TL;DR

Telescoping rolls are caused by incorrect rewind tension taper or misaligned rewind cores. Check the tension taper profile, core alignment, and unwind brake for the current material.

What you might see

rewind roll edges not flush, visible step between adjacent wraps
telescoping increasing from the roll core to the outside
web weaving between the slit zone and the rewind
rewind roll hardness inconsistent from core to outside

Likely causes

Tap to mark as ruled out

Tension taper too low, not increasing tension sufficiently as roll diameter builds
Core alignment out of position causing the web to lay unevenly on the roll
Unwind brake set too low, allowing the unwind reel to surge and release web slack
Web guiding system not centering the web to the core position

Required tools

Dial indicator for core runout measurement
Tension meter or rewind tension display
LOTO kit

Safety first

Rewind rolls at full diameter are heavy. Use appropriate lifting equipment when removing rolls from the rewind shaft.
Web under tension can snap back and cause laceration. Release web tension before any core or shaft adjustment.

Procedure

7 steps · ~45 min

1
Run a test roll at current settings and note at which diameter the telescoping begins. Core-area telescoping indicates core alignment. Outside telescoping indicates tension taper.[1]
2
Verify core chuck alignment for all rewind positions. Measure core runout with a dial indicator. Runout above 0.5 mm will cause telescoping.[1]
3
Check the tension taper setpoint. Increase taper by 5% increments and run a test roll after each change until telescoping is eliminated.
4
Verify the unwind brake tension against the grade recipe. Insufficient brake tension allows the unwind reel to overspin and dump slack into the web path.
5
Check the web guiding sensor for the rewind position. Confirm the guide is tracking to the core center and not hunting.
6
Inspect the rewind nip rider roll for uneven contact across the roll width. A crowned or worn rider roll applies uneven web tension.
7
After corrections, run a full production set and inspect the finished rolls for telescoping before releasing.

Sources

Atlas Converting Atlas CW1000 / 5000 Slitter Rewinder general technical documentation, Atlas Converting
Slitter rewinder tension taper setup and telescoping roll correction, general converting machinery practice (general)

More guides for Atlas Converting Atlas CW1000 / 5000

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How to reduce web breaks at the slit zone on an Atlas CW1000 Slitter Rewinder

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