{"id":2412,"date":"2026-06-30T08:59:20","date_gmt":"2026-06-30T08:59:20","guid":{"rendered":"https:\/\/hydrauliccylindersprice.com\/product\/injection-molding-machine-mold-opening-and-closing-cylinder\/"},"modified":"2026-06-30T08:59:21","modified_gmt":"2026-06-30T08:59:21","slug":"injection-molding-machine-mold-opening-and-closing-cylinder","status":"publish","type":"product","link":"https:\/\/hydrauliccylindersprice.com\/ja\/product\/injection-molding-machine-mold-opening-and-closing-cylinder\/","title":{"rendered":"Injection Molding Machine Mold Opening and Closing Cylinder"},"content":{"rendered":"

<\/p>\n

<\/p>\n

\n
\n
\n Injection Molding Machine<\/span>
\n Mold Opening & Closing Cylinder<\/span>\n <\/div>\n

Open Fast.
Close Carefully.
Protect the Mold.<\/h2>\n

A precision injection mold costs $50,000 to $500,000 or more. The mold opening and closing cylinder moves the moving platen that carries half of this investment \u2014 opening the mold to release the part, then closing it for the next shot. Closing sounds simple. It is not. A stuck part, a fallen fragment, or a misaligned core pin between the mold halves will be crushed when the mold closes \u2014 destroying cavity surfaces that took weeks to machine. The closing phase must detect any obstruction and stop before damage occurs.<\/p>\n

\n
\n
384 KN<\/div>\n
Max Thrust<\/div>\n<\/div>\n
\n
50\u2013140mm<\/span><\/div>\n
Bore<\/div>\n<\/div>\n
\n
\u2264700mm<\/span><\/div>\n
Stroke<\/div>\n<\/div>\n
\n
25MPa<\/span><\/div>\n
Working Pressure<\/div>\n<\/div><\/div>\n<\/p><\/div>\n<\/section>\n

<\/p>\n

\n

Two Opposite Motions, Two Different Engineering Problems<\/h2>\n

The cylinder performs two opposite motions every cycle \u2014 and each places different demands on the hydraulic circuit and the cylinder’s response characteristics:<\/p>\n

\n
\n
\n

Opening \u2014 Break Apart and Clear<\/h3>\n<\/div>\n
\n

The mold halves are locked together under hundreds of tonnes of clamping force. The opening cylinder must first break the mold halves apart (overcoming the residual clamping force and any vacuum between the mold faces), then retract the moving platen to full-open position as fast as possible. The initial break-open force is the highest force the cylinder produces. Once the halves separate, the retraction force drops to the platen’s mass and rail friction \u2014 and the speed should increase to minimise cycle time. The part either stays on the core (to be ejected by the ejection cylinder<\/a>) or falls free by gravity.<\/p>\n<\/p><\/div>\n<\/p><\/div>\n

\n
\n

Closing \u2014 Three Phases, One Chance<\/h3>\n<\/div>\n
\n

Closing is the dangerous motion. The cylinder advances the moving platen through three distinct phases: fast traverse (full speed, low pressure \u2014 covering 80% of the stroke in minimum time), slow approach (reduced speed, reduced pressure \u2014 the “mold protection” zone where the machine detects any resistance that shouldn’t be there), and final close (full pressure \u2014 seating the mold halves together and engaging the clamping lock-up). If the slow approach detects unexpected resistance, the machine stops and reverses \u2014 before the mold is damaged.<\/p>\n<\/p><\/div>\n<\/p><\/div>\n<\/p><\/div>\n

Korea Ever-Power manufactures the mold opening and closing cylinder with proportional-valve-compatible port sizing and low-friction seals that respond smoothly across the full speed range \u2014 from the fast traverse to the slow mold-protection crawl. Browse the complete injection moulding machine cylinder family<\/a>.<\/p>\n<\/section>\n

<\/p>\n

\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 Mold Opening and Closing Cylinder<\/td>\n<\/tr>\n
Function<\/td>\nTraverse the moving platen \u2014 open and close the mold<\/td>\n<\/tr>\n
Bore Diameter<\/td>\n50 mm \u2013 140 mm<\/td>\n<\/tr>\n
Rod Diameter<\/td>\n28 mm \u2013 100 mm<\/td>\n<\/tr>\n
Stroke<\/td>\n\u2264 700 mm<\/td>\n<\/tr>\n
Maximum Thrust<\/td>\n384 KN (bore 140 mm \/ pressure 25 MPa)<\/td>\n<\/tr>\n
Working Pressure<\/td>\nUp to 25 MPa<\/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
\n

Mold Protection \u2014 The $500,000 Reason for Slow Closing<\/h2>\n

Mold protection is the most important function of the mold opening\/closing cylinder \u2014 more important than speed, more important than force. Here is what it prevents:<\/p>\n

\n
\n Stuck part between mold halves<\/strong><\/p>\n

If the ejection cylinder failed to push a part out completely, it hangs between the mold halves. Closing the mold at full speed and pressure crushes the part into the cavity surface \u2014 imprinting its shape into the polished cavity steel. Repairing the cavity requires re-machining, re-polishing, and possibly re-plating \u2014 weeks of mold shop time and $10,000\u2013$100,000 in repair cost. The mold protection phase detects the 2\u20135 mm of resistance that the stuck part creates and stops the close before impact.<\/p>\n<\/p><\/div>\n

\n Debris on the mold face<\/strong><\/p>\n

A metal chip from a runner cut, a fragment of flash, or even a dropped tool can land on the mold face between cycles. Closing on this debris indents the cavity surface \u2014 a permanent defect that prints onto every part until the mold is repaired. The mold protection phase runs at low pressure \u2014 if the cylinder encounters any resistance beyond the expected platen friction, the machine stops.<\/p>\n<\/p><\/div>\n

\n Misaligned core pin or slide<\/strong><\/p>\n

Complex molds have moving cores and slides that must retract before the mold closes. If a core pin fails to retract, the mold half closes onto it \u2014 bending or breaking the pin and potentially cracking the cavity block. The mold protection phase gives the machine controller time to verify all core and slide positions before committing to full closing force. Contact the hydraulic cylinder engineering team<\/a> for mold protection specifications.<\/p>\n<\/p><\/div>\n<\/p><\/div>\n<\/p><\/div>\n<\/section>\n

<\/p>\n

\n

Three-Phase Closing \u2014 Fast, Slow, Lock<\/h2>\n
\n \"Three-phase<\/p>\n

Phase 1 \u2014 Fast traverse (0\u201380% of stroke).<\/strong> The moving platen advances at maximum speed, covering most of the open gap in minimum time. Hydraulic pressure is moderate \u2014 just enough to overcome the platen mass and rail friction. This phase determines the “dry cycle time” (the minimum time for the machine to open, eject, and close without any injection) \u2014 faster traverse = more parts per hour.<\/p>\n

Phase 2 \u2014 Mold protection (80\u201398% of stroke).<\/strong> The cylinder slows to a crawl \u2014 typically 5\u201320 mm\/second. The hydraulic pressure drops to a low, adjustable value (the “mold protection pressure”). At this low pressure, even a small obstruction \u2014 a stuck part, a chip, a core pin \u2014 generates enough resistance to stop the platen. The machine controller monitors the platen position; if it does not reach the “mold closed” position within the expected time window, it alarms and reverses.<\/p>\n

Phase 3 \u2014 Final lock-up (last 2%).<\/strong> The mold halves touch. The cylinder builds to full system pressure to seat the halves together, compress the mold parting line, and \u2014 on toggle-clamp machines \u2014 drive the toggle to its over-centre locked position. The clamping force (which is much larger than the cylinder’s traverse force) is then held by the toggle lock or by a separate high-pressure clamp circuit.<\/p>\n<\/p><\/div>\n

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

<\/p>\n

\n

Two Machine Architectures \u2014 One Cylinder, Different Roles<\/h2>\n
\n \"Toggle<\/p>\n

Toggle-clamp machines.<\/strong> The mold opening\/closing cylinder drives a toggle linkage \u2014 a system of hinged arms that amplifies the cylinder’s force at the end of travel. The cylinder provides the traverse motion (opening and closing the toggle arms); the toggle’s over-centre geometry provides the clamping force (typically 5\u201310\u00d7 the cylinder’s thrust). The cylinder is relatively small (50\u2013100 mm bore) because it only needs to drive the toggle \u2014 the toggle does the heavy clamping.<\/p>\n

Direct-hydraulic-clamp machines.<\/strong> No toggle \u2014 the cylinder provides both the traverse motion and the clamping force directly. The cylinder bore is larger (100\u2013140 mm range) because it must produce the full clamping force without mechanical advantage. Some designs use a separate high-pressure short-stroke “booster” cylinder for the final clamping force, with the opening\/closing cylinder providing the long-stroke traverse only.<\/p>\n

Korea Ever-Power manufactures the mold opening\/closing cylinder for both architectures \u2014 with the bore diameter, rod diameter, and stroke matched to the specific machine’s toggle geometry or direct-clamp force requirement. The 50\u2013140 mm bore range covers small to mid-sized injection moulding machines across both architectures.<\/p>\n<\/p><\/div>\n

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

<\/p>\n

\n \"Mold
\n<\/section>\n

<\/p>\n

\n

Manufacturing<\/h2>\n

\"Korea<\/p>\n

The mold opening\/closing cylinder must transition smoothly from fast traverse to the slow mold-protection crawl without stiction or jerky motion. If the cylinder sticks at the start of the slow phase, the platen jumps forward \u2014 potentially bypassing the mold protection zone entirely. Korea Ever-Power specifies low-friction seals (polyurethane piston seal, PTFE-bronze rod seal) to minimise the difference between static and dynamic friction, ensuring smooth speed transitions at all flow rates. The bore is honed to Ra 0.2\u20130.4 \u00b5m. Chrome plating is 30\u201350 \u00b5m (clean environment). Every cylinder is hydrostatic tested at 1.5\u00d7 working pressure and functionally tested for smooth speed transition from full speed to the mold-protection crawl speed \u2014 verifying that the cylinder responds proportionally without stick-slip at the critical transition point.<\/p>\n<\/section>\n

<\/p>\n

\n

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

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

Machine clamping architecture (toggle or direct), platen mass, required traverse speed (open and close), mold protection zone length and speed, maximum force (break-open and close), stroke, system pressure, toggle geometry (if applicable \u2014 link lengths, pivot positions), and the platen\/tie-bar assembly drawing showing cylinder mounting positions.<\/p>\n<\/div><\/div>\n

\n
\n

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

Engineering drawing with bore, rod, stroke, low-friction seal specification, port sizing (for proportional valve compatibility at the required traverse and mold-protection speeds), and mounting dimensions. Hydrostatic test + speed-transition functional test. 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

Does this cylinder provide the clamping force that holds the mold closed during injection?<\/h3>\n

On toggle machines: indirectly \u2014 the cylinder drives the toggle to its over-centre position, and the toggle geometry provides the mechanical clamping force (which is much larger than the cylinder’s thrust). On direct-clamp machines: yes \u2014 the cylinder (or a combination of this cylinder plus a short-stroke booster) provides the clamping force directly. Korea Ever-Power sizes the bore diameter based on which architecture the machine uses \u2014 toggle machines need less cylinder force because the toggle amplifies it.<\/p>\n<\/p><\/div>\n

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How fast should the mold protection zone be?<\/h3>\n

Typically 5\u201320 mm\/second, covering the last 20\u201350 mm of closing travel. Slower = safer (more time for the controller to detect resistance and stop) but slower = longer cycle time. The optimum balance depends on the mold’s value, the part’s complexity (how likely a stuck part is), and the production volume (higher volume justifies more aggressive cycle times). The cylinder must respond smoothly at these very low speeds \u2014 any stick-slip can be misinterpreted by the controller as an obstruction, causing false stops.<\/p>\n<\/p><\/div>\n

\n

How does this cylinder coordinate with the ejection and shooting cylinders?<\/h3>\n

Through the machine controller’s sequencing logic: the mold must be fully open (confirmed by the opening\/closing cylinder’s position sensor) before the ejection cylinder<\/a> extends. The mold must be fully closed (confirmed by the same sensor or a toggle lock sensor) before the shooting cylinder<\/a> advances the nozzle. These interlocks prevent the ejector pins from extending into an open mold area (safety risk) or the nozzle from docking to an unclamped mold (injection blowout risk). Browse the full hydraulic cylinder product range<\/a>.<\/p>\n<\/p><\/div>\n<\/p><\/div>\n<\/section>\n

<\/p>\n

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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 mold opening and closing cylinder \u2014 the traverse actuator that moves the moving platen along the machine tie bars to open and close the mold. Opening requires speed and moderate force to break the part free from the cavity side. Closing requires a three-phase approach: fast traverse (to save cycle time), slow approach (to detect obstructions), and final lock-up (to seat the mold halves precisely). The slow-approach “mold protection” phase is the most critical \u2014 if the mold closes on a stuck part or debris, the mold is damaged. A precision injection mold costs $50,000\u2013$500,000+. The opening\/closing cylinder is the actuator that protects that investment. Bore 50\u2013140 mm, stroke \u2264700 mm, 25 MPa, 384 KN. Korea Ever-Power. ISO 9001. OEM & ODM.<\/div>","protected":false},"featured_media":2413,"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-2412","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\/2412","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=2412"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/hydrauliccylindersprice.com\/ja\/wp-json\/wp\/v2\/media\/2413"}],"wp:attachment":[{"href":"https:\/\/hydrauliccylindersprice.com\/ja\/wp-json\/wp\/v2\/media?parent=2412"}],"wp:term":[{"taxonomy":"product_brand","embeddable":true,"href":"https:\/\/hydrauliccylindersprice.com\/ja\/wp-json\/wp\/v2\/product_brand?post=2412"},{"taxonomy":"product_cat","embeddable":true,"href":"https:\/\/hydrauliccylindersprice.com\/ja\/wp-json\/wp\/v2\/product_cat?post=2412"},{"taxonomy":"product_tag","embeddable":true,"href":"https:\/\/hydrauliccylindersprice.com\/ja\/wp-json\/wp\/v2\/product_tag?post=2412"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}