Experimental Research on Behaviour of 3D Printed Gripper Soft Jaws

Dragos-Florin Chitariu,Victorita Stefanescu,Iulian Constantin,Sorin Berbece,Catalin-Gabriel Dumitras,Gures Dogan,Mihaita Horodinca,Emilian Paduraru,Mehmet Ilhan,Adrian Beznea,Florin Negoescu

doi:10.37358/mp.20.4.5437

Abstract

In this paper, the problem of the behaviour of soft jaws that can be used to replace the steel jaws of grippers is studied. One of the advantages of additive manufacturing is the printing of fully functional parts. Choice of material is often related to the part strength. The mechanical properties of 3D printed parts should meet the service loading and, also, must be comparable with parts produced by traditional manufacturing techniques - machined parts or injection moulding. From the specialized literature information regarding the test results for effect of various printing parameters on part strength are available made in laboratory conditions and for standard test sample. For ABS materials various values for Young module are presented varying from 1.5 GPa to 2.15 GPa, for 100% infill rate and various modified parameters such as raster orientation. In order to study the behaviour of soft gripper jaws several part were printing and the resistance to bending was tested, by simulating the way a gripper works. An experimental stand was built using a force transducer and a displacement transducer to measure the deformation of the jaw, obtained by 3D printing, under load. The mechanical elastic hysteresis loop during an experimental loading/unloading was plotted and the amount of mechanical energy lost during a cycle, dissipated because the internal friction, was determined. Finite element analysis method was applied to make a comparison with the experimental results. In the finite element analysis, several simulations were considered, varying Young s modulus for the tested material.

Highlights

Grippers are used for orientation-positioning and tightening of the object / part during handling, processing, control and assembly
First important experimental information available here is the area of hysteresis loop (0.02285N·m)
In the performed experiment a modified jaw, in order to clamp a soda can, was 3D printed with 100% infill, from a De-sta-co gripper model De-sta-co 84A3-3300AAAA

Summary

Introduction

Grippers are used for orientation-positioning and tightening of the object / part during handling, processing, control and assembly. To ensure the fulfilment of the functions presented, the materials used in the construction of devices and grippers are usually alloy steel. The requirements of grippers are similar to those of clamping fixtures, namely: precise orientation and positioning according to machining requirements, rigidity depending on the size of the workpiece and machining forces, reliability, low maintenance, standardized components, high productivity, costs low [1]. To ensure the performance of the functions presented, the materials used in the construction of devices and grippers are usually alloy steel with an HRC hardness of up to 55-60 HRC for the clamping components. There are cases where "flexible" jaws / soft jaws are needed to reduce the deformation of workpieces, especially for thin-walled thin parts when clamping. Soft jaws are one of the simplest methods of customized workholding and can be machined to the negative shape of the workpiece

Methods

Results

Conclusion