Purpose

Fused filament fabrication (FFF) using tough poly lactic acid (PLA) was determined to be the most suited method to achieve low-cost prosthetic sockets. However, improvement in the material properties is desirable to strengthen these sockets. This study aims to evaluate annealing as a potential method to improve material properties by a heat treatment of the object after 3D printing.

Design/methodology/approach

Four different annealing methods and a control group were tested according to ISO standard 527–1 and ISO standard 527–2. The four annealing methods included: oven; sand; water; and glycerol annealing. Tests were performed on longitudinal and transversal 3D printed samples. Deformation was determined on 3D printed test rings.

Findings

Annealing using an oven, sand and water resulted in a significant increase in tensile strength in longitudinally 3D printed tensile test samples. However, the tensile strength was decreased in the transversally 3D printed tensile test samples. The tensile modulus had no significant increase in the longitudinally and transversally printed samples. Sand annealing resulted in the least deformation, with a shrinkage of 2.04% of inner diameter and an increase in height of 1.99% for the horizontally annealed test rings.

Research limitations/implications

The annealing of prosthetic sockets is not recommended as a decrease in tensile strength in transversally printed tensile test samples was observed. More research is needed towards the strengthening of tough PLA in both print directions.

Originality/value

This paper fulfils the need for understanding the impact of annealing on 3D printed items intended for daily use, such as a prosthetic socket.

中文翻译：

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退火对韧性PLA变形和机械强度的影响及其在3D打印假肢窝中的应用

目的

使用坚韧的聚乳酸 (PLA) 的熔融长丝制造 (FFF) 被确定为最适合实现低成本假肢窝的方法。然而，需要改进材料特性以加强这些插座。本研究旨在评估退火是一种通过对 3D 打印后物体进行热处理来改善材料性能的潜在方法。

设计/方法/方法

根据 ISO 标准 527-1 和 ISO 标准 527-2 测试了四种不同的退火方法和一个对照组。四种退火方法包括：烤箱；沙; 水; 和甘油退火。对纵向和横向 3D 打印样品进行了测试。变形是在 3D 打印的测试环上确定的。

发现

使用烤箱、沙子和水进行退火导致纵向 3D 打印拉伸测试样品的拉伸强度显着增加。然而，横向 3D 打印拉伸测试样品的拉伸强度降低。纵向和横向印刷样品的拉伸模量没有显着增加。砂型退火的变形最小，水平退火试验环内径收缩2.04%，高度增加1.99%。

研究限制/影响

不建议对假肢窝进行退火，因为观察到横向印刷拉伸测试样品的拉伸强度降低。需要更多的研究来加强两个打印方向的坚韧 PLA。

原创性/价值

本文满足了了解退火对日常使用的 3D 打印物品（例如假肢窝）的影响的需要。