Expander rolls can select variety of rubber types and additional options. Compared to other spreader rolls, you might be wondering, “How should I decide among the many choices?”
We will generally select the appropriate roll based on the following conditions, this time we will explain the part of process “how we make a decisions”.
The basic item to be confirmed are:
①Web width、②Web type、③Ambient temperature、④Conveyance speed、⑤Conveyance tension、⑥Contact angle、⑦Environment of usage
These are the seven points that determine the following elements:
(1)Roll Type (Variable Bow type or Fixed Bow type)
This is a particularly important item. If the curvature setting is incorrect, even if other specifications are optimal, wrinkles may not be completely removed, or excessive tension may cause other issues. If there is no usage result or if multiple base materials are handled with one device, we recommend the variable bow type. (Variable Bow Expander roll).
(2)Effective Surface Length
Depending on space constraints, this is generally the web width plus 100-200mm.
(3)Outer Diameter and Shaft Diameter
Rotating bodies have a resonance speed range that significantly affects roll life and vibration of roll. To Increase the outer diameter and shaft diameter raise the resonance speed range and able to avoid the resonance speed range. But this will also increase costs, contact angle and startup tangential force, so the optimal size must be selected.
(4)Rubber Type
The selection of rubber type varies depending on the environment of use and purpose (e.g., whether a rubber with high grip or high slip is required). We can derive this from our experience, but the detail is expertise so we will skip about this condition. (Please contact us!)
(5)Additional Options (Low Torque, Drive Pulley, etc.) Required or not
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Recently, increase of low tension conveyance required due to the base material thinning. Structure of the expander, multiple bearings are installed inside makes resulting in relatively high rotational resistance which is not ideal for free rotation. An additional option to solve this problem is “low torque specification”, by using special bearings. Reduce of rotational resistance allows free stress to the base material under low tension conveyance. |
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Additionally, surface friction is a very important factor for free rotation. But the friction decreases when the air inflow between the base material and the roll. By processing micro grooves on the rubber pipe surface of expander roll enable the air to release and friction can be maintained. Micro Groove Processing |
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Summary
This time, we explained “How to Select an Expander Roll.”
For inquiries related to this content or companies wishing to solve wrinkle problems, please feel free to contact us through the inquiry form!
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