Investigation of Friction Weldability of En Aw 6063 Aluminium Alloy Tube to Tube Plate Using an External Tool
The traditional welding methods are commonly used tube to tube plate of heat exchangers and economiser. In this study it was investigated that application of an alternative welding method which called friction welding of tube to tube plate by using an external tool was used joining of AlMg0,7Si (EN AW 6063) aluminium alloy. The AlMg0,7Si plates with dimensions 5x50x70 mm were drilled Ø20,5, Ø21, Ø21,5, Ø22 mm. The four different sizes AlMg0,7Si tubes with dimensions 2 mm wall thickness, 20 mm outer diameter, respectively 45,5, 46, 46,5, and 47 mm length friction welded to plate using an external tool (FWTPET) at constant 900 min-1 tool rotational speed. The vertical force between tool shoulder and tube was constant during the welding, and temperature was measured at every different welding parameters. The shear test was done for determining for welded joints using special fixture. Shear strength of welded joints were determined depend on welding parameters
Eco-friendly aspects associated with friction welding of tube-to-tube plate using an external tool process
The competitiveness among the manufacturers has been forcing the manufacturing processes to be eco-friendly so as to deliver products with lesser impact on the environment, energy demand and other resources consumption. In this regard, this article presents the unique environmentally friendlier aspects associated with an innovative welding process namely friction welding of tube-to-tube plate using an external tool (FWTPET). This process is capable of generating robust weld joints with lesser energy consumption. A comparative analysis of FWTPET with conventional tungsten inert gas welding process has been narrated.
Submicron polymer structures with X-ray lithography and hot embossing
This article describes the process chain for replication of submicron structures with varying aspect ratios (AR) up to 6 in polymethylmethacrylate (PMMA) by hot embossing to show the capability of the entire LIGA process to fabricate structures with these dimensions. Therefore a 4.7 μm thick layer of MicroChem 950k PMMA A11 resist was spin-coated on a 2.3 μm Ti/TiOx membrane. It was patterned with X-ray lithography at the electron storage ring ANKA (2.5 GeV and λc ≈ 0.4 nm) at a dose of 4 kJ/cm3 using a Si3N4 membrane mask with 2 μm thick gold-absorbers. The samples were developed in GG/BDG and resulted in AR of 6–14. Subsequent nickel plating at 52°C resulted in a 200 μm thick nickel tool of 100 mm diameter, which was used to replicate slit-nozzles and columns in PMMA. Closely packed submicron cavities with AR 6 in the nickel shim were filled to 60% during hot embossing.