The purpose of designing the heel and toe difference of the cover plate is to ensure that the flat card clothing of the cover plate and the cylinder arc card clothing maintain the best carding position. The wear of the heel and toe surfaces of the rotary cover affects the accuracy of the cylinder spacing of the cover. To achieve good carding, it is required that the straightness and dynamic balance of the cylinder iron tires meet the requirements for boarding, and that the iron frame of the rotary cover plate has good straightness, flatness and consistency. Therefore, only by strengthening the control of the heel and toe surfaces of the cover plate and adopting correct maintenance methods can we achieve the process goal of “tight gauge and strong carding”.
The effect of the heel and toe difference of the rotary flat plate and its impact on carding quality The influence of the heel and toe difference of the rotary flat plate
The effect of the heel and toe difference of the rotary flat plate makes the straight needle teeth of the flat plate and the cylinder The arc-shaped needle teeth cooperate with each other to achieve pulsed and progressive carding of each flat plate, improving fiber straightness, parallelism and separation. In actual operation, if there are problems such as natural wear, abnormal wear, large plane deformation of the keel, poor processing status, etc. on the heel and toe surfaces of the rotary cover plate, it will cause a large difference in consistency of the exit point position, which directly affects product quality.
The impact of heel and toe differential wear on carding
The relationship between cylinder and flat card clothing The free combing between the needles is guaranteed by the number of needle points and the distance between the two needle surfaces. The greater the wear on the heel surface, the greater the heel-toe difference. The two needle surfaces are only in point-line contact instead of surface-to-surface contact. The rotary cover plate and the cylinder are not parallel and twisted, and the free carding effect is affected. The free carding of the cylinder and cover plate cannot achieve the desired effect, which will cause problems such as increased short lint, neps, and impurities, as well as cloud spots on the cotton web.
The level difference between the front and rear chute plate of the flat plate grinding machine, the big difference between the heel and toe plate of the flat plate grinding machine and the heel and toe difference of the rotary flat plate, and the heel and toe difference of the rotary flat plate are seriously worn, etc. , the flat surface of the flat card clothing is often ground into a “V” shape. The large plane deformation difference of the cover keel is large, resulting in inaccurate spacing, reduced carding performance, damage to the cover, and embedded cover and other adverse consequences. Therefore, it is necessary to improve the maintenance level of the equipment, reduce the wear and distortion of the heel and toe differences during the operation of the cover plate, pay attention to the condition and processing capabilities of the auxiliary machines, ensure the effective combination of parts, and achieve fine carding.
Analysis of the wear causes of the heel and toe surfaces of the rotary cover plate
Natural wear
When the cover plate runs for a long time, the heel and toe surfaces rub against the surface of the large curved rail, resulting in wear between the heel and toe surfaces and the surface of the large curved rail. The heel-toe difference design means that the toe surface is higher than the heel surface. Judging from the running trajectory of the cover plate, the heel surface wear is greater than the toe surface. This is caused by the center of gravity being biased toward the heel surface.
Unnatural wear
1) Poor lubrication
The lead powder block is too hard or defective, resulting in poor lubrication; improper refueling can cause flowers to be caught in the cover chain, causing the cover chain to elongate.
2) The verticality of the cylinder wall panel
The deviation between the rack level and the verticality of the large wall panel, on one or both sides The entrance and exit position of the large wall panel is not parallel to the end face of the cylinder, causing the surface of the large curved rail to be non-parallel to the surface of the cylinder. During operation, one or both sides of the heel and toe surfaces of the cover plate form angle point friction with the surface of the large curved rail, rather than the cover plate. The heel-toe surface rubs parallel to the large curved rail plane, causing uneven wear on the inside and outside of the heel-toe. The normal positions on both sides of the large wall panel are inconsistent, causing the wear points on the heel and toe surfaces to be in different directions from the line position.
3) The normal position between the wall panel and the cylinder is inaccurate
The normal position between the large wall panel and the cylinder is inaccurate , the positioning of the wall panels on both sides is inaccurate, the rotating cover plate is not parallel to the cylinder, and twists and runs on both sides of the large curved rail, accelerating the wear of the heel and toe line.
4) The position of the curved track and the star guide plate
Finely calibrate the 14T corners of the rotary cover star guide plate and the flat plate Consistent to prevent both sides of the cover plate from being twisted due to 14T and different twisting directions causing distortion and wear on the heel-toe surface and the large curved rail surface.
5) The cover chain is elongated
The length of the chain is different, and the heel and toe are twisted and worn differently. The chain tension on both sides should be consistent. If the tension on one side is too high, the elongation will be inconsistent, which will cause the cover plate to twist and wear faster on the heel and toe surfaces.
6) The quality of the cover keel is poor
The iron frame material of the rotary cover does not meet the requirements and has poor wear resistance. The greater the large-plane deformation of the rotary cover plate, the greater the difference in flatness of the needle surface of the cover plate.
7) The cover plate floats.
After the cover plate floats, the contact point of the heel and toe surface is not fixed, causing non-fixed wear. It will cause the wear surface to be uneven, causing problems such as unilateral wear and loose sides. At the same time, the cover plate will float, and the needle surface spacing of the cover plate will deviate, which will affect the carding effect.
The influence of auxiliary machine processing factors
1) The influence of improper processing methods
The heel surface of the rotary cover plate matches the toe surface of the heel and toe plate of the grinding flat plate machine: the heel surface of the cover plate matches the toe surface of the heel and toe plate, and the toe surface of the rotary cover plate matches the heel surface of the heel and toe plate. The left and right heel and toe plates of the flat plate grinding machine are installed backwards, causing the heel to match the toe and the heel surface of the flat plate to be ground is lower and the entrance to the toe surface is smaller. The angle between the needle faces is larger, which affects the combing effect. There are two types of heel and toe plates for flat plate grinding machines: 0.9 mm and 0.56 mm. The selection must be accurate.
2) Improper adjustment of the horizontal position of the heel and toe plates
The two pairs of heel and toe plates of the cover plate grinding machine should be ground according to the Replace it if it is poor, but every time you replace it, you need to readjust the front and rear level of the chute plate. If the level of the toe surface is low, the inlet of the toe surface will be worn larger and larger; if the level of the heel surface is low, the outlet of the heel surface will be larger and the outlet of the toe surface will be worn smaller and smaller; the angle between the grinding surfaces needs to be determined according to the horizontal size and the heel surface. Determined by the size of the toe difference wear. </p
