Evaluating the delamination in the drilling process of a melamine coated medium density ...

Medium density fiberboard (MDF) is an engineering product that is used in many industrial and general applications. Generally, MDF products are generated by screw joints using the drilling process. However, the drilling process of the MDF panels leads to the delamination at the entrance and exit of the drill bit that should be controlled. In this work, the effect of the processing parameters including the feed rate and cutting speed on the delamination of a melamine coated MDF were investigated. For this, two different tools with different tool geometry (a special wood drill bit and a commonly used high speed steel (HSS) drill bit) were examined. Image processing was used to measure the conventional delamination factor together with a new delamination factor referred to as area delamination factor for the drilled holes. It was found that the delamination value decreases with increasing cutting speed and increases with increasing feed rate. Though, there were some fluctuations in the results. The trend of changing the delamination respect to the investigated parameters was the same for both applied drill bits; however, smaller value of delamination was obtained using the HSS drill bit. Using the proposed area delamination factor the effect of process parameters on the delamination presented with higher magnitudes but with the same behavior. This, together with the ability of characterization of the water absorption of drilled holes makes the area delamination factor a more appropriate parameter to evaluate the delamination. The overall results were in consistent with previously published works.