[{"data":1,"prerenderedAt":579},["ShallowReactive",2],{"catalog:meta":3,"guides:page:\u002Finjection-molding-machine-parts\u002Fejector\u002Fejector-rod:*":258,"guides:topics:ejector:\u002Finjection-molding-machine-parts\u002Fejector\u002Fejector-rod:path,title,short":443,"guides:page:\u002Finjection-molding-machine-parts\u002Fejector:diagram":460,"diagram:id:ejector":461,"catalog:parts::MC-ES-08":571},{"categories":4,"machines":132,"zones":212,"totals":255},[5,35,59,122],{"id":6,"name":7,"slug":8,"description":9,"partCount":10,"subcategories":11},"EC","Electrical Components","electrical","Electrical systems and components for injection molding machines including heaters, thermocouples, servo motors, and controllers.",11,[12,17,22,27,31],{"id":13,"name":14,"slug":15,"partCount":16},"EC-CBC","Circuit Boards & Controllers","circuit-boards",4,{"id":18,"name":19,"slug":20,"partCount":21},"EC-CE","Connectors & Cables","connectors-cables",2,{"id":23,"name":24,"slug":25,"partCount":26},"EC-GEP","Servo Motors & Drives","servo-motors",1,{"id":28,"name":29,"slug":30,"partCount":21},"EC-HT","Heaters","heaters",{"id":32,"name":33,"slug":34,"partCount":21},"EC-SF","Safety Components","safety",{"id":36,"name":37,"slug":38,"description":39,"partCount":40,"subcategories":41},"HY","Hydraulic Components","hydraulic","Complete range of hydraulic system components including pumps, valves, motors, and pressure controls for injection molding machines.",14,[42,46,51,55],{"id":43,"name":44,"slug":45,"partCount":26},"HY-AU","Accumulators","accumulators",{"id":47,"name":48,"slug":49,"partCount":50},"HY-CV","Control Valves","control-valves",6,{"id":52,"name":53,"slug":54,"partCount":26},"HY-MO","Monitors & Gauges","monitors-gauges",{"id":56,"name":57,"slug":58,"partCount":50},"HY-PW","Pumps & Motors","pumps-motors",{"id":60,"name":61,"slug":62,"description":63,"partCount":64,"subcategories":65},"MC","Mechanical Components","mechanical","Mechanical parts and assemblies including barrels, screws, tie bars, bushings, platens, and clamping components.",42,[66,71,75,80,85,89,93,97,101,105,109,114,118],{"id":67,"name":68,"slug":69,"partCount":70},"MC-BC","Barrels & Cylinders","barrels-cylinders",5,{"id":72,"name":73,"slug":74,"partCount":16},"MC-SB","Screw Barrels & Seals","screws",{"id":76,"name":77,"slug":78,"partCount":79},"MC-TC","Tie Bars & Columns","tie-bars",7,{"id":81,"name":82,"slug":83,"partCount":84},"MC-GZ","Bushings & Guides","bushings-guides",8,{"id":86,"name":87,"slug":88,"partCount":26},"MC-PP","Platens","platens",{"id":90,"name":91,"slug":92,"partCount":70},"MC-TL","Toggle & Links","toggle-links",{"id":94,"name":95,"slug":96,"partCount":21},"MC-CC","Clamping Components","clamping",{"id":98,"name":99,"slug":100,"partCount":21},"MC-GMP","Tools & Accessories","tools-accessories",{"id":102,"name":103,"slug":104,"partCount":21},"MC-ES","End Caps & Plates","end-caps",{"id":106,"name":107,"slug":108,"partCount":26},"MC-SR","Seals & Rings","seals-rings",{"id":110,"name":111,"slug":112,"partCount":113},"MC-JM","Joints & Mounts","joints-mounts",3,{"id":115,"name":116,"slug":117,"partCount":26},"MC-SG","Safety Guards","safety-guards",{"id":119,"name":120,"slug":121,"partCount":26},"MC-CR","Clamping Mechanism","clamping-mechanism",{"id":123,"name":124,"slug":125,"description":126,"partCount":113,"subcategories":127},"O","Other Components","other","Additional components including filters, cooling systems, lubrication parts, and other auxiliary equipment.",[128],{"id":129,"name":130,"slug":131,"partCount":113},"O-TC","Filters & Cooling","filters-cooling",[133,143,161,172,180,188,194,200,205],{"id":134,"name":135,"slug":134,"series":136,"partCount":142},"haitian","Haitian International",[137,138,139,140,141],"Mars Series (MA)","Jupiter Series (JU)","Zhafir Venus Series (VE)","Zhafir Zeres Series (ZE)","Zhafir Jeres Series (JE)",68,{"id":144,"name":145,"slug":144,"series":146,"partCount":160},"yizumi","Yizumi",[147,148,149,150,151,152,153,154,155,156,157,158,159],"A6 Series","A5-EU Series","A5-N Series","SKIII Series","DP Series","D1 Series","FF Series","FF-M Series","P Series","CG-P Series","VM Series","SPET Series","LSR Series",12,{"id":162,"name":163,"slug":162,"series":164,"partCount":171},"chen-hsong","Chen Hsong",[165,166,167,168,169,170],"JETMASTER MK Series","JETMASTER SVP Series","SUPERMASTER Series","EASYMASTER Series","SPARK Series","JETMASTER C2 Series",10,{"id":173,"name":174,"slug":173,"series":175,"partCount":179},"tederic","Tederic",[176,177,178],"NEO Series","D Series (Two-Platen)","DE Series (All-Electric)",0,{"id":181,"name":182,"slug":181,"series":183,"partCount":179},"borch","Borch",[184,185,186,187],"BU Series (Two-Platen)","BS-III Series (Servo)","BE Series (All-Electric)","BM Series (Multi-color)",{"id":189,"name":190,"slug":189,"series":191,"partCount":179},"log-machine","LOG Machine",[192,193],"LOG-SE Series","LOG-EE Series (All-Electric)",{"id":195,"name":196,"slug":195,"series":197,"partCount":179},"donghua","Donghua",[198,199],"DH Series (Servo)","DH-TP Series (Two-Platen)",{"id":201,"name":202,"slug":201,"series":203,"partCount":179},"sunbun","Sunbun",[204],"Sunbun Servo Series",{"id":206,"name":207,"slug":206,"series":208,"partCount":179},"lijin","L.K. Machinery (Lijin)",[209,210,211],"POTENZA Series","FORZA Series (Two-Platen)","ELETTRICA Series (All-Electric)",[213,217,221,225,228,231,235,238,242,248,251],{"id":214,"number":26,"name":215,"role":216,"partCount":21},"clamp-cylinder","Clamping cylinder","The hydraulic cylinder behind the rear platen. It drives the crosshead that straightens the toggle links, which opens and closes the mold and builds the clamping force.",{"id":218,"number":21,"name":219,"role":220,"partCount":50},"toggle","Toggle mechanism","Links, pins and bushings between the rear and moving platens. They multiply the force of the clamping cylinder and lock the mold shut while plastic is injected.",{"id":222,"number":113,"name":223,"role":224,"partCount":113},"ejector","Ejector","A small cylinder behind the moving platen that pushes the ejector rods and plate forward to release the finished part from the mold.",{"id":78,"number":16,"name":226,"role":227,"partCount":40},"Tie bars & bushings","Four steel columns that join the platens, guide the moving platen and carry the clamping force. Tie bar nuts lock them in place; bushings guide the moving platen along them.",{"id":88,"number":70,"name":229,"role":230,"partCount":21},"Platens & mold plates","The fixed and moving platens carry the two halves of the mold; the rear platen anchors the toggle. Locating rings and clamping plates center and hold the mold.",{"id":232,"number":50,"name":233,"role":234,"partCount":50},"barrel-screw","Barrel, screw & nozzle","The screw turns inside the heated barrel to melt and mix the plastic, then moves forward to inject it through the nozzle into the mold. The screw tip and check ring stop melt from flowing back.",{"id":30,"number":79,"name":236,"role":237,"partCount":113},"Heater bands & sensors","Heater bands around the barrel and nozzle melt the plastic. Thermocouples measure each heating zone so the controller can hold the set temperature.",{"id":239,"number":84,"name":240,"role":241,"partCount":79},"injection-unit","Injection unit","Injection cylinders push the screw forward, the hydraulic (plasticizing) motor turns it, and the carriage moves the unit against the mold on its guide rails.",{"id":243,"number":244,"name":245,"role":246,"partCount":247},"hydraulics",9,"Hydraulic unit","The pump, motor, valves, accumulator, filters and oil cooler in the machine base. They supply and control the oil pressure for every movement of the machine.",16,{"id":8,"number":171,"name":249,"role":250,"partCount":244},"Electrical cabinet","The controller, I\u002FO and drive boards, servo drives, contactors and safety switches that run and protect the machine.",{"id":252,"number":10,"name":253,"role":254,"partCount":21},"feet","Machine feet","Leveling bolts and anti-vibration pads under the machine base that keep the machine level and stop vibration spreading to the floor.",{"parts":256,"subcategories":257},70,23,{"id":259,"title":260,"body":261,"description":415,"diagram":416,"extension":417,"faq":418,"item":431,"lastModified":432,"meta":433,"navigation":434,"order":26,"parts":435,"path":437,"seo":438,"seoTitle":439,"short":440,"stem":441,"__hash__":442},"guides\u002Finjection-molding-machine-parts\u002Fejector\u002Fejector-rod.md","Ejector rods of an injection molding machine",{"type":262,"value":263,"toc":406},"minimark",[264,268,273,282,286,303,306,310,313,328,332,349,352,356,376,384,388],[265,266,267],"p",{},"An injection molding machine ejector rod, also called a knock-out rod or KO rod, is the hardened steel rod that carries the ejector force from the machine to the mold. One end screws into the ejector's connecting plate behind the moving platen; the rod passes through a hole in the moving platen, and its other end pushes the mold's ejector plate. When the ejector cylinder moves the connecting plate forward, the rods move the mold's plate, and its ejector pins push the part out.",[269,270,272],"h2",{"id":271},"where-the-ejector-rods-sit","Where the ejector rods sit",[265,274,275,276,281],{},"The moving platen has a center bore and a pattern of extra ejector holes around it. A small mold may use only the central rod; a larger mold, or one with a long ejector plate, uses several rods so that the plate is pushed at several points and moves square. The mold design decides which holes are used: the mold's clamping plate has matching holes through which the rods reach the mold's ejector plate. The platen's hole pattern is shown on the machine's platen drawing; see the ",[277,278,280],"a",{"href":279},"\u002Finjection-molding-machine-parts\u002Fplatens\u002F","platens guide",".",[269,283,285],{"id":284},"coupled-and-uncoupled-ejector-rods","Coupled and uncoupled ejector rods",[287,288,289,297],"ul",{},[290,291,292,296],"li",{},[293,294,295],"strong",{},"Uncoupled (push only)."," The rods only push. After ejection they pull back, and the mold's ejector plate is returned by the mold's own return springs and, at the latest, by its return pins when the mold closes.",[290,298,299,302],{},[293,300,301],{},"Coupled."," The rod ends are screwed into the mold's ejector plate, directly or through adapters, or locked to it with a quick coupling. The machine then pulls the plate back as well as pushing it forward. Coupling is needed when the pins must be fully back before the mold closes, for example where they sit under slides, and it is often used when the ejector makes several strokes per cycle.",[265,304,305],{},"A coupled mold must be uncoupled before it is taken out of the machine, and the ejector settings must suit the coupled mold.",[269,307,309],{"id":308},"setting-the-rod-length","Setting the rod length",[265,311,312],{},"The rod length decides where the mold's ejector plate sits at both ends of the stroke:",[314,315,316,319,322,325],"ol",{},[290,317,318],{},"With the machine's ejector fully back, the rod ends must not push the mold's ejector plate forward. On an uncoupled mold they should sit at or just behind the platen face, so the mold sits flat and its plate can return fully.",[290,320,321],{},"With the ejector fully forward, the rods must move the plate through the travel the mold needs, but never beyond its stops. Set the ejector forward position on the controller to suit the mold.",[290,323,324],{},"All the rods used on one mold must be the same length, so the plate is pushed square. One long rod tilts the plate, and the pins bind or break.",[290,326,327],{},"Screw each rod fully into the connecting plate, and lock it if the design has a lock nut, so it cannot unscrew.",[269,329,331],{"id":330},"signs-of-wear-or-failure","Signs of wear or failure",[287,333,334,337,340,343,346],{},[290,335,336],{},"A rod that drags or scrapes in its platen hole, or score marks along its surface: the rod is bent, or the hole has a burr.",[290,338,339],{},"Damaged or stretched threads, or a rod that keeps unscrewing.",[290,341,342],{},"A burred or mushroomed end where the rod meets the mold's plate.",[290,344,345],{},"Rods of different lengths in the same set, often after a mold change with mixed rods.",[290,347,348],{},"A broken rod, usually at the thread.",[265,350,351],{},"Common causes are ejecting with the mold closed or blocked, a stroke set longer than the mold allows, rods that were not tightened, a tilted plate that bends the rods sideways, and too much ejector force.",[269,353,355],{"id":354},"inspecting-and-replacing-ejector-rods","Inspecting and replacing ejector rods",[314,357,358,361,364,367,370,373],{},[290,359,360],{},"Retract the ejector, then switch off and lock out the machine.",[290,362,363],{},"Unscrew the rods from the connecting plate and clean them.",[290,365,366],{},"Roll each rod on a flat surface, or turn it between centers under a dial indicator, to see whether it is bent.",[290,368,369],{},"Inspect the threads and the ends, and measure the rods of each set to check that they are the same length.",[290,371,372],{},"Clean the platen holes and remove any burrs.",[290,374,375],{},"Fit straight rods of the right length, tighten them fully, and run the ejector slowly with the mold to check the stroke before production.",[265,377,378,379,383],{},"The ",[277,380,382],{"href":381},"\u002Fparts\u002Fmc-es-08\u002F","ejector rods"," we supply are ground and hardened, in 45# or 42CrMo steel, with the diameter made to suit the machine.",[269,385,387],{"id":386},"what-to-send-for-a-replacement-quote","What to send for a replacement quote",[265,389,390,391,395,396,400,401,405],{},"Send the machine brand, model and serial number; the rod length and diameter; the thread size and pitch at each end and whether it is male or female; the shape of the push end; how many rods you need; and a photo. ",[277,392,394],{"href":393},"\u002Frequest-quote\u002F","Request a quote",", and see the ",[277,397,399],{"href":398},"\u002Finjection-molding-machine-parts\u002Fejector\u002F","ejector guide"," and the ",[277,402,404],{"href":403},"\u002Finjection-molding-machine-parts\u002Fejector\u002Fejector-plate\u002F","ejector plate"," page for the rest of the system.",{"title":407,"searchDepth":21,"depth":21,"links":408},"",[409,410,411,412,413,414],{"id":271,"depth":21,"text":272},{"id":284,"depth":21,"text":285},{"id":308,"depth":21,"text":309},{"id":330,"depth":21,"text":331},{"id":354,"depth":21,"text":355},{"id":386,"depth":21,"text":387},"What the ejector rods of an injection molding machine do, coupled and uncoupled rods, how to set rod length for a mold, signs of bent or loose rods, and replacement.",null,"md",[419,422,425,428],{"question":420,"answer":421},"What is an ejector rod on an injection molding machine?","An ejector rod, or knock-out rod, is a hardened steel rod that passes through the moving platen and carries the force of the machine's ejector to the mold's ejector plate.",{"question":423,"answer":424},"How long should ejector rods be?","Long enough to move the mold's ejector plate through its full travel, but not so long that they push the plate forward when the machine's ejector is fully back. All rods used on one mold must be the same length.",{"question":426,"answer":427},"What is the difference between coupled and uncoupled ejector rods?","Uncoupled rods only push the mold's ejector plate, and the mold's return pins and springs bring it back. Coupled rods are screwed or locked into the plate, so the machine also pulls it back.",{"question":429,"answer":430},"Why do ejector rods bend or break?","Usually because the ejector was driven against a closed or blocked mold, the stroke was set longer than the mold allows, or the plate was pushed off square by rods of different lengths.","ejector-rods","2026-10-31",{},true,[436],"MC-ES-08","\u002Finjection-molding-machine-parts\u002Fejector\u002Fejector-rod",{"title":260,"description":415},"Injection Molding Machine Ejector Rod: Length, Fit and Wear","Ejector rods","injection-molding-machine-parts\u002Fejector\u002Fejector-rod","JnaMXI8aSJhQdV8g5qHnkgLc4NcE829-hHxXox9dPNk",[444,448,452,456],{"path":445,"title":446,"short":447},"\u002Finjection-molding-machine-parts\u002Fejector\u002Fejector-plate","Ejector plate in injection molding","Ejector plate",{"path":449,"title":450,"short":451},"\u002Finjection-molding-machine-parts\u002Fejector\u002Fejector-pins","Ejector pins in injection molding","Ejector pins",{"path":453,"title":454,"short":455},"\u002Finjection-molding-machine-parts\u002Fejector\u002Freturn-springs","Ejector return springs","Return springs",{"path":457,"title":458,"short":459},"\u002Finjection-molding-machine-parts\u002Fejector\u002Fejector-cylinder","Ejector cylinder of an injection molding machine","Ejector cylinder",{"diagram":222},{"diagram":462},{"title":463,"description":464,"base":465,"labels":475,"items":480},"Parts of the ejector","Side view of the ejector system: ejector cylinder, connecting plate and pins, return springs, moving platen, ejector rods and the mold ejector plate, numbered.",{"solid":466,"line":470,"hidden":473},[467,468,469],"M310 96h110v148h-110z","M420 96h80v148h-80z","M502 70h26a2 2 0 0 1 2 2v216a2 2 0 0 1 -2 2h-26a2 2 0 0 1 -2 -2v-216a2 2 0 0 1 2 -2z",[471,472],"M140 138L140 84L270 84","M140 202L140 256L270 256",[474],"M414 146h12v48h-12z",[476],{"x":477,"y":478,"text":479},460,90,"MOLD",[481,499,515,527,539,558],{"id":482,"name":459,"role":483,"parts":484,"marker":486,"shapes":490},"ejector-cylinder","Small hydraulic cylinder mounted behind the moving platen. It pushes the ejector plate forward to free the part, then pulls it back.",[485],"MC-CC-02",[487,488,487,489],128,24,138,{"solid":491,"hidden":496},[492,493,494,495],"M93 138h84a3 3 0 0 1 3 3v58a3 3 0 0 1 -3 3h-84a3 3 0 0 1 -3 -3v-58a3 3 0 0 1 3 -3z","M104 128h10v10h-10z","M152 128h10v10h-10z","M180 163h36v14h-36z",[497,498],"M132 142h10v56h-10z","M142 170L180 170",{"id":500,"name":501,"role":502,"parts":503,"marker":505,"shapes":509},"connecting-plate","Connecting plate and pins","Plate that joins the cylinder rod to the ejector rods so they all move together. Guide pins through it keep it square.",[504],"MC-ES-09",[506,488,507,508],190,223,96,{"solid":510,"line":512},[511],"M218 96h10a2 2 0 0 1 2 2v144a2 2 0 0 1 -2 2h-10a2 2 0 0 1 -2 -2v-144a2 2 0 0 1 2 -2z",[513,514],"M200 104L270 104","M200 236L270 236",{"id":516,"name":455,"role":517,"parts":518,"marker":520,"shapes":523},"return-springs","Springs on the guide pins that push the plate back after ejection, so the ejector rods are clear before the mold closes.",[519],"MC-SR-05",[521,488,521,522],244,98,{"line":524},[525,526],"M230 104L234 98L239 110L244 98L249 110L254 98L259 110L264 98L268 104L270 104","M230 236L234 230L239 242L244 230L249 242L254 230L259 242L264 230L268 236L270 236",{"id":528,"name":529,"role":530,"parts":531,"marker":533,"shapes":536},"moving-platen","Moving platen","The ejector rods pass through holes in the moving platen to reach the mold.",[532],"MC-PP-01",[534,488,535,256],296,290,{"solid":537},[538],"M272 70h36a2 2 0 0 1 2 2v216a2 2 0 0 1 -2 2h-36a2 2 0 0 1 -2 -2v-216a2 2 0 0 1 2 -2z",{"id":431,"name":440,"role":540,"parts":541,"marker":542,"shapes":546},"Hardened rods that carry the ejector force through the platen to the mold’s ejector plate.",[436],[543,488,544,545],340,324,125,{"solid":547,"hidden":551},[548,549,550],"M230 125h40v10h-40z","M230 165h40v10h-40z","M230 205h40v10h-40z",[552,553,554,555,556,557],"M270 125L340 125","M270 135L340 135","M270 165L340 165","M270 175L340 175","M270 205L340 205","M270 215L340 215",{"id":559,"name":560,"role":561,"marker":562,"shapes":566},"mold-ejector","Mold ejector plate and pins","Part of the mold, not the machine: the plate carries the pins that push the molded part off the core.",[563,488,564,565],384,350,108,{"hidden":567},[568,569,570],"M340 108h14v124h-14z","M354 134L420 134","M354 206L420 206",[572],{"partNumber":436,"name":573,"subcategory":102,"subcategoryName":574,"shortDescription":575,"inStock":434,"zone":222,"compatibleMachines":576},"Ejector Rod","Ejector System","Machine ejector rod for injection molding machine ejector system.",[577,578],"Haitian MA Series","Haitian MA II Series",1793548979120]