Review of Recent Development in Deep Drawing Process
Deep drawing is a common metal forming process used to manufacture recessed threedimensional parts from flat sheet metals. The research in deep drawing has been generic over the last few decades and various aspects of this process have been investigated. The paper aims to review the following aspects of deep drawing process that affect the quality of the product, tooling life and process design: i. The development of a theoretical model for the isoviscous hydrodynamic lubrication of deep drawing and its comparison with experimental results, the effect of lubrication on die expansion that could be used as an indirect means of detecting and measuring the presence of a hydrodynamic lubricant film thickness. ii. The improvement in deep drawing tooling that covers analysis for the blank holder, the effect of punch geometry on the deep drawing process, and introducing an alternative tooling materials for batch production. iii. The recent developments and future direction of research.
Design considerations for hydromechanical deep drawing of sheet components with concave features
Abstract Design for hydromechanical deep drawing of sheet components with concave features requires more detailed considerations than that for the forming of components with convex features. FE simulations were conducted to examine the deformation of the sheet during the forming of these component-forms and to qualify the influence of counter-pressure paths on the product-quality, with a view to developing a reference for process, tool and component design considerations for the hydromechanical drawing of such component-forms. The results suggested that in order to prevent the initiation of forming-defects and to achieve high-quality products, the counter-pressure paths should be designed to match the component-forms to be produced.
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.