{"id":35397,"date":"2026-03-27T21:20:16","date_gmt":"2026-03-27T13:20:16","guid":{"rendered":"https:\/\/zetarmold.com\/?p=35397"},"modified":"2026-04-14T16:10:58","modified_gmt":"2026-04-14T08:10:58","slug":"sprue-vs-runner","status":"publish","type":"post","link":"https:\/\/zetarmold.com\/fr\/sprue-vs-runner\/","title":{"rendered":"Entonnoir vs Canal d'Alimentation dans le Moulage par Injection"},"content":{"rendered":"<div class=\"callout-key\" style=\"background:#f0f7ff; border-left:4px solid #2563eb; padding:1em 1.2em; border-radius:6px; margin:1.5em 0;\">\n<strong>Principaux enseignements<\/strong><\/p>\n<ul>\n<li>Ligne de s\u00e9paration, embranchement<\/li>\n<li>Runners distribute molten plastic horizontally from the sprue to each gate and cavity.<\/li>\n<li>Cold runner systems generate waste scrap; hot runner systems eliminate sprue and runner waste.<\/li>\n<li>Proper runner balancing ensures uniform fill pressure across all cavities in a multi-cavity mold.<\/li>\n<li>Gate location and runner geometry directly affect part quality, cycle time, and material waste.<\/li>\n<\/ul>\n<\/div>\n<h2>What Is the Difference Between a <a href=\"https:\/\/zetarmold.com\/fr\/carotte-et-glissiere\/\">Tige<\/a><sup id=\"fnref1:1\"><a href=\"#fn:1\" class=\"footnote-ref\">1<\/a><\/sup> and a Runner?<\/h2>\n<p>The sprue is the main vertical channel that connects the injection molding machine nozzle directly to the mold; the runner is the horizontal branching network that distributes melt from the sprue to each individual <a href=\"https:\/\/zetarmold.com\/fr\/quest-ce-que-la-conception-des-canaux-et-des-portes-pour-les-moules-dinjection\/\">porte<\/a><sup id=\"fnref1:3\"><a href=\"#fn:3\" class=\"footnote-ref\">3<\/a><\/sup>. A sprue has a single entry point and a tapered bore (typically 3\u20137 mm diameter), while runners are machined into the mold parting line and branch to feed multiple cavities simultaneously.<\/p>\n<p>In our factory, understanding this distinction is fundamental to gating design. The sprue sets the pressure entry point; the runner balances flow to all cavities; the gate controls fill rate and freeze-off sequence. Errors at any level\u2014oversized sprue, unbalanced runners, or mislocated gates\u2014cascade into part defects ranging from short shots to excessive flash.<\/p>\n<figure style=\"text-align:center;margin:2em 0;\">\n<img decoding=\"async\" src=\"https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/02\/800x457_plastic-injection-molding-diagram.webp\" alt=\"Sprue vs Runner : Guide de Conception et d&#039;Optimisation\" style=\"max-width:100%;height:auto;\" \/><figcaption style=\"font-size:0.78em; color:#888; font-style:italic; margin-top:4px; text-align:center;\">Sprue and runner system layout<\/figcaption><\/figure>\n<h2>What Is a Sprue and How Does It Work?<\/h2>\n<p>Un canal d'attaque est un canal cylindrique conique perc\u00e9 dans la bague d'attaque, situ\u00e9e au centre du moule et align\u00e9e avec la buse de la machine. La conicit\u00e9 (g\u00e9n\u00e9ralement un angle compris de 1\u00b0 \u00e0 3\u00b0) permet \u00e0 la carotte d'attaque solidifi\u00e9e de se lib\u00e9rer lors de l'ouverture du moule. La bague d'attaque est en acier tremp\u00e9, rectifi\u00e9e \u00e0 un rayon correspondant qui s'appuie contre la buse de la machine pour emp\u00eacher les fuites de mati\u00e8re.<\/p>\n<p>During injection, molten plastic enters the sprue at the machine nozzle tip, flows downward through the tapered bore, and enters the <a href=\"https:\/\/zetarmold.com\/fr\/carotte-et-glissiere\/\">syst\u00e8me de coureurs<\/a><sup id=\"fnref1:2\"><a href=\"#fn:2\" class=\"footnote-ref\">2<\/a><\/sup> \u00e0 la base du canal d'attaque. Le canal d'attaque refroidit en dernier dans un syst\u00e8me \u00e0 canaux froids car il a la plus grande section transversale. Cela prolonge le temps de cycle par rapport aux conceptions \u00e0 canaux chauds, o\u00f9 une tubulure chauff\u00e9e remplace enti\u00e8rement le canal d'attaque froid.<\/p>\n<div class=\"claim claim-false\" style=\"background-color: #f7e8e8; border-color: #f7e8e8; color: #8a4a4a;\">\n<p><svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewbox=\"0 0 24 24\" width=\"20\" height=\"20\" fill=\"currentColor\"><path d=\"M19 6.41L17.59 5 12 10.59 6.41 5 5 6.41 10.59 12 5 17.59 6.41 19 12 13.41 17.59 19 19 17.59 13.41 12z\"><\/path><\/svg><b>\u00ab Un canal d'attaque surdimensionn\u00e9 est pr\u00e9f\u00e9rable car il garantit un remplissage complet de l'empreinte. \u00bb<\/b><span class=\"claim-true-or-false\">Faux<\/span><\/p>\n<p class=\"claim-explanation\">An oversized sprue increases material waste and extends cycle time \u2014 the sprue is the last element to solidify in a cold runner system due to its large cross-section. The entrance diameter should be only 1 mm larger than the nozzle orifice. Oversizing adds cooling time every cycle without improving fill quality.<\/p>\n<\/div>\n<div class=\"claim claim-true\" style=\"background-color: #eff7ef; border-color: #eff7ef; color: #5a8a5a;\">\n<p><svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewbox=\"0 0 24 24\" width=\"20\" height=\"20\" fill=\"currentColor\"><path d=\"M9 16.17L4.83 12l-1.42 1.41L9 19 21 7l-1.41-1.41z\"><\/path><\/svg><b>\u00ab Un canal d'attaque correctement dimensionn\u00e9 r\u00e9duit le temps de cycle et minimise le gaspillage de mati\u00e8re. \u00bb<\/b><span class=\"claim-true-or-false\">Vrai<\/span><\/p>\n<p class=\"claim-explanation\">Sizing the sprue entrance 1 mm larger than the nozzle orifice prevents flow restriction while keeping the slug volume small. A proper 1\u00b0\u20133\u00b0 taper ensures clean ejection without sticking in the bushing. These two dimensions \u2014 entrance diameter and taper angle \u2014 are the most critical sprue design parameters.<\/p>\n<\/div>\n<p>Sprue dimensions are critical. An undersized sprue creates high <a href=\"https:\/\/zetarmold.com\/fr\/processus-de-moulage-par-injection-5\/\">pressure drop<\/a><sup id=\"fnref1:4\"><a href=\"#fn:4\" class=\"footnote-ref\">4<\/a><\/sup> and fill restrictions; an oversized sprue increases material waste, extends cycle time, and may create a cosmetic witness mark if the sprue puller pin leaves a scar. In our factory, we size the sprue entrance diameter to be at least 1 mm larger than the machine nozzle orifice to prevent flow restriction while minimizing waste.<\/p>\n<p>The sprue puller pin is a feature opposite the sprue bushing that retains the solidified sprue slug on the ejection side of the mold during opening, ensuring clean separation. Without a properly designed sprue puller, the sprue may stick in the bushing, halting production. Cold slugs from the sprue-nozzle interface are captured by a cold-slug well at the sprue base, preventing cold material from entering the runner and cavities.<\/p>\n<div class=\"claim claim-true\" style=\"background-color: #eff7ef; border-color: #eff7ef; color: #5a8a5a;\">\n<p><svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewbox=\"0 0 24 24\" width=\"20\" height=\"20\" fill=\"currentColor\"><path d=\"M9 16.17L4.83 12l-1.42 1.41L9 19 21 7l-1.41-1.41z\"><\/path><\/svg><b>\u00ab La conicit\u00e9 du canal d'attaque est essentielle pour permettre \u00e0 la carotte solidifi\u00e9e de s'\u00e9jecter proprement de la bague d'attaque. \u00bb<\/b><span class=\"claim-true-or-false\">Vrai<\/span><\/p>\n<p class=\"claim-explanation\">Without taper, the solidified sprue grips the bushing walls by mechanical interference, causing it to stick. A 1\u00b0\u20133\u00b0 draft on the sprue bore provides the release geometry needed for reliable automatic ejection every cycle.<\/p>\n<\/div>\n<div class=\"claim claim-false\" style=\"background-color: #f7e8e8; border-color: #f7e8e8; color: #8a4a4a;\">\n<p><svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewbox=\"0 0 24 24\" width=\"20\" height=\"20\" fill=\"currentColor\"><path d=\"M19 6.41L17.59 5 12 10.59 6.41 5 5 6.41 10.59 12 5 17.59 6.41 19 12 13.41 17.59 19 19 17.59 13.41 12z\"><\/path><\/svg><b>\u00ab Le canal d'attaque doit toujours \u00eatre situ\u00e9 au centre g\u00e9om\u00e9trique du moule. \u00bb<\/b><span class=\"claim-true-or-false\">Faux<\/span><\/p>\n<p class=\"claim-explanation\">L'emplacement du canal d'attaque est d\u00e9termin\u00e9 par l'espacement des barres de serrage de la machine et la position de la buse, et non par le centre g\u00e9om\u00e9trique du moule. Pour les moules \u00e0 entr\u00e9e lat\u00e9rale ou les moules multi-empreintes avec des dispositions asym\u00e9triques, le canal d'attaque peut \u00eatre d\u00e9centr\u00e9 tant qu'il est align\u00e9 avec l'axe de la buse.<\/p>\n<\/div>\n<h2>What Is a Runner System and What Types Exist?<\/h2>\n<p>The runner system is the network of channels machined into the mold parting line (or in a separate runner plate) that carries melt from the sprue base to the gates of each cavity. Runner cross-sections are typically full-round (ideal for flow efficiency), trapezoidal (easy to machine in one mold half), or half-round. Full-round runners have the lowest pressure drop per unit length and are preferred for demanding applications.<\/p>\n<figure style=\"text-align:center;margin:2em 0;\">\n<img decoding=\"async\" src=\"https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/02\/800x457_plastic-injection-molding-gates.webp\" alt=\"Injection mold gate and runner configurations\" style=\"max-width:100%;height:auto;\" \/><figcaption style=\"font-size:0.78em; color:#888; font-style:italic; margin-top:4px; text-align:center;\">Gate and runner configurations<\/figcaption><\/figure>\n<p>Runner systems fall into two primary categories. Cold runner systems keep the runner at ambient mold temperature, allowing the plastic to solidify each cycle and producing runner scrap that must be ground and recycled or discarded. Cold runners are simpler and cheaper to build but generate material waste of 10\u201330% of total shot weight. Hot runner systems maintain the runner at melt temperature using electric heater cartridges and thermocouples, eliminating runner scrap and reducing cycle time by 10\u201330%.<\/p>\n<p>Within cold runner systems, naturally balanced layouts (like H-tree or radial runners) ensure equal runner length from sprue to each gate, producing uniform fill pressure across all cavities. Artificially balanced runners use asymmetric channel diameters to equalize fill despite unequal path lengths. For critical multi-cavity molds, our factory uses Melt Flipper technology or MeltFusion runner balancing to eliminate cavity-to-cavity variation caused by shear-induced melt imbalances.<\/p>\n<p>Runner diameter must be sized based on material flow length, shot weight, and cycle time targets. General guidelines specify runner diameters of 4\u201310 mm for most commodity resins. Undersized runners cause excessive pressure drop, fill imbalance, and degraded surface quality. Oversized runners waste material and increase cycle time. Our <a href=\"https:\/\/zetarmold.com\/fr\/analyse-du-flux-des-moules\/\">analyse du flux des moules<\/a> service optimizes runner diameter, length, and branching geometry to minimize waste while ensuring balanced fill.<\/p>\n<div class=\"claim claim-true\" style=\"background-color: #eff7ef; border-color: #eff7ef; color: #5a8a5a;\">\n<p><svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewbox=\"0 0 24 24\" width=\"20\" height=\"20\" fill=\"currentColor\"><path d=\"M9 16.17L4.83 12l-1.42 1.41L9 19 21 7l-1.41-1.41z\"><\/path><\/svg><b>\u00ab Les syst\u00e8mes \u00e0 canaux chauds \u00e9liminent les d\u00e9chets de canaux et r\u00e9duisent le temps de cycle par rapport aux moules \u00e0 canaux froids. \u00bb<\/b><span class=\"claim-true-or-false\">Vrai<\/span><\/p>\n<p class=\"claim-explanation\">By maintaining the runner at melt temperature, hot runner systems prevent solidification between shots. This eliminates runner material waste entirely and removes the cooling time needed to solidify the runner, reducing cycle time by 10\u201330%.<\/p>\n<\/div>\n<div class=\"claim claim-false\" style=\"background-color: #f7e8e8; border-color: #f7e8e8; color: #8a4a4a;\">\n<p><svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewbox=\"0 0 24 24\" width=\"20\" height=\"20\" fill=\"currentColor\"><path d=\"M19 6.41L17.59 5 12 10.59 6.41 5 5 6.41 10.59 12 5 17.59 6.41 19 12 13.41 17.59 19 19 17.59 13.41 12z\"><\/path><\/svg><b>\u00ab Les syst\u00e8mes \u00e0 canaux chauds sont toujours le meilleur choix pour les moules d'injection multi-empreintes. \u00bb<\/b><span class=\"claim-true-or-false\">Faux<\/span><\/p>\n<p class=\"claim-explanation\">Les syst\u00e8mes \u00e0 canaux chauds ajoutent 5 000 \u00e0 30 000 $ au co\u00fbt de l'outillage et n\u00e9cessitent une maintenance plus complexe. Pour les s\u00e9ries \u00e0 faible volume (&lt; 50 000 pi\u00e8ces), les mat\u00e9riaux sensibles \u00e0 la chaleur, ou les applications o\u00f9 les changements de couleur sont fr\u00e9quents, les syst\u00e8mes \u00e0 canaux froids restent plus \u00e9conomiques et pratiques.<\/p>\n<\/div>\n<h2>How Does the Gate Connect the Runner to the Cavity?<\/h2>\n<p>The gate is the restricted opening at the end of the runner that controls material entry into the cavity. Gate size, location, and type profoundly affect part quality. Typical gate types include edge gates (simple, versatile), submarine gates (self-degating, hidden on part), pin gates (small point entry, used in hot runner systems), fan gates (for wide, flat parts), and film gates (thin film across entire edge for stress-free fill).<\/p>\n<p>Gate sizing follows the rule that gate cross-section should be 50\u201380% of the wall thickness at the gate location. Undersized gates cause jetting, excessive shear heating, and premature freeze-off before the cavity is full. Oversized gates leave visible vestige marks and require longer hold time. Gate location should be at the thickest wall section to ensure fill flows from thick to thin, preventing air entrapment and weld line formation in critical areas.<\/p>\n<figure style=\"text-align:center;margin:2em 0;\">\n<img decoding=\"async\" src=\"https:\/\/zetarmold.com\/wp-content\/uploads\/2026\/02\/800x457_plastic-injection-molding-edge-gate.webp\" alt=\"Edge gate detail on injection mold\" style=\"max-width:100%;height:auto;\" \/><figcaption style=\"font-size:0.78em; color:#888; font-style:italic; margin-top:4px; text-align:center;\">Edge gate cross-section detail<\/figcaption><\/figure>\n<p>In our factory, gate location decisions are validated using <a href=\"https:\/\/zetarmold.com\/fr\/analyse-du-flux-des-moules\/\">analyse du flux des moules<\/a> before mold cutting. Simulation identifies weld line positions, air trap locations, and fill pressure distribution for proposed gate positions. By comparing alternatives in simulation, we optimize gate placement to minimize weld lines on structural features and eliminate air traps that would otherwise require manual venting operations.<\/p>\n<h2>Sprue vs Runner vs Gate: Key Comparison<\/h2>\n<table style=\"width:100%;border-collapse:collapse;margin:1.5em 0;\">\n<caption style=\"font-weight:bold;margin-bottom:0.5em;\">Sprue, Runner, and Gate Comparison<\/caption>\n<thead>\n<tr>\n<th style=\"border:1px solid #ddd;padding:8px;background:#f5f5f5;\">Fonctionnalit\u00e9<\/th>\n<th style=\"border:1px solid #ddd;padding:8px;background:#f5f5f5;\">Tige<\/th>\n<th style=\"border:1px solid #ddd;padding:8px;background:#f5f5f5;\">Coureur<\/th>\n<th style=\"border:1px solid #ddd;padding:8px;background:#f5f5f5;\">Portail<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td style=\"border:1px solid #ddd;padding:8px;\">Localisation<\/td>\n<td style=\"border:1px solid #ddd;padding:8px;\">Vertical, center of mold<\/td>\n<td style=\"border:1px solid #ddd;padding:8px;\">Parting line, branching<\/td>\n<td style=\"border:1px solid #ddd;padding:8px;\">La perte de charge est une r\u00e9duction de la pression de fusion mesur\u00e9e en bar ou MPa qui se produit lorsque le plastique fondu s'\u00e9coule \u00e0 travers le syst\u00e8me d'attaque, de canal et d'entr\u00e9e pendant l'injection.<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #ddd;padding:8px;\">Cross-section<\/td>\n<td style=\"border:1px solid #ddd;padding:8px;\">Tapered cylinder, 3\u20137 mm<\/td>\n<td style=\"border:1px solid #ddd;padding:8px;\">Round\/trap, 4\u201310 mm<\/td>\n<td style=\"border:1px solid #ddd;padding:8px;\">0.5\u20133 mm typical<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #ddd;padding:8px;\">Fonction<\/td>\n<td style=\"border:1px solid #ddd;padding:8px;\">Entry from machine nozzle<\/td>\n<td style=\"border:1px solid #ddd;padding:8px;\">Distributes melt to gates<\/td>\n<td style=\"border:1px solid #ddd;padding:8px;\">Controls fill rate<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #ddd;padding:8px;\">Waste in cold system<\/td>\n<td style=\"border:1px solid #ddd;padding:8px;\">Sprue slug (significant)<\/td>\n<td style=\"border:1px solid #ddd;padding:8px;\">Runner scrap (10\u201330%)<\/td>\n<td style=\"border:1px solid #ddd;padding:8px;\">Gate vestige (small)<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #ddd;padding:8px;\">Hot variant<\/td>\n<td style=\"border:1px solid #ddd;padding:8px;\">Heated sprue bushing<\/td>\n<td style=\"border:1px solid #ddd;padding:8px;\">Hot runner manifold<\/td>\n<td style=\"border:1px solid #ddd;padding:8px;\">Hot tip or valve gate<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #ddd;padding:8px;\">Defect if undersized<\/td>\n<td style=\"border:1px solid #ddd;padding:8px;\">Fill restriction, slow cycle<\/td>\n<td style=\"border:1px solid #ddd;padding:8px;\">Pressure drop, imbalance<\/td>\n<td style=\"border:1px solid #ddd;padding:8px;\">Jetting, short shot<\/td>\n<\/tr>\n<tr>\n<td style=\"border:1px solid #ddd;padding:8px;\">Defect if oversized<\/td>\n<td style=\"border:1px solid #ddd;padding:8px;\">Long cycle, large slug<\/td>\n<td style=\"border:1px solid #ddd;padding:8px;\">Excessive waste<\/td>\n<td style=\"border:1px solid #ddd;padding:8px;\">Visible vestige mark<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>The table above clarifies that while sprue, runner, and gate all serve the purpose of delivering melt to cavities, each operates at a different scale and with different design priorities. Sprue design is driven by machine compatibility; runner design by cavity balance and material efficiency; gate design by part aesthetics, structural requirements, and fill dynamics.<\/p>\n<h2>How Does the Injection Molding Process Flow Through Sprue and Runner?<\/h2>\n<p>During injection, the sequence is: machine nozzle \u2192 sprue \u2192 primary runner \u2192 secondary runner \u2192 gate \u2192 cavity. Melt enters at 200\u2013400\u00b0C and 500\u20132,000 bar injection pressure. Pressure drops at each transition: approximately 10\u201330% through the sprue, 20\u201340% through the runner, and 20\u201350% through the gate. The remaining cavity fill pressure must be sufficient to pack the cavity and compensate for shrinkage during solidification.<\/p>\n<div class=\"claim claim-false\" style=\"background-color: #f7e8e8; border-color: #f7e8e8; color: #8a4a4a;\">\n<p><svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewbox=\"0 0 24 24\" width=\"20\" height=\"20\" fill=\"currentColor\"><path d=\"M19 6.41L17.59 5 12 10.59 6.41 5 5 6.41 10.59 12 5 17.59 6.41 19 12 13.41 17.59 19 19 17.59 13.41 12z\"><\/path><\/svg><b>\u00ab Les pertes de charge \u00e0 travers le canal d'attaque, le canal et l'orifice d'entr\u00e9e sont n\u00e9gligeables en moulage par injection. \u00bb<\/b><span class=\"claim-true-or-false\">Faux<\/span><\/p>\n<p class=\"claim-explanation\">Pressure drops are substantial at every transition: roughly 10\u201330% through the sprue, 20\u201340% through the runner, and 20\u201350% through the gate. Ignoring them leads to undersized injection pressure, incomplete cavity fill, and flash. Each element must be sized to keep the cumulative drop within machine capacity.<\/p>\n<\/div>\n<div class=\"claim claim-true\" style=\"background-color: #eff7ef; border-color: #eff7ef; color: #5a8a5a;\">\n<p><svg xmlns=\"http:\/\/www.w3.org\/2000\/svg\" viewbox=\"0 0 24 24\" width=\"20\" height=\"20\" fill=\"currentColor\"><path d=\"M9 16.17L4.83 12l-1.42 1.41L9 19 21 7l-1.41-1.41z\"><\/path><\/svg><b>\u00ab L'\u00e9quilibrage de la perte de charge \u00e0 travers le canal d'attaque, le canal et l'orifice d'entr\u00e9e est essentiel pour obtenir des pi\u00e8ces sans d\u00e9fauts. \u00bb<\/b><span class=\"claim-true-or-false\">Vrai<\/span><\/p>\n<p class=\"claim-explanation\">Melt enters at 200\u2013400 \u00b0C and 500\u20132,000 bar. Every transition consumes pressure. The remaining cavity pressure must pack the part and offset shrinkage. Mold flow simulation maps the full pressure gradient before tooling is cut, allowing engineers to right-size the sprue, balance runners, and confirm gate locations produce uniform fill.<\/p>\n<\/div>\n<p>Le <a href=\"https:\/\/zetarmold.com\/fr\/processus-de-moulage-par-injection-de-plastique-4\/\">processus de moulage par injection<\/a> cycle integrates sprue and runner cooling into overall cycle time optimization. In cold runner molds, the sprue is typically the last element to solidify due to its large cross-section. Cycle time cannot advance to ejection until the sprue is frozen enough to demold cleanly. This constraint motivates hot runner adoption for high-volume molds where cycle time directly drives cost.<\/p>\n<h2>Questions fr\u00e9quemment pos\u00e9es<\/h2>\n<h3>What is the difference between a sprue and a runner in injection molding?<\/h3>\n<p>Le canal d'attaque est le canal vertical unique qui relie la buse de la machine d'injection au syst\u00e8me de canaux du moule. Il est conique pour l'\u00e9jection et align\u00e9 avec l'axe central de la machine. Le canal est le r\u00e9seau de distribution horizontal usin\u00e9 dans le plan de joint qui distribue la mati\u00e8re fondue depuis la base du canal d'attaque vers chaque orifice d'entr\u00e9e. La diff\u00e9rence cl\u00e9 r\u00e9side dans la fonction et l'orientation : le canal d'attaque est le point d'entr\u00e9e et est toujours unique ; le canal se ramifie et \u00e9quilibre l'\u00e9coulement vers plusieurs orifices d'entr\u00e9e. Dans les syst\u00e8mes \u00e0 canaux chauds, le canal d'attaque est remplac\u00e9 par une bague d'attaque chauff\u00e9e et les canaux par une tubulure chauff\u00e9e, \u00e9liminant ainsi compl\u00e8tement les d\u00e9chets de solidification.<\/p>\n<h3>Why does a cold runner system produce waste material?<\/h3>\n<p>Dans un syst\u00e8me \u00e0 canaux froids, la temp\u00e9rature du moule est maintenue en dessous de la temp\u00e9rature de solidification du plastique. \u00c0 chaque cycle d'injection, la mati\u00e8re fondue dans le canal d'attaque et le r\u00e9seau de canaux se solidifie avec les pi\u00e8ces. Lorsque le moule s'ouvre, la carotte d'attaque et les d\u00e9chets de canaux s'\u00e9jectent attach\u00e9s aux pi\u00e8ces et doivent \u00eatre s\u00e9par\u00e9s manuellement ou automatiquement. Ces d\u00e9chets de canaux repr\u00e9sentent 10 \u00e0 30 % du poids total de l'injection. Bien que le broyage et le recyclage des d\u00e9chets soient possibles pour certains mat\u00e9riaux, de multiples cycles de retraitement d\u00e9gradent les propri\u00e9t\u00e9s m\u00e9caniques. Les syst\u00e8mes \u00e0 canaux chauds r\u00e9solvent ce probl\u00e8me en maintenant le plastique dans les canaux \u00e0 l'\u00e9tat fondu en permanence, \u00e9liminant ainsi compl\u00e8tement les d\u00e9chets.<\/p>\n<h3>How is runner balance achieved in a multi-cavity mold?<\/h3>\n<p>Runner balance ensures that molten plastic arrives at every gate simultaneously and at equal pressure, so all cavities fill at the same rate. Natural balance uses geometrically symmetric runner layouts (H-tree or radial) where every path from sprue to gate has identical length and cross-section. Artificial balance uses different runner diameters to equalize flow resistance when symmetric geometry is not possible. Advanced methods use Melt Flipper inserts or flow analysis to correct shear-induced imbalances where the inside and outside layers of melt enter alternating branches at different temperatures and viscosities. Our factory validates runner balance via mold flow simulation before cutting tooling.<\/p>\n<h3>When should a hot runner system be used instead of a cold runner?<\/h3>\n<p>Hot runner systems are justified when: (1) production volume exceeds 100,000 parts and runner scrap material cost is significant; (2) cycle time reduction of 10\u201330% provides competitive advantage; (3) the material is heat-sensitive and repeated solidification\/remelting degrades its properties; (4) color consistency is critical and runner-induced color mixing must be eliminated; (5) part aesthetics prohibit gate vestiges that cold sub-gates would leave. Conversely, cold runners are preferred for low volumes, frequent color or material changes, and when the added $5,000\u2013$30,000 tooling cost of a hot runner cannot be recovered within the production run.<\/p>\n<h3>What is a sprue bushing and why is it important?<\/h3>\n<p>La bague d'attaque est un composant en acier tremp\u00e9 install\u00e9 au centre du moule qui abrite le canal d'attaque et fournit une surface d'appui de pr\u00e9cision pour la buse de la machine d'injection. Son rayon sph\u00e9rique doit correspondre au rayon de l'extr\u00e9mit\u00e9 de la buse \u00e0 \u00b10,5 mm pr\u00e8s pour \u00e9viter les fuites de mati\u00e8re, les bavures et les dommages \u00e0 la buse. La bague d'attaque est soumise \u00e0 la plus grande contrainte de cyclage thermique dans le moule, car la buse entre en contact avec elle et s'en retire \u00e0 chaque cycle. Les bagues d'attaque tremp\u00e9es et nitrur\u00e9es durent des millions de cycles, tandis que les non tremp\u00e9es s'usent rapidement. L'ajustement correct du rayon entre la buse et la bague est l'une des v\u00e9rifications de r\u00e9glage les plus courantes que nos techniciens effectuent lors de l'installation du moule.<\/p>\n<h3>How does gate location affect part quality in injection molding?<\/h3>\n<p>Gate location determines where melt enters the cavity and therefore controls weld line positions, air trap locations, orientation of polymer chains (affecting anisotropic shrinkage), and surface appearance. Gates near structural features minimize weld lines through those features. Gates at thick sections allow melt to flow from thick to thin, preventing premature freeze-off. Gates on non-cosmetic surfaces (hidden flanges, bottom faces) avoid visible gate vestiges on appearance surfaces. Poor gate location causes: weld lines at high-stress areas (reducing strength by 10\u201330%), air traps requiring manual venting, differential shrinkage causing warping, and jetting streaks when gate is undersized or misaligned. Mold flow simulation validates gate location before tooling.<\/p>\n<hr style=\"margin:2em 0;border:none;border-top:1px solid #e0e0e0;\" \/>\n<ol class=\"footnotes\">\n<li id=\"fn:1\">\n<p><strong>sprue:<\/strong> Sprue is a cylindrical channel in an injection mold that connects the machine nozzle to the runner system, allowing molten plastic to flow from the barrel into the mold. <a href=\"#fnref1:1\" class=\"footnote-backref\">\u21a9<\/a><\/p>\n<\/li>\n<li id=\"fn:2\">\n<p><strong>runner system:<\/strong> Runner system refers to the network of channels in an injection mold that distributes molten plastic from the sprue to the individual gate locations feeding each cavity. <a href=\"#fnref1:2\" class=\"footnote-backref\">\u21a9<\/a><\/p>\n<\/li>\n<li id=\"fn:3\">\n<p><strong>gate:<\/strong> Gate is a restricted opening in an injection mold that connects the runner to the mold cavity, controlling the flow rate, direction, and freeze-off of molten plastic. <a href=\"#fnref1:3\" class=\"footnote-backref\">\u21a9<\/a><\/p>\n<\/li>\n<li id=\"fn:4\">\n<p><strong>pressure drop:<\/strong> Pressure drop is a reduction in melt pressure measured in bar or MPa that occurs as molten plastic flows through the sprue, runner, and gate system during injection. <a href=\"#fnref1:4\" class=\"footnote-backref\">\u21a9<\/a><\/p>\n<\/li>\n<\/ol>","protected":false},"excerpt":{"rendered":"<p>Points Cl\u00e9s  \nLe canal de coul\u00e9e est le conduit vertical principal reliant la buse de la machine au syst\u00e8me d\u2019alimentation.  \nLes canaux d\u2019alimentation distribuent horizontalement la mati\u00e8re plastique fondue du canal de coul\u00e9e vers chaque orifice d\u2019entr\u00e9e et cavit\u00e9.  \nLes syst\u00e8mes \u00e0 canaux froids g\u00e9n\u00e8rent des d\u00e9chets de rebut ; les syst\u00e8mes \u00e0 canaux chauds \u00e9liminent les d\u00e9chets de canal de coul\u00e9e et d\u2019alimentation.  \nUn \u00e9quilibrage correct des canaux assure une pression de remplissage uniforme dans toutes les cavit\u00e9s de [\u2026]<\/p>","protected":false},"author":1,"featured_media":53145,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_seopress_robots_primary_cat":"none","_seopress_titles_title":"Sprue vs Runner: Design & Optimization Guide","_seopress_titles_desc":"Guide to sprue and runner design in injection molding, including cold vs hot runners, gate flow, runner balance, and ways to reduce waste.","_seopress_robots_index":"","_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[43],"tags":[162,164,159,160,163],"meta_box":{"post-to-quiz_to":[]},"_links":{"self":[{"href":"https:\/\/zetarmold.com\/fr\/wp-json\/wp\/v2\/posts\/35397"}],"collection":[{"href":"https:\/\/zetarmold.com\/fr\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/zetarmold.com\/fr\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/zetarmold.com\/fr\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/zetarmold.com\/fr\/wp-json\/wp\/v2\/comments?post=35397"}],"version-history":[{"count":0,"href":"https:\/\/zetarmold.com\/fr\/wp-json\/wp\/v2\/posts\/35397\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/zetarmold.com\/fr\/wp-json\/wp\/v2\/media\/53145"}],"wp:attachment":[{"href":"https:\/\/zetarmold.com\/fr\/wp-json\/wp\/v2\/media?parent=35397"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/zetarmold.com\/fr\/wp-json\/wp\/v2\/categories?post=35397"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/zetarmold.com\/fr\/wp-json\/wp\/v2\/tags?post=35397"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}