Carding Dynamics Part II: Development of a Device for On-Line Measurement of Two-Dimensional Fiber Loading on Card Elements

Abstract

The first part of this series shows that empirical and theoretical relationships developed to relate cardability to fiber movement and distribution have no practical value without a technique to measure fiber loading on card elements. This paper closely examines and compares off-and on-line techniques and devices implemented by previous researchers to measure fiber loads on card elements. Additionally, this part presents research efforts to develop a new optimum device with flexible features to measure two-dimensional fiber loading on card elements.From the empirical and theoretical investigations reviewed in Part I [ 13 ] of this study on fiber movement and transfer, we realized immediately the need to measure fiber loading and the collecting power of carding elements to determine carding performance. Realizing the importance of fiber loading on the cards, Zeidman and Batra' proposed a general concept for assessing fiber loading on the cards. For a flat-top card, the feed stream or fiber loading on the doffer, the load on the flats, the fiber load on any one of the cylinder regions, and the waste ratios at different points must be known to determine the fiber density in all regions of the card; for a roller-top card, the feed stream or fiber loading on the doffer, the loads on all workers, the fiber load on one of the cylinder regions, and the waste ratios at different points must be known to determine fiber density in all regions of the card. Attempts to find an effective way to measure fiber loads on any carding elements go back to the early 1940s [ 1-5, '7-I 2, 14, 15].2 These attempts mainly depended on tedious offline manual measurement procedures [ 10, 12 J . It soon became apparent that stopping, collecting, and weighing to determine the fiber load was restricting research progress because of its slowness and discontinuity.During late 60s, light reflection methods simplified measurements on the cylinder and the doffer. Measurement Techniques OFF-LINE TECHNIQUESThe earliest attempt to measure fiber load on a roller-top card was made by Martindale [ 12 ] , who conducted an experiment to determine the collecting power of the workers. He assumed the amount of fibers on the cylinder was equal to the feed rate. He found the amount of fibers on the worker by stopping the card, removing the worker chain and stripper belt, turning the worker by hand, and stripping the fibers from it by an oscillating motion of the stripper. The criticism of this method was that the fiber on the worker was picked up while the machine was slowing down to a standstill, which did not represent actual working conditions. Martindale conducted further tests to support his argument. The machine was run at full speed as one of the workers was lifted clear off the cylinder and held until the machine stopped. The fiber on it was then removed for weighing. A comparison of the methods showed that they gave slightly different results, but the difference was not sufficient to invalidate the earlier experimental results. Abhiraman and George [I] ...

Role of Fiber Finish in the Conversion of Fiber to Nonwovens — Part II: Finish Performance as a Mechanical Processing Aid in Carding

“…The schematic diagram of the IR-based device and the possible mounting positions on a card is given in Figure 1. A more detailed description of the principle and working of the NCRC IR-based photometric device are given by Seyam et al [5].…”

“…Seven IR LED and sensor assembly was mounted on the doffer at the recommended distance of 25 mm from the doffer surface and 25 o to the axis perpendicular to the doffer surface [5]. The device needs to be calibrated for each fiber type used, as the reflectance property varies depending on the type of fiber and surface characteristics of the fiber.…”

Formation of Carded Webs from Microfibers

“…In order to investigate fiber load distribution on doffer surface across card, an IR-based device, designed and developed by Seyam et al [7], was used. Seven sensors equally spaced were located beneath the doffer in cross card direction.…”

“…For each experimental run, 2,000 data points were obtained from each sensor at a rate of 60 points per second. The fiber load distributions across and along card were estimated using a calibration curve [7].…”

The investigation of fiber carding performance with the application of static electricity to carded nonwoven fabric process

“…There is a significant relationship between the degree of fiber openness and fiber loading (the collecting power of the carding element). Many researchers have concentrated on measuring fiber loading on card cylinder in literatures [2][3][4].…”