Process and tool development of single lip drills due to an optimisation of the circumferential shape and surface topography

采用三种不同的制备方法，分析了原基础工程单齿钻头周向表面形貌的产生及其影响。由此产生的孔质量的改善为许多应用提供了提高工艺质量的可能性。例如，医疗行业用于生产骨钉钻孔，用于加热/冷却钻孔的工具和模具制造，用于海上工业和汽车工业的注射部件。对于汽车工业，特别是商用车共轨喷射系统的高低压孔的生产，提高孔质量是一个主要目标。这是必要的，因为目前的工具不能满足最大粗糙度深度Rmax < 10微米的要求。因此，该方法的目的是通过弹性结合磨削来改善表面形貌，从而改变刀具的周向形状。此外，有必要用优化的涂层工艺来考虑上述方面，以实现凹槽的最大深度的最小化。基础项目的结果表明，由于圆周形状的刀具制备，在lc = 3 m Rmax = 4微米到Rmax = 2.2微米的刀具寿命期间，Rmax = 8.5微米到Rmax = 2.6微米的磨合行为和孔质量的改善是可能的。这是通过改变刀具的圆周形状以及在未涂覆状态下将导向条的表面质量从Rz = 1微米提高到Rz = 0.7微米来实现的。对于工业过程中发现的原型实施，有必要通过适当的工艺链转移优化单齿钻头的知识，并避免通过适应的涂层工艺进行后处理。

The former fundamental project, the production and influencing of the circumferential surface topography of single-lip drills, was analysed using three different preparation methods. The resulting improvement of the bore quality offers the possibility of increasing the process quality for numerous applications. These include, for example, the medical industry for the production of boreholes in bone nails, the tool and mold making for heating/cooling bores, the usage in the offshore industry and the automotive industry for injection components. For the automotive industry, especially for the production of high and low pressure bores in commonrail injection systems of commercial vehicles (CV), is the increase of the bore quality a main target. This is necessary because current tools cannot meet the requirements for the maximum roughness depth Rmax < 10 microns. Therefore, the aim of the approach is a modification of the circumferential tool shape in combination with a surface topography improvement by grinding with an elastic bonding. In addition, it is necessary to consider the mentioned aspects with an optimized coating process to achieve a minimization of the maximum depth of the grooves. The results of the fundamental project show that due to a tool preparation of the circumferential shape, an improvement of the run-in behaviour of Rmax = 8.5 microns to Rmax = 2.6 microns and of the bore quality over the tool life of lc = 3 m Rmax = 4 microns to Rmax = 2,2 microns is possible. This is achieved by changing the circumferential tool shape as well as by improving the surface quality of the guiding strips from Rz = 1 microns to Rz = 0.7 microns in the uncoated state. For the prototypical implementation of the findings on industrial processes, it is necessary to transfer the knowledge of optimizing the single-lip drills by a suitable process chain and to avoid post-treatments by an adapted coating process.