The article presents the results of a study on the quality of conical picks for the purposes of tender procedures in accordance with the public procurement law in Poland. The pick studies presented here are one of the few that in practice allow the selection of an offer based on objectively determined numerical indicators defining the quality of the product and not only on the basis of price. Thanks to this, the contracting party can decide the relevance of price and quality in their evaluation of a pick. The geometrical and material parameters required in a tender, if not met, are the basis for rejecting a given offer of picks. The numerical parameter influencing the final evaluation of the offer is the picks’ rate of wear. Conical picks are tools for mining minerals, rocks, asphalt or concrete. They are used in many industries, especially in mining, construction and road engineering. In difficult working conditions, the durability of knives is limited to as little as several hours. Several dozen picks work on a cutting unit at the same time, and taking into account the price of a knife which oscillates around several dozen euros, significant operating costs are incurred. Therefore, the selection of tools with an optimum price-quality ratio is crucial. The article presents the results of studies on geometric parameters, material parameters and the rate of wear of 48 sets of picks conducted for a tender consisting of 14 tasks. The tender was conducted for 6 underground mines of a coal company. Five producers submitted their offers for selected tasks in the tender.
The article concerns the condition of automation and robotization of underground mining in Poland. Attention has been focused on the specific character of the mining industry. This limits the possibility of using robotization, and sometimes even the mechanization of certain processes. In recent years, robotic and automated machines and machine system solutions have been developed and applied in Poland. They are autonomous to a various degree, depending on the branch. The type of automation and artificial intelligence depends on the specific use. Some examples presently being used include the MIKRUS automated longwall system and autonomous device(s) for breaking rocks or mining rescue work. In Poland, fully automated plow systems produced by foreign companies are also used. Companies in Poland and international research centers are also actively engaged in the development of underwater and space mining. where robotization is of key importance. Research is also being undertaken by Robotics in Mining, euRobotics and PERASPERA as well as Space Mining Conference.
Conical picks are cutting tools used in many branches, in particular in the mining, road construction and building branch. Contact with the excavated face causes their constant wear, which is an unfavorable but unavoidable process. Milling heads of working machines are equipped with several dozen conical picks, and mining in abrasive or hardly accessible rocks can reduce their life to a few hours. It is in the interest of both users and producers to increase their durability, as tools replacement, apart from purchase and logistic costs, results in machine downtimes. In the article various solutions of conical picks, their construction, dimensions and materials used have been discussed. Technical procedures applied to increase the durability of conical picks and their regeneration as well as methods of extending the life of picks working in difficult conditions have been presented. Two author’s methods of extending the life of picks working in difficult conditions, covered by a patent application, have also been presented. The first solution involves ensuring an uninterrupted rotational movement of the pick in the holder. Patent claims include an innovative method of equipping the additional sleeve integrated with the holder with a rotational bearing, which enables a continuous rotation of the pick. The tool equipped with a bearing generates much lower movement resistance than the standard mounting. The holder is designed to mount classic commercial picks. What is important, the pick replacement does not require interfering with the bearing assembly. The second solution concerns the manner of protecting the working part of the pick by means of a special element made of an abrasion resisting material. This element is the pick tip, the geometry of which varies from the commonly applied posts made of sintered carbide. In this solution, the tip has a shape corresponding to the form of conical pick’s wear, which causes that its steel body does not wear. Moreover, there is a possibility of applying a mobile, rotational mounting of the tip to the body.
The cutting drums are the basic working components of many mining machines. The article focuses on differences in the design of cutting drums depending on the expected working conditions. Then, the unique calculation procedure is presented which allows to determine the load on the unit by reducing the forces acting on a single pick, taking into account the picks bent on the cut-off disc. Until now, this has been omitted in the literature. The results of the calculations for the selected cutting drum performed in MATLAB are also presented. The further section proposes to use Autodesk Inventor Professional's iLogic Tool for quick modelling of cutting drums. The principles of creating parameterized models and compositions using programming elements in the form of iLogic scripts are presented. The articles presented a ready-made units generator, taking into account the possibility to determine values of selected numerical parameters of the unit: diameter, web, number of patches and cutting pitch. The generator also allows you to select the type of pick holders, conical pick types, as well as the choice of pick system for repositioning or matching picks.
Procedure of the quality assessment of tangential-rotary picks used in various types of mining machines, has been described in the present study. Authorial method of the quality assessment of tangential--rotary picks based on examination of geometrical and material factors, including pick wear rate, has been discussed. The method is based on parametrical factors and the described examinations tailored to determined conditions of the machine operations, including user requirements. Testing results collected in form of measurement cards allow selection of the optimal pick, including the influence of chosen parameters into the pick wear rate.
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