제지기 릴 드럼 커버: 교체 시 고려 사항
Replacing a paper machine reel drum cover starts with identifying the correct drum at the end of the paper machine, where the moving sheet meets the growing parent reel. The reel spool carries the parent reel. Downstream winder drums and rewinding pressure rollers are separate components with different specifications.
Check the existing surface before ordering. If a rubber-covered reel drum has produced acceptable reels under unchanged conditions, its original specification is a practical replacement starting point. A hard-coated drum requires a different covering process. Changes in paper grade, reel load, or contact performance should be checked before repeating the old rubber cover design.
Confirm the Drum and Its Existing Cover
A drawing marked “reel drum cover” may not identify the covering material. Check the original equipment drawing, part number, or a photo showing the drum’s installed position.
A reel drum may have a compliant rubber cover or a hard surface coating. Some hard coatings are thermally sprayed. These surfaces have different construction and finishing requirements, and changing from one to the other requires an approved design change.
Which Part Are You Replacing?
| Existing Component | Replacement Direction |
|---|---|
| Rubber-covered reel drum | Use the original drum drawing and rubber cover specification. |
| Hard-coated reel drum | Confirm the original coating and finishing requirements. Any conversion to rubber needs an approved design. |
| Reel spool | Use the spool drawing and its own covering specification. |
When Can You Reproduce the Original Rubber Cover?
If the existing drum has performed well for years with the same paper grades and operating conditions, the established specification is a sound basis for replacement.
The original drawing and covering records may already define the rubber material, hardness, cover thickness, surface finish, and finished diameter. These are more useful than choosing a new cover solely from a similar drum’s hardness.
Pay attention to the difference between the original specification and the old drum’s current condition.
A worn cover may have lost thickness. Previous grinding may also have changed its diameter and surface. If the old measurements disagree with the drawing, confirm the intended finished dimensions before manufacturing.
What if the Old Cover Is No Longer Performing Well?
Consider a mill that introduces a smoother coated paper grade. The new grade develops surface marks, while the previous grade still runs normally.
Start by comparing the paper grades, contact conditions, and existing cover condition. The change in paper may have introduced a different contact requirement.
If marks started immediately after re-covering or grinding, the new surface finish, finished diameter, and covering records deserve closer attention.
Premature wear, cracking, or changes in surface hardness also provide reasons to review the old cover before ordering.
For these cases, the original cover specification and its actual operating history provide a more reliable starting point than copying a material name or hardness value from another machine.
How Paper Grade and Air Affect Reel Drum Contact
Air travels with the moving paper into the contact area between the reel drum and the growing parent reel.
At higher machine speeds, smooth paper with low air permeability can make air removal more difficult. Air may collect ahead of the contact point or become trapped inside the developing reel. When it cannot escape adequately, wrinkles and other reel defects can develop.
A compliant rubber cover can accommodate variations in the growing reel surface. Suitable drum grooves provide paths for air removal. The covering and groove arrangement should match the paper grade and the existing reel design.
Smooth and Dense Paper
Coated and calendered grades can be sensitive to surface marks and crepe wrinkles, particularly at higher speeds.
For example, if wrinkles appear only when a smooth coated grade runs faster, the mill should check the incoming paper and reeling conditions. On the drum itself, look for worn grooves, an altered surface finish, or changes in the rubber cover.
If the drum surface remains in its specified condition and the problem follows a change in paper or reel loading, those operating factors need attention before a new covering is specified.
There is no reason to automatically order a softer cover from the appearance of wrinkles alone.
Bulky Paper and Board
Bulky grades require attention to how the sheet responds to compression.
Excessive contact loading can reduce the bulk the mill needs to preserve. If the mill has increased reel loading, changing the rubber hardness alone will not address that operating condition.
For a replacement, the useful references are the original paper grades, acceptable reel results, and the established covering specification. When the product mix changes, compare the new grade’s requirements with what the old cover has already handled successfully.
Why the Original Grooves and Finished Diameter Matter
Some reel drums use grooves to remove air from different parts of the contact area.
On certain designs, vent grooves help remove air collecting between the incoming paper and the drum ahead of the nip. Shallower chevron grooves help release air associated with the growing reel.
These features are specific to the drum design. Slower machines or different reeling arrangements may have no need for the same groove configuration.
An old drum can be misleading after repeated grinding.
Grinding may remove shallow grooves while deeper grooves remain visible. The surface can still look grooved even though part of the original air-removal arrangement has been lost.
When replacing the rubber cover, check the approved groove drawing against the old drum’s condition. Preserve the specified pattern and dimensions where the original design is still applicable. Avoid copying a worn pattern directly from a photograph.
The finished outside diameter also needs to follow the intended specification.
For example, if the drum shell remains unchanged but the replacement cover is thicker, the finished drum diameter increases. That changes the contact geometry in the existing reel arrangement.
Use the approved finished outside diameter, covered face length, and cover thickness. Where drawings and old measurements differ, resolve the discrepancy before production.
Check the Drum Structure, Weight and Delivery Conditions
For a complete reel drum replacement, the drum shell, shaft ends, journals, bearing interfaces, and mounting dimensions must fit the existing machine.
The original drum construction and load records become particularly useful if the mill has increased parent reel size or operating load. Confirm the structural requirements from the approved drawing before manufacturing a complete new drum.
If the existing core remains suitable for reuse, selected re-covering can be discussed.
Large drums need an early check of manufacturing and transport feasibility.
Outside diameter, overall length, weight, and projecting shaft ends affect machining, lifting, packing, and shipping. Unloading equipment and access at the mill may also limit the available delivery arrangements.
A drawing and approximate weight are useful starting points. Final manufacturing feasibility, handling arrangements, and delivery commitments must be confirmed against the actual drum and transport conditions.
For a confirmed rubber-covered reel drum, send Wolorin drawings, dimensions or old-drum photos for replacement quotation or manufacturing confirmation. Without full records, start with the roller position, paper grade, contact medium and current cover issue; large drums also need weight and shipping details.