Installing a Preform Injection Moulding Machine

The machine arrives, the mould is late, and the plant decides to commission the machine on its own and run the mould trial as soon as the tool lands. That decision is made to save a week and it costs the first six months of preform quality, because every dimension the mould trial is supposed to prove is being measured on a machine whose foundation, chilled water supply and pneumatic pressure have not yet been verified.

The cost of a rushed installation appears in a predictable sequence. First, levelling and alignment are skipped, so the platens and the tie bars carry loads they were not designed for and the tool wears at an angle. Then the utilities turn out to be marginal: chilled water that cannot hold temperature, plant air that sags when the robot fires, an electrical supply with more voltage distortion than the controller tolerates. Every one of these looks like a machine fault during the first production month, and every one of them is actually a site-preparation fault. Sorting them out afterwards means stopping production, not delaying a trial.

Sailwin has built PET injection moulding machines for 15+ years, with 500+ machines delivered into 60+ countries, CE marking, ISO 9001:2015 manufacturing and a 2-year whole-machine warranty. The SW-P series covers 14 models from 170 kN to 5500 kN and supports valve-gate hot runners up to 64 cavities, with dedicated PET screws, far-infrared nano heating coils, PID temperature control to about ±1 °C, continuous logging of 40+ parameters and an EUROMAP 67 robot interface. Every machine is load-tested at the factory before shipment, and on-site installation and commissioning typically take 3 to 7 days. This article sets out what has to be ready before the machine arrives, and the acceptance tests that should be run before the production mould goes in.

1. Why Installation Decides the First Six Months of Preform Quality

A preform is a precision part produced by a machine that is subject to substantial cyclic loads. Every shot closes a mould under hundreds or thousands of kilonewtons of clamping force and injects melt at high pressure. If the machine frame is not sitting level and evenly supported, those loads are distributed unevenly through the platens, the tie bars and the mould, and the resulting deflection repeats on every cycle. The symptom is not a dramatic failure; it is a small, persistent cavity-to-cavity difference in weight and wall thickness that gets attributed to the hot runner or to the cooling design.

Utilities cause the second class of problem, and they are harder to recognise because they are intermittent. A chilled water supply running a few degrees warm in the afternoon will not stop the machine, but it slows cooling and shifts preform dimensions as the day warms. Plant air that sags when the take-out robot and the mould movements fire together will not stop the machine either, but a valve actuator that does not fully seat produces a shot subtly different from its neighbours. Both are invisible in a single measurement and obvious in a parameter log, which is why the 40+ parameters Sailwin machines record continuously are worth reviewing in the first weeks.

The commercial argument for doing installation properly is that it protects the two things you have already paid for: the mould and the warranty. A mould asked to prove itself on an unlevelled machine absorbs the misalignment into its own wear surfaces, and a performance claim is far easier to settle when a signed installation record shows the machine was set up to specification with the utility readings logged against the requirement sheet.

Precision Engineering & Core Components: sw p228 pet preform injection molding machine

2. Site Preparation and Utility Requirements

The table below lists the site items that should be verified before the machine arrives. The requirement column states what to prepare; the verification column states what evidence to hold, because a commitment from a contractor is not the same as a measurement. Exact figures for floor loading, power rating and water flow depend on the specific model in the SW-P range and should be taken from the machine requirement sheet for that model.

Two rows cause most installation delays, and neither is expensive to fix if it is caught early. Compressed air looks adequate on paper and is marginal in practice, because the peak demand occurs when the robot, the mould movements and the ejector all actuate within the same fraction of a second; sizing on average consumption rather than peak demand is the standard mistake. Chilled water is the other: a circuit sized for a smaller machine delivers the right temperature at the wrong flow, so the machine holds temperature poorly under load while appearing correct at idle.

3. Foundation, Levelling and Alignment Before the Mould Goes In

Levelling is the step most often compressed because its benefit is invisible on the day it is done. Set the machine on its designed support points, adjust each point with a precision level until the frame is level in both axes, confirm every support point is carrying load, and anchor or grout only after the level is confirmed. Re-check after the first week of operation, which catches settling that would otherwise become permanent misalignment.

Platen parallelism and tie bar alignment belong to the same exercise. A machine that is level but has non-parallel platens clamps the mould unevenly, and unequal clamping force across a multi-cavity preform tool is a direct route to uneven filling, cavity-to-cavity weight variation and accelerated wear on the mould’s leader pins. Check it with the tool out, on a clean platen face, and record the result.

Grouting or anchoring comes last, and whether to anchor at all depends on the machine size and the foundation design. What matters is that the final state is documented: a signed levelling record showing the measurement at each support point establishes that the machine was correct when installed and that any later change in level happened in service.

The cheapest mould protection you will ever buy is a levelling record made before the mould was installed. Nobody can argue with a number taken on a clean platen.

4. Safety Circuits, Robot Interface and the Acceptance Tests to Run

Safety circuits should be proven with the machine empty, before any tool is installed. A defeated guard interlock, a light curtain that does not stop the closing stroke, or an emergency stop that does not remove energy from the correct circuits are all faults far cheaper to find with nothing in the platens. Test every guard, every interlock, the safety gate, the emergency stop at each station and the hydraulic or servo isolation, and sign the results. The machine carries CE marking to the applicable machinery safety requirements, but factory conformity does not verify the wiring and reinstatement work done on site.

The robot interface belongs in the same pre-mould phase. The EUROMAP 67 interface on the SW-P machines is the standard connection between the machine and a take-out robot, and it should be tested through a complete cycle sequence before the production tool is installed: every signal both ways, confirmation that the mould area is clear before clamping is permitted, timing against the machine cycle so the sequence does not stretch it, and the behaviour when the robot faults mid-cycle. A robot integrated after the tool goes in is a common cause of a poor first week.

Then run the acceptance tests in a defined order, with a defined pass criterion for each, and record the results in one document. A practical sequence is to start with functions that need no material at all, then move to material and a simple tool, then to the production tool. The test list below is a workable structure for a preform installation; the specific values come from the machine and mould requirement sheets rather than from a generic table.

• Utility verification. Power under load, air pressure at the machine inlet during a full cycle, chilled water flow and temperature per circuit against the machine requirement sheet.
• Dry cycle and safety function test. Full sequence without material, with each guard, interlock and emergency stop proven and recorded.
• Temperature control verification. Barrel and hot runner zones brought to setpoint and held, with the PID stability confirmed against the machine’s stated control of about ±1 °C and the deviation trend read from the parameter log.
• Short-shot and cushion check. Shot size established, cushion position and repeatability verified, screw recovery time measured.
• Capability run with the production tool. Continuous running at target rate with preform weight, dimensions and reject count recorded per cavity, and the mould change procedure walked through with the operators.
• Handover documents. Parameter sheet per mould, utility readings signed against the requirement sheet, safety test record, levelling record, spare parts list, maintenance schedule and warranty registration.

The parameter log deserves particular attention at handover. Because the machine records 40+ parameters continuously, the first week of production documents how the process behaves from a cold start through the first temperature stabilisation, into steady state and across the first weekend shutdown. Training operators to export that history and send it with a question is far more productive than describing a symptom by telephone, and it is why Sailwin supports machines on a 7×24 remote basis with common wear parts shipping within 48 hours. The factory acceptance test proves the machine under load at the factory; the on-site record proves it in your plant, which is why installation and commissioning typically take 3 to 7 days when the site is ready first.

5. Case Study: A First Month of Weight Variation Traced Back to the Floor

A preform producer installed a new machine on an existing slab and put the production tool in as soon as it arrived, to meet a delivery commitment. From the first week, weight varied between cavities more than it had on the older machine next to it, and the difference persisted after the hot runner was checked twice.

Scenario based on a Sailwin customer project; site-specific figures available on request during engineering review.

Industrial Machinery Assembly & Workshop: sw p300 pet preform injection molding machine

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