Feeder Guide

An NC servo feeder held 0.05 mm in the morning and drifted to 0.14 mm by mid-afternoon, and the toolroom had already checked the die twice. This traces the fault to a 58C cabinet, a drive derated 32 percent and a clipped acceleration ramp, then prices four fixes from a $600 fan to a $5,400 drive. It logs the week after the repair, and lists the four symptoms that look thermal but are not.

A plant solved slip on oily cold-rolled strip by knurling its feed rolls, then moved 0.4 mm stainless onto the same NC servo feeder and lost 4 percent of output to marks. This compares smooth steel, polyurethane, knurled and carbide-coated surfaces on grip, marking threshold, wear and price, and converts controller bar readings into the kilonewtons the strip actually sees. It closes with a four-hour test that settles the choice on a strip sample.

A fresh set of pilots lasted nine days because the feed unit sat 0.3 mm off the press centreline, a number nobody had measured since installation. The sequence runs from fixing a permanent datum to proving the result with a strip, with the tolerance for each check and what 0.2 mm of skew does to a pilot bush. It also sets out the four conditions where alignment is not the answer.

A feed error that comes and goes with the weather is not an encoder problem. On three of the last five servo feeder slip complaints we traced, the clamp was not holding because supply pressure fell mid-stroke. This article covers the gauge logging that separates an air fault from everything else, four faults that look identical at the die, line sizing for 350 litres a minute, and the four observations that rule the air theory out.

A line that had run 1,200 mm coil for two years moved to a 400 mm strip and started scrapping 9% of parts. This field case walks through the diagnosis: 0.09 mm of roll deflection at mid-span, 3 mm of strip walk over 200 strokes, and pilot release timing set for a much wider strip. It records what each fix actually moved, what made the marking worse, and the width ratio below which a wide feeder cannot be saved.

A power cut at 14:20 can leave a servo feeder delivering 296 mm on a 300 mm command for the rest of the shift. This checklist covers the six steps from dead power to a verified first part, the difference between absolute and incremental encoders, what to do with a strip still gripped in the die, and the four settings worth photographing so the next restart takes twenty minutes instead of ninety.

A line that holds tolerance at 90 SPM and drifts at 190 SPM has a feed window, inertia and release timing problem, not a worn machine. Five causes, three test runs, and the checks....

This sets out the sequence that works: grind flush, trigger the release on feed count rather than a timer, hold 40-50% speed, watch the loop and the edge guide, and log the joint.

This sets out the six steps in the order they must happen, converts the window into milliseconds at 200 and 300 SPM, lists the six symptoms of a mistimed release with the die cost of each.

An 18-month payback on a servo feeder is achievable, and it is achieved on changeover time rather than on scrap. Scrap savings are the number buyers inflate and suppliers repeat.

Rated speed is a cycle time, not a number on a plate. Most feeders that appear slow are being asked to complete their feed inside a window the press has already shortened. This breaks the audit into three causes, each measurable in under an hour, and gives the numbers that separate a feeder limit from a press limit.

A cam feeder and a servo feeder both feed strip at 300 strokes a minute, and they get there by different routes. One is mechanical and repeatable, the other is programmable and forgiving.

The order went out as a 200-ton press, so the feeder was picked to match. It ran fine for four months, then a thin-gauge job exposed short feeds that no amount of tuning could remove.

The first sign of a worn roll set on an NC servo feeder is a feed length that needs a small correction every second shift, not a mark on the strip. This article sets out the three symptoms worth acting on...