[{"data":1,"prerenderedAt":659},["ShallowReactive",2],{"catalog:meta":3,"guides:page:\u002Finjection-molding-machine-parts\u002Fejector\u002Fejector-cylinder:*":258,"guides:topics:ejector:\u002Finjection-molding-machine-parts\u002Fejector\u002Fejector-cylinder:path,title,short":522,"guides:page:\u002Finjection-molding-machine-parts\u002Fejector:diagram":539,"diagram:id:ejector":540,"catalog:parts::MC-CC-02":650},{"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":494,"diagram":495,"extension":496,"faq":497,"item":510,"lastModified":511,"meta":512,"navigation":513,"order":70,"parts":514,"path":516,"seo":517,"seoTitle":518,"short":519,"stem":520,"__hash__":521},"guides\u002Finjection-molding-machine-parts\u002Fejector\u002Fejector-cylinder.md","Ejector cylinder of an injection molding machine",{"type":262,"value":263,"toc":485},"minimark",[264,268,273,315,319,335,338,351,355,393,397,418,422,452,455,459,473],[265,266,267],"p",{},"The ejector cylinder is the small double-acting hydraulic cylinder mounted on the back of the moving platen of a hydraulic injection molding machine. It drives the ejector: its rod pushes the connecting plate and the ejector rods forward to eject the part, then pulls them back. All-electric machines usually do the same job with a servo motor and a ball screw instead of a cylinder.",[269,270,272],"h2",{"id":271},"how-the-ejector-cylinder-works","How the ejector cylinder works",[274,275,276,280,283,297],"ol",{},[277,278,279],"li",{},"A directional valve sends oil to the rear of the piston. The rod moves forward, pushing the connecting plate and the ejector rods, and the rods move the mold's ejector plate.",[277,281,282],{},"At the set forward position the valve switches, and oil sent to the rod side pulls the piston back.",[277,284,285,286,291,292,296],{},"The ejector speed and force in each direction are set on the controller, which controls them through the machine's valves: see ",[287,288,290],"a",{"href":289},"\u002Finjection-molding-machine-parts\u002Fhydraulics\u002Fdirectional-valve\u002F","directional valves"," and ",[287,293,295],{"href":294},"\u002Finjection-molding-machine-parts\u002Fhydraulics\u002Fproportional-valve\u002F","proportional valves",".",[277,298,299,300,304,305,309,310,314],{},"The position is measured by a ",[287,301,303],{"href":302},"\u002Finjection-molding-machine-parts\u002Felectrical\u002Flinear-transducer\u002F","linear transducer"," on many current machines, or by ",[287,306,308],{"href":307},"\u002Finjection-molding-machine-parts\u002Felectrical\u002Fproximity-sensor\u002F","proximity sensors"," or ",[287,311,313],{"href":312},"\u002Finjection-molding-machine-parts\u002Felectrical\u002Flimit-switch\u002F","limit switches"," at set points on simpler ones. The controller uses it for the stroke settings and to confirm that the ejector is back before the mold closes.",[269,316,318],{"id":317},"variants","Variants",[320,321,322,329],"ul",{},[277,323,324,328],{},[325,326,327],"strong",{},"A single cylinder"," on the center line of the moving platen.",[277,330,331,334],{},[325,332,333],{},"Two or more cylinders"," spaced evenly across the platen, so that a large connecting plate is pushed evenly.",[265,336,337],{},"Which layout a machine uses depends on its make and size: check the machine manual or parts list.",[265,339,340,341,345,346,350],{},"Small cylinders of the same type are also used as clamping boosters or for other auxiliary movements. The ",[287,342,344],{"href":343},"\u002Fparts\u002Fmc-cc-02\u002F","auxiliary cylinder"," we supply is listed for clamping booster or auxiliary ejection use, and the ",[287,347,349],{"href":348},"\u002Finjection-molding-machine-parts\u002Fclamp-cylinder\u002Fauxiliary-cylinder\u002F","auxiliary cylinder page"," covers its other uses.",[269,352,354],{"id":353},"signs-of-a-worn-or-faulty-ejector-cylinder","Signs of a worn or faulty ejector cylinder",[320,356,357,363,369,375,381,387],{},[277,358,359,362],{},[325,360,361],{},"Oil on the back of the platen, the connecting plate or the mold:"," a leaking rod seal or a loose fitting.",[277,364,365,368],{},[325,366,367],{},"Ejector slow or weak"," at the usual settings: internal leakage past worn piston seals, or a valve or pressure problem.",[277,370,371,374],{},[325,372,373],{},"Ejector creeps forward"," when it should stay back: leakage in the cylinder or in the valve that holds it.",[277,376,377,380],{},[325,378,379],{},"Jerky movement:"," air in the cylinder, a sticking valve, or a connecting plate binding on its guide pins.",[277,382,383,386],{},[325,384,385],{},"Position errors or ejector-not-back alarms:"," a faulty transducer or switch, a loose sensor mounting, or a cylinder that does not complete its return.",[277,388,389,392],{},[325,390,391],{},"A scored or pitted rod",", which destroys new rod seals quickly.",[269,394,396],{"id":395},"causes-of-wear","Causes of wear",[320,398,399,406,409,412,415],{},[277,400,401,402,296],{},"Contaminated or degraded oil, which wears the seals and scores the bore: see ",[287,403,405],{"href":404},"\u002Finjection-molding-machine-parts\u002Fhydraulics\u002Fhydraulic-oil\u002F","hydraulic oil",[277,407,408],{},"Side loads from a tilting connecting plate or from ejector rods of different lengths.",[277,410,411],{},"A loose rod connection or loose mounting bolts, which let the cylinder knock at each end of the stroke.",[277,413,414],{},"Heat from the mold and platen, which ages the seals.",[277,416,417],{},"Dirt on the rod, which gets past a damaged wiper.",[269,419,421],{"id":420},"inspecting-and-repairing-the-ejector-cylinder","Inspecting and repairing the ejector cylinder",[274,423,424,427,430,433,436,449],{},[277,425,426],{},"Watch the ejector run at slow speed. Look for leaks, jerks and creep, and compare the stroke time with earlier records.",[277,428,429],{},"Switch off, lock out and release the hydraulic pressure before opening any fitting.",[277,431,432],{},"Check the mounting bolts and the rod connection to the connecting plate.",[277,434,435],{},"Check the rod surface for scoring, pitting and worn chrome.",[277,437,438,439,443,444,448],{},"To reseal, remove the cylinder, take out the piston and rod, and replace the piston seals, rod seals and wiper as a set. The ",[287,440,442],{"href":441},"\u002Finjection-molding-machine-parts\u002Fclamp-cylinder\u002Fcylinder-seal-replacement\u002F","cylinder seal replacement"," page describes the general procedure, and the ",[287,445,447],{"href":446},"\u002Finjection-molding-machine-parts\u002Fclamp-cylinder\u002Frod-seals\u002F","rod seals"," page the seal types.",[277,450,451],{},"Refit the cylinder, bleed the air, and check the stroke and position readings before running with a mold.",[265,453,454],{},"If the bore or the rod is badly scored, a new cylinder is often the better repair.",[269,456,458],{"id":457},"what-to-send-for-a-replacement-quote","What to send for a replacement quote",[274,460,461,464,467,470],{},[277,462,463],{},"The machine brand, model and serial number.",[277,465,466],{},"The cylinder's bore, rod diameter and stroke, from the nameplate or measured.",[277,468,469],{},"The mounting type and bolt pattern, the rod end thread, and the port sizes and positions.",[277,471,472],{},"Photos of the cylinder from several sides, and the OEM part number if you have it.",[265,474,475,479,480,484],{},[287,476,478],{"href":477},"\u002Frequest-quote\u002F","Request a quote",", and see the ",[287,481,483],{"href":482},"\u002Finjection-molding-machine-parts\u002Fejector\u002F","ejector guide"," for how the cylinder works with the rest of the ejector.",{"title":486,"searchDepth":21,"depth":21,"links":487},"",[488,489,490,491,492,493],{"id":271,"depth":21,"text":272},{"id":317,"depth":21,"text":318},{"id":353,"depth":21,"text":354},{"id":395,"depth":21,"text":396},{"id":420,"depth":21,"text":421},{"id":457,"depth":21,"text":458},"How the hydraulic ejector cylinder of an injection molding machine works, its settings and position sensing, signs of worn seals, and what to send for a quote.",null,"md",[498,501,504,507],{"question":499,"answer":500},"What does the ejector cylinder do?","The ejector cylinder is a small hydraulic cylinder on the back of the moving platen. It pushes the connecting plate and ejector rods forward to eject the part from the mold, then pulls them back.",{"question":502,"answer":503},"Why is my ejector creeping forward?","Creeping usually means oil is leaking internally, past worn piston seals or through the valve that should hold the cylinder back. Check the valve and the cylinder seals.",{"question":505,"answer":506},"Why is oil leaking at the ejector?","The most common cause is a worn rod seal or wiper, often after the rod has been scratched. Loose fittings and hoses at the cylinder are the other usual source.",{"question":508,"answer":509},"Do all-electric injection molding machines have an ejector cylinder?","All-electric machines usually drive the ejector with a servo motor and a ball screw instead of a hydraulic cylinder. The connecting plate, ejector rods and mold side work in the same way.","ejector-cylinder","2026-11-01",{},true,[515],"MC-CC-02","\u002Finjection-molding-machine-parts\u002Fejector\u002Fejector-cylinder",{"title":260,"description":494},"Injection Molding Ejector Cylinder: Function and Repair","Ejector cylinder","injection-molding-machine-parts\u002Fejector\u002Fejector-cylinder","MRYhFYq8vt5RpNsG_wwdrJ4l8ms1cXI04JoF0vYH1Oo",[523,527,531,535],{"path":524,"title":525,"short":526},"\u002Finjection-molding-machine-parts\u002Fejector\u002Fejector-rod","Ejector rods of an injection molding machine","Ejector rods",{"path":528,"title":529,"short":530},"\u002Finjection-molding-machine-parts\u002Fejector\u002Fejector-plate","Ejector plate in injection molding","Ejector plate",{"path":532,"title":533,"short":534},"\u002Finjection-molding-machine-parts\u002Fejector\u002Fejector-pins","Ejector pins in injection molding","Ejector pins",{"path":536,"title":537,"short":538},"\u002Finjection-molding-machine-parts\u002Fejector\u002Freturn-springs","Ejector return springs","Return springs",{"diagram":222},{"diagram":541},{"title":542,"description":543,"base":544,"labels":554,"items":559},"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":545,"line":549,"hidden":552},[546,547,548],"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",[550,551],"M140 138L140 84L270 84","M140 202L140 256L270 256",[553],"M414 146h12v48h-12z",[555],{"x":556,"y":557,"text":558},460,90,"MOLD",[560,576,592,604,616,637],{"id":510,"name":519,"role":561,"parts":562,"marker":563,"shapes":567},"Small hydraulic cylinder mounted behind the moving platen. It pushes the ejector plate forward to free the part, then pulls it back.",[515],[564,565,564,566],128,24,138,{"solid":568,"hidden":573},[569,570,571,572],"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",[574,575],"M132 142h10v56h-10z","M142 170L180 170",{"id":577,"name":578,"role":579,"parts":580,"marker":582,"shapes":586},"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.",[581],"MC-ES-09",[583,565,584,585],190,223,96,{"solid":587,"line":589},[588],"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",[590,591],"M200 104L270 104","M200 236L270 236",{"id":593,"name":538,"role":594,"parts":595,"marker":597,"shapes":600},"return-springs","Springs on the guide pins that push the plate back after ejection, so the ejector rods are clear before the mold closes.",[596],"MC-SR-05",[598,565,598,599],244,98,{"line":601},[602,603],"M230 104L234 98L239 110L244 98L249 110L254 98L259 110L264 98L268 104L270 104","M230 236L234 230L239 242L244 230L249 242L254 230L259 242L264 230L268 236L270 236",{"id":605,"name":606,"role":607,"parts":608,"marker":610,"shapes":613},"moving-platen","Moving platen","The ejector rods pass through holes in the moving platen to reach the mold.",[609],"MC-PP-01",[611,565,612,256],296,290,{"solid":614},[615],"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":617,"name":526,"role":618,"parts":619,"marker":621,"shapes":625},"ejector-rods","Hardened rods that carry the ejector force through the platen to the mold’s ejector plate.",[620],"MC-ES-08",[622,565,623,624],340,324,125,{"solid":626,"hidden":630},[627,628,629],"M230 125h40v10h-40z","M230 165h40v10h-40z","M230 205h40v10h-40z",[631,632,633,634,635,636],"M270 125L340 125","M270 135L340 135","M270 165L340 165","M270 175L340 175","M270 205L340 205","M270 215L340 215",{"id":638,"name":639,"role":640,"marker":641,"shapes":645},"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.",[642,565,643,644],384,350,108,{"hidden":646},[647,648,649],"M340 108h14v124h-14z","M354 134L420 134","M354 206L420 206",[651],{"partNumber":515,"name":652,"subcategory":94,"subcategoryName":653,"shortDescription":654,"image":655,"inStock":513,"zone":214,"compatibleMachines":656},"Clamping Cylinder — Small \u002F Auxiliary","Clamping Cylinders","Auxiliary clamping or ejection cylinder for injection molding machine.","\u002Fpart-images\u002FMC\u002FMC-CC-02\u002F423bf4c1-6171-48d3-98d9-06feab16d665.png",[657,658],"Haitian MA Series","Haitian Jupiter Series",1793548979287]