The Complete Used Injection Molding Machine Buying Guide

An injection molding machine melts plastic granules and injects them under pressure into a mould. Almost every moulded plastic object — closures, housings, crates, bumpers — comes off one. A new machine is a two-to-four month lead time and a capital decision; a good used machine of the same tonnage is a fraction of the price and can be in your plant within weeks.

Used machines reach the market three ways, and the route matters more than most buyers realise:

• Upgrade retirements. A working factory replaces a machine that still runs, usually to gain servo efficiency or a bigger clamp. These are normally the best-maintained machines on the market, because someone was depending on them last week.
• Plant closures and relocations. Whole-shop liquidations. Condition varies enormously and machines may have sat idle for months — long enough for seals to dry out and hydraulic oil to absorb water.
• Lease returns. Well documented, often with a service history, but frequently high-hour.

Two levels of preparation are sold. An as-is machine is cleaned, tested and sold as it stands. A refurbished machine has wear parts replaced, hydraulics resealed, paint made good and the machine re-tuned; expect to pay 10–20% more for it. Which is right depends on whether you have maintenance capability in-house.

Ask where a machine came from. It is a fair question and the answer tells you a lot. A machine retired from a running production line has a very different history from one recovered out of a closed plant.

The blunt version: for a given budget, buying used usually lets you step up a tonnage class, or buy a second machine. For a plant with orders ramping and cash flow that is not, that is the fastest route to capacity there is.

Used is not right for everything. Optical parts, thin-wall high-cavitation work, medical mouldings under a validated process and anything needing all-electric repeatability are cases where a new machine earns its price. For general industrial and consumer mouldings — which is most of the market — a good used machine is more than enough.

The real risk in a used machine is not its age. It is the seller. Which is why sections 6 and 7 — how to inspect, and how to structure the payment — are the heart of this guide.

Clamping force is the single most consequential specification. Too little and the mould flashes or will not fill; too much and you have paid for capacity you now heat, power and maintain forever. The working rule:

Required clamping force (t) ≈ projected area (cm²) × material factor (0.3–0.7 t/cm²)

• Projected area is the shadow the part casts in the mould-opening direction. Multiply by the number of cavities and add the runner system.
• The factor follows how easily the material flows: free-flowing PP, PE and PS take 0.3–0.45; ABS around 0.45–0.55; stiffer-flowing PC and PA 0.55–0.7. Thin walls and long flow paths push you to the top of the band.
• Add 10–20% margin — for process drift, for a future part, and because a machine running at 95% of its clamp all day is a machine wearing out its toggles.

Worked example: a stacking chair projects roughly 1,600 cm². In PP at 0.35 that is 560 t; with margin, a 650 t machine is the safe buy.

Do not calculate it alone if you are unsure. Send a photograph of the part with its weight and material and we will size it — free, and with no obligation. We do this most weeks.

Within a tonnage class, three things separate machines: the drive, the clamp architecture, and the controller generation.

• Servo versus fixed-pump hydraulic. A servo drive turns the pump only as fast as the moment demands, instead of running flat out and dumping the surplus over a relief valve. Energy savings of 30–60% against an old fixed-pump machine are realistic, and where industrial electricity is expensive this alone can decide the purchase.
• Toggle (three-platen) versus two-platen. Toggle clamps dominate below about 1,000 t: fast, cheap to maintain, well understood. Above that, two-platen designs take 20–30% less floor length, give a longer mould-opening stroke and hold clamping force more evenly across a large platen.
• Controller generation. An older controller is not a fault, but check that its display, keypad and I/O cards are still obtainable. A machine whose controller is unobtainable is a machine with a hard end-of-life.

Whatever the badge, the practical questions are the same three: can I buy parts for it locally, can I hire someone who knows it, and will it resell. A machine that scores well on those three is worth paying a little more for.

• Year of build. On the machine plate, alongside the serial number. Photograph both. A plate can be swapped; a serial number can be checked against the manufacturer’s records, which is why the serial belongs in your contract.
• Running hours. The controller logs total run time. As a reference, a machine in full three-shift production accumulates roughly 6,000–7,000 hours a year. Hour meters on used machines are frequently unreliable and are sometimes reset — treat the figure as one data point, not as fact.
• The places that do not lie. Date codes on the contactors and relays inside the electrical cabinet. The condition of hydraulic hose fittings and crimps. Wear polish on the tie-bars and guide rails. Paint can be renewed in a week; those three cannot.

A repainted machine is not a dishonest machine. But a machine that has been repainted, whose hour meter reads implausibly low, with ten-year-old date codes in the cabinet, is telling you something. Ask for the cabinet on camera.

Work this list on any machine, from any seller, and you avoid most of what goes wrong. Every item below can be covered on a video call; for a large order, add a physical or third-party inspection on top.

You do not have to remember all of it. Book a video inspection and we will put the camera on every item above, in this order. This is exactly why inspecting before paying is possible at all.

Nearly every cross-border used-equipment fraud fails on the same point: money paid in full before anyone saw the machine. Avoiding it is not a matter of judging character. It is a matter of structure.

• Inspect first, pay after. A seller who will not open a video call on the machine, or let you visit, has ended the conversation for you.
• Split the payment. A deposit reserves the machine; the balance falls due only after the pre-shipment check passes. Refuse to pay in full up front, from anyone.
• Check the goods before releasing the balance. Do it yourself on video, or appoint SGS, Bureau Veritas or your own forwarder. A seller who resists this is telling you what the machine looks like.
• Verify the payee. The receiving account name must match the seller company named in the contract. “Please pay our finance manager’s personal account” is where you stop.
• Put it in writing. Model, serial number, year, full configuration list, refurbishment scope, warranty terms and default liability. Verbal promises are not terms.

Our seven-step process exists to make this structure the default rather than something you have to negotiate: inspection, optional visit, contract and deposit, refurbishment, pre-shipment check, balance, loading. Your money has an exit at every step before the last.

The window between the deposit and shipping is the cheapest time in the machine’s life to change anything about it. Once it is in a container the same work costs several times as much.

• Standard refurbishment. Seals, hydraulic oil, filters and batteries replaced; full clean and service; re-test under power.
• Screw and barrel. A different screw type, or a material-specific screw for PET, PVC or filled compounds. T-slots cut where your tooling needs them.
• Attachments. Robot interface, mould temperature controller, drying hopper, auto-feeder — fitted and tested together, so the line runs on arrival rather than after a second procurement round.
• Voltage and frequency. Adapted to your grid (380 V / 415 V / 440 V, 50 or 60 Hz). Discovering a mismatch after the container is opened is a common and entirely avoidable delay.

Get every item onto the configuration list before you sign. The pre-shipment check verifies the machine against that list — anything not on it is not being checked, and is not owed to you.

Injection molding machines classify under HS heading 8477.10. The standard document set is the commercial invoice, packing list, bill of lading and certificate of origin; some destinations add an inspection certificate.

• Up to roughly 250 t: often one or two machines in a 40 ft container.
• 320–800 t: usually one machine per 40 ft container; hopper, guards or the safety gate may come off to make height.
• Above about 1,000 t: broken down — clamping unit, injection unit and cabinet packed separately — on a flat rack or break bulk, with assembly guidance on arrival.
• Packing: waterproof film and stretch wrap, loose electrical parts in ISPM15-compliant fumigated crates, steel-wire bracing inside the container.

Rules change. Everything above is a starting point for a conversation with your own customs broker, not a substitute for one. Confirm the current requirement in your country before you pay a deposit, and get the confirmation in writing.

The workshop price is the largest line but never the only one. Total landed cost is:

machine price (EXW) + inland haulage and export declaration + sea freight + duty and VAT + port handling and lifting + installation and commissioning

Price within a tonnage class is driven by year, hours, drive type, controller generation and condition — a recent servo machine and a decade-old fixed-pump machine of the same clamping force are not in the same market. As indicative bands for recent-year used machines, EXW China:

Those bands are a sense of scale, not a quotation: they move with year, condition, configuration and the market. Current prices for machines we actually hold are on the machine pages.

Sea freight for a single container to South-East Asia is commonly in the low thousands of dollars, more to India, the Middle East and Latin America. Many countries apply a reduced duty rate — occasionally zero — to production equipment, so check the tariff line for 8477.10 with your broker rather than assuming the general rate.

Ask for a landed figure, not a machine price. Send us your destination port and we will quote the machine with freight, and flag the duty position, so nothing turns up as a surprise at the port.

• Foundation. Build the level foundation and anchor pockets to the foundation drawing before the machine arrives. For medium and large tonnage an anti-vibration trench is worth the money.
• Lifting. Hoist only from the marked lifting points. Never let slings bear on the rails, the tie-bars or the oil lines.
• Services. Confirm voltage and phase sequence before energising. Keep mould cooling water and oil-cooler water on separate circuits.
• Levelling. Level the frame with a precision level. A machine that is not level wears its rails and clamping mechanism at a rate you will notice.
• First start. Check the oil level, grease rails and tie-bars, run dry at low speed for half an hour, then mount a mould and trial.

Call before you improvise. Remote video support during commissioning costs nothing and prevents the two or three mistakes that turn a good machine into a warranty argument.