How to Thread Strip into an NC Servo Feeder Correctly?

Why Does Proper Strip Threading Matter for an NC Servo Feeder?

An NC servo feeder holds its ±0.05 mm feeding accuracy only when the strip passes through the machine cleanly. Every time the strip scrapes a roll, it transfers a tiny groove into the roll surface, and a grooved feed roll marks every subsequent strip that passes through it, which becomes a surface defect on your stamped parts. Likewise, a strip threaded with a bend or burr can jam between rolls, trip the servo's torque limit, and stop the line in the middle of a shift. Threading is also a safety task: hands are near moving rolls and sharp strip edges, and a strip that slips during threading can cut or pinch. Doing it correctly, the same way every time, protects the machine, the parts, and the operator.

The bigger picture is uptime. On a line that changes coils twice a shift, each threading job takes five to fifteen minutes by hand. Standardizing the procedure cuts that to a repeatable minimum, and adding an automatic threading table cuts it further. Over a year of two-shift operation, the minutes saved by good threading practice add up to full production shifts recovered.

How Do You Prepare the Strip End Before Threading?

The condition of the strip end decides how smoothly the whole threading job goes. A rough, bent, or burred end will fight you at every roll gap. Prepare the end correctly and the strip will glide through the feeder like it was designed to.

• Cut the strip end square. Shear the first 200 mm of the coil end so the leading edge is square, not stepped or ragged.
• Deburr the leading edge. File or grind the burrs off the cut edge so they cannot scratch rolls or hang on guides.
• Flatten any bend. If the end has a coil-set bend, lightly flatten the first 100 mm with a straightening pass.
• Taper the tip for thin strip. For strip under 0.5 mm, cut a small taper on the tip so it enters roll gaps without folding.
• Check for edge cracks. Inspect the first metre for edge cracks or laps; a cracked edge can break during pay-off.
• Remove oil or debris. Wipe the strip end clean so oil does not make the feed rolls slip during the first cycles.

How Do You Thread Strip Through the Straightening Rolls?

With the strip end prepared, follow the machine's material path in order: entry guide, straightener rolls, feed rolls, and exit guide. Never skip a station. First, open the straightener roll gap wide enough for the strip thickness, typically using the roll-lift lever or the adjustment handwheel; on a FANTY NC servo feeder, loosen the roll pressure and raise the upper roll bank. Second, feed the strip into the entry guide and push it gently forward until the tip reaches the first straightener roll pair. Third, lower the rolls and set the initial pressure to roughly half of the production setting, then jog the strip forward through each roll pair using the jog button, never pulling by hand. Fourth, when the tip reaches the feed rolls, open the feed roll gap, pass the strip through, and close the rolls with the standard clamping pressure. Fifth, jog the strip through the exit guide to the die entry, then set the final straightener pressure and feed roll pressure for the material. Finally, run a test feed of the full pitch length and confirm the strip tracks straight between the side guides.

If the strip will not advance when jogging, stop immediately. Forcing a jammed strip with the jog button can burn the servo or bend a roll shaft. Open the gap, check for a folded tip or a trapped burr, correct the end, and try again. A strip that fights you at the rolls is almost always a strip-end problem, not a machine problem.

Threading Mistakes That Damage an NC Servo Feeder

Every feeder shop has its own list of threading accidents. The table below collects the most common ones and how to prevent each.

How Do You Automate Threading on a High-Volume Line?

For plants that change coils more than four times a shift, manual threading is the bottleneck. FANTY offers automatic threading options on NC servo feeders and complete 3-in-1 decoiler straightener feeder lines. In an automatic threading system, the strip end is prepared once, fed into a powered entry table, and then driven through the straightener and feed rolls by the feeder's own servo at low speed, following preset roll gaps, until the tip stops at the die entry. The operator watches from the HMI, intervenes only if a sensor flags a fold or a jam, and the whole changeover takes minutes instead of a quarter-hour. The investment pays for itself in reduced operator time, fewer scratched rolls, and fewer changeover-related delays, and it also removes the hands-from-the-machine safety risk entirely. If you are designing a new line or replacing an old feeder, ask for the automatic threading option; it is one of the highest-return upgrades available on a coil feeding line.

Frequently Asked Questions About Threading an NC Servo Feeder

Your Strip Threading Action Plan

Threading is a procedure, and procedures live or die by training and tools. Shear and deburr every strip end before threading, follow the material path station by station, use the jog button instead of your hands, and stop at the first sign of a jam. Standardize the sequence so every operator does it the same way, and if your changeover volume justifies it, add automatic threading to take the hands and the minutes out of the job. FANTY NC servo feeders and 3-in-1 decoiler straightener feeder lines are built to make threading fast and safe, and our commissioning engineers train your operators on exactly this procedure. Send us your coil and strip details for a feeder configuration with the threading options that fit your line.