ACCURACY OF HOLE PROCESSING WITH A COMBINED TOOL

Cement, powder metallurgy and various large-sized equipment are used in the industry of building materials for grinding raw materials. During operation, such equipment is exposed to external influences, especially at the joints, which reduce the reliability of the units. This leads to the early replacement of wearing parts. Large components of grinding mills are connected by flanges. The flanges are fastened with bolts, some of which must be precision, since they take the load of the equipment and ensure the tightness of the connection. The holes for precision bolts, respectively, must be accurate and of high quality. A study of the processing of holes with a reamer is given. The cutting elements of the tool, in the form of multifaceted plates, are mechanically attached to the body, which makes it possible to quickly replace the plate in case of wear or breakage. Such an assembled combined cutting tool allows to perform countersinking and reaming in one operation and thereby reduce the processing time of one hole and, in general, all precision holes in the flanges of the mill being repaired. The dependence of the precision hole accuracy on the shape and spatial deviation from the cutting modes of processing when using a combined tool is derived. The dependence is established for processing using a portable device with a rising spindle, as the most used equipment for repairs. The presented dependence makes it possible to predict the accuracy of machining holes with a combined tool, taking into account the rigidity of the technological system and calculate the required reamer accuracy.

DESIGN AND EXPERIMENT OF ADJUSTABLE SOCKET-WHEEL PRECISION FERTILIZER APPARATUS FOR DRY DIRECT-SEEDING RICE

To solve problems of non-adjustable fertilizer and low fertilization precision in the precision hole fertilization of dry direct-seeding rice, an adjustable socket-wheel precision hole fertilizer apparatus for rice was designed. The basic structure and working principle of the fertilizer apparatus were expounded, the structural parameters of key components were determined. The numerical simulation experiments based on the discrete element method were carried out by using sulfurized urea as the research object. Selecting the rotation speed of the socket-wheel, the length of the trough, the depth of the socket as the experimental factors, and taking the average amount of fertilizer discharging and the coefficient of variation of fertilization uniformity as evaluation indicators, the orthogonal rotation combined experiments with three factors and five levels were carried out. A multi-objective optimization method was used to determine the best parameter combination under the constraint of the target value of the hole fertilizer discharging of 1.500 g. The simulation results show that the coefficient of variation of fertilizer uniformity was the smallest and the coefficient of variation was 15.80% when the rotation speed of socket-wheel was 26.57 r/min, the length of the trough was 5.36 mm and the depth of socket was 5.64 mm. By using slow-release urea, sulfurized urea and bio-organic fertilizer as test materials, the bench test and field test was carried out on the fertilizer apparatus and the reliability of the simulation results and the adaptability of the fertilizer apparatus were verified.

Design and Testing of a Punching-on-Film Precision Hole Seeder for Peanuts

HighlightsThe designed precision seeder meets the agronomic requirements for on-film hole seeding.Influencing factors were found by studying the operating principle and key parameters.A response model was successfully built and verified by experiments.This study provides technical support for punching-on-film hole seeding technology.Abstract. To satisfy the agronomic requirements for punching-on-film precision seeding of peanuts, a precision hole seeder was designed in this study. The seeder can perform simultaneous functions of film mulching, film punching, pipe laying, precision hole seeding, and seed covering. The overall structure and operating principle of the device were analyzed, and its major components, including a seed-metering device, soil-covering roller, and drip irrigation pipes, were theoretically studied. To optimize the operating parameters and achieve favorable performance, a three-factor quadratic orthogonal test was performed to test the effects of the vacuum chamber pressure, advancing speed of the seeder, and height of the type hole boss on the seeding performance; the variance and range of the test results were analyzed accordingly. Through the field experiments, when the vacuum chamber pressure, advancing speed of the seeder, and height of the type hole boss were optimized to 7.5 kPa, 4.2 km h-1, 5.3 mm, respectively, the qualification index, re-seeding index, and miss-seeding index of the seeder were 92.7%, 3.8%, and 3.5%, respectively. Thus, the developed seeder satisfies the agronomic requirements, and the study results provide a technical reference for the punching-on-film precision seeding of peanuts. Keywords: Model, Peanut, Precision seeding of peanut, Punching-on-film hole, Seeder.

Development and Evaluation of a Hole-Punch Applicator for Precision Application of Preemergence Herbicides in Plasticulture Production

Preemergence herbicides are typically applied by broadcasting to the top of raised beds before laying the plastic mulch in plasticulture production systems. Broadleaf and grass emergence is limited to transplant holes in the mulch. As a result, most herbicides are applied under the mulch in locations where weeds cannot emerge and herbicides are unnecessary. To reduce this excessive off-target application, a precision hole-punch sprayer was developed at the University of Florida for use in plasticulture production systems. The technology facilitates the application of herbicides during the hole-punch operation immediately before transplant. Application of napropamide andS-metolachlor in an application volume of 233 L ha−1of water using the precision hole-punch applicator had no effect on tomato and bell pepper growth and yield. Equipment accuracy ranged from 55% to 90%. Preemergence herbicide use was reduced by 88% to 92% with no reduction in weed control. The hole-punch applicator is an effective way to reduce PRE herbicide use in transplant vegetables grown using the plasticulture production system.

Precision Hole Making on Laminates Composite: Comparison between Drilling and Punching

Accurate and strong fastener assembly depends on precision of the hole. For structural material likes composites, these criteria is very important. Drilling is the most common method in producing hole on composites. But the main problem of drilling is excessive tool wear that may affect the quality of the holes. Punching is another alternative in making a hole. The main objective of this study is to compare between drilling and punching in terms of hole quality. The scanned images of the produced hole will be captured using commercial 3D optical surface measurement method namely Alicona IFM. The effect to the quality of the produced hole will be measured and compared between drilling and punching.