How much do you know about how to deal with defects during aluminum foil roll process(2)
Due to more production processes, more difficult processing technology and the thinnest finished product thickness of aluminum foil rolling, the probability of defects is many times higher than other pressure processing, and efforts to reduce and eliminate rolling defects is one of the keys to achieve safe, high-quality, efficient and low-consumption production. Nine defects may appear during the process are following:
No.5 Edge Crack
The condition of the longitudinal edge of the aluminum foil surface breaking. In severe cases, obvious notch can be seen at the edge.
The main causes of split edges are as follows:
a) Improper control of roll shape causes tensile stress on the edge of aluminum foil;
b) Insufficient intermediate annealing, poor metal plasticity;
c) Improper feeding when cutting material, one side is not cut off;
d) Rolling reduction is too much;
e) The edge cutter is not sharp enough or improperly adjusted;
Measure
1, Control the edge, try to relax the edge (upper bend).
2, Adopt light back tension, low speed rolling can reduce the crack edge.
3, Cut edges as much as possible.
4, Selection of DC rather than CC material.
5.,Check the condition of the edge cutter.
6, Improve and optimize the rolling process.
No.6 Burr
A hair-like spike of varying size present on the edge of sheared foil.
The main causes of burrs are as follows:
a) The blade is not sharp when cutting;
b) Improper lubrication of the cutting edge;
c) Improper adjustment of cutting edge clearance and overlap;
d) After cutting the edge, the end face of the aluminum foil has a spiky aluminum chip;
f) Cutting edges may occur when aluminum foil is rolled;
Measure
1, Replace the cutting knife
2, Re-adjust the cutting knife
No.7 Poor Profile
The phenomenon of part undulating of the foil surface due to uneven deforming is poor profile.
According to the location of defects, it can be divided into middle wave, side wave, two-ribbed wave and composite wave. The defect on the side is called the side wave, defect on the middle wave is called the middle wave. Both of them is called the composite wave. Neither on the middle nor on the side is called two-ribbed wave.
The main causes of poor profile shape are as follows:
a) Incoming plate shape quality is not good, the thickness deviation on plate exceeds the standard;
b) The pressure adjustment is unbalanced, and the roll shape control is improper;
c) Reduction in rolling pass is improper;
d) The roll shape is unreasonable;
e) The amount of rolling oil spray is abnormal;
Measure
1, Increase the back tensile and load production according to the shape of incoming plate.
2, Input correct board shape parameters.
3, Always pay attention to the shape of the plate on the line and make adjustments in time.
4, If the shape of the plate can not be improved, after continuous adjustment, notify the relevant personnel to find the reason.
5, If the production stops in the middle and the plate shape deteriorates inexplicably after reproduction, roll production can be changed.
No.8 Non-metalindentation
Non-metallic inclusion pressed into the surface of the foil causing the surface shows obvious spot or long yellow black strip defect.
The main causes of non-metalindentation are as follows:
a) The rolling process equipment is not clean;
b) Rolling oil is unclean;
c) The surface of the billet is pressed by non-metal;
d) The ingot contains non-metallic inclusions;
Measure
1, Check surface of the blanks.
2, Control the material tail to avoid the tail swinging.
3, Wash the front and back rollers after each turn finished.
4, Wash the rolling mill regularly and scrub the smoke hood to ensure no oil and dirt.
No.9 Transverse Mark
The locally dense grain formed on the surface of the aluminum foil at a certain Angle to the rolling direction has poor luster, some are single in line, and some are shaped like fishtail and chevron.
The main causes of transverse mark are as follows:
1, Reduction in rolling pass is too large;
2, Reduction in rolling pass is not match with roll, and temperature is uneven;
3, Incoming plate have uneven defects or local twill, herringbone pattern;
4, The metal deformation resistance of rolling is too heavy;
5, There is twill on the roll;
6, Insufficient lubrication during rolling;
Measure
1, Improve the lubrication.
2, Optimize the pass process, reduce the reduction in rolling pass.
3, Change the rolling process parameters.
4, The roll must be replaced if there is twill.
No.5 Edge Crack
The condition of the longitudinal edge of the aluminum foil surface breaking. In severe cases, obvious notch can be seen at the edge.
The main causes of split edges are as follows:
a) Improper control of roll shape causes tensile stress on the edge of aluminum foil;
b) Insufficient intermediate annealing, poor metal plasticity;
c) Improper feeding when cutting material, one side is not cut off;
d) Rolling reduction is too much;
e) The edge cutter is not sharp enough or improperly adjusted;
Measure
1, Control the edge, try to relax the edge (upper bend).
2, Adopt light back tension, low speed rolling can reduce the crack edge.
3, Cut edges as much as possible.
4, Selection of DC rather than CC material.
5.,Check the condition of the edge cutter.
6, Improve and optimize the rolling process.
No.6 Burr
A hair-like spike of varying size present on the edge of sheared foil.
The main causes of burrs are as follows:
a) The blade is not sharp when cutting;
b) Improper lubrication of the cutting edge;
c) Improper adjustment of cutting edge clearance and overlap;
d) After cutting the edge, the end face of the aluminum foil has a spiky aluminum chip;
f) Cutting edges may occur when aluminum foil is rolled;
Measure
1, Replace the cutting knife
2, Re-adjust the cutting knife
No.7 Poor Profile
The phenomenon of part undulating of the foil surface due to uneven deforming is poor profile.
According to the location of defects, it can be divided into middle wave, side wave, two-ribbed wave and composite wave. The defect on the side is called the side wave, defect on the middle wave is called the middle wave. Both of them is called the composite wave. Neither on the middle nor on the side is called two-ribbed wave.
The main causes of poor profile shape are as follows:
a) Incoming plate shape quality is not good, the thickness deviation on plate exceeds the standard;
b) The pressure adjustment is unbalanced, and the roll shape control is improper;
c) Reduction in rolling pass is improper;
d) The roll shape is unreasonable;
e) The amount of rolling oil spray is abnormal;
Measure
1, Increase the back tensile and load production according to the shape of incoming plate.
2, Input correct board shape parameters.
3, Always pay attention to the shape of the plate on the line and make adjustments in time.
4, If the shape of the plate can not be improved, after continuous adjustment, notify the relevant personnel to find the reason.
5, If the production stops in the middle and the plate shape deteriorates inexplicably after reproduction, roll production can be changed.
No.8 Non-metalindentation
Non-metallic inclusion pressed into the surface of the foil causing the surface shows obvious spot or long yellow black strip defect.
The main causes of non-metalindentation are as follows:
a) The rolling process equipment is not clean;
b) Rolling oil is unclean;
c) The surface of the billet is pressed by non-metal;
d) The ingot contains non-metallic inclusions;
Measure
1, Check surface of the blanks.
2, Control the material tail to avoid the tail swinging.
3, Wash the front and back rollers after each turn finished.
4, Wash the rolling mill regularly and scrub the smoke hood to ensure no oil and dirt.
No.9 Transverse Mark
The locally dense grain formed on the surface of the aluminum foil at a certain Angle to the rolling direction has poor luster, some are single in line, and some are shaped like fishtail and chevron.
The main causes of transverse mark are as follows:
1, Reduction in rolling pass is too large;
2, Reduction in rolling pass is not match with roll, and temperature is uneven;
3, Incoming plate have uneven defects or local twill, herringbone pattern;
4, The metal deformation resistance of rolling is too heavy;
5, There is twill on the roll;
6, Insufficient lubrication during rolling;
Measure
1, Improve the lubrication.
2, Optimize the pass process, reduce the reduction in rolling pass.
3, Change the rolling process parameters.
4, The roll must be replaced if there is twill.
