The Design Of Embedded Control System Used In Laser Truing And Dressing Diamond Grinding Wheels

Diamond grinding wheels have ultrahigh hardness, and this makes the dressingand truing of diamond grinding wheels more difficult. At present, the dressing andtruing of diamond grinding wheels has some problems, such as, the precision, theefficiency and the cost can’t be satisfied together, the wheels after dressing and truingalso exist high spots on its surface. As a non-contact method, dressing and truinggrinding wheels by laser avoids the hurt of abrasive and binder caused by theinteraction of force, and it’s a promising technology. The control system is studied inthis paper. Through applying the control system to production of laser ablation, itrealizes selective dressing and truing of diamond grinding wheels, and solves theproblem of roundness error which is caused by laser ablation without control.Meanwhile, by choosing a set of optimal parameters of pulse laser and process, itfinally achieves the goal of high precision and efficiency.In accordance with the process of laser dressing and truing, a real-time controlsystem which adopts high-precision CCD laser displacement sensor as measure deviceand adopts ARM microcomputer as the core of calculation processing and control isdesigned in this paper. The system which is based on principle of triangulation, adoptsthe method which can detect and ablate in synchrony. It collects the topographicsignal of the object by sensor, then accomplishes the comparation between samplingvalue and reference value in the ARM, and exports the TTL level to control theacousto-optic Q-switched Nd:YAG pulsed laser according to the result of comparation.The system is described from the hardware and software design,and finally realizesthe selective dressing and truing of diamond grinding wheels which a great pulse laseris launched to the high spot of grinding wheel and not launched to the low spot,through the coordination of hardware and software.Secondly, in the aspect of reference value’s choosing, a LabVIEW virtualinstrument is designed based on PC computer, according to the inconvenience of thechoosing, meanwhile, it realizes the free transmission of the reference value betweenPC computer and ARM microcomputer which can change the reference value withoutmodification of the program, through calling semaphores of Linux operation system.It reduces the workload and improves the efficiency of laser’s dressing and truing.Finally, a series of optimal parameters such as the laser average power, pulse repetition rate, the wheel speed and the axial machine automatically feed rate areselected to do some experiments which adopts this control system as controlequipment, the acousto-optic Q-switched Nd:YAG as tool, and the diamond grindingwheels as material. The finished grinding wheel surface topography and geometryprecision are analyzed and evaluated. The result of experiments shows that thedressing precision and surface quality after laser trimming with this control system isgood.