Flatness
Leveler roll diameter design is a complex calculation including material tensile strength, palsticication ratio, roll clearance, roll deformation,
For example, metal material of tensile strength 400 Mpa, the reference diameter of leveler rolls are below.
Ø50mm for material max. 2.0mmt.
Ø60mm for material max. 3.0mmt,
Ø70mm for material max. 4.5mmt,
If one leveler can't cover all the material thickness , two levelers or exchangeable double cassette levelers can be considered.
For example, one cassette leveler with Ø50mm rolls can manage material up to 2.0mm in thickness. but maximum material is 3mm in thickness, then another cassette with Ø60mm leveler rolls will fit. The product range of same cut-to-length line extended from 2mm thickness to 3mm thickness.
Some customers even choose levelers of Ø50mm rolls and Ø70mm rolls in separate two, so the product range is enlarged from maximum 2 mm to 4.5 mm.
Two types, stop-to-cut type with guillotine shear or non-stop cutting type with rotary or flying shear. The differences are as below table.
|
ItemType |
Stop-to-cut |
Non-stop cutting |
|
Shear type |
Guillotine shear |
Rotary or flying shear |
|
Shear drive |
Hydraulic |
Servo motor |
|
Cutting process |
Feeding – stop – waiting shear to cut (one cycle) |
Non-stop feeding & shear tracking length to cut |
|
Material thickness |
0.2~ 25mmT |
0.2~ 4.5mmT |
|
Scratch on surface |
No scratch |
No scratch |
|
Roll mark on surface |
Depends on material |
No mark |
|
Critical required surface |
Not recommended |
Recommended |
|
Productivity |
As standard base |
About 2~5 times higher |
In short, the advantage of rotary shear and flying shear is faster production speed, no roller mark on material surface, and that of guillotine shear is cost lower.