Process modeling for robotic polishing
Abstract This paper presents the solutions adopted for a robotic polishing cell for mold manufacturing. Mold finishing is frequently carried out manually; these kinds of operations are iterative, time consuming and require experience. Automation can introduce cost reduction minimizing production times on such manual finishing operations. The research shown in this paper provides an overall solution without discarding aspects that could be relevant to the task considered in the mold making environment. Most of the mold makers usually employ CAD/CAM systems in order to design workpieces and to prepare the CNC programs to manufacture the parts, this CAD data can also be used to prepare programs for the actual robot finishing of these parts. In this work, an automatic planning and programming system based on data from a CAD system is described. The direct use of the paths implies difficulties of adaptation mostly when free-shaped surfaces are treated, so that the use of a constant contact force control has also been considered. To accomplish the automation of the process it is necessary to establish a behavior model of the system’s variables. This fact allows the definition of the task specifications of the tools and, as a result, both the planning system and the control strategy by stages of the polishing process.
Compound control of the robotic polishing process basing on the assistant electromagnetic field
Robotic polishing process has been widely used for the metal mould finishing. The quality and the efficiency of the polishing process are important to the lead time and the lifecycle of the mould. In order to improve the robotic polishing process with free abrasive and soft polishing tool, the compound control system made up of compensable path planning module and assistant electromagnetic field is developed in this paper to fit for the common commercial industrial robot, which is hard to be controlled online for its closed control system. The compensable path planning module based on CAM module is developed to generate the uniform robotic polishing path for the complex curvature surface, which can also compensate the elastic deformation and the abrasion of the soft polishing tool. A minitype electromagnet is also connected to the robotic end-effector, which can act on the polishing process along with the robotic moving. The electromagnet is coiled as solenoid that the polishing tool and the electrical spindle can be fixed in the hollow. Experiments are executed to test the influence between the electromagnetic field intensity and the polishing removal efficiency. The result shows that the polished material removal can increase obviously with the increasing of the electromagnetic field intensity.
Methodology of Parametric Programming for Error Compensation on CNC Centres
Although work has been carried out on parametric programming on CNC centres, there have been few papers which focus on error compensation. Parametric programming for error compensation is presented in this paper on the basis of a simple model of machining system deflections induced by the radial cutting force in CNC turning operations. The resulting errors are introduced as compensation values to the conventional tool movements along the programmed tool path. This can result in a complex tool path. Parametric programming is applied to handle this complexity for error compensation.