A dryer can remove water effectively and still fail the production line if thin boards lift, flutter or shift on the conveyor. More blower output may make the instability worse. The correction should begin with the board’s support and the direction of the air force, then verify the minimum air setting that achieves the required drying result.
Towwind’s PCB horizontal-line selection guide covers the whole system. This guide isolates one commissioning problem: keeping approved board formats stable at the drying station.
Describe exactly when the board moves
Record which board formats move, their position on the conveyor, and the point at which movement begins. Does the leading edge lift under the first knife? Does the trailing edge flutter as support decreases? Does one side shift toward a guide? Does the problem occur only at a particular line speed or after a product changeover?
Use a safe observation method approved for the machine. A slow-motion recording from outside the guarded area can reveal a repeatable pattern. Do not reach into an operating conveyor to “feel” the jet or hold a moving board in place. Compare the moving board with a stable format at the same air setting.
Check mechanical support before airflow
A thin board is easier to move if a roller gap, worn belt, poor guide setting or carrier transition leaves it unsupported at the air knife. Verify the intended product path and support geometry against the equipment drawing. Look for a board that arrives already curled or skewed. If the instability begins before the drying jet, treating the blower as the root cause will waste time.
Fixture or conveyor changes must preserve drainage and cleaning access. A support that holds a board down but traps rinse water can trade a movement defect for a drying defect. Check both outcomes during the same trial.
Review how the jet acts on the board
The air knife’s angle, stand-off and direction relative to travel determine where the force acts. A jet aimed under an unsupported edge can create lift even if total airflow is moderate. Examine top and bottom knife timing, the distance from each outlet to the board, and whether a branch is disproportionately strong. Towwind’s air-knife angle article explains the geometry; the stability trial should apply it to one actual board format.
If the line has several knives, change only one setting per run. Reducing one knife’s output may stabilize the board but leave water behind at a later stage. The acceptance criterion must include both board position and dryness.
Establish a controlled adjustment sequence
Start from a recorded baseline: product format, line speed, support arrangement, knife positions, blower command, measured pressure and drying result. Correct obvious support or alignment faults first. Then adjust jet direction or distance within the machine builder’s permitted range. Finally, reduce or redistribute air output while checking the accepted drying result.
Run the final setting across the approved product range, not just the lightest board. A thicker board may require a different drying mode. If the machine changes settings by recipe, verify that the recipe is selected reliably and that a wrong selection is detectable before product damage occurs. Record the setting used for each accepted format.
When a different blower is justified
If the current source cannot provide stable, controllable air across required modes, define the duty at each mode before considering replacement. A new blower must meet the drying requirement without forcing the line to operate at an unstable setting. Towwind can review the measured flow and pressure together with control requirements and the PCB line layout, then assess the TW750, TW1500 or TW2000 against that duty. Share the application data for a model review.