Burr
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Burr
Theory and Application
Vikki Franke Stuttgart, Germany
History Burrs are an economically very important issue in many machining operations. Therefore, a lot of research has been done in the last 50 years to understand, control, and minimize burr formation. The first published works on burrs cover burr formation in punching. Pekelharing (1964) was the first to describe burr formation mechanisms in metal cutting processes. He described the chip formation process and closely interlinked burr formation to chip formation. The first fundamental work describing an analytical model of burr formation, which enables to predict burr properties, was done by Gillespie et al., published in 1976 (Gillespie and Blotter 1976). After a basic understanding of the burr formation mechanisms was gained, research activities turned to the topic of deburring. In 2009, CIRP published a keynote paper on burrs by Aurich et al. (2009). The paper gives a review of the topic of burrs in machining operations.
Definition There are several definitions for burrs, but they all describe the same phenomenon. Burrs are undesired but mainly unavoidable. A burr is a material accumulation, which is created on the surface during the manufacturing of a workpiece. It extends over the intended and actual workpiece surface and has a slightly higher volume in comparison with the workpiece (Beier 1999). Burrs are uncut material remaining on the workpiece after being machined. Burrs occur at the workpiece surface in cutting as well as in shearing operations at the workpiece edges. Further, laser machining can lead to burrs as well. This essay focuses on burrs of machining and shearing processes. Burrs are of great industrial relevance as they interfere with the workpiece performance and functionality. Ideally, workpieces would be free of burrs, but, as this is often not the case, burrs can only be reduced either by changing the machining parameters, tool path, or tool. Alternatively, the burrs will have to be removed by time-consuming and expensive deburring processes.
Burr Classification There is no overall classification of burrs. However, classifications of burrs defining the edges of workpieces, for example, in drilling or milling, as well as an ISO standard, are available. CODEF (the Consortium on Deburring and Edge Finishing) classified five drilling burr types
# CIRP 2018 The International Academy for Production Engineering et al. (eds.), CIRP Encyclopedia of Production Engineering, https://doi.org/10.1007/978-3-642-35950-7_6393-4
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Burr
Burr, Fig. 1 Typical drilling burrs (Aurich et al. 2009)
Burr, Fig. 2 Types of burr according to Gillespie (1999)
Burr, Fig. 3 Definition of workpiece edges according to ISO 13175
(Fig. 1). Gillespie introduces four types of burrs: poisson burr, rollover burr, tear burr, and cutoff burr (Fig. 2) (Gillespie 1999). The ISO 13715 standard defines the edges of workpieces as sharp, free of burrs, rounded, chamfered, or with burr (Fig. 3) (ISO 13715). Nevertheless, many companies use an in-house classification, as an overal
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