Mechanical strength (CP)

The following summarizes some guidelines for coded FFF process chain (CP) cases with their respective references.

CP-03. Printed parts must be coated to improve surface finish and mechanical strength (see Figure 1).

Depending on the type of coating and material, the roughness, hardness, mechanical strength, and leak resistance of the part are improved, but in exchange for increased thicknesses and tolerances [1], [14], [15], [16],[17], [18], [19], [20]. 

CP-04. Heat treatments can be applied to crystalline printed parts to improve impact resistance. Applicable to materials with a crystalline structure, e.g., PLA [9].

CP-05. The resin must be infiltrated into the printed part to improve mechanical strength. However, optimization depends on several factors of both the FFF process and the type of additive [10].

CP-07. Additives should be used in printed material, such as short and especially continuous fibers, to improve the mechanical strength significantly.

Additives such as short fibers, continuous fibers, and multi-material printing demonstrate significant improvements in mechanical properties, depending on the specific materials and mechanical properties [11], [12], [13], [14], [15], [10], [16], [8].

CP-08. Indirect manufacturing (example, molding with printed mold like Figure 2) should be used to expand the possibilities of FFF, both in terms of materials and processes, applications, and uses, while increasing strength, reducing manufacturing times and costs, reducing tolerances and fits, reducing roughness and reducing the weight of parts, among other competitive advantages [21], [22], [23],  [24], [15], [25], [26], [27], [28], [29], [30], [31], [32], [33], [34].

For more guidelines using FFF process chain, go to the database.

Improvements in Mechanical Strength

During the case analysis, improvements in properties such as tolerances, roughness, mechanical strength, and times/costs were identified through the combination of FFF or FDM with conventional processes. Table 1 provides a partial overview of the results obtained specifically for the Mechanical Strength case.

To interpret the findings in Table 1, an example is provided:

  1. The maximal improvement in mechanical strength is associated to Multilateral case (1300%). The improvement values are presented as ranges (min and max), because the specific values depend on the interaction of FFF processing factors and conventional manufacturing. Also, the specific properties depends on the specific research and process case, in the cases of improvement of 1300% it refers to impact strength [14].

To use the figures in Table 1 or the process chain database, from which these figures are derived, when designing a product, one should:

a) To know in advance what properties or specifications the product being designed should have, and in that case, to determine which process combination achieves the desired properties.

b) On the other hand, in the case of redesigning parts manufactured with FFF, whose properties are not by the desired specifications, the same table indicates the percentages of improvement possible by combining FFF with other specific processes; in this case, the processes that achieve the required improvements for the application to be designed are identified.

c) Once the possible processes or processes have been identified, the process chain database must be consulted to consult how the processes and their parameters are combined with FFF and print parameters.

d) The same database also contains process costs and times and the health and environmental impacts of using additional materials. This information will allow making objective decisions about the properties and costs associated with combining other materials and processes.

e) any details to expand or clarify can be read directly in the coded bibliographic reference.

The handling for other properties, such as tolerances, assembly, and others, is similar.

 

References

[1]         J. S. Chohan and R. Singh, “Pre and post processing techniques to improve surface characteristics of {FDM} parts: a state of art review and future applications,” Rapid Prototyp. J., vol. 23, no. 3, pp. 495–513, 2017.

[2]         Stratasys, “TECHNICAL APPLICATION GUIDE: Guidelines for Preparing and Painting FDM Parts.” 2015.

[3]         Stratasys, FDM for Composite Tooling. Stratasys, 2017.

[4]         J. Mireles et al., “Analysis of sealing methods for FDM-fabricated parts,” in Proceeding from Solid Free-form Fabrication Symposium, 2011, pp. 185–196.

[5]         Stratasys, “TECHNICAL APPLICATION GUIDE: Comparison of Sealing Methods for FDM Materials.” 2014.

[6]         M. S. Khan, S. B. Mishra, M. A. Kumar, and D. Banerjee, “Optimizing Surface Texture and Coating Thickness of Nickel Coated {ABS}-3D Parts,” Mater. Today Proc., vol. 5, no. 9, pp. 19011–19018, 2018.

[7]         S. Kannan and D. Senthilkumaran, “Assessment of mechanical properties of Ni-coated abs plastics using FDM process,” IJMME-IJENS, vol. 14, no. 3, pp. 30–35, 2014.

[8]         L. L. L. Taborda et al., “Experimental study of resin coating to improve the impact strength of fused filament fabrication process pieces,” Rapid Prototyp. J., vol. ahead-of-p, no. ahead-of-print, Mar. 2021.

[9]         C. Benwood, A. Anstey, J. Andrzejewski, M. Misra, and A. K. Mohanty, “Improving the Impact Strength and Heat Resistance of 3D Printed Models: Structure, Property, and Processing Correlationships during Fused Deposition Modeling (FDM) of Poly (Lactic Acid),” ACS Omega, vol. 3, no. 4, pp. 4400–4411, 2018.

[10]      J. F. P. Lovo, I. L. de Camargo, L. A. O. Araujo, and C. A. Fortulan, “Mechanical structural design based on additive manufacturing and internal reinforcement,” Proc. Inst. Mech. Eng. Part C J. Mech. Eng. Sci., vol. 234, no. 2, pp. 417–426, 2020.

[11]      D.-A. Türk, H. Einarsson, C. Lecomte, and M. Meboldt, “Design and manufacturing of high-performance prostheses with additive manufacturing and fiber-reinforced polymers,” Prod. Eng., vol. 12, no. 2, pp. 203–213, Feb. 2018.

[12]      X. Gao, D. Zhang, S. Qi, X. Wen, and Y. Su, “Mechanical properties of 3D parts fabricated by fused deposition modeling: Effect of various fillers in polylactide,” J. Appl. Polym. Sci., vol. 136, no. 31, p. 47824, 2019.

[13]      A. T. Miller, D. L. Safranski, K. E. Smith, D. G. Sycks, R. E. Guldberg, and K. Gall, “Fatigue of injection molded and 3D printed polycarbonate urethane in solution,” Polymer (Guildf)., vol. 108, pp. 121–134, 2017.

[14]      M. A. Caminero, J. M. Chacon, I. Garcia-Moreno, and G. P. Rodriguez, “Impact damage resistance of 3D printed continuous fibre reinforced thermoplastic composites using fused deposition modelling,” Compos. Part B Eng., vol. 148, pp. 93–103, 2018.

[15]      A. S. de León, A. Domínguez-Calvo, and S. I. Molina, “Materials with enhanced adhesive properties based on acrylonitrile-butadiene-styrene (ABS)/thermoplastic polyurethane (TPU) blends for fused filament fabrication (FFF),” Mater. Des., vol. 182, p. 108044, 2019.

[16]      S. Pava, K. Álvarez, and L. López, “Caracterización De Las Probetas De Policarbonato Fabricadas Por FDM Sometidas A Fatiga Por Flexión Rotativa Y Recubiertas Con Resina Epoxi,” UNIVERSIDAD DEL ATLÁNTICO, FACULTAD DE INGENIERÍA, PROGRAMA DE INGENIERÍA MECÁNICA, Puerto Colombia, Atlantico, Colombia, 2019.

[17]      C. C. Ploch, C. S. S. A. Mansi, J. Jayamohan, and E. Kuhl, “Using 3D Printing to Create Personalized Brain Models for Neurosurgical Training and Preoperative Planning,” World Neurosurg., vol. 90, pp. 668–674, Jun. 2016.

[18]      O. C. Burdall, E. Makin, M. Davenport, and N. Ade-Ajayi, “3D printing to simulate laparoscopic choledochal surgery,” J. Pediatr. Surg., vol. 51, no. 5, pp. 828–831, May 2016.

[19]      Stratasys, “TECHNICAL APPLICATION GUIDE: Silicone Molding With FDM Patterns.” 2015.

[20]      Y. He, G. Xue, and J. Fu, “Fabrication of low cost soft tissue prostheses with the desktop 3D printer,” Sci. Rep., vol. 4, no. 1, Nov. 2014.

[21]      M. Chhabra and R. Singh, “Rapid casting solutions: a review,” Rapid Prototyp. J., vol. 17, no. 5, pp. 328–350, 2011.

[22]      S. Singh and R. Singh, “Fused deposition modelling based rapid patterns for investment casting applications: a review,” Rapid Prototyp. J., vol. 22, no. 1, pp. 123–143, 2016.

[23]      Stratasys, “APPLICATION GUIDE: Thermoforming.” 2015.

[24]      M. HÉCTOR, A. ORTIZ, and L. LOPEZ, “DISEÑO Y CONSTRUCCIÓN DE PROTOTIPO DE MOLDE PARA RECONSTRUCCIÓN ÓSEA A PARTIR DE TOMOGRAFÍA COMPUTARIZADA MEDIANTE IMPRESIÓN 3D,” UNIVERSIDAD DEL ATLÁNTICO, FACULTAD DE INGENIERÍA, DEPARTAMENTO DE INGENIERÍA, PROGRAMA DE INGENIERÍA MECÁNICA, Puerto Colombia – Atlántico, COLOMBIA, 2021.

[25]      L. Ruiz-Huerta, Y. C. Almanza-Arjona, A. Caballero-Ruiz, H. A. Castro-Espinosa, C. M. D\’\iaz-Aguirre, and E. E. y Pérez, “{CAD} and {AM}-fabricated moulds for fast cranio-maxillofacial implants manufacture,” Rapid Prototyp. J., vol. 22, no. 1, pp. 31–39, 2016.

[26]      P. A. Thomas, P. K. Aahlada, N. S. Kiran, and J. Ivvala, “A Review On Transition In The Manufacturing Of Mechanical Components From Conventional Techniques To Rapid Casting Using Rapid Prototyping,” Mater. Today Proc., vol. 5, no. 5, pp. 11990–12002, 2018.

[27]      O. Abdelaal, S. Darwish, K. A. Elmougoud, and S. Aldahash, “A new methodology for design and manufacturing of a customized silicone partial foot prosthesis using indirect additive manufacturing,” Int. J. Artif. Organs, vol. 42, no. 11, pp. 645–657, 2019.

[28]      Stratasys, “TECHNICAL APPLICATION GUIDE FDM Tooling for Sheet Metal Forming: Hydroforming and Rubber Pad Press.” 2015.

[29]      Stratasys, “TECHNICAL APPLICATION GUIDE: FDM FOR SAND CASTING.” 2013.

[30]      Stratasys, “TECHNICAL APPLICATION GUIDE: Investment Casting with FDM Patterns.” 2015.

[31]      D. A. Roberson, A. R. T. Perez, C. M. Shemelya, A. Rivera, E. MacDonald, and R. B. Wicker, “Comparison of stress concentrator fabrication for 3D printed polymeric izod impact test specimens,” Addit. Manuf., vol. 7, pp. 1–3, 2015.

[32]      D. Espalin et al., “Analysis of bonding methods for FDM-manufactured parts,” in 21st Annual International Solid Freeform Fabrication Symposium-An Additive Manufacturing Conference, 2010, pp. 37–47.

[33]      E. CASTRO, DARIO EDEL CASTAÑO and L. LOPEZ, “CARACTERIZACIÓN MECÁNICA DE PROBETAS DE POLIETILENO TEREPHTHALATE CON GLICOL IMPRESAS EN 3D MEDIANTE EL MÉTODO DE MODELADO POR DEPOSICIÓN FUNDIDA,” UNIVERSIDAD DEL ATLÁNTICO, FACULTAD DE INGENIERÍA, PROGRAMA DE INGENIERÍA MECÁNICA, Puerto Colombia, Atlantico, Colombia, 2021.

[34]      H. Martínez, A. Rizo, and L. Lopez, “Caracterización mecánica de probetas fabricadas con Poliuretano termoplástico (TPU) por el proceso de Modelado de Deposición Fundida (FDM),” UNIVERSIDAD DEL ATLÁNTICO, FACULTAD DE INGENIERÍA, PROGRAMA DE INGENIERÍA MECÁNICA, Puerto Colombia, Atlantico, Colombia, 2021.