AccScience Publishing / IJB / Online First / DOI: 10.36922/IJB026130118
RESEARCH ARTICLE
Early Access

Model establishment, mechanism analysis, and control strategy for extrusion hysteresis of hydrogels in piston-extrusion 3D printing

Haoran Ren1 Zhen Wang1,2* Chuanzhen Huang1,2 Longhua Xu1 Shuiquan Huang1 Meina Qu1 Zhengkai Xu1 Dijia Zhang1 Baosu Guo1 Tianye Jin1 Xiaodan Wang1 Bowen Li1
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1 School of Mechanical Engineering, Yanshan University, Qinhuangdao 066004, China
2 State Key Laboratory of Crane Technology, Yanshan University, Qinhuangdao 066004, China
Received: 26 March 2026 | Revised: 30 April 2026 | Accepted: 14 May 2026 | Published online: 14 May 2026
© 2026 by the Author(s). This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution 4.0 International License ( https://creativecommons.org/licenses/by/4.0/ )
Abstract

Piston extrusion-based 3D bioprinting is a widely used technology in tissue engineering; however, the phenomenon of extrusion hysteresis severely constrained its printing accuracy. This study investigates the hysteresis mechanism using a low-viscosity gelatin hydrogel as a model material and develops effective control strategies through mathematical modeling. Rheological characterization determined the material's gelation point (29.8 ℃)and the optimal printing temperature window. Subsequently, precise syringe temperature control was achieved using a heat transfer model, which exhibited a low prediction error of only 0.0064 ℃. We constructed an extrusion hysteresis model that simultaneously accounts for the elastic deformation of the syringe and the compressibility of the material. A static model derived from mechanical analysis provided a formula for calculating the extrusion hysteresis volume, while a dynamic model revealed that the resulting flow rate follows an exponential decay law. Experimental validation assessed the influences of critical parameters, including piston velocity (0.015-0.03 mm/s), nozzle diameter (0.46-0.75 mm), temperature (30-35 ℃), and various material types. The results demonstrated that the compressible model predictions aligned well with experimental data. However, the finest nozzle (0.46 mm) exhibited larger errors, attributed to rapid heat dissipation and increased susceptibility to premature gelation. Based on the dynamic model, we propose a control strategy employing "premature extrusion stop with adjusted movement speed." Printing experiments confirmed that for low-viscosity hydrogels, this strategy reduced accidental deposition in non-printing areas compared to standard retraction (withdrawal) strategies. This research provides a theoretical for optimizing the accuracy of piston extrusion systems and advances the mitigation of defects caused by extrusion hysteresis in the 3D printing of low-viscosity hydrogels.

Keywords
Piston extrusion-based 3D bioprinting
Extrusion hysteresis modeling
Dynamic control strategy
Gelatin hydrogel
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International Journal of Bioprinting, Electronic ISSN: 2424-8002 Print ISSN: 2424-7723, Published by AccScience Publishing