# ELID Dressing Behaviors of Non-Abrasive Iron-Based Grinding Wheels
## 1 Introduction  
As early as the 1980s, cast-iron-bonded grinding diamond wheels with micro-scaled powders were innovatively fabricated by [PERSON] [1; 2; 3]. However, due to their small pores, which were easily blocked and caused passivation, these fine-grain, cast-iron-bonded grinding diamond wheels proved difficult to popularize and apply in common grinding processes of that era [4; 5; 6; 7]. To address the issue of abrasive passivation, significant progress has been made in achieving nano-level surface quality by applying the ELID grinding method to sharpen the abrasives (H.Ohmori). As a result, Electrolytic In-Process Dressing (ELID) grinding is gaining increasing attention in the field of ultra-precision machining [8; 9; 10]. Though conducted at the nanoscopic scale, ELID grinding often results in deep scratches on finely ground surfaces. Even a minor scratch on a highly precise nanoscale surface can be catastrophic or irreparable. Researchers have identified a root cause of these surface scratches. They found that passivated abrasive particles detach and fall into the electrolyte. When this electrolyte participates in the grinding processes, these abrasive particles cause secondary scratches on the surfaces, leading to defects. In recent years, innovative diamond wheel designs have been proposed to super-sede traditional hard cast-iron-bonded diamond wheels [11], including porous metal-bonded grinding diamond wheels [12; 13; 14; 15], iron-resin-bonded diamond wheels [16; 17; 18; 19], conductive rubber diamond wheels [20; 21; 22; 23], and plant-carbon-bonded grinding diamond wheels [24; 25; 26; 27], multi-layer brazed coarse-grained diamond wheel [28; 29; 30]. Researchers have also combined PEIID and 3D printing techniques to manufacture new grinding diamond wheels [31; 32; 33]. These advanced bonded diamond wheels are effective in achieving higher surface quality and broadening the application fields for ELID grinding due to their ability to attain higher grain density and avoid agglomeration compared to the traditional sintering technique. Indeed, these new grinding diamond wheels mitigate the scratches on finely ground surfaces, but they do not eliminate all scratches. Although significant progress has been made in achieving high precision and high-quality machining surfaces in ELID grinding, avoiding secondary scratches caused by passivated abrasive particles remains a challenge. This paper introduces a novel iron-based grinding diamond wheel devoid of abrasive particles. This non-abrasive particle diamond wheel is manufactured to form an iron oxide film as the primary component on the surface through the ELID electrolysis process [34]. Notably, the oxide film generates \(\alpha\)-Fe\({}_{2}\)O\({}_{3}\) on the surface of the iron-based grinding diamond wheels via an electrochemical reaction under high grinding temperatures. Large quantities of \(\alpha\)-Fe\({}_{2}\)O\({}_{3}\) particles are favorable, serving as an excellent agent for polishing in place of abrasive particles. Due to the absence of abrasive particles, our new diamond wheels address the issue of passivating particles that may detach and scratch the processed surface [35; 36]. The non-abrasive iron-based grinding diamond wheel introduced in this study represents an initial development, making it crucial to understand its electrolysis process, oxidation film formation, and oxide film performance. We examine the impact of the oxide film's characteristics and its composition, properties, iron group content, and \(\alpha\)-Fe\({}_{2}\)O\({}_{3}\) particle conversion on the polishing performance of ELID. Our focus is on the electrolysis mechanism of the non-abrasive iron-based grinding diamond wheel, discussing the decisive factors that differentiate non-abrasive diamond wheels from other iron-based grinding diamond wheels. The mechanical properties of the oxide film were tested by polishing plate glass using the electrolyzed, non-abrasive iron-based grinding wheel.