface-visible \u2014 which is the easy case. The expensive defects are the ones you cannot see until the tube leaks.<\/figcaption><\/figure>\n<div class=\"toc\"><\/div>\n<h2 id=\"taxonomy\">Defects sort into four families, and each has a different owner<\/h2>\n<p>When a tube line starts producing rejects, the argument usually starts before anyone has identified the defect. The fastest way to end it is to put the fault in the right family, because each family belongs to a different part of the process \u2014 and often to a different department.<\/p>\n<table>\n<thead>\n<tr>\n<th>Family<\/th>\n<th>\u00d6rnekler<\/th>\n<th>Owned by<\/th>\n<th>Usually visible<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Malzeme<\/td>\n<td>Gels, black specks, contamination, colour streaks<\/td>\n<td>Resin supply, handling, housekeeping<\/td>\n<td>Yes, on the surface<\/td>\n<\/tr>\n<tr>\n<td>Die and flow<\/td>\n<td>Die lines, weld lines, melt fracture, uneven gloss<\/td>\n<td>Tooling, die maintenance<\/td>\n<td>Yes, longitudinal and repeatable<\/td>\n<\/tr>\n<tr>\n<td>Process stability<\/td>\n<td>Surging, bambooing, wall drift, diameter banding<\/td>\n<td>Extruder setting, screw, temperature control<\/td>\n<td>Yes, periodic along the length<\/td>\n<\/tr>\n<tr>\n<td>A\u015fa\u011f\u0131 Ak\u0131\u015f<\/td>\n<td>Ovality, bow, scoring, drag marks, cutter marks<\/td>\n<td>Sizing, cooling, haul-off, cutting<\/td>\n<td>Sometimes only after ageing<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"tablecap\">Table 1 \u2014 Defect families. A defect that repeats at a fixed interval along the tube is almost always process stability or a roll; a defect that runs the full length is die or material.<\/p>\n<p>That last distinction is the most useful diagnostic in the plant. A mark that runs the entire length of the tube, in the same angular position, is a die or a material problem. A mark that repeats every 200 mm is a roll, a belt or a haul-off issue. A mark that appears at random intervals is contamination or a feed problem.<\/p>\n<h2 id=\"gels\">Gels: the defect that is always the material's fault, except when it is not<\/h2>\n<p>A gel is a small lens-shaped lump of high-molecular-weight material that has not melted with the rest of the melt. It appears as a glossy dot, typically 0.1 \u2013 1 mm, standing slightly proud of the surface. On a printed tube it shows as a white spot where the ink did not transfer.<\/p>\n<p>Gels come from four different places and they look almost identical, which is why plants replace resin for months without solving the problem.<\/p>\n<table>\n<thead>\n<tr>\n<th>Kaynak<\/th>\n<th>G\u00f6r\u00fcn\u00fc\u015f<\/th>\n<th>How to confirm<\/th>\n<th>Fix<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Cross-linked resin (over-cooked in the reactor)<\/td>\n<td>Hard, cannot be dented with a fingernail<\/td>\n<td>DSC or hot-stage microscopy; check lot history<\/td>\n<td>Change resin lot<\/td>\n<\/tr>\n<tr>\n<td>Unmelted resin (cold feed, low temperature)<\/td>\n<td>Softens and smears when pressed hot<\/td>\n<td>Raise melt temperature 10 \u00b0C and re-check<\/td>\n<td>Barrel profile, screw speed<\/td>\n<\/tr>\n<tr>\n<td>Degraded material (burnt in a dead spot)<\/td>\n<td>Dark or brown centre, often with a tail<\/td>\n<td>Purge and inspect; check the die and adapter<\/td>\n<td>Strip and clean, remove dead spots<\/td>\n<\/tr>\n<tr>\n<td>Foreign contamination (dust, other polymer, dried ink)<\/td>\n<td>Irregular shape, sometimes coloured<\/td>\n<td>Microscope and FTIR<\/td>\n<td>Housekeeping, hopper covers, screen pack<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"tablecap\">Table 2 \u2014 Gel sources. The fingernail test separates the two most common causes in under a minute.<\/p>\n<p>The fingernail test is crude and reliable. Press a hard gel with a fingernail: if it will not dent, it is cross-linked and no amount of screw tuning will fix it. If it smears, it never melted and the barrel profile or screw speed is wrong. That one check has saved more resin changes than any analytical method.<\/p>\n<p>Degraded material behaves differently again: it usually has a brown or black centre and a comet tail pointing downstream. That tail is the signature of a char particle that has been dragged along the die surface. It means there is a dead spot \u2014 a thread, a thermocouple pocket, a step in the adapter \u2014 where material sits and cooks.<\/p>\n<div class=\"callout\">\n<p><strong>The counter-intuitive part:<\/strong> raising the melt temperature often <em>reduces<\/em> gels in a PE tube. Higher temperature improves melting of the cold fraction faster than it creates new degradation, as long as the residence time is short and there are no dead spots. If the melt is at 175 \u00b0C and the tube is full of gels, going to 190 \u00b0C and re-checking tells you in ten minutes whether you have an unmelt problem or a resin problem.<\/p>\n<\/div>\n<h2 id=\"dielines\">Die lines: longitudinal, permanent, and always in the same place<\/h2>\n<p>A die line is a fine longitudinal groove or ridge running the full length of the tube. It does not move around the circumference, and it does not go away when you change speed \u2014 which is exactly what distinguishes it from a weld line.<\/p>\n<table>\n<thead>\n<tr>\n<th>Neden<\/th>\n<th>Signature<\/th>\n<th>Fix<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Scratch or burr on the die lip<\/td>\n<td>Sharp, single line, constant position<\/td>\n<td>Polish the land; inspect with a magnifier<\/td>\n<\/tr>\n<tr>\n<td>Carbon build-up on the die land<\/td>\n<td>Wide, soft-edged line, grows over a run<\/td>\n<td>Clean the die; check for dead spots upstream<\/td>\n<\/tr>\n<tr>\n<td>Damage to the sizing sleeve<\/td>\n<td>Line appears after sizing, not at the die<\/td>\n<td>Replace or polish the sleeve<\/td>\n<\/tr>\n<tr>\n<td>Draw-down too high<\/td>\n<td>Multiple faint lines, worse at speed<\/td>\n<td>Reduce draw-down, open the die gap<\/td>\n<\/tr>\n<tr>\n<td>Poor die-lip finish from manufacture<\/td>\n<td>Faint line from day one<\/td>\n<td>Re-polish; specify the finish on the drawing<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"tablecap\">Table 3 \u2014 Die line causes. A line that grows slowly during a run is carbon, not a scratch.<\/p>\n<p>Polishing the die land is the fix for most of these, and it is a job that needs to be done properly. A die lip polished across the flow direction leaves microscopic scratches that become die lines; the polish has to run along the flow, and it has to end at a finish that is better than the surface you want on the tube. A 0.4 \u00b5m finish on the land is normal for a packaging tube die.<\/p>\n<p>The draw-down effect is the one that catches people. At a draw-down ratio of 6:1, any 1 \u00b5m imperfection on the land becomes a visible line because it is stretched out and the polymer orientation makes it show. Reduce the draw-down and the same die produces an acceptable tube. This is why a die that worked at 3:1 \"suddenly\" fails when the wall is thinned to save resin.<\/p>\n<h2 id=\"weldlines\">Weld lines: where the melt rejoins<\/h2>\n<p>A weld line forms wherever two flow fronts meet. In a crosshead die there should be none \u2014 the melt flows around the mandrel as a continuous annulus. If you see a weld line on a crosshead tube, one of three things is happening.<\/p>\n<ul>\n<li><strong>The die is a spider type.<\/strong> Support legs split the flow and it re-joins downstream. The line is faint but permanent. Spider dies are cheaper and they always leave a line.<\/li>\n<li><strong>The die has a damaged or obstructed flow path.<\/strong> A build-up on one side of the mandrel creates a local stagnation and a visible knit line.<\/li>\n<li><strong>The melt is too cold at the recombination point.<\/strong> Two fronts meet without enough mobility to interdiffuse, and the interface is weak as well as visible.<\/li>\n<\/ul>\n<p>The third case is the dangerous one, because the line is not just cosmetic. A cold weld line is a mechanical weak point, and on a thin-wall tube it becomes the place where the tube splits when squeezed. If a weld line is visible and the tube also fails a burst test at the same angular position, it is a cold weld, not a surface mark.<\/p>\n<div class=\"myth\">\n<p><strong>Common assumption:<\/strong> \"a visible weld line means the die is worn out.\"<\/p>\n<p>Usually it means the melt is too cold where the flows rejoin, or the flow path is partly blocked. Check the melt temperature and strip the die before ordering a new one. A die that produces a weld line at 175 \u00b0C often produces none at 190 \u00b0C.<\/p>\n<\/div>\n<h2 id=\"surging\">Surging and bambooing: the periodic defects<\/h2>\n<p>If the tube diameter varies in a regular rhythm along its length, you have a stability problem, and the period tells you where.<\/p>\n<table>\n<thead>\n<tr>\n<th>Period<\/th>\n<th>Likely cause<\/th>\n<th>Check<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Every few seconds, roughly constant<\/td>\n<td>Screw speed fluctuation, feed pulsation<\/td>\n<td>Log screw RPM and melt pressure at 1 Hz<\/td>\n<\/tr>\n<tr>\n<td>Every 30 \u2013 90 seconds<\/td>\n<td>Temperature controller hunting on a barrel zone<\/td>\n<td>Watch the zone's actual value, not the setpoint<\/td>\n<\/tr>\n<tr>\n<td>Every 100 \u2013 300 mm of tube<\/td>\n<td>Haul-off belt slip or roll eccentricity<\/td>\n<td>Mark the belt and check if the period matches<\/td>\n<\/tr>\n<tr>\n<td>Random, with long quiet periods<\/td>\n<td>Bridging in the hopper, inconsistent feed<\/td>\n<td>Hopper level, resin bulk density, regrind ratio<\/td>\n<\/tr>\n<tr>\n<td>Once per batch<\/td>\n<td>Regrind or lot change<\/td>\n<td>Compare bulk density and melt index of lots<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"tablecap\">Table 4 \u2014 Periodic defects and their period. Measuring the period is faster than any other diagnostic.<\/p>\n<p>Bambooing \u2014 the tube looks like a bamboo culm, with regular bulges \u2014 is usually a haul-off problem rather than an extruder problem. If the belt tension is low, the tube slips and catches, and the resulting speed oscillation appears as a diameter wave. It is often blamed on the screw, which is expensive and wrong.<\/p>\n<p>Real screw surging is different: the melt pressure trace shows a slow oscillation with a period of tens of seconds, and it is usually caused by a feed zone that is too cold, a compression ratio that is too high for the resin, or a screen pack that is progressively blocking. The pressure trace is the instrument that settles it \u2014 a stable screw with a wandering pressure is a die or screen problem, and a wandering screw speed with stable pressure is a drive or feed problem.<\/p>\n<h2 id=\"surface\">Surface defects: melt fracture, gloss bands and drag marks<\/h2>\n<table>\n<thead>\n<tr>\n<th>Kusur<\/th>\n<th>G\u00f6r\u00fcn\u00fc\u015f<\/th>\n<th>Neden<\/th>\n<th>Fix<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Melt fracture (sharkskin)<\/td>\n<td>Fine roughness, matte patches<\/td>\n<td>Shear rate at the die lip too high<\/td>\n<td>Raise melt temperature, open the die gap, lower output<\/td>\n<\/tr>\n<tr>\n<td>Gross melt fracture<\/td>\n<td>Deep helical ridges<\/td>\n<td>Severe shear, die too small<\/td>\n<td>Redesign the die; this cannot be tuned out<\/td>\n<\/tr>\n<tr>\n<td>Gloss bands<\/td>\n<td>Alternating shiny and matte rings<\/td>\n<td>Cooling oscillation, vacuum fluctuation<\/td>\n<td>Stabilise vacuum and water flow<\/td>\n<\/tr>\n<tr>\n<td>Drag marks<\/td>\n<td>Longitudinal scuffs, often on one side<\/td>\n<td>Tube rubbing on the sizing sleeve or a guide<\/td>\n<td>Align guides, check vacuum distribution<\/td>\n<\/tr>\n<tr>\n<td>Internal scoring<\/td>\n<td>Faint helical scratches inside<\/td>\n<td>Filling nozzle, or mandrel damage<\/td>\n<td>Check the nozzle; inspect the mandrel<\/td>\n<\/tr>\n<tr>\n<td>Orange peel<\/td>\n<td>Uniform fine texture<\/td>\n<td>Moisture in the resin, or cold melt<\/td>\n<td>Dry the resin, raise the profile<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"tablecap\">Table 5 \u2014 Surface defects. Sharkskin appears above a critical shear rate, so it is a speed problem before it is a temperature problem.<\/p>\n<p>Sharkskin has a specific signature: it starts at the die lip and gets worse toward the exit, and it disappears if you slow down or raise the temperature. That is because it comes from the stress at the die wall exceeding what the polymer can relax before it freezes. The fix is to reduce shear stress \u2014 larger die gap, higher temperature, lower output \u2014 not to polish the die harder.<\/p>\n<h2 id=\"triage\">The triage order that saves the most time<\/h2>\n<p>When a defect appears, work through this list in order. It runs from cheapest to most expensive, and most problems are solved in the first three steps.<\/p>\n<ol>\n<li><strong>Is the defect longitudinal and fixed in position?<\/strong> Die or material. Go to the die.<\/li>\n<li><strong>Is the period measurable?<\/strong> Process stability or a roll. Log the period and compare against belt circumference and screw RPM.<\/li>\n<li><strong>Does it disappear at a different melt temperature?<\/strong> Unmelt or cold weld. Adjust the profile before touching the tool.<\/li>\n<li><strong>Does it appear on every cavity or every lane?<\/strong> If only one, it is local tooling. If all, it is material or the main flow path.<\/li>\n<li><strong>Did it start at a lot change?<\/strong> Material. Check bulk density, melt index and gel count on the incoming resin.<\/li>\n<li><strong>Did it start after maintenance?<\/strong> Assembly error \u2014 a seal reversed, a thermocouple in the wrong pocket, a die not fully seated.<\/li>\n<\/ol>\n<p>Step four is the one that is skipped most often on multi-lane lines. If a line runs four tubes from one die head and only one lane is affected, the material is innocent and the answer is in that lane's flow path. Checking all four lanes separately takes five minutes and eliminates half the possible causes.<\/p>\n<h2 id=\"cost\">What defects actually cost<\/h2>\n<table>\n<thead>\n<tr>\n<th>Kusur<\/th>\n<th>Detection point<\/th>\n<th>Cost consequence<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Gels<\/td>\n<td>Printing (ink skips)<\/td>\n<td>Tube scrapped after printing \u2014 full cost lost<\/td>\n<\/tr>\n<tr>\n<td>Die lines<\/td>\n<td>Printing or goods-in<\/td>\n<td>Scrap, or downgrade to unprinted<\/td>\n<\/tr>\n<tr>\n<td>Ovality<\/td>\n<td>Capping on the filling line<\/td>\n<td>Line stop at the customer, chargeback<\/td>\n<\/tr>\n<tr>\n<td>Weak weld line<\/td>\n<td>Consumer squeeze<\/td>\n<td>Leak in market, recall risk<\/td>\n<\/tr>\n<tr>\n<td>Short length<\/td>\n<td>Tail crimping<\/td>\n<td>Leak, rejected at the filler<\/td>\n<\/tr>\n<tr>\n<td>Black specks<\/td>\n<td>Visual at goods-in<\/td>\n<td>Whole batch rejected, no salvage<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"tablecap\">Table 6 \u2014 Cost of detection point. The further downstream a defect is caught, the more value has been added on top of it.<\/p>\n<p>The economics are brutal in one direction: a gel costs almost nothing to scrap as a plain tube, and it costs the full printed, welded, capped and boxed value to scrap after decoration. Every hour of production after a defect starts is value added to a part that will be thrown away. This is why the inspection point belongs as early in the line as it can be made to work.<\/p>\n<div class=\"faq\">\n<h3>What is the difference between a gel and a black speck?<\/h3>\n<p>A gel is clear or translucent high-molecular-weight material that has not melted \u2014 it is the same polymer, just not fused. A black speck is degraded material, usually oxidised or carbonised, and it is dark because it has been hot for too long. Gels come from the resin or from cold melting; black specks come from dead spots in the flow path.<\/p>\n<h3>How do I tell a die line from a weld line?<\/h3>\n<p>A die line stays in the same angular position and does not move when you change speed. A weld line is also fixed but it changes intensity with melt temperature, and it often corresponds to a spider leg or a flow obstruction. If the line disappears when you raise the temperature 15 \u00b0C, it is a weld line.<\/p>\n<h3>Why do my tubes go oval overnight?<\/h3>\n<p>Residual stress. Fast cooling or a high draw-down ratio freezes stress into the wall; when the tube is cut, the constraint is released and the section relaxes. It develops over hours. Slower cooling, warmer water and a lower draw-down all help. Measuring immediately after cutting hides the problem rather than solving it.<\/p>\n<h3>What causes a rough, matte patch on an otherwise glossy tube?<\/h3>\n<p>Sharkskin, from shear stress at the die lip exceeding what the melt can relax. It appears above a critical output rate. Reduce output, raise the melt temperature or open the die gap. Polishing the die does not fix it because the surface is not the problem.<\/p>\n<h3>Can I run regrind in a packaging tube?<\/h3>\n<p>Yes, up to about 20 \u2013 30 % for non-food industrial tubes, provided the regrind is clean, dry and consistently sized. Above that, gels and black specks increase sharply and the wall tolerance becomes hard to hold. Food-contact and pharma tubes usually exclude regrind entirely unless the loop is closed and documented.<\/p>\n<h3>Why do I get black specks only at the start of a run?<\/h3>\n<p>Because the material that sat in the die during the shutdown has degraded. Purge properly before stopping, and purge again at start-up until the specks clear. If they persist beyond ten minutes, there is a dead spot that needs stripping, not more purging.<\/p>\n<h3>What causes a diameter that drifts slowly over a shift?<\/h3>\n<p>Usually thermal drift in the die or a slowly blocking screen pack. As the screen blocks, melt pressure rises and output falls slightly, and the wall thins. Check the pressure trend, not the instantaneous value \u2014 a rise of 10 \u2013 15 bar over a shift is the signal.<\/p>\n<h3>Is a visible weld line always a reject?<\/h3>\n<p>Not always for appearance, but always for strength if it is a cold weld. If the line is visible and the tube passes a burst test at that position, it is cosmetic and can be accepted against a limit sample. If it fails at the line, it is a cold weld and the melt temperature or flow path needs fixing.<\/p>\n<\/div>\n<div class=\"cta\">\n<p class=\"cta-h\">Chasing a defect that will not go away?<\/p>\n<p>Send us a photo, the tube section, the resin grade and the line settings. We will tell you which family the defect belongs to and what to change first.<\/p>\n<p><a class=\"btn\" href=\"https:\/\/uplastech.com\/tr\/boru-ve-tup-ekstruzyonlari\/\">Get a defect diagnosis<\/a>\n<\/div>\n<div class=\"rel\">\n<h4>Continue reading<\/h4>\n<ul>\n<li><a href=\"https:\/\/uplastech.com\/tr\/plastic-packaging-tube-extrusion\/\">Plastic Packaging Tube Extrusion: From Die to Finished Tube<\/a><\/li>\n<li><a href=\"https:\/\/uplastech.com\/tr\/packaging-tube-tolerances-wall-thickness\/\">Packaging Tube Tolerances: Diameter, Wall and Ovality<\/a><\/li>\n<li><a href=\"https:\/\/uplastech.com\/tr\/plasti%cc%87k-ekstruzyon-hatalari\/\">Plastic Extrusion Defects: 12 Problems, Causes and Fixes<\/a><\/li>\n<li><a href=\"https:\/\/uplastech.com\/tr\/extrusion-die-design\/\">Extrusion Die Design: Flow Balance, Land and Die Swell<\/a><\/li>\n<li><a href=\"https:\/\/uplastech.com\/tr\/packaging-tube-barrier-coextrusion\/\">Barrier Co-Extrusion for Tubes: EVOH and Tie Layers<\/a><\/li>\n<\/ul>\n<\/div>\n<\/div>","protected":false},"excerpt":{"rendered":"<p>Four defect families and who owns each, the fingernail test that separates a resin problem from a melting problem, why a periodic defect tells you its own cause, and the triage order that saves the most time.<\/p>","protected":false},"author":1,"featured_media":7628,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_seopress_titles_title":"Tube Extrusion Defects: Gels, Die Lines, Weld Lines","_seopress_titles_desc":"Packaging tube extrusion defects: gels, die lines, weld lines, surging, melt fracture and ovality \u2014 causes, diagnosis and fixes, plus a triage order.","_seopress_robots_index":"1","_seopress_robots_follow":"1","_seopress_robots_imageindex":"","_seopress_robots_snippet":"","_seopress_robots_primary_cat":"17","_seopress_robots_breadcrumbs":"","_seopress_robots_freeze_modified_date":"","_seopress_robots_custom_modified_date":"","_seopress_robots_canonical":"https:\/\/uplastech.com\/packaging-tube-extrusion-defects\/","_seopress_social_fb_title":"","_seopress_social_fb_desc":"","_seopress_social_fb_img":"","_seopress_social_fb_img_attachment_id":0,"_seopress_social_fb_img_width":0,"_seopress_social_fb_img_height":0,"_seopress_social_twitter_title":"","_seopress_social_twitter_desc":"","_seopress_social_twitter_img":"","_seopress_social_twitter_img_attachment_id":0,"_seopress_social_twitter_img_width":0,"_seopress_social_twitter_img_height":0,"_seopress_redirections_value":"","_seopress_redirections_enabled":"","_seopress_redirections_enabled_regex":"","_seopress_redirections_logged_status":"","_seopress_redirections_param":"","_seopress_redirections_type":0,"_seopress_analysis_target_kw":"tube extrusion defects","footnotes":""},"categories":[17],"tags":[],"class_list":["post-7633","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-plastic-extrusion-process"],"meta_box":{"post-to-quiz_to":[]},"_links":{"self":[{"href":"https:\/\/uplastech.com\/tr\/wp-json\/wp\/v2\/posts\/7633","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/uplastech.com\/tr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/uplastech.com\/tr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/uplastech.com\/tr\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/uplastech.com\/tr\/wp-json\/wp\/v2\/comments?post=7633"}],"version-history":[{"count":0,"href":"https:\/\/uplastech.com\/tr\/wp-json\/wp\/v2\/posts\/7633\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/uplastech.com\/tr\/wp-json\/wp\/v2\/media\/7628"}],"wp:attachment":[{"href":"https:\/\/uplastech.com\/tr\/wp-json\/wp\/v2\/media?parent=7633"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/uplastech.com\/tr\/wp-json\/wp\/v2\/categories?post=7633"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/uplastech.com\/tr\/wp-json\/wp\/v2\/tags?post=7633"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}