FEED LENGTH ADJUSTMENT

Feed length is the distance the strip advances with each press stroke. In a roller feeder, this setting must match the die progression and remain stable under real press speed, material thickness, and roll pressure conditions.

Executive Summary:

  • Use the die progression as the target feed length, then verify the actual strip movement with repeated-stroke measurement.
  • Mechanical roller feeder adjustment is practical for fixed-pitch work, but it is less convenient when every job needs a different pitch.
  • If feed length changes often or must be stored as recipes, an NC servo feeder may be the better production tool.
roller feeder feed length adjustment reference
roller feeder feed length adjustment reference
mechanical roller feeder for fixed pitch strip feeding
mechanical roller feeder for fixed pitch strip feeding

What is feed length in a stamping feeder?

Feed length, also called feed pitch, die pitch or progression, is the distance between one stamped position and the next. In progressive die work, it is normally determined by the die design. The feeder must move the strip close to the correct position, and the die pilots may complete the final correction when pilot release is used.

Short pitchSmall electronic, connector, clip, or lamination parts often need stable short-index feeding.
Long pitchLonger parts need more travel and more careful checking for slip, strip support, and press timing.
Fixed pitchMechanical roller feeders fit stable production where the same pitch runs repeatedly.
Variable pitchServo-controlled feeding fits jobs that change pitch, recipe, or feeding pattern frequently.

How do you measure the real feed length?

A practical method is to mark the strip at a fixed reference point, run a known number of press strokes at safe speed, mark again, and divide the total distance by the number of feeds. This gives a more realistic reading than one single feed movement. For a fuller method, see our guide to measuring and calibrating feeder pitch.

  • Remove excessive oil or debris that could make the feed rolls slip.
  • Check that the strip is not dragging against entry guides or die edges.
  • Measure after the feeder, not only at the coil loop.
  • Repeat the test after speed increases, because vibration and timing can expose hidden problems.

How do you adjust the feed length of a roller feeder?

On a mechanical roller feeder, feed adjustment is made on the eccentric disc at the press crankshaft end. The crank pin (spindle) on the disc sets how far the pull rod and rocker arm swing on each stroke, and that swing sets the feed length: the farther the crank pin sits from the disc center, the longer the feed. An eccentric disc feed length adjustment takes four steps:

  1. Read the target pitch from the die. The required feed length is the die pitch, often engraved on the die as a P value.
  2. Measure the current feed. Scribe lines on the strip, run the press for a set number of strokes and divide the measured travel by the number of strokes.
  3. Move the crank pin. If the feed is too short, move the crank pin outward, away from the disc center; if it is too long, move it inward. Lock it again after each change.
  4. Fine-tune and verify. Use the vernier scale on the eccentric disc for small corrections, then repeat the measurement until the feed matches the die pitch.
How to Adjust the Feed Length of a High-Speed Roller Feeder

When is a mechanical roller feeder not enough?

Production need Mechanical roller feeder NC servo feeder
Same pitch runs for long periods Strong fit when press synchronization and setup are correct. Works, but may be more than the job requires.
Frequent pitch changes Adjustment takes more setup time. Better fit because feed length can be entered and stored.
Recipe control or job memory Limited or unavailable. Strong fit for recipe-based production.
Very high fixed-pitch speed Often selected for suitable press-driven high-speed work. Depends on servo capacity, pitch, and press synchronization.

What data should be checked before model selection?

A roller feeder article can explain the method, but final equipment selection still depends on the actual press line. Prepare the data below before requesting a quotation or comparing feeder types.

MaterialStrip material, thickness, width, surface requirement, and whether marking is allowed.
Pitch and dieFeed pitch, progressive die layout, guide-pin design, and required release timing.
Press dataPress type, stroke, SPM target, shaft position, installation space, and feed line height.
Line layoutExisting decoiler, straightener, loop control, lubrication, scrap path, and downstream operation.

For fixed-pitch high-speed stamping, review the high-speed mechanical roller feeder. For frequent pitch changes or recipe-based feeding, compare the NC servo feeder. For economical simple feeding on suitable presses, compare the pneumatic air feeder. For coil supply before the feeder, check the coil decoiler machine.

Continue with the correct setup page

Feed length is one setting inside a larger press-line setup. Use the next page that matches the observed problem.

FAQ

Why is my feed length correct at slow speed but wrong at production speed?

Speed can expose strip slip, guide friction, poor loop control, or release timing errors. Verify pressure, material path, and timing at a controlled ramp-up speed.

Why does the actual feed length differ from the setting?

The setting on the eccentric disc is a starting point, so always measure the real feed. Common reasons for a difference are clamping pressure that is too loose, so the strip slips and the feed lengths become uneven; release timing that leaves the rollers holding the strip while the pilot pins try to position it, which can buckle or stretch the strip; and a reading taken from a single stroke instead of a set number of strokes. Correct the cause first, then fine-tune on the eccentric disc’s vernier scale. For other symptoms, see roller feeder troubleshooting.

Can a roller feeder handle different feed lengths?

Yes, but mechanical adjustment takes time. If pitch changes frequently, an NC servo feeder is usually easier to operate.

What information is needed before choosing a roller feeder model?

Material width, thickness, feed pitch, press SPM, die type, guide-pin condition, feed line height, and surface protection requirements should be checked first.

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