{"id":2410,"date":"2026-06-30T08:59:01","date_gmt":"2026-06-30T08:59:01","guid":{"rendered":"https:\/\/hydrauliccylindersprice.com\/product\/injection-molding-machine-ejection-cylinder\/"},"modified":"2026-06-30T08:59:17","modified_gmt":"2026-06-30T08:59:17","slug":"injection-molding-machine-ejection-cylinder","status":"publish","type":"product","link":"https:\/\/hydrauliccylindersprice.com\/ja\/product\/injection-molding-machine-ejection-cylinder\/","title":{"rendered":"Injection Molding Machine Ejection Cylinder"},"content":{"rendered":"

<\/p>\n

<\/p>\n

\n
\n
\n Injection Molding Machine<\/span>
\n Ejection Cylinder<\/span>\n <\/div>\n

The Last 600 mm
That the Customer Sees<\/h2>\n

The shooting cylinder docks. The injection ram fills the mould. The plastic cools. The mould opens. And then the ejection cylinder pushes the finished part out \u2014 the only cylinder in the injection moulding machine whose performance is directly visible on the product itself. Every ejector pin mark on a phone case, every warped edge on a dashboard panel, and every stuck part that halts the production line is a consequence of how this cylinder delivers its 600 mm of stroke.<\/p>\n

\n
\n
760 KN<\/div>\n
Max Thrust<\/div>\n<\/div>\n
\n
90\u2013220mm<\/span><\/div>\n
Bore (Largest)<\/div>\n<\/div>\n
\n
10MPa<\/span><\/div>\n
Lowest Pressure<\/div>\n<\/div>\n
\n
\u2264600mm<\/span><\/div>\n
Stroke<\/div>\n<\/div><\/div>\n<\/p><\/div>\n<\/section>\n

<\/p>\n

\n

How Ejection Works \u2014 One Cylinder, Many Pins, One Chance<\/h2>\n

After the mould opens, the plastic part remains stuck in the mould cavity \u2014 held in place by friction, vacuum suction, and the part’s slight contraction around cavity features. The ejection cylinder pushes a steel ejector plate mounted behind the mould cavity. The ejector plate carries 4\u201350 ejector pins (depending on part size and complexity), each positioned to contact the plastic part at a specific point. When the cylinder extends, all pins advance simultaneously through holes in the cavity face, pushing the part out of the cavity and clear of the mould.<\/p>\n

The ejection stroke is the only moment in the entire injection moulding cycle when a mechanical component physically pushes against the finished product. Every other phase (injection, packing, cooling) involves liquid or heat transfer \u2014 only ejection involves direct mechanical force on the solidified part. If the force is wrong, the speed is wrong, or the timing is wrong, the part is damaged. Korea Ever-Power manufactures ejection cylinders as part of the injection moulding machine cylinder family<\/a>.<\/p>\n

\"Injection
\n<\/section>\n

<\/p>\n

\n

Technical Specifications<\/h2>\n
\n\n\n\n\n\n\n\n\n\n\n\n\n
Parameter<\/th>\nValue<\/th>\n<\/tr>\n<\/thead>\n
Product<\/td>\nInjection Molding Machine Ejection Cylinder<\/td>\n<\/tr>\n
Function<\/td>\nEject the moulded product via ejector plate and pins<\/td>\n<\/tr>\n
Bore Diameter<\/td>\n90 mm \u2013 220 mm<\/td>\n<\/tr>\n
Rod Diameter<\/td>\n50 mm \u2013 140 mm<\/td>\n<\/tr>\n
Stroke<\/td>\n\u2264 600 mm<\/td>\n<\/tr>\n
Maximum Thrust<\/td>\n760 KN (bore 220 mm \/ pressure 10 MPa)<\/td>\n<\/tr>\n
Working Pressure<\/td>\nUp to 10 MPa (lowest in family \u2014 by design)<\/td>\n<\/tr>\n
Certification<\/td>\nISO 9001 \u00b7 100% hydrostatic tested<\/td>\n<\/tr>\n<\/tbody>\n<\/table><\/div>\n<\/section>\n

<\/p>\n

\n

10 MPa \u2014 Why the Lowest Pressure Protects the Product<\/h2>\n
\n \"Ejection<\/p>\n

The shooting cylinder (#24) operates at 25 MPa. The mold opening cylinder operates at similar pressures. But the ejection cylinder uses only 10 MPa \u2014 by design, not by limitation. The reason is the product itself.<\/p>\n

At the moment of ejection, the plastic part has just solidified \u2014 it is cool enough to hold its shape but still warm enough to be pliable. Excess ejection force at this stage pushes the ejector pins into the warm plastic, leaving visible dents (ejector pin marks) or, in severe cases, punching through thin wall sections. On cosmetic surfaces (visible faces of consumer products), pin marks are a reject-level defect. On structural parts, excessive ejection force can distort ribs, bosses, or snap-fit features while they are still below full strength.<\/p>\n

The large bore (90\u2013220 mm) at low pressure (10 MPa) provides ample force capacity (up to 760 KN) while keeping the system pressure low enough that the machine operator’s pressure adjustment has fine resolution \u2014 small pressure changes produce small force changes, giving precise control over the ejection force applied to delicate parts.<\/p>\n<\/p><\/div>\n

<\/div>\n<\/section>\n

<\/p>\n

\n
\n

Three-Phase Ejection Speed \u2014 Break, Clear, Decelerate<\/h2>\n

The ejection stroke is not a single-speed push. The optimal ejection uses three distinct speed phases \u2014 each serving a different purpose and requiring different cylinder behaviour:<\/p>\n

\n
\n Phase 1: Break-free (slow, 0\u20135 mm)<\/strong><\/p>\n

The part is stuck to the cavity wall by friction, vacuum, and contraction. The initial push must break all adhesion points simultaneously \u2014 which requires high force at very low speed. A fast start tears the part at the weakest adhesion point instead of releasing it uniformly, causing warpage. The cylinder must deliver maximum force at minimum velocity \u2014 slow, steady, even pressure build-up.<\/p>\n<\/p><\/div>\n

\n Phase 2: Clear (fast, 5\u2013580 mm)<\/strong><\/p>\n

Once the part is free from the cavity, the pins push it out rapidly \u2014 the faster, the better for cycle time. The part is no longer touching the cavity walls, so force is minimal (just the weight of the part and the friction of the ejector pins in their guide holes). This phase is speed-limited, not force-limited.<\/p>\n<\/p><\/div>\n

\n Phase 3: Decelerate (580\u2013600 mm)<\/strong><\/p>\n

The ejector plate must stop smoothly at the end of stroke \u2014 not slam into the mechanical stop. Hard impact at the end of every ejection stroke (thousands per day) fatigues the ejector plate, the return pins, and the cylinder cushion. Korea Ever-Power calibrates the end-of-stroke cushion for the specific ejector plate mass and ejection speed.<\/p>\n<\/p><\/div>\n<\/p><\/div>\n

This three-phase speed profile is achieved through the machine’s proportional valve \u2014 the ejection cylinder must respond smoothly to the valve’s flow commands across the full speed range, from the slow break-free crawl to the fast clearing sweep. Contact the hydraulic cylinder engineering team<\/a> for ejection speed profile specifications.<\/p>\n<\/p><\/div>\n<\/section>\n

<\/p>\n

\n

Four Ways Ejection Fails \u2014 And What the Cylinder Can Prevent<\/h2>\n
\n
\n Pin marks (cosmetic defect)<\/strong><\/p>\n

Visible dents or shiny spots where the ejector pins contacted the part. Caused by: excessive ejection force, insufficient cooling time (part too soft at ejection), or pins with too-small contact area. The cylinder’s adjustable pressure setting lets the operator reduce ejection force to the minimum needed \u2014 eliminating pin marks without risking sticking.<\/p>\n<\/p><\/div>\n

\n Warpage (dimensional defect)<\/strong><\/p>\n

The part bends or twists during ejection because the ejection force is applied unevenly \u2014 some pins push harder than others due to unequal friction on different parts of the cavity. The ejection cylinder must deliver uniform force to all points of the ejector plate simultaneously \u2014 which requires a centred rod connection and a rigid plate to distribute the force evenly to all pins.<\/p>\n<\/p><\/div>\n

\n Sticking (production stop)<\/strong><\/p>\n

The part does not release from the cavity \u2014 the ejection force is insufficient to overcome adhesion, vacuum, or undercut interference. The machine alarms and stops. An operator must manually remove the stuck part. Each stuck-part event costs 1\u20135 minutes of production time. The cylinder must provide enough force reserve to handle the occasional difficult ejection without operating at maximum force (which would cause pin marks on normal parts).<\/p>\n<\/p><\/div>\n

\n Short shot ejection (scrap creation)<\/strong><\/p>\n

If the injection was incomplete (a “short shot”), the partially filled part has thin, weak sections that break during ejection \u2014 leaving fragments inside the mould that block the next cycle. The cylinder’s slow break-free phase helps detect stuck fragments (unusual resistance during the initial push triggers an alarm) before the fast phase drives a broken part into the cavity.<\/p>\n<\/p><\/div>\n<\/p><\/div>\n<\/section>\n

<\/p>\n

\n \"Ejection
\n<\/section>\n

<\/p>\n

\n

Manufacturing<\/h2>\n

\"Korea<\/p>\n

The ejection cylinder’s bore (90\u2013220 mm) is honed to Ra 0.2\u20130.4 \u00b5m \u2014 the Korea Ever-Power standard for consistent, low-friction motion. The rod is chrome plated at 30\u201350 \u00b5m (clean environment specification). Seals are standard NBR or polyurethane selected for low breakaway friction \u2014 the slow break-free phase demands that the cylinder starts moving smoothly at very low speed without stiction (stick-slip). The end-of-stroke cushion is calibrated for the ejector plate mass and maximum ejection speed. Every ejection cylinder is hydrostatic tested at 1.5\u00d7 working pressure (15 MPa) and functionally tested for smooth low-speed start and full-speed extend with cushion deceleration verification.<\/p>\n<\/section>\n

<\/p>\n

\n

OEM & ODM<\/h2>\n
\n
\n
\n

What You Provide<\/h3>\n<\/div>\n
\n

Maximum ejection force (KN), ejector plate mass, stroke (determined by the deepest cavity feature that the pins must clear), ejection speed (cycles per minute), mounting geometry (central mounting behind the moving platen), system hydraulic pressure, and the mould platen drawing. Optionally combined with the shooting, mold opening\/closing, and mold shifting cylinders for the complete injection moulding machine hydraulic set.<\/p>\n<\/div><\/div>\n

\n
\n

What the Factory Delivers<\/h3>\n<\/div>\n
\n

Engineering drawing with bore (sized for required ejection force at 10 MPa), rod, stroke, low-friction seal specification (for smooth break-free phase), end-of-stroke cushion calibration, and mounting dimensions. Hydrostatic test + low-speed functional test with cushion verification. Seal kits. Browse the complete injection moulding machine cylinder family<\/a>.<\/p>\n<\/div><\/div>\n<\/p><\/div>\n<\/section>\n

<\/p>\n

\n

FAQ<\/h2>\n
\n
\n

Why is the ejection cylinder bore larger than the shooting cylinder?<\/h3>\n

Because the ejection cylinder operates at lower pressure (10 MPa vs 25 MPa for the shooting cylinder<\/a>). To produce adequate ejection force at this lower pressure, the bore must be larger \u2014 the piston area compensates for the lower pressure. The lower pressure provides finer force adjustment resolution, which protects part quality.<\/p>\n<\/p><\/div>\n

\n

Can the ejection cylinder perform multiple ejection strokes per cycle?<\/h3>\n

Yes \u2014 some parts require a “double eject” or “vibrate eject” pattern where the cylinder extends partially, retracts, then extends again. This rocking motion helps release parts with slight undercuts or high-friction surfaces that a single push cannot free. The machine controller commands the multi-stroke pattern; the cylinder must reverse direction quickly and smoothly at each partial stroke. Korea Ever-Power designs the cushion and seal specification to accommodate multi-stroke ejection duty.<\/p>\n<\/p><\/div>\n

\n

How does the ejection cylinder return to the retracted position?<\/h3>\n

The ejection cylinder retracts hydraulically (double-acting \u2014 pressure applied to the rod side). The ejector plate has mechanical return pins that physically push it back as the mould closes \u2014 providing a redundant return mechanism. Both the hydraulic retraction and the mechanical return pins must bring the ejector plate to the exact same retracted position every cycle, so the pins do not protrude into the cavity during the next injection. Consistent retraction is verified during Korea Ever-Power’s factory functional test. Browse the full hydraulic cylinder product range<\/a> including forklift cylinders<\/a> and telescopic cylinders<\/a>.<\/p>\n<\/p><\/div>\n<\/p><\/div>\n<\/section>\n

<\/p>\n

\n

Related Categories<\/h2>\n
\n <\/p>\n
\n
\"Telescopic\"<\/div>\n
\n
Telescopic Hydraulic Cylinders \u2192<\/div>\n
Dump truck, trailer, hoist.<\/div>\n<\/div>\n<\/div>\n

<\/a>
\n <\/p>\n

\n
\"Forklift\"<\/div>\n
\n
Forklift Hydraulic Cylinders \u2192<\/div>\n
Lift, tilt, steer \u2014 OEM.<\/div>\n<\/div>\n<\/div>\n

<\/a>
\n <\/p>\n

\n
\"AWV\"<\/div>\n
\n
Aerial Work Vehicle Cylinders \u2192<\/div>\n
Scissor, boom, platforms.<\/div>\n<\/div>\n<\/div>\n

<\/a>\n <\/div>\n<\/section>\n

<\/main><\/p>","protected":false},"excerpt":{"rendered":"

Injection molding machine ejection cylinder \u2014 the actuator that pushes the ejector plate forward after the mould opens, driving the ejector pins that push the finished plastic part out of the mould cavity. This is the cylinder whose output the customer actually sees \u2014 every ejector pin mark, every warpage from excessive force, and every stuck part from insufficient force is a direct consequence of how this cylinder performs. Bore 90\u2013220 mm (the largest in the injection moulding family), stroke \u2264600 mm, thrust 760 KN at only 10 MPa \u2014 the lowest pressure in the family, because the part is still warm and pliable during ejection, and excess force deforms it. Korea Ever-Power. ISO 9001. OEM & ODM.<\/div>","protected":false},"featured_media":2411,"comment_status":"closed","ping_status":"open","template":"","meta":{"_et_pb_use_builder":"","_et_pb_old_content":"","_et_gb_content_width":""},"product_brand":[],"product_cat":[852],"product_tag":[],"class_list":["post-2410","product","type-product","status-publish","has-post-thumbnail","product_cat-industrial-engineering-hydraulic-cylinders","pa_editor-cxm","first","instock","product-type-simple"],"_links":{"self":[{"href":"https:\/\/hydrauliccylindersprice.com\/ja\/wp-json\/wp\/v2\/product\/2410","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/hydrauliccylindersprice.com\/ja\/wp-json\/wp\/v2\/product"}],"about":[{"href":"https:\/\/hydrauliccylindersprice.com\/ja\/wp-json\/wp\/v2\/types\/product"}],"replies":[{"embeddable":true,"href":"https:\/\/hydrauliccylindersprice.com\/ja\/wp-json\/wp\/v2\/comments?post=2410"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/hydrauliccylindersprice.com\/ja\/wp-json\/wp\/v2\/media\/2411"}],"wp:attachment":[{"href":"https:\/\/hydrauliccylindersprice.com\/ja\/wp-json\/wp\/v2\/media?parent=2410"}],"wp:term":[{"taxonomy":"product_brand","embeddable":true,"href":"https:\/\/hydrauliccylindersprice.com\/ja\/wp-json\/wp\/v2\/product_brand?post=2410"},{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/hydrauliccylindersprice.com\/ja\/wp-json\/wp\/v2\/product_cat?post=2410"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/hydrauliccylindersprice.com\/ja\/wp-json\/wp\/v2\/product_tag?post=2410"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}