Drilling of Holes in Aluminum Matrix Composites at Dry and with the Minimum Quantity Lubrication of the Cutting Zone

Abstract

Holes in metal matrix composites can be created by unconventional techniques such as EDM or laser drilling. However, these methods do not guarantee the quality of the holes, the production efficiency. The work carried out conventional drilling studies of aluminum matrix composite reinforced with ceramic fibers and the nonreinforced matrix. The tests were made dry and under conditions of minimum quantity lubrication (MQL) of the cutting zone. Oil mist was applied external. The measured and observed machinability indicators were surface roughness, cutting force, hole shape error, and chip shape. It was found that the use of oil mist in drilling improves the shape quality and surface of the holes. The positive effect of lubrication decreases with increased drilling feed. Oil mist slightly reduces cutting resistance and does not change the shape of the chips. It is shown that by drilling holes in aluminum matrix composite under conditions of minimal quantity lubrication, it is possible to achieve such a quality that it is possible to eliminate roughing. An additional advantage of using oil mist is a smaller dispersion of test results, which shows that the treatment with minimal lubrication is more stable.

Dry and Oil Mist Milling of Aluminium Matrix Composite Reinforced With Saffil Fibres

“…In addition, the wide variety of composite materials, which differ in matrix material, reinforcement, reinforcement shape and arrangement, as well as volumetric content of the reinforcement, makes it difficult to compare published research results and relate them to a specific newly designed composite material. The results presented in this paper are a continuation of studies on the machinability of Al/Al2O3f composite presented in [9,23,28].…”

“…The results of the roughness measurements after milling at a cutting speed of 178 m/min are shown in the graphs (Figs. [21][22][23]. In contrast to machining at lower speed, in this case the machining fluid quantity has no effect on the quality of the machined surface.…”

“…The wear of the blades is reduced if the milling of the composites is supported by oil mist [20,21]. The quality of the machined surface of the composite is also improved by using MQL, both in turning [22] and drilling [23,24]. Improvement in the technological effects of the machining of aluminium matrix composites using MQL is not limited to low cutting speeds [25].…”

Debonding of bonded composite joints with TEP modified epoxy adhesives

“…To distinguish surface roughness from potential surface waviness and shape fault, a Gaussian filter (2.5 mm and 0.8 mm for Ra,1 and Ra,2, respectively) was also applied for the calculations (Fig. 12) [28]. Sandblasting of GFRP increased the surface roughness by 111% (i.e., Sa increased from 6.29 mm to 13.3 mm), and plasma surface treatment raised Sa by 37.4% (to 8.65 mm).…”

“…Thermally expandable particles (TEPs), developed by Dow Chemicals, are well-known microsphere-based materials used in debonding technologies. Lu et al [1] examined debonding characteristics of aluminum (Al) adherends bonded with 3M 9323 epoxy mixed with Expancel 920 DU 120 HEMA (28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38) µm diameter) at room temperature (RT) and their residual (Res.) strength after heating up 270 o C. Nishiyama et al [2] studied the debonding effects of Matsumoto F-30 miscrospheres (10-30 µm diameter range) inside Epikote 828 epoxy on gridblasted and gridpaper surface treated Al alloy adherends.…”