# Research on Grinding Force of Ultrasonic Vibration-Assisted Grinding of C/SiC Composite Materials
## 2 Experimental Plan
### Test Devices and Process Parameters  
The test was performed on a high-speed machining center (DMG Ultrasonic 20 Linear DMG MORI, Bielefeld, North Rhine-Westphalia, Germany). Both the common grinding test and the UVAG test were carried out with a 14h6 ultrasonic tool holder, as is shown in Figure 3. The tool used was a Schott cup-shaped sintered diamond grinding wheel, hollow structure, a total length of 60 mm, an outside diameter of \(\diameter\)24 mm, and wall thickness of 2 mm. The average diamond abrasive particle size was about 300 \(\upmu\)m, and the edge height was about 100 \(\upmu\)m. Under the same grinding process conditions, the larger the diamond abrasive particle size, the smaller the grinding wheel mesh number. A larger abrasive particle size means larger chip space, which is helpful for material removal. The smaller the abrasive particle size, the smaller the top cone angle of the diamond abrasive particle, and the sharper it is. Under the same conditions, the contact area was smaller, and the grinding force was smaller. In order to study the influence of ultrasonic vibration on the grinding force, the grinding wheel with larger grain size and coarser was selected in this paper to fully study the influence of ultrasonic vibration on C/SiC grinding under small cutting data. Figure 1: C/SiC composite components. (**a**) Macroscopic structure. (**b**) Microstructure. Figure 3: The 14h6 ultrasonic tool holder. Figure 2: C/SiC composite sample after split. During the test, we replaced or modified the grinding wheel once for each single factor test. The coolant used was a water-based emulsion (Castrol, Berkshire, England) with a concentration of about 4\(\sim\)5%.During the test, both internal and external cooling were turned on, the internal cooling pressure was 20 bar, and the external cooling pressure was 4 bar. The specific test device conditions are shown in Table 1.  
The specific grinding process parameters for side grinding and end grinding are shown in Tables 2 and 3, respectively. The grinding width \(b=5\) mm during side grinding (6 samples for the test), and the grinding width \(b=8\) mm during end grinding (12 samples for the test). The ultrasonic vibration amplitude was set as 6 \(\upmu\)m, and the main consideration was that the vibration amplitude should be less than the grinding depth so that the machining process was always maintained in the continuous vibration grinding state. In the continuous vibration range, the larger the vibration amplitude, the more prominent the effect of ultrasonic-assisted vibration on the grinding force. The test scheme is determined separately to obtain the empirical formula of grinding force for common grinding and UVAG. The process parameters of side grinding and end grinding are shown in Tables 4 and 5. The rest of the test conditions are the same as the previous test scheme, including four samples for side grinding and eight samples for face grinding. The grinding position of the sample is shown in Figure 4. \begin{table}
\begin{tabular}{c c} \hline
**Item** & **Description** \\ \hline Machine tool & DMG Ultrasonic 20 Linear \\ Schott cup-shaped sintered & 6A9 – Do.24 – X = 2 – U = 6 – D91H \\ diamond grinding wheel & KISTLER9272 three-way \\ Grinding force measuring device & piezoelectric crystal dynamometer \\ Amplitude measuring device & LV-S01-HF Laser Vibrometer \\ \hline \end{tabular}
\end{table} 
Table 1: Specific parameters of test device. \begin{table}
\begin{tabular}{c c c c} \hline  & **A** & **B** & **C** \\  & **Grinding Wheel Linear Speed** & **Feed Rate** & **Grinding Depth** \\  & \(v_{\text{S}}\) (m/s) & \(v_{\text{W}}\) ( mm/min) & \(a_{\text{p}}\) (mm) \\ \hline Condition 1 & 1.26 & 50 & 0.01 \\ Condition 2 & 5.04 & 200 & 0.02 \\ Condition 3 & 8.82 & 350 & 0.03 \\ Condition 4 & 12.6 & 500 & 0.04 \\ \hline \end{tabular}
\end{table} 
Table 2: C/SiC composite side grinding process parameters (\(f=33.9\) kHz, A \(\approx 6\) \(\upmu\)m).