How to calculate the number of knives and tools for the new slitting machine?
Views : 3562
Author : Mr. Jiang
Update time : 2021-02-20 12:15:19
1. The number of knives and tools required for the first slitting machine mainly depends on the following eight factors:
a. The maximum number of strips.
b. Number of heads.
c. The thickness range of the coils.
d. Setup assembly mode.
a. The maximum number of strips.
b. Number of heads.
c. The thickness range of the coils.
d. Setup assembly mode.
e. The narrowest width of the incoming coils.
f. The narrowest strip width.
g. Strip width and clearance increment.
h. The amount of budget funds.
2. According to the above principles, for the slitting machine with only one machine head and fully supported by the bonded stripper ring, the basic configuration principles of the tools are as follows:
a. The min. number of knives that can guarantee the max. number of strips = 2 x the maximum number of strips + 2.
b. The number of male bonded stripper rings is equal to the maximum number of strips.
c. If the thickness range of the coil is not large, only one set of female bonded stripper rings is equipped, and the number of bonded stripper rings is equal to the maximum number of strips. But if the thickness range of the coil has a large range, such as from 0.5 to 3mm, three sets of female bonded stripper rings with different outer diameters and different colors are required, and the number of bonded stripper rings in each set is still the same with the maximum number of strips. However, for bonded stripper rings above 20mm, such as 40mm, 50mm, 80mm, 100mm, etc., the number of strips will be reduced due to the increase of the strip width, so the number of these wide bonded stripper rings should be determined according to the possible strip width and number. If it is allocated according to the maximum number of strips, it is a waste.
d. For the thin spacers that adjusts the clearance and strip width, the number is basically equal to twice the number of the most strips, half is used for the male unit, and half is used for the female unit. However, for some special thin spacers, such as 1mm, 1. 005mm, 1.01mm, 1. 02mm, 1. 03mm, 1. 06mm, 1. 1mm, 1. 2mm, 1. 3mm, 1. 6mm, 2mm etc., we need extra 1 ~ 2 pieces to adjust the first clearance.
e. Thick spacers, mainly used to fill the gaps outside the two outermost knives of the slitting machine shaft. If the effective length of the shaft is 650mm, and the narrowest coil width is 350mm, the total gap between the upper and lower shafts is 600mm. If the cutting is positioned on the center line, each small gap must be 150mm, and the whole machine often needs two pieces for 40mm and 20mm, and one piece for 10mm, 8mm, and 4mm. Since there are 4 gaps in total, each thickness needs 4 times the quantity. The number of 80m thick spacers is determined by the largest gap outside the knife when slitting the narrowest coil.
3. Multi-head configuration. A slitting machine often has multiple heads, at least two, to meet the needs of production plan adjustment and knife regrinding. When one head is occupied on the machine, the other can be prepared and equipped with slitting tools off the machine. If there are three machine heads, another set of tools can be reground outside which is good for the production arrangement and improves the production efficiency. Due to the diversity of production varieties, it is impossible for each machine head to produce a product of same specification. Therefore, from the perspective of saving investment, the following suggestions are made:
a. Number of the first head: 100% of the maximum number of strips.
b. Number of the second head: 75% of the maximum number of strips.
c. Number of the third head: 50% of the maximum number of strips.
d. Number of the fourth head: 25% of the maximum number of strips.
4. Number of knives. The number of knives mentioned above is a theoretical min. configuration. If it is possible, you might as well buy more knives, which will bring some benefits as follows:
a. It can effectively extend the life of the bonded stripper ring. Because the life of the bonded stripper ring depends not only on itself, but also on whether there are enough knives for it to continue to use. If there are not enough knives, when the knife needs to be reground, all bonded stripper rings and even those unused bonded stripper rings will be reground accordingly.
b. During production, crack of knives cannot be absolutely avoided. Or some circular slitting knives have not been used, while the number of unused knives is not enough to meet setup requirement. If there is not a sufficient number of knives, then all knives, whether used or unused, must be reground, which will also cause a lot of waste. If there are 2 times, 3 times or even more knives, this will not happen, and the production cost can be greatly reduced.
c. If the outer diameter of all slitter knives is reground at once, the consistency of their outer circle is very good, which can effectively control the deviation of the overlap of the knives.
g. Strip width and clearance increment.
h. The amount of budget funds.
2. According to the above principles, for the slitting machine with only one machine head and fully supported by the bonded stripper ring, the basic configuration principles of the tools are as follows:
a. The min. number of knives that can guarantee the max. number of strips = 2 x the maximum number of strips + 2.
b. The number of male bonded stripper rings is equal to the maximum number of strips.
c. If the thickness range of the coil is not large, only one set of female bonded stripper rings is equipped, and the number of bonded stripper rings is equal to the maximum number of strips. But if the thickness range of the coil has a large range, such as from 0.5 to 3mm, three sets of female bonded stripper rings with different outer diameters and different colors are required, and the number of bonded stripper rings in each set is still the same with the maximum number of strips. However, for bonded stripper rings above 20mm, such as 40mm, 50mm, 80mm, 100mm, etc., the number of strips will be reduced due to the increase of the strip width, so the number of these wide bonded stripper rings should be determined according to the possible strip width and number. If it is allocated according to the maximum number of strips, it is a waste.
d. For the thin spacers that adjusts the clearance and strip width, the number is basically equal to twice the number of the most strips, half is used for the male unit, and half is used for the female unit. However, for some special thin spacers, such as 1mm, 1. 005mm, 1.01mm, 1. 02mm, 1. 03mm, 1. 06mm, 1. 1mm, 1. 2mm, 1. 3mm, 1. 6mm, 2mm etc., we need extra 1 ~ 2 pieces to adjust the first clearance.
e. Thick spacers, mainly used to fill the gaps outside the two outermost knives of the slitting machine shaft. If the effective length of the shaft is 650mm, and the narrowest coil width is 350mm, the total gap between the upper and lower shafts is 600mm. If the cutting is positioned on the center line, each small gap must be 150mm, and the whole machine often needs two pieces for 40mm and 20mm, and one piece for 10mm, 8mm, and 4mm. Since there are 4 gaps in total, each thickness needs 4 times the quantity. The number of 80m thick spacers is determined by the largest gap outside the knife when slitting the narrowest coil.
3. Multi-head configuration. A slitting machine often has multiple heads, at least two, to meet the needs of production plan adjustment and knife regrinding. When one head is occupied on the machine, the other can be prepared and equipped with slitting tools off the machine. If there are three machine heads, another set of tools can be reground outside which is good for the production arrangement and improves the production efficiency. Due to the diversity of production varieties, it is impossible for each machine head to produce a product of same specification. Therefore, from the perspective of saving investment, the following suggestions are made:
a. Number of the first head: 100% of the maximum number of strips.
b. Number of the second head: 75% of the maximum number of strips.
c. Number of the third head: 50% of the maximum number of strips.
d. Number of the fourth head: 25% of the maximum number of strips.
4. Number of knives. The number of knives mentioned above is a theoretical min. configuration. If it is possible, you might as well buy more knives, which will bring some benefits as follows:
a. It can effectively extend the life of the bonded stripper ring. Because the life of the bonded stripper ring depends not only on itself, but also on whether there are enough knives for it to continue to use. If there are not enough knives, when the knife needs to be reground, all bonded stripper rings and even those unused bonded stripper rings will be reground accordingly.
b. During production, crack of knives cannot be absolutely avoided. Or some circular slitting knives have not been used, while the number of unused knives is not enough to meet setup requirement. If there is not a sufficient number of knives, then all knives, whether used or unused, must be reground, which will also cause a lot of waste. If there are 2 times, 3 times or even more knives, this will not happen, and the production cost can be greatly reduced.
c. If the outer diameter of all slitter knives is reground at once, the consistency of their outer circle is very good, which can effectively control the deviation of the overlap of the knives.
