Flexo Printer Commissioning Checklist

Commissioning is the short window when a new flexo printer is proven, and it decides whether the machine runs at its rated speed for the next decade. A machine that is accepted on a light test print and a hand-fed sheet can hide registration drift, drying problems and safety bypasses that appear only in production. The checklist should be written before the machine arrives, with the supplier's obligations and the plant's acceptance criteria in the same document. This FAQ covers what to check before power-on, how registration is set, which ink and wash-up checks belong in the first week, which safety devices must be proven, and what record to sign at the end. Flexo Printer Commissioning Checklist is a project document, not a formality.

What should be checked before a flexo printer is powered for the first time?

Before power-on, check the foundation and the level, because a frame that is out of level will show as registration drift later. Confirm the power supply matches the nameplate, including voltage, phase and the earthing arrangement, and confirm the compressed air quality and pressure at the machine inlet. Inspect the machine for transit damage, especially on the cylinders and the guides, and confirm that all shipping locks are removed. Check that the guards are fitted and that the emergency stops are wired, not merely present. Verify that the lubricants and the ink are the specified types, because a wrong lubricant can void a warranty. Record every finding with a photograph before the supplier's engineer energizes the machine, so responsibility is clear. Keep the pre-power-on findings in a single log with photographs, because a dispute about transit damage is settled by the date on the image.

How is print registration set during commissioning?

Registration is set in stages: mechanical alignment of the stations, then static registration with a test forme, then dynamic registration at increasing speed. Start with a single-color job to confirm the sheet path and the impression setting, then add colors one at a time. Use the same board grade the plant will run, because board thickness changes the print gap. Record the register error at each speed and at each edge of the sheet, not only in the center. A machine that holds register at low speed and drifts at production speed has a transport or a tension problem, and it should be fixed before acceptance. Keep the test sheets as the baseline for future comparison. Keep the test sheets from each speed in a folder with the date, because they become the baseline for every later registration question.

What ink and wash-up checks belong in the first week?

In the first week, confirm that the ink viscosity control works across a shift and that the drying matches the press speed. Run the heaviest coverage the plant expects and check for set-off when the sheets are stacked, because a drying problem often appears in the stack rather than on the sheet. Check the wash-up cycle time and the solvent consumption against the supplier's claim, and confirm that the wash-up does not leave residue on the anilox. Inspect the anilox for damage after the first week, since a damaged cell shows as a streak that will not clean out. Confirm the ink circuit does not leak and that the pH or viscosity sensor reads correctly. These checks are cheap in week one and expensive in month six. Where the wash-up time exceeds the supplier's figure, check the solvent temperature and the nozzle condition before blaming the cycle.

Which safety devices must be proven before production?

Every guard, interlock and emergency stop must be proven by test, not by inspection. Open each guard and confirm the machine stops in the specified manner; press each emergency stop and confirm the same; test the reverse and the inch functions at the lowest speed. Confirm that the nip points are guarded and that the line clear function works before a restart. Check that the lockout point is accessible and that the procedure is written. Record the test with the device name, the result and the witness. A machine accepted with one bypassed interlock will be run with that bypass for years, and the liability sits with the plant that signed the acceptance. Test the guards with the machine at the lowest speed first, then repeat at production speed, because some interlocks behave differently under load.

What acceptance record should be signed at the end of commissioning?

The acceptance record should list the tests performed, the results, the deviations and the date each deviation will be closed. It should include the run speed achieved, the register error measured, the reject rate on the acceptance run and the drying result at the heaviest coverage. Attach the training record with the names of the operators trained and the topics covered. Attach the spare parts list and the recommended first stock. State the warranty start date and the conditions that keep it valid. Both sides should sign, and the plant should keep a copy with the machine file. A clear acceptance record turns a later argument about performance into a reference to a measured number. Pair it with Spare Parts List Every Paper Machine Buyer Should Hold before the supplier leaves site. Where a deviation is accepted, record the date it will be closed and who owns it, so the acceptance does not become a permanent exception.

Prepared for yoco-group.com.