{"id":7704,"date":"2025-08-29T09:00:00","date_gmt":"2025-08-29T08:00:00","guid":{"rendered":"https:\/\/uplastech.com\/heavy-gauge-thermoforming-large-enclosures\/"},"modified":"2025-08-29T09:00:00","modified_gmt":"2025-08-29T08:00:00","slug":"heavy-gauge-thermoforming-large-enclosures","status":"publish","type":"post","link":"https:\/\/uplastech.com\/ar\/heavy-gauge-thermoforming-large-enclosures\/","title":{"rendered":"Heavy Gauge Thermoforming for Large Enclosures: Sag, Wall and Warpage"},"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\/heavy-gauge-thermoforming-large-enclosures.jpg\" alt=\"Wall thickness distribution across a deep draw in heavy gauge thermoforming and cycle time by sheet thickness\" width=\"1536\" height=\"909\"><figcaption>In heavy gauge forming the sheet is not a membrane, it is a structure. It sags under its own weight, cools unevenly and remembers every degree of the oven it came out of.<\/figcaption><\/figure>\n<div class=\"toc\"><\/div>\n<h2 id=\"difference\">What makes heavy gauge different<\/h2>\n<p>Heavy gauge thermoforming is usually defined as sheet above 3 mm, and the boundary is real rather than arbitrary. Below it, the sheet behaves as a membrane: it heats quickly, sags little, forms fast and cools fast. Above it, gravity and heat conduction start to dominate, and most of the process assumptions from thin gauge stop applying.<\/p>\n<table>\n<thead>\n<tr>\n<th>\u0623\u0633\u0628\u0643\u062a<\/th>\n<th>Thin gauge (under 3 mm)<\/th>\n<th>Heavy gauge (over 3 mm)<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Sheet feed<\/td>\n<td>Roll<\/td>\n<td>Cut sheet, sheet-by-sheet<\/td>\n<\/tr>\n<tr>\n<td>\u0627\u0644\u062a\u062f\u0641\u0626\u0629<\/td>\n<td>Contact or short-wave IR, seconds<\/td>\n<td>Oven, minutes<\/td>\n<\/tr>\n<tr>\n<td>Sag before forming<\/td>\n<td>Negligible<\/td>\n<td>The dominant defect source<\/td>\n<\/tr>\n<tr>\n<td>\u0636\u063a\u0637 \u0627\u0644\u062a\u0634\u0643\u064a\u0644<\/td>\n<td>Vacuum is usually enough<\/td>\n<td>Pressure forming often needed<\/td>\n<\/tr>\n<tr>\n<td>\u0632\u0645\u0646 \u0627\u0644\u062f\u0648\u0631\u0629<\/td>\n<td>5 \u2013 30 s<\/td>\n<td>2 \u2013 10 min<\/td>\n<\/tr>\n<tr>\n<td>Cooling share of cycle<\/td>\n<td>30 \u2013 45%<\/td>\n<td>55 \u2013 70%<\/td>\n<\/tr>\n<tr>\n<td>\u0627\u0644\u062a\u0634\u0630\u064a\u0628<\/td>\n<td>In-line steel rule die<\/td>\n<td>CNC or robot, separate station<\/td>\n<\/tr>\n<tr>\n<td>Mould material<\/td>\n<td>Aluminium, cast resin<\/td>\n<td>Aluminium with temperature control<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"tablecap\">Table 1 \u2014 Thin gauge and heavy gauge compared. The differences are not incremental; almost every assumption has to be rebuilt.<\/p>\n<div class=\"callout\">\n<p><strong>The oven, not the mould, decides the part.<\/strong> On heavy gauge, the temperature profile through the sheet thickness at the moment of forming determines how the material distributes. Most wall thickness problems are oven problems wearing a mould-problem disguise.<\/p>\n<\/div>\n<h2 id=\"heating\">Heating: sag is the first problem<\/h2>\n<p>A 4 mm sheet of ABS at 1,200 \u00d7 800 mm weighs about 4.6 kg. At forming temperature it has the stiffness of a wet cloth. It is held only at the edges, so it sags in the middle, and by the time it touches the mould it is no longer flat.<\/p>\n<table>\n<thead>\n<tr>\n<th>\u0627\u0644\u0645\u0648\u0627\u062f<\/th>\n<th>Forming temperature<\/th>\n<th>Typical sag over 1 m span<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>\u0645\u0644\u0627\u062d\u0638\u0629<\/td>\n<td>130 \u2013 150 \u00b0C<\/td>\n<td>15 \u2013 30 mm<\/td>\n<\/tr>\n<tr>\n<td>ABS<\/td>\n<td>150 \u2013 170 \u00b0C<\/td>\n<td>20 \u2013 40 mm<\/td>\n<\/tr>\n<tr>\n<td>\u0627\u0644\u0628\u0648\u0644\u064a \u0625\u064a\u062b\u064a\u0644\u064a\u0646 \u0639\u0627\u0644\u064a \u0627\u0644\u0643\u062b\u0627\u0641\u0629<\/td>\n<td>135 \u2013 155 \u00b0C<\/td>\n<td>25 \u2013 45 mm<\/td>\n<\/tr>\n<tr>\n<td>\u0635<\/td>\n<td>150 \u2013 165 \u00b0C<\/td>\n<td>25 \u2013 50 mm<\/td>\n<\/tr>\n<tr>\n<td>\u0643\u0645\u0628\u064a\u0648\u062a\u0631 \u0634\u062e\u0635\u064a<\/td>\n<td>175 \u2013 200 \u00b0C<\/td>\n<td>10 \u2013 25 mm<\/td>\n<\/tr>\n<tr>\n<td>\u0628 \u0645 \u0623 \u0645 \u0623<\/td>\n<td>160 \u2013 180 \u00b0C<\/td>\n<td>15 \u2013 30 mm<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"tablecap\">Table 2 \u2014 Sheet sag at forming temperature over a one-metre unsupported span. Semi-crystalline resins sag more because their stiffness falls sharply above the melting point.<\/p>\n<p>Sag has three consequences. It changes the distance between the heater and the sheet, so the sheet heats unevenly. It changes the amount of material available at the centre, so the finished wall is thinner there. And if the sag is large enough, the sheet touches the mould before forming starts, producing a cold mark that cannot be removed.<\/p>\n<p>The countermeasures are mechanical rather than thermal. Reduce the unsupported span with a support frame or a sag band. Turn the sheet over part-way through heating so both faces see the same radiant history. Use a two-sided oven so the sheet heats from above and below at once, which roughly halves the time and reduces the differential. And on very large parts, use a vacuum plate or a perforated support that holds the sheet until the moment of forming.<\/p>\n<h2 id=\"mould\">The mould: temperature, texture and draft<\/h2>\n<p>A large heavy-gauge mould is a temperature-controlled aluminium tool. Aluminium because the tool has to be heated and cooled quickly and evenly across a large area, and steel is too slow. Temperature-controlled because on a 6 mm part, mould temperature sets both the surface finish and the cycle time.<\/p>\n<table>\n<thead>\n<tr>\n<th>Mould material<\/th>\n<th>Heat transfer<\/th>\n<th>Tool life<\/th>\n<th>\u0627\u0644\u0623\u0641\u0636\u0644 \u0644\u0640<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Cast aluminium<\/td>\n<td>\u062c\u064a\u062f<\/td>\n<td>10k \u2013 50k parts<\/td>\n<td>Prototypes, low volume<\/td>\n<\/tr>\n<tr>\n<td>Machined aluminium<\/td>\n<td>Very good<\/td>\n<td>50k \u2013 200k<\/td>\n<td>Production, textured surfaces<\/td>\n<\/tr>\n<tr>\n<td>Aluminium with conformal cooling<\/td>\n<td>\u0645\u0645\u062a\u0627\u0632<\/td>\n<td>50k \u2013 200k<\/td>\n<td>Thick sections, tight cycle<\/td>\n<\/tr>\n<tr>\n<td>\u0627\u0644\u0641\u0648\u0644\u0627\u0630<\/td>\n<td>\u0641\u0642\u064a\u0631<\/td>\n<td>Very long<\/td>\n<td>Very high volume, abrasive sheet<\/td>\n<\/tr>\n<tr>\n<td>Epoxy \/ cast resin<\/td>\n<td>\u0641\u0642\u064a\u0631<\/td>\n<td>100 \u2013 1,000<\/td>\n<td>Prototypes only<\/td>\n<\/tr>\n<tr>\n<td>Wood \/ MDF<\/td>\n<td>Very poor<\/td>\n<td>1 \u2013 50<\/td>\n<td>Forming trials<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"tablecap\">Table 3 \u2014 Mould materials for large heavy-gauge parts. Steel is rarely used because its slow heat transfer adds minutes to every cycle.<\/p>\n<p>Draft angle on a deep enclosure should be at least 2\u00b0 per side, and 3\u00b0 where the surface is textured. Textured aluminium releases worse than polished, and the texture depth adds to the effective draft requirement. A 0.5 mm texture on a vertical wall needs roughly 1\u00b0 of extra draft to release cleanly.<\/p>\n<p>Mould temperature is the balance point. Hotter moulds give better surface reproduction and lower residual stress, but lengthen the cycle and increase sag on the next sheet. Typical values are 60\u201380 \u00b0C for PS and ABS, 80\u201395 \u00b0C for PC and PMMA, and 40\u201360 \u00b0C for polyolefins.<\/p>\n<h2 id=\"pressure\">Pressure forming for large parts<\/h2>\n<p>Vacuum gives at most one atmosphere \u2014 about 1 bar \u2014 of forming pressure. On a deep draw with a large radius, that is not enough to pull the sheet into the corners before it cools. Pressure forming adds 2\u20136 bar of air on the back face, which is three to seven times the forming force.<\/p>\n<table>\n<thead>\n<tr>\n<th>\u0627\u0644\u0637\u0631\u064a\u0642\u0629<\/th>\n<th>\u0636\u063a\u0637 \u0627\u0644\u062a\u0634\u0643\u064a\u0644<\/th>\n<th>Corner detail<\/th>\n<th>Tool cost<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Vacuum only<\/td>\n<td>1 bar<\/td>\n<td>Soft, radiused<\/td>\n<td>Base<\/td>\n<\/tr>\n<tr>\n<td>Vacuum plus plug assist<\/td>\n<td>1 bar<\/td>\n<td>Better wall control, mechanical mark risk<\/td>\n<td>+15 \u2013 25%<\/td>\n<\/tr>\n<tr>\n<td>Pressure forming<\/td>\n<td>3 \u2013 7 bar<\/td>\n<td>Sharp, near-injection quality<\/td>\n<td>+30 \u2013 50%<\/td>\n<\/tr>\n<tr>\n<td>Pressure plus plug<\/td>\n<td>3 \u2013 7 bar<\/td>\n<td>Best wall distribution and detail<\/td>\n<td>+50 \u2013 70%<\/td>\n<\/tr>\n<tr>\n<td>Twin-sheet<\/td>\n<td>1 \u2013 3 bar<\/td>\n<td>Hollow parts with moulded-in features<\/td>\n<td>Doubles tool count<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"tablecap\">Table 4 \u2014 Forming methods. Pressure forming is the reason heavy-gauge parts can compete with injection moulded ones on appearance.<\/p>\n<p>The cost of pressure forming is in the tool, not the machine. A pressure box has to seal against the sheet, the clamp frame has to withstand the force, and the mould has to be strong enough not to deflect under it. On a large part that force is substantial: 4 bar over 1 m\u00b2 is 40 tonnes.<\/p>\n<h2 id=\"wall\">Wall distribution and the sheet you start with<\/h2>\n<p>Wall thickness in a formed part is never uniform, because the sheet has a fixed volume and stretching it over a shape redistributes that volume. The corners and the deepest draw are always thinnest.<\/p>\n<table>\n<thead>\n<tr>\n<th>Region of a deep enclosure<\/th>\n<th>Vacuum only<\/th>\n<th>Pressure + plug<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Flange<\/td>\n<td>95 \u2013 100% of sheet<\/td>\n<td>95 \u2013 100%<\/td>\n<\/tr>\n<tr>\n<td>Upper sidewall<\/td>\n<td>70 \u2013 80%<\/td>\n<td>80 \u2013 88%<\/td>\n<\/tr>\n<tr>\n<td>Lower sidewall<\/td>\n<td>45 \u2013 60%<\/td>\n<td>60 \u2013 72%<\/td>\n<\/tr>\n<tr>\n<td>Bottom corner radius<\/td>\n<td>30 \u2013 45%<\/td>\n<td>50 \u2013 62%<\/td>\n<\/tr>\n<tr>\n<td>Base centre<\/td>\n<td>55 \u2013 70%<\/td>\n<td>65 \u2013 78%<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"tablecap\">Table 5 \u2014 Wall retention across a 400 mm deep enclosure formed from 4 mm sheet. The corner radius is the critical number for structural parts.<\/p>\n<p>The design consequence is that the sheet thickness must be chosen from the thinnest point, not the nominal. If the corner needs 1.5 mm and the process retains 40% there, the starting sheet has to be 3.75 mm \u2014 and the flange will then be 3.75 mm, which is usually thicker than necessary and costs material.<\/p>\n<p>Plug assist is the main tool for improving distribution. A plug pushes material from the centre towards the walls before the pressure is applied, so less stretching is needed at the corners. Plug material, temperature and shape all matter: a cold plug marks the sheet, a hot plug sticks to it, and a badly shaped plug pushes material to the wrong place.<\/p>\n<h2 id=\"cooling\">Cooling and warpage<\/h2>\n<p>Heavy-gauge parts cool from one side only \u2014 the mould side \u2014 because the other side is exposed to air. That asymmetry is the main source of warpage: the mould side contracts first and the free side follows, and the part bows towards the mould.<\/p>\n<table>\n<thead>\n<tr>\n<th>Gauge<\/th>\n<th>Cooling time on the tool<\/th>\n<th>Total cycle<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>3 mm<\/td>\n<td>45 \u2013 70 s<\/td>\n<td>2.5 \u2013 4 min<\/td>\n<\/tr>\n<tr>\n<td>4 mm<\/td>\n<td>80 \u2013 120 s<\/td>\n<td>4 \u2013 6 min<\/td>\n<\/tr>\n<tr>\n<td>6 mm<\/td>\n<td>180 \u2013 260 s<\/td>\n<td>7 \u2013 11 min<\/td>\n<\/tr>\n<tr>\n<td>8 mm<\/td>\n<td>320 \u2013 450 s<\/td>\n<td>12 \u2013 18 min<\/td>\n<\/tr>\n<tr>\n<td>10 mm<\/td>\n<td>500 \u2013 700 s<\/td>\n<td>18 \u2013 26 min<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"tablecap\">Table 6 \u2014 Cycle time by gauge for a large enclosure. Cooling follows the square law, so doubling the thickness quadruples the cooling time.<\/p>\n<p>Warpage control has three levers. Cool the part on the tool for longer than the minimum, so the mould side is not fighting a still-hot free side. Use a cooling fixture \u2014 a shaped jig that holds the part after demoulding while it finishes cooling. And design the part with ribs or a textured free side, which reduces the differential contraction by breaking up the surface.<\/p>\n<p>Demould temperature matters more than people expect. A part taken off at 90 \u00b0C will move by several millimetres as it cools to room temperature; the same part taken off at 60 \u00b0C moves much less. The extra minute on the tool is usually cheaper than the fixture and the scrap.<\/p>\n<h2 id=\"trimming\">Trimming large parts<\/h2>\n<table>\n<thead>\n<tr>\n<th>\u0627\u0644\u0637\u0631\u064a\u0642\u0629<\/th>\n<th>\u0627\u0644\u0623\u0641\u0636\u0644 \u0644\u0640<\/th>\n<th>Edge quality<\/th>\n<th>Set-up cost<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>CNC router, 5-axis<\/td>\n<td>Complex 3D trim lines<\/td>\n<td>\u0645\u0645\u062a\u0627\u0632<\/td>\n<td>Low \u2014 program only<\/td>\n<\/tr>\n<tr>\n<td>Robot with knife or saw<\/td>\n<td>High volume, simple trim<\/td>\n<td>\u062c\u064a\u062f<\/td>\n<td>Medium \u2014 fixture and program<\/td>\n<\/tr>\n<tr>\n<td>Steel rule die<\/td>\n<td>Flat parts, high volume<\/td>\n<td>\u062c\u064a\u062f<\/td>\n<td>High \u2014 die cost<\/td>\n<\/tr>\n<tr>\n<td>Hand trimming<\/td>\n<td>Prototypes, one-offs<\/td>\n<td>\u0645\u062a\u063a\u064a\u0631<\/td>\n<td>None<\/td>\n<\/tr>\n<tr>\n<td>Waterjet<\/td>\n<td>Very thick, heat-sensitive<\/td>\n<td>\u0645\u0645\u062a\u0627\u0632<\/td>\n<td>\u0645\u062a\u0648\u0633\u0637<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p class=\"tablecap\">Table 7 \u2014 Trimming options for large formed parts. CNC routing has largely replaced steel rule dies below about 20,000 parts per year.<\/p>\n<p>The trimming fixture matters as much as the cutter. A large part is floppy until it is held, and a fixture that clamps it out of shape produces a part that is trimmed accurately to the wrong geometry. Vacuum fixtures that hold the part against a shaped bed are the usual answer.<\/p>\n<h2 id=\"checklist\">Specification checklist<\/h2>\n<p>When specifying a large heavy-gauge part, five numbers decide whether it can be made economically: the deepest draw, the minimum wall at the worst point, the draft angle, the trim tolerance and the flatness requirement. Get any of them wrong and the cost moves by a large factor.<\/p>\n<p>The most common specification error is a minimum wall thickness quoted at the nominal rather than the worst point. A 3 mm nominal with 1.2 mm at the corner is a 3 mm part in the drawing and a 1.2 mm part in service. Quote the minimum, and let the supplier choose the sheet.<\/p>\n<div class=\"faq\">\n<h3>What counts as heavy gauge thermoforming?<\/h3>\n<p>Generally sheet over 3 mm, formed sheet by sheet rather than from a roll. The practical boundary is where sag, oven time and cooling dominate the process, which happens around 3\u20134 mm depending on the material.<\/p>\n<h3>How deep can a heavy gauge part be drawn?<\/h3>\n<p>A draw ratio of 1:1 (depth equal to width) is comfortable with pressure forming and plug assist. Beyond 1.5:1 the wall thins severely at the corners and the economics usually favour a different process or a two-piece assembly.<\/p>\n<h3>Why does my part warp after demoulding?<\/h3>\n<p>Asymmetric cooling. One face touches the mould and cools fast, the other faces air and cools slowly. Longer time on the tool, a cooling fixture and a lower demould temperature all reduce it. Ribs on the free side help by breaking up the contraction.<\/p>\n<h3>Do I need pressure forming?<\/h3>\n<p>If the part needs sharp corners, fine texture or a wall tolerance tighter than about \u00b115%, yes. Vacuum alone gives soft detail because one atmosphere is not much force on a cold, thick sheet.<\/p>\n<h3>What mould temperature should I use?<\/h3>\n<p>60\u201380 \u00b0C for PS and ABS, 80\u201395 \u00b0C for PC and PMMA, 40\u201360 \u00b0C for polyolefins. Hotter moulds give better surface and lower stress but cost cycle time. On thick parts the cycle cost is the deciding factor.<\/p>\n<h3>How do I stop the sheet sagging in the oven?<\/h3>\n<p>Reduce the unsupported span with a support frame, heat from both sides, and turn the sheet over part-way through the cycle. On very large sheets a vacuum plate holds the sheet flat until forming.<\/p>\n<h3>Can large enclosures compete with injection moulding?<\/h3>\n<p>Below roughly 2,000 parts per year, yes \u2014 the tool cost is a fraction and the lead time is weeks rather than months. Above that, injection moulding usually wins on piece price and repeatability.<\/p>\n<h3>How is the trim line defined?<\/h3>\n<p>Usually from the CAD model of the formed part, projected to a 5-axis CNC path. The trim fixture is designed at the same time, because the part has to be held in a known position before it can be cut accurately.<\/p>\n<\/div>\n<div class=\"cta\">\n<p class=\"cta-h\">Designing a large formed enclosure?<\/p>\n<p>Send us the model and the annual volume. We will tell you the draw ratio, the wall you will actually get, whether pressure forming is needed and what the tool and piece price will look like.<\/p>\n<p><a class=\"btn\" href=\"https:\/\/uplastech.com\/ar\/%d8%a7%d9%84%d8%aa%d8%b4%d9%83%d9%8a%d9%84-%d8%a8%d8%a7%d9%84%d8%aa%d9%81%d8%b1%d9%8a%d8%ba\/\">Talk to a thermoforming engineer<\/a>\n<\/div>\n<div class=\"rel\">\n<h4>Continue reading<\/h4>\n<ul>\n<li><a href=\"https:\/\/uplastech.com\/ar\/vacuum-forming-cooling-cycle-time\/\">Cooling and Cycle Time in Vacuum Forming<\/a><\/li>\n<li><a href=\"https:\/\/uplastech.com\/ar\/thick-gauge-vs-thin-gauge-thermoforming\/\">Thick Gauge vs Thin Gauge Thermoforming<\/a><\/li>\n<li><a href=\"https:\/\/uplastech.com\/ar\/pressure-forming-vs-vacuum-forming\/\">Pressure Forming vs Vacuum Forming<\/a><\/li>\n<li><a href=\"https:\/\/uplastech.com\/ar\/spring-back-thermoformed-parts\/\">Spring-Back and Dimensional Control in Thermoformed Parts<\/a><\/li>\n<li><a href=\"https:\/\/uplastech.com\/ar\/vacuum-forming-mold-design\/\">Vacuum Forming Mold Design<\/a><\/li>\n<\/ul>\n<\/div>\n<\/div>","protected":false},"excerpt":{"rendered":"<p>Sheet over 3 mm is not a membrane, it is a structure. Oven sag, pressure forming, wall retention across a deep draw and the cooling that sets the cycle.<\/p>","protected":false},"author":1,"featured_media":7698,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_seopress_titles_title":"Heavy Gauge Thermoforming for Large Enclosures: Sag, Wall an","_seopress_titles_desc":"Sheet over 3 mm is not a membrane, it is a structure. Oven sag, pressure forming, wall retention across a deep draw and the cooling that sets the cycle.","_seopress_robots_index":"","_seopress_robots_follow":"","_seopress_robots_imageindex":"","_seopress_robots_snippet":"","_seopress_robots_primary_cat":"29","_seopress_robots_breadcrumbs":"","_seopress_robots_freeze_modified_date":"","_seopress_robots_custom_modified_date":"","_seopress_robots_canonical":"","_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":"heavy gauge thermoforming enclosures","footnotes":""},"categories":[29],"tags":[],"class_list":["post-7704","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-vacuum-forming"],"meta_box":{"post-to-quiz_to":[]},"_links":{"self":[{"href":"https:\/\/uplastech.com\/ar\/wp-json\/wp\/v2\/posts\/7704","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/uplastech.com\/ar\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/uplastech.com\/ar\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/uplastech.com\/ar\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/uplastech.com\/ar\/wp-json\/wp\/v2\/comments?post=7704"}],"version-history":[{"count":0,"href":"https:\/\/uplastech.com\/ar\/wp-json\/wp\/v2\/posts\/7704\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/uplastech.com\/ar\/wp-json\/wp\/v2\/media\/7698"}],"wp:attachment":[{"href":"https:\/\/uplastech.com\/ar\/wp-json\/wp\/v2\/media?parent=7704"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/uplastech.com\/ar\/wp-json\/wp\/v2\/categories?post=7704"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/uplastech.com\/ar\/wp-json\/wp\/v2\/tags?post=7704"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}