Design And Fabrication Of Inkjet Print-head Polymer Chamber

As an indispensable part in daily life,inkjet print-head is not only used for text and commercial printing,but also for packaging,ceramic printing,integrated circuit printing and other fields.In this paper,the design and fabrication of piezo inkjet print-heads was studied and four parts were included.(1)Reviews of inkjet print head researches progresses and inkjet print head chamber processes.The development of micro-electro-mechanical systems(MEMS)provides a new way for the production of inkjet print-heads,taking the advantages of short production cycle,high alignment accuracy,low cost and high print head resolution.(2)Optimizing the structure of inkjet print-head chamber.The properties of silicon and its compounds,metal(Ni),glass,Parylene,PI,SU-8 photoresist were compared.And SU-8 was chosen as the chamber material of inkjet print-head.Combined with piezoelectric theory and flow equation,COMSOL was used to optimize the pressure chamber size,nozzle plate thickness and nozzle shape.The pressure chamber had length of 1000~1200?m,width of 120?m and height of 140~160?m.(3)Production and optimization of inkjet printing-head chamber.Lithography process and bonding process were selected to fabricate SU-8 chamber of inkjet print-head.The intensity distribution model of SU-8 photoresist with different depth was obtained by absorption model and direct-side diffraction model in the manufacture process of SU-8 photoresist lithography,which provided the theoretical basis for the production of polymer conical nozzle.Polymer mechanical properties and interfacial bonding mechanism were studied,providing theoretical guidance for the bonding process.The bonding rate,bonding deformation and bonding strength were proposed to evaluate the bonding quality.The relationship between the cross-linking of SU-8 photoresist and the process parameters of the chamber was quantitatively analyzed.Using low exposure(105mJ/cm2)and low baking temperature(65?),a weakly cross-linked SU-8 photoresist nozzle plate was fabricated whose the glass transition temperature was 60? and epoxy resin conversion was 47.2%,.And then low temperature bonding was used to bond the nozzle plate and open chamber.The bonding temperature and pressure were set as 60 ? and 0.1~0.12 MPa respectively to meet inkjet requirements.The SU-8 photoresist conical nozzle was produced by the non-contact exposure method,whose the nozzle taper increases along with the exposure gap.When exposure dose ranged from100 to 110mJ/cm2,through-hole rate was more than 95%.Using 120?m exposure gap,a small conical SU-8 photoresist nozzle was finally fabricated with large pore size of 30?m,small aperture of 20?m and depth of 45?m.(4)Characterization of polymer chamber performance.The bonding strength was tested to be 0.95 Mpa,greater than the maximum stress at the interface between the orifice and the chamber during the inkjet process.The inkjet test of strobe method was carried out.The ink droplet velocity is 5.9 m/s,the volume is 12.7 p L and the droplet diameter is 28.9?m.