İşlem parametrelerinin ve tavlama işleminin PLA numunelerinin mekanik ve yüzey özelliklerine etkisi

Öz

Bağlam— Erimiş Katmanlı Üretim (FDM), ekonomik üretim, geometrik çok yönlülük ve geniş malzeme bulunabilirliği sunduğu için yaygın olarak benimsenen bir eklemeli üretim yöntemi haline gelmiştir. FDM'de kullanılan termoplastikler arasında, çevre dostu yapısı ve elverişli işleme özellikleri nedeniyle polilaktik asit (PLA) yaygın olarak tercih edilmektedir. Bununla birlikte, FDM ile üretilen PLA parçalarının mekanik özellikleri ve yüzey kalitesi, hem üretim parametrelerine hem de işlem sonrası uygulamalara karşı oldukça hassastır. Önceki araştırmalar, katman kalınlığı, dolgu yoğunluğu ve tavlama gibi faktörlerin ayrı ayrı etkilerini raporlamış olsa da, bunların birleşik etkisini sistematik olarak değerlendiren çalışmalar hala azdır. Amaç— Bu araştırma, katman kalınlığı, dolgu yoğunluğu ve tavlama sıcaklığındaki varyasyonların FDM ile üretilen PLA parçalarının çekme performansı ve yüzey özelliklerini nasıl etkilediğini incelemeye odaklanmıştır. Özellikle, çalışma, hangi işleme parametrelerinin çekme dayanımı, elastik modül, uzama, özgül çekme dayanımı ve yüzey pürüzlülüğünü en güçlü şekilde etkilediğini belirlemeyi ve ayrıca basılı PLA parçalarında sertlik ve süneklik arasındaki dengeyi sağlamadaki rollerini açıklamayı amaçlamıştır. Yöntem— Katman kalınlığının 0,12, 0,16 ve 0,20 mm, dolgu yoğunluğunun %20, %40 ve %60 ve tavlama durumlarının (baskı sonrası, 60 °C ve 90 °C) etkisini değerlendirmek için bir L9 Taguchi ortogonal dizisi uygulandı. PLA'dan yapılmış çekme numuneleri, kontrollü işlem koşulları altında FDM tabanlı bir 3D baskı sistemi kullanılarak üretildi. Mekanik karakterizasyon, çekme dayanımı, elastik modül ve uzama değerlerini elde etmek için çekme testi yoluyla gerçekleştirildi; özgül çekme dayanımı ise numune kütle ölçümleri entegre edilerek belirlendi. Yüzey kalitesi, üç boyutlu optik profilometre ile ortalama yüzey pürüzlülüğünün (Ra) ölçülmesiyle değerlendirildi. Seçilen parametrelerin etkileri ve göreceli önemi, sinyal-gürültü oranları ve varyans analizi teknikleri kullanılarak istatistiksel olarak analiz edildi. Sonuçlar— Sonuçlar, dolgu yoğunluğunun çekme dayanımını etkileyen en önemli faktör olduğunu ve katkı oranının %87,76 olduğunu, yaklaşık 43-45 MPa'lık maksimum dayanımların ise %60 dolguda elde edildiğini göstermiştir. Katman kalınlığı, elastik modülü (%48,17) ve uzamayı (%71,64) kontrol eden baskın parametre olarak belirlenmiş ve sertlik-süneklik dengesinde kritik bir rol oynamıştır. Daha kalın katmanlar daha belirgin ve görünür katman basamak yapıları oluşturdukça yüzey pürüzlülüğü artmıştır. Katman kalınlığının yüzey pürüzlülüğü üzerindeki genel etkisi %84,73 olmuştur. Sonuç— Bu çalışma, birden fazla işleme parametresinin PLA bileşenlerinin mekanik davranışını ve yüzey özelliklerini nasıl etkilediğine dair bütünleşik bir değerlendirme sunmaktadır. Sonuçlar, dayanım, süneklik, ağırlık verimliliği ve yüzey kalitesinin optimizasyonunu desteklemekte ve FDM ile üretilen PLA parçalarının mühendislik tasarımı için pratik bilgiler sağlamaktadır.

Anahtar Kelimeler

• FDM
• PLA
• Mekanik özellikler
• Yüzey pürüzlülüğü

Effect of process parameters and annealing treatment on mechanical and surface properties of PLA samples

Abstract

Context— Fused Deposition Modeling (FDM) has become a commonly adopted additive manufacturing method because it offers economical production, geometric versatility, and broad material availability. Among the thermoplastics used in FDM, polylactic acid (PLA) is widely preferred due to its environmentally friendly nature and favorable processing characteristics. Nevertheless, the mechanical properties and surface finish of PLA parts produced by FDM are highly sensitive to both manufacturing parameters and post-processing practices. Although previous research has reported the separate effects of factors such as layer thickness, infill density, and annealing, studies that systematically evaluate their combined impact are still scarce. Objective— This research focused on examining how variations in layer thickness, infill density, and annealing temperature affect the tensile performance and surface characteristics of PLA parts produced by FDM. In particular, the study aimed to determine which processing parameters most strongly influence tensile strength, elastic modulus, elongation, specific tensile strength, and surface roughness, as well as to explain their role in balancing stiffness and ductility in printed PLA parts. Method— An L9 Taguchi orthogonal array was implemented to assess the influence of layer thickness set at 0.12, 0.16, and 0.20 mm, infill density levels of 20, 40, and 60 percent, and annealing states consisting of as-printed, 60 °C, and 90 °C. Tensile samples made of PLA were fabricated using an FDM-based 3D printing system under controlled processing conditions. Mechanical characterization was carried out through tensile testing to obtain tensile strength, elastic modulus, and elongation values, whereas specific tensile strength was determined by incorporating sample mass measurements. Surface quality was evaluated by measuring the average surface roughness (Ra) with a three-dimensional optical profilometer. The effects and relative significance of the selected parameters were statistically analyzed using signal-to-noise ratios and analysis of variance techniques. Results— The results showed that infill density was the most important factor affecting tensile strength, with a contribution ratio of 87.76%, and maximum strengths of approximately 43–45 MPa obtained at 60% infill. Layer thickness was identified as the dominant parameter controlling elastic modulus (48.17%) and elongation (71.64%), its critical role in the stiffness–ductility balance. Surface roughness increased as thicker layers formed more pronounced and visible layer-step structures. Surface roughness increased as thicker layers produced more pronounced and visible layer-step structures. The overall effect of layer thickness on surface roughness was 84.73%. Conclusion— This work presents an integrated assessment of how multiple processing parameters influence the mechanical behavior and surface characteristics of PLA components. The results support the optimization of strength, ductility, weight efficiency, and surface finish, and contribute practical insight for the engineering design of PLA parts manufactured by FDM.

Keywords

• FDM
• PLA
• Mechanical properties
• Surface roughness

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