| Popis: |
The knowledge about machinability indices for distinct machining processes allows finding the most appropriate values of the relevant factors for definite machining operations. Several criteria can be used to characterize machinability, such as the tool wear, the magnitude of the cutting forces, the roughness of the machined surfaces, or the shape of the chips that are formed during the machining process. One of the methods for studying the machinability is based on the analysis of drilling operations that are made under constant feed force. A drill press is probably the most readily available device to implement an experimental setup for drilling machinability tests. In normal operation, however, the chip accumulation at the dead end of the machined hole has a detrimental impact on the results of machinability tests, so that an improved setup was designed. A two-level, full factorial experiment with three independent factors (the drilling tool diameter, the rotational speed of the spindle and the feed force) has proven the suitability of the new experimental setup. Using it, we could find a power-type empirical model that explains the impact of the input factors in the depth of a hole that is machined in a pre-defined time interval. |
