Flexible Packaging Line: Where the Power Goes

A flexible packaging line is bought for what it makes, but it runs on what it draws. Between the extruder at one end and the tube cutter at the other, five machines sit on the same plant supply, and the electricity they pull shapes decisions before the machine order is even placed: how big the plant supply must be, and where the running energy actually goes. XIAOPAI - Wenzhou Xiaopai Electric Power Technology Co., Ltd. - supplies the line through two routes: solventless laminators come from SINSTAR, whose authorized global distributor XIAOPAI is, and the film blowing, flexo printing, slitting and paper tube cutting machines come from long-established Chinese manufacturers that XIAOPAI works with. Here is the power map, machine by machine.

1. THE POWER MAP

Start with the numbers on the nameplates, because they vary by an order of magnitude across a single line. The Master Series CI flexo printing machine carries a 100 kW installation. The XPM-1080RN automatic film laminating machine with hot knife lists 85 kW machine power. The Type 1300 slitting machine runs on a 5.5 kW main motor. The blown film line's published figures are speed and output - a three-layer co-extrusion line at up to 120 m/min take-up speed and 200-300 kg/h output - while the solventless laminator's headline figure is a saving rather than a draw: 60,000 kWh of electricity, according to its product page, because there is no drying oven to heat. Five machines, five electrical profiles - and that spread is exactly why a line cannot be powered by rule of thumb. A common mistake in plant planning is to size the incoming supply on the sum of all installations, then wonder why the running load is a fraction of it; the reverse mistake - sizing on measured running load alone - shows up the first time every machine starts at once after a power cut.

2. INSTALLED POWER IS NOT WORKING POWER

The distinction that decides the electrical room is installed power versus working power. The XPM-1080RN film laminating machine is the clean example: 85 kW installed, but a stated working power of 30-35 kW/h - the machine does not draw its full installation in normal production, because heating, drive and feeder loads peak at different moments within its cycle. Design the plant supply on the installed figure and every line pays for capacity it rarely touches; design on working power alone and the start-up case is missed. Two further figures belong in the same calculation: the start-up behaviour of each machine - an extruder's heater bank and motor inrush are transient, not continuous - and the power factor of the mix, since drives, heaters and motors present different characteristics to the supply. The honest calculation uses the installed figure for switchgear and cable sizing, and the working figure for load studies and generator sizing - with the actual simultaneity of the line measured rather than assumed.

3. THE DRYING SYSTEM THAT IS NOT THERE

On a solvent-based or dry laminator, the drying oven is the single largest continuous load: it holds temperature through the whole shift, whether the web is running or not. The WRJ Fi9 solventless laminating machine - SINSTAR builds it in Chongqing, and XIAOPAI supplies it as SINSTAR's authorized global distributor - eliminates the drying system entirely, which is where its product-page figure of 60,000 kWh of electricity saved comes from - no high-temperature drying process to power. What remains to drive is mostly coating, laminating and tension control, a fundamentally different electrical profile from the oven it replaces. What the no-oven design changes beyond the energy figure: no solvent means no VOC handling, no explosion-proof drying zone and no solvent recovery plant - the environmental control equipment that surrounds a solvent-based line simply is not part of the scope. The machine runs at lamination speeds up to 450 m/min across working widths of 1050, 1350 or 1650 mm, with a five-roll coating system and closed-loop tension control keeping the adhesive layer uniform - so the energy that would have gone into drying goes nowhere, and the process still holds quality.

4. WHY SERVO DRIVES SAVE MORE THAN THEY DRAW

Servo drives are often filed under "draws more, runs better" - and on a converting line the second half is the measurable part. The Master Series flexo press uses full-servo sleeve drive with each print deck positioned independently; the slitting machine pairs pneumatic shafts and magnetic powder tension control with a photoelectric guiding system for a ±0.5 mm guiding accuracy; the paper tube re-cutting machine is servo-driven through the cut. The common thread is that servo control keeps the process inside tolerance: less start-up waste, fewer jam stops, fewer reruns. On a line that extrudes, prints and laminates, every wasted metre of film was already paid for in energy at every upstream stage - the extruder that melted it, the press that printed it. To size the effect: a line running 300 kg/h of film and wasting 5% of it at start-up is losing 15 kg/h of finished film, and that material already carries every upstream kilowatt-hour embedded in it - the resin that was melted, the film that was cooled, the tension that was held. Pull the same output down to 3% waste and the saved tonnes of film are the largest single energy lever most converters have, measured in kilowatt-hours per finished kilogram rather than in nameplate ratings. Energy efficiency on a converting line is, in large part, a waste-avoidance story told in servo, tension and registration control.

5. PLANNING THE SUPPLY

When the line is specified, four numbers belong in the electrical brief: the installed power of each machine, the working power at normal production, the simultaneity factor of the line, and the growth margin for the next machine. The five machines on a typical line do not peak together - an extruder's start-up surge, a press at running speed and a slitter at rewind all occur at different moments - which is exactly why a measured load study beats a simple sum of nameplates. Growth margin deserves its own line in the brief: packaging lines grow by adding machines, not by replacing them, so the switchgear is usually sized for the line after next while the cables are sized for the line at hand. Site electrical infrastructure follows the same logic from the other side: XIAOPAI also manufactures the transformers and switchgear that sit upstream of a plant supply, so a project can be planned from the incoming feeder to the last machine on one set of electrical figures rather than two.

6. THE ENERGY CONVERSATION, CLOSED

The industry's own reporting keeps moving in this direction: sustainability requirements are reshaping equipment specifications across packaging and processing (see the PMMI report on sustainability reshaping equipment requirements), and the trends reworking flexible packaging keep returning to resource use per unit produced (five sustainability trends transforming flexible packaging). For a buyer, the practical version of that conversation is the power map: know what each machine draws, know what it actually uses, and design the supply for the difference. Ask any supplier for those numbers in writing - installed power, working power, simultaneity - and the line's energy plan writes itself from there. A specification that leaves them out hands the electrical design to guesswork, and guesswork on a plant supply is paid for twice: once in equipment oversized for daily running, and once on the day the line grows. The machines described here - the solventless laminator, the flexo press, the slitting line - each publish their electrical figures, and those figures are the first column of a line's energy plan.