Preliminary Comparative Assessment of Hole Quality and Geometrical Tolerances in AM-Built and CNC-Drilled PLA Components

Abstract:

The increasing adoption of polymer additive manufacturing (AM) in functional applications has intensified the need for reliable hole-making strategies, particularly when printed components require mechanical fastening or post-processing. However, the layered architecture of fused-filament fabrication (FFF) parts typically leads to dimensional inaccuracy and thermally induced defects during drilling. This study examines the quality of holes made directly with FFF technology and those obtained through traditional drilling on PLA components produced with two different layer heights (0.20 and 0.28 mm). Additively manufactured holes were analysed via least-squares circle fitting and roundness evaluation, revealing high repeatability but substantial undersizing (>1 mm deviation from the 6.35 mm nominal diameter). CNC drilling tests were then performed under a full-factorial combination of spindle speed and feed rate, assessing thrust force, torque, infrared-based cutting temperature, and burr formation for both top and bottom sample side. Results show that CNC drilling can restore near-nominal dimensional accuracy, but only within a restricted process parameters window. Low feed rates promote severe thermal-viscoplastic deformation, while specific combinations of spindle speed and entry surface strongly influence burr formation.

• Periodical: Solid State Phenomena (Volume 391)
• Pages: 29-42
• DOI: https://doi.org/10.4028/p-aFH2MU
• Online since: April 2026
• Authors: Martina Panico*, Guido Di Bella, Massimo Durante, Mohamed Chairi, Antonio Langella, Luca Boccarusso
• Keywords: AM-Built Holes, CNC Drilling, Fuse Deposition Modeling (FDM), Hole Quality

References

[1] Islam MA, Mobarak MH, Rimon MIH, Al Mahmud MZ, Ghosh J, Ahmed MMS, et al. Additive manufacturing in polymer research: Advances, synthesis, and applications. Polym Test 2024;132:108364.

DOI: 10.1016/j.polymertesting.2024.108364

[2] Su J, Ng WL, An J, Yeong WY, Chua CK, Sing SL. Achieving sustainability by additive manufacturing: a state-of-the-art review and perspectives. Virtual Phys Prototyp 2024;19.

DOI: 10.1080/17452759.2024.2438899

[3] Lalegani Dezaki M, Mohd Ariffin MKA, Hatami S. An overview of fused deposition modelling (FDM): research, development and process optimisation. Rapid Prototyp J 2021;27:562–82.

DOI: 10.1108/RPJ-08-2019-0230

[4] Solouki A, Aliha M, Makui A. A Methodology for Optimizing Impact Strength, Dimensional Accuracy and Costs of Manufacturing with Three-Dimensional Printing of Polylactic Acid. Arab J Sci Eng 2024;49:7545–69.

DOI: 10.1007/s13369-023-08422-3

[5] Pratheesh Kumar MR, Saravanakumar K, Arun Kumar C, Saravanakumar R, Abimanyu B. Experimental investigation of the process parameters and print orientation on the dimensional accuracy of fused deposition modelling (FDM) processed carbon fiber reinforced ABS polymer parts. Mater Today Proc 2024;98:166–73.

DOI: 10.1016/j.matpr.2023.10.062

[6] Zaborniak M, Bremek M, Budzik G, Kluczyński J. Analysis of the Dimensional and Shape Accuracy and Repeatability of Models Produced in the Process of Additive Extrusion of Thermoplastic Polymers Using Fused Filament Fabrication Technology. Applied Sciences 2024;14:6404.

DOI: 10.3390/app14156404

[7] Rebaioli L, Fassi I. A review on benchmark artifacts for evaluating the geometrical performance of additive manufacturing processes. The International Journal of Advanced Manufacturing Technology 2017;93:2571–98.

DOI: 10.1007/s00170-017-0570-0

[8] Gómez-Gras G, Pérez MA, Fábregas-Moreno J, Reyes-Pozo G. Experimental study on the accuracy and surface quality of printed versus machined holes in PEI Ultem 9085 FDM specimens. Rapid Prototyp J 2021;27:1–12.

DOI: 10.1108/RPJ-12-2019-0306

[9] Popescu D, Gheorghe Amza C, Marinescu R, Cristiana Iacob M, Luminiţa Căruţaşu N. Investigations on Factors Affecting 3D-Printed Holes Dimensional Accuracy and Repeatability. Applied Sciences 2022;13:41.

DOI: 10.3390/app13010041

[10] Chang D-Y, Lin C-H, Wu X-Y, Yang C-C, Chou S-C. Cutting force, Vibration, and Temperature in Drilling on a Thermoplastic Material of PEEK. Journal of Thermoplastic Composite Materials 2023;36:1088–112.

DOI: 10.1177/08927057211052325

[11] Lalegani Dezaki M, Mohd Ariffin MKA, Baharuddin BTHT. Experimental Study of Drilling 3D Printed Polylactic Acid (PLA) in FDM Process, 2021, p.85–106.

DOI: 10.1007/978-3-030-68024-4_5

[12] Vishwadarshan, Shetty G, Shetty R, J P S, V B, Hegde A. Comprehensive analysis of drilling responses in additively manufactured PLA using a regression—based statistical learning approach. Mater Res Express 2025;12:055302.

DOI: 10.1088/2053-1591/adcf7b

[13] Panico M, Langella A, Boccarusso L. On the influence of clamping conditions and cutting edge geometry on drilling of thin aluminium stacks. CIRP J Manuf Sci Technol 2025;61:572–87.

DOI: 10.1016/j.cirpj.2025.08.004

[14] Panico M, Begemann E, Gebhardt A, Hartmann F, Herrmann T, Langella A, et al. Evaluating the impact of boundary conditions and clamping force in robotic one-up drilling of hybrid stacks. CIRP J Manuf Sci Technol 2025;60:1–14.

DOI: 10.1016/j.cirpj.2025.04.003

[15] Yaman U. Shrinkage compensation of holes via shrinkage of interior structure in FDM process. The International Journal of Advanced Manufacturing Technology 2018;94:2187–97.

DOI: 10.1007/s00170-017-1018-2

[16] Sajan N, John TD, Sivadasan M, Singh NK. An investigation on circularity error of components processed on Fused Deposition Modeling (FDM). Mater Today Proc 2018; 5: 1327-34.

DOI: 10.1016/j.matpr.2017.11.218

[17] Jiang Y, Wang X, Li H, Huang Y, Zhou Z. Experimental study for the effect of typical hole geometric deviation on film cooling effectiveness. Thermal Science and Engineering Progress 2026; 69:104446.

DOI: 10.1016/j.tsep.2025.104446