Investigation of dimensional accuracy in the production of TPMS-based lattice structures by SLM method

Abstract

In this study, it was aimed to examine the geometric precision of the production of triple periodic minimal surface (TPMS) based lattice structures produced from CoCr powder by SLM method. Two different TPMS lattice structures with 10% relative density of 4x4x4 unit cell sizes, primitive lattice and body centred cubic (BCC), were used. In order to evaluate the dimensional accuracy after production, microscope images and micro-CT were taken from each sample and production was simulated by finite element analysis (FEA). In the results obtained, it was observed that there were significant dimensional deviations due to mass agglomeration, stair effect and bonded particle formation in the production of TPMS-based lattice structures by SLM method. When the dimensions of the designed lattice structure and the dimensions obtained as a result of production are examined, it is seen that the thickness value of each unit lattice structure deviates by 15% for the primitive lattice and 32% for the BCC lattice, while the primitive lattice deviates by 4% and the BCC lattice by 27% in the width value, and finally in the length values. On the other hand, it was determined that the primitive lattice deviated by 3% and the BCC lattice deviated by 55%.

Keywords

• Additive manufacturing
• Selective laser melting
• TPMS lattice structure
• Dimensional accuracy

ÜPMY tabanlı kafes yapılarının SLE yöntemi ile üretiminde boyut hassasiyetinin incelenmesi

Öz

Bu çalışmada CoCr tozundan üretilen üçlü periyodik minimum yüzey (ÜPMY) tabanlı kafes yapılarının seçmeli lazer ergitme (SLE) yöntemi ile üretimindeki boyutsal hassasiyetin incelenmesi amaçlanmıştır. İlkel kafes ve hacim merkezli kübik (HMK) olmak üzere 4x4x4 birim hücre boyutlarında %10 nispi yoğunluklu 2 farklı ÜPMY kafes yapısı kullanıldı. Üretim sonrası boyutsal hassasiyetin değerlendirilebilmesi için her bir numuneden mikroskop ve micro-CT görüntüleri alınmış ve sonlu elemanlar analizi (SEA) ile üretim simüle edilmiştir. Elde edilen sonuçlarda SLE yöntemi ile ÜPMY bazlı kafes yapılarının üretiminde kütle birikimi, merdiven etkisi ve yapışmış partikül oluşumundan kaynaklı belirgin boyutsal sapmaların meydana geldiği görülmüştür. Tasarlanan kafes yapısı boyutları ile üretim sonucu elde edilen boyutlar incelendiğinde her bir birim kafes yapısının kalınlık değerinin ilkel kafes için %15, HMK kafes için %32 saptığı, genişlik değerinde ise ilkel kafesin %4, HMK kafesin ise %27 saptığı ve son olarak uzunluk değerlerinde ise ilkel kafesin %3, HMK kafesin ise %55 saptığı tespit edilmiştir.

Anahtar Kelimeler

• Eklemeli imalat
• Seçmeli lazer ergitme
• ÜPMY kafes yapısı
• Boyut hassasiyeti

Kaynakça

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