Assessment of the Structure of Cutting Heads with Regard to the Mining Machine Load Using Proprietary Software

The cutting heads currently used in longwall shearers, roadheaders, road milling machines and excavators are equipped with cutting tools called picks. The most commonly applied are conical picks, less frequently—radial picks or tangent picks. The picks are detachably mounted in holders installed on the body of the cutting head, to which they are usually welded (shearers) or, less frequently, form-connected (road milling machines). The arrangement of picks and holders (positioning) on the body of the cutting head, according to a previously designed diagram (pick arrangement), enables extraction of the mineral with a specific width (web) and diameter (height). Ideally, the pick arrangement should generate the lowest cutting resistance, which loads the cutting machine. The pick arrangement is characterized by design parameters (number of holders, pitch in the line and between the cutting lines) and kinematic parameters (rotational speed and advance speed). The values of these parameters result mainly from the properties of the mineral and the type of mining machine. Therefore, the correct positioning of the holders on the cutting head and their setting (cutting angles) are vitally important. This applies to both the design and implementation stages. For this purpose, the authors first developed models of pick arrangements and, next, the algorithm and software enabling the determination of cutting resistance, both in terms of the average value and its variation. Then, based on the performed calculations and the obtained results, it can be assessed whether the cutting head and the pick arrangement are properly designed. As a result of the performed calculations and analysis of the test results, the average values of the cutting resistance moment and the cutting machine advance forces were determined. It was found that the proposed pick arrangements are characterized by similar values of moments and forces. The greatest differences were found in the variability of these parameters, which translates into the dynamics of the cutting machine operation.