Citation: Formas, K.; Kurowska, A.;
Janusz, J.; Szczygieł, P.; Rajzer, I.
Injection Molding Process Simulation
of Polycaprolactone Sticks for Further
3D Printing of Medical Implants.
Materials 2022, 15, 7295. https://
doi.org/10.3390/ma15207295
Academic Editors: Ludwig Cardon
and Clemens Holzer
Received: 30 September 2022
Accepted: 17 October 2022
Published: 18 October 2022
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Article
Injection Molding Process Simulation of Polycaprolactone
Sticks for Further 3D Printing of Medical Implants
Krzysztof Formas, Anna Kurowska, Jarosław Janusz , Piotr Szczygieł and Izabella Rajzer *
Department of Mechanical Engineering Fundamentals, Faculty of Mechanical Engineering and Computer Science,
University of Bielsko-Biala, 43-309 Bielsko-Biala, Poland
* Correspondence: irajzer@ath.bielsko.pl
Abstract:
The aim of the present study was a simulation of the injection molding process of poly-
caprolactone filament sticks for further 3D printing of osteochondral implants. Polycaprolactone data
are not available in the data banks of popular injection molding simulation programs. Therefore,
thermal and rheological data from the literature were imported to the material database of Solid-
works Plastics software to simulate the injection molding process of filament sticks. The influence
of several injection molding parameters including melt temperature, injection time, and injection
pressure on the geometry of filament stick (final part) was investigated. Based on the results of the
performed simulation and analyses, it was possible to improve the injection process parameters.
The accuracy of simulation predictions, based on the literature data, demonstrates the potential of
using simulation as a tool to develop polycaprolactone parts for future implants and to optimize the
injection molding process.
Keywords: injection molding; polycaprolactone; process simulation; filament; biomaterials
1. Introduction
Facial injuries are a growing clinical problem not only for patients, but also for laryn-
gologist and plastic surgeons. The main cause of injuries is various types of accidents,
as well as diseases, congenital deformities, or cancer of supporting tissues such as bone
and cartilage. Treatment of osteochondral defects remains a great challenge for many
reconstructive surgical procedures.
Three-dimensional (3D) printing is revolutionizing and enhancing the medical indus-
try as it allows for the personalization of the treatment to match a patient’s individual
needs. FDM is a 3D printing techniques and offers great flexibility in the handling and
processing of materials. In this method, implants are created through the layer-by-layer
deposition of a thermoplastic polymer using a 3D printer. The polymeric filament is loaded
into the 3D printer, heated above its melting point, softened, and extruded through the
nozzle. Usually, the polymers used for biomedical applications are very expensive. Fil-
ament materials are generally supplied in spools that are not entirely used during the
production of small implants for cartilage or bone replacement [
1
]. In order to produce
filament without such a consumption of biomedical materials, the idea of small sticks that
can be joined together was developed by the authors. Moreover, this will provide us an
opportunity to put together differently modified sticks and produce personalized implants
using a commercially available 3D printer. For their production, injection molding can be
applied. The results of the injection molding simulation process presented in this paper
will also help us to set the production parameters for the polymer modified with various
additives such as hydroxyapatite, bioglass, graphene, drugs, or antibiotics. Therefore,
soon, instead of buying entire filament spool, it will be possible to buy a set of differently
modified sticks and organize them depending on the patient’s requirements, using a 3D
printer. We will be able to produce various scaffolds without having to change the spool as
Materials 2022, 15, 7295. https://doi.org/10.3390/ma15207295 https://www.mdpi.com/journal/materials
