Problem statement: Single Point Diamond Turning (SPDT) is highly deterministic and versatile in producing various forms of precise optics. A typical example is the production of large offaxis aspheric mirrors and various infrared mirrors and mandrels. However, the fine periodical turning marks left in the surface critically limit its performance and they are difficult to be avoided for traditio...

This in vitro study determined the surface roughness (Ra) and absolute gloss (AG) values for 2 resin composites: a microhybrid and a microfill. Eight groups (n = 4) of each resin composite were prepared, along with 4 controls (Mylar strip) for the 2 resin composites. After finishing with a medium polishing disc, the specimens from each resin composite material were subjected to 7 polishing proc...

The fatigue strength of flapper valves depends among other things on surface properties of the steel. This paper deals with the effect of a tumbling method*) on bending and tensile fatigue properties of test bars. For carbon steel SANDVIK 20C an improvement was observed in several test series, particularly in the transverse direction of the strip, whereas there was little effect for stainless s...

During endodontic therapy, cleaning of root canals is performed using endodontic files and auxiliary chemical substances, and it is important that the endodontist be familiar with the instruments used in daily practice. This study evaluated, under scanning electron microscopy (SEM), the quality of the surface finishing of unused rotary endodontic instruments. Fifty sizes 20, 25 and 30 rotary fi...

The robotization of on-site surface finishing work, particularly sandblasting, is considered. A possible system design is presented with a cost estimate. Costs and benefits of applying the proposed robot system to on-site sandblasting are outlined and estimated. Net present value of the contractor's investment in the robot equipment is analyzed. Conclusions regarding the purchase price of the r...

Subsurface damages (SSD), which are introduce during grinding process of optical components for high power lasers applications, act as initiator for laser damage and are responsible of the low lifetime of these components. The knowledge of the SSD depth is essential to remove the damaged layer of the optical component during the last finishing step of grinding. However, existing methods to meas...