Abstract: An attempt is made here to measure the forces of three directions, under conditions of different feed speeds, different tilt angles of tool and without or with the pin on the tool, by using octagonal ring dynamometer in the AA2024 aluminum FSJ (Friction Stir Joining) process, and investigate how four main factors influence forces in the FSJ process. It is found that, high feed speed lead to small feed force and small lateral force, but high feed speed leads to large feed force in the stable joining stage of process. As the rotational speed increasing, the time of axial force drop from the maximum to the minimum required increased in the push-up process. In the stable joining stage, the rotational speed has little effect on the feed force; large rotational speed leads to small lateral force and axial force. The maximum axial force increases as the tilt angle of tool increases at the downward movement stage. At the moment of start feeding, as tilt angle of tool increases, the amplitudes of the axial force increasing become large. In the stable joining stage, with the increase of tilt angle of tool, the axial force is increased, the lateral force is decreased, and the feed force almost unchanged. The tool with pin will decrease axial force in the downward movement stage. The feed force and lateral force will increase, but the axial force will reduced in the stable joining stage by using the tool with pin compare to by using the tool without pin.
Abstract: Non-water based fixed abrasive polishing was adopted
to manufacture LBO crystal for nano precision surface quality because
of its deliquescent. Ethyl alcohol was selected as the non-water based
slurry solvent and ethanediamine, lactic acid, hydrogen peroxide was
added in the slurry as a chemical additive, respectively. Effect of
different additives with non-water based slurry on material removal
rate, surface topography, microscopic appearances, and surface
roughness were investigated in fixed abrasive polishing of LBO
crystal. The results show the best surface quality of LBO crystal with
surface roughness Sa 8.2 nm and small damages was obtained by
non-water based slurry with lactic acid. Non-water based fixed
abrasive polishing can achieve nano precision surface quality of LBO
crystal with high material removal.
Abstract: Experimental study on slicing of sapphire with fixed
abrasive diamond wire saw was conducted in this paper. The process
parameters were optimized through orthogonal experiment of three
factors and four levels. The effects of wire speed, feed speed and
tension pressure on the surface roughness were analyzed. Surface
roughness in cutting direction and feed direction were both detected.
The results show that feed speed plays the most significant role on the
surface roughness of sliced sapphire followed by wire speed and
tension pressure. The optimized process parameters are as follows:
wire speed 1.9 m/s, feed speed 0.187 mm/min and tension pressure
0.18 MPa. In the end, the results were verified by analysis of variance.
Abstract: Chemical vapor deposition (CVD) diamond coated
cutting tool has excellent cutting performance, it is the most ideal tool
for the processing of nonferrous metals and alloys, composites,
nonmetallic materials and other difficult-to-machine materials
efficiently and accurately. Depositing CVD diamond coating on the
cemented carbide with high cobalt content can improve its toughness
and strength, therefore, it is very important to research on the
preparation technology and cutting properties of CVD diamond coated
cemented carbide cutting tool with high cobalt content. The
preparation technology of boron-doped diamond (BDD) coating has
been studied and the coated drills were prepared. BDD coating were
deposited on the drills by using the optimized parameters and the SEM
results show that there are no cracks or collapses in the coating.
Cutting tests with the prepared drills against the silumin and aluminum
base printed circuit board (PCB) have been studied. The results show
that the wear amount of the coated drill is small and the machined
surface has a better precision. The coating does not come off during
the test, which shows good adhesion and cutting performance of the
drill.