Directions for increasing conical picks’ durability

Abstract

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.

Conical Picks for Undeground Mining

“…The durability of tools is primarily determined by their proper adjustment to the anticipated mining and geological conditions, and, in particular, by the physical properties of the excavated face. Important parameters influencing the proper course of the cutting process are the geometrical and kinematic parameters of the pick in the holder and the cutting machine head (Bołoz, 2019).…”

“…As a result, the carbide insert gets chipped or broken, and the pick needs to be replaced. The previously presented treatments quoted in the subject literature (Bołoz, 2019) allow for increasing the durability of the pick, especially by protecting its working part, but do not protect the body throughout the service life. By analysing both the construction of conical picks and the form of their wear, a new solution of the conical pick has been developed.…”

“…Tests were done for cemented carbide (Nahak et al, 2015), steel (Gajdzik & Sitko, 2014 as well as for the complete pick (Songyong et al, 2017) or picks forming the cutting head (Krauze et al, 2015, Krauze & Kotwica, 2007. Implementation works were also carried out with the aim of applying modern tools and heads in difficult conditions , , as well as applying alternative tool solutions (Gospodarczyk et al, 2013(Gospodarczyk et al, , 2016, (Kotwica, 2018, Bołoz, 2019. Also the procedures for assessing the quality of picks enabling the best offer to be chosen by the user during public tenders were subjected to research (Bołoz, 2018).…”

An Improved Procedure for the Quality Control of Sintered Carbide Tips for Mining Applications, Based on Quantitative Image Analysis of the Microstructure

“…By the quality of the picks, we should understand fulfilling the set requirements and achieving the highest possible durability. The acceptable quality of the picks is in the interest of both the users and the manufacturers, because tool replacement, beside the costs related to purchasing and logistics, causes machine shutdowns as well as a drop in efficiency, which means a reduction in the daily output [ 3 , 4 , 5 , 6 , 7 ].…”

Conical Pick Production Process

“…Tests were done for cemented carbide (Nahak et al, 2015), steel (Gajdzik & Sitko, 2014 as well as for the complete pick (Songyong et al, 2017) or picks forming the cutting head (Krauze et al, 2015, Krauze & Kotwica, 2007. Implementation works were also carried out with the aim of adjusting modern tools and machines to difficult conditions as well as using alternative tools in the form of discs (Gospodarczyk et al, 2013, Anchor, 2018, Bołoz, 2019. The subject of works was also the procedure for assessing the quality of picks enabling the user to choose the best offer in public tenders (Bołoz, 2018).…”