Experimental Research On Multi-material 3D Printing Technology With Soft Materials For Soft Robotics

Due to its unique driving method,flexible functional structure,and high flexibility,soft robots have broad application prospects in auxiliary medical care,environmental exploration,and object grasping.However,with the increasingly complex structural design and increasingly diversified functions of soft robots the traditional manufacturing scheme can no longer manufacture soft robots with complex functional structures.As an emerging manufacturing method,the combination of 3D printing and soft robots has developed rapidly in recent years,and it will gradually become the main manufacturing method of soft robots in the future.However,the traditional 3D printing manufacturing ware robot can only print a single material software robot with simple structure,which is difficult to realize the integrated printing of composite functional soft robot.In order to solve the current problems and realize the manufacture of soft robot system composed of a variety of functional components,sensing elements,control elements and actuators.This paper proposes a soft robot manufacturing method based on multi-material 3D printing.The feasibility of 3D printing of composite materials by software robot is discussed in detail from the aspects of building 3D printing platform,performance analysis of printing ink,modeling and simulation,process parameter optimization experiment and so on.Finally,the soft robot and soft functional devices based on composite materials are printed successfully.The main contents of this subject are as follows:(1)Several 3D printing platforms with multiple nozzles for soft materials with different performance have been built.The 3D printing of silicone soft materials and liquid metal functional materials is realized.According to the process requirements,the soft material extrusion module,three-axis motion module,software and hardware control module are designed and refitted.The open source firmware is also modified to meet the needs of software multi-material 3D printing.(2)Ecoflex-0030,PDMS silicone soft materials and functional liquid metals were analyzed and tested.By adding modifiers to control its rheological properties,the most suitable ink preparation scheme and detailed material ratio for soft material printing are obtained.Secondly,the flow velocity of ink nozzle and the extrusion process of sol material are simulated,and the flow parameters of ink nozzle and com material are obtained.(3)The process parameter optimization experiments of soft materials and functional soft materials involved in the process of multi-material 3D printing are carried out,and the optimal process parameter combination of corresponding soft materials is obtained,so as to ensure the high-quality curing and molding of soft material 3D printing.The effects of extrusion pressure,nozzle moving speed,layer height and other process parameters on the molding quality of the soft material Ecoflex-0030 silicone during 3D printing were explored.For functional materials,the effects of process parameters including printing relative height,curing temperature and printing flow on the thickness,flatness and liquid metal forming quality of PDMS substrates were studied respectively.(4)Several soft robots based on composite materials have been fabricated by multi-material 3D printing technology,including a liquid metal-based flexible strain sensor with a strain grid structure,a composite air pressure control valve based on pressure control,and a multi-airbagbased soft gripper based on Yeoh.The design principle of each soft robot and its 3D printing manufacturing method are introduced in detail,and a functional verification experiment is carried out to obtain its detailed performance curve.Finally,the above-mentioned flexible functional devices are integrated into a set of human-computer interaction three-finger software hand system integrating sensing,control and execution,which can grasp objects of different sizes and masses on the basis of gesture control.It verifies the ability of the multi-material 3D printing platform system described in this paper to achieve efficient,high-precision,and integrated printing of composite material soft robots.