 reduce burr height in titanium drilling is presented in which a biocompatible coating (PMMA) is applied to the upper and lower surfaces of a titanium sheet

To experimentally evaluate the proposed method, two thicknesses of coating and two different drills diameter were tested. The efficacy of the method in terms of burr homogeneity and height was analyzed with scanning electron microscope (SEM) and 3D digital microscopy, respectively. The results highlight some benefits and critical aspects of the proposed approach.

Of interest is the suitability of the method for application in biomedical device production. Titanium is strong, biocompatible, and completely resistant to bodily fluids, making it the material of choice for the manufacture of a myriad of medical and dental devices, such as artificial valves in the heart \[[@B19-micromachines-10-00838]\]; stents in blood vessels \[[@B20-micromachines-10-00838]\]; and replacement implants in shoulders, knees, hips, elbows \[[@B21-micromachines-10-00838]\] ears, and dental structures \[[@B22-micromachines-10-00838]\]. These devices often require machining, including micro-drilling. However, if the drilling process generates a significant amount of burr that cannot be removed, it may have an adverse influence on the survival of the implant and trigger adverse side effects in recipients; therefore, methods to reduce burr height play a fundamental role in medical device production, yet they must be developed with the constraint of using materials that do not contaminate the biocompatibility of the workpiece.

2. Materials and Methods {#sec2-micromachines-10-00838}
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2.1. Coating Process {#sec2dot1-micromachines-10-00838}
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The top and bottom of the part to be machined are first covered with a film (step A), as shown in [Figure 1](#micromachines-10-00838-f001){ref-type="fig"}. After machining, a cleaning process is executed to eliminate the coating, while avoiding surface microstructure modifications. Finally, a hole with a re