scholarly journals Design and Repeatability Analysis of Desktop Tool for Rapid Pre-Cracking of Notched Ductile Plastic Fracture Specimens

2019 ◽  
Author(s):  
Albert E. Patterson ◽  
Charul Chadha ◽  
Iwona M. Jasiuk ◽  
James T. Allison

Fracture testing is a useful mechanical testing process to explore the properties and behavior of materials, one that has seen much development and refinement in recent decades. One of the most important steps in preparing samples for testing is the production of a sharp pre-crack to initiate crack propagation in a predictable way. While several methods have been developed for doing this, particularly for metals and brittle plastic materials, a quick and reliable method for more ductile materials is lacking. This technical note describes the design and verification of a simple desktop-sized pre-cracking device which safely uses a razor blade and hammer to quickly produce straight and sharp pre-cracks of consistent depth in ductile polymeric material samples. To verify its capability and consistency, a series of tests were performed using both molded and 3-D printed acrylonitrile butadiene styrene (ABS). First, a series of 40 notched 25 mm x 9.5 mm ABS bars were pre-cracked, and the distance under the crack measured on both sides of the bar. Several bars were then broken along the cracks to examine the quality of the pre-crack front. These tests were then repeated 20 times each for two print orientations of fused deposition modeling (FDM) ABS printed at 100% density. All 80 pre-cracks were found to be straight, sharp, and within 1% of the nominal distance under the crack for all samples. The consistency of the pre-cracks throughout the sample cross-section was also observed to be excellent, with all 80 tests showing less than 0.25 mm of deviation, even on the highly-anisotropic FDM samples.

Author(s):  
Shajahan Bin Maidin ◽  
Zulkeflee Abdullah ◽  
Ting Kung Hieng

One of the disadvantages of fused deposition modeling (FDM) is waste produced during the printing processes. This investigation focuses on using 100% recycled Acrylonitrile Butadiene Styrene (ABS) for the FDM process. The recycling begins with re-granule the waste ABS material and produces it into a new filament. The new recycled filament was used to print the test specimen. Investigation on the mechanical properties and the surface quality of the test specimen and comparison with standard ABS specimen was done. The result shows that the recycled ABS can be produced into filament with 335°C of extrusion temperature and 1.5 mm/s travel speed of the extruder conveyor. The surface roughness of recycled specimen is 6.94% higher than the standard ABS specimen. For ultimate tensile strength, there is a small difference in X and Y orientation between the standard and the recycled ABS specimen which are 22.93% and 19.98%, respectively. However, in Z orientation, it is 52.33% lower. This investigation proves that ABS can be recycled without significantly affecting its mechanical properties.


2016 ◽  
Vol 832 ◽  
pp. 152-158
Author(s):  
Juraj Beniak ◽  
Miloš Matúš ◽  
Peter Križan

Technologies dedicated to the rapid prototyping uses a wide range of materials. The mostly used plastic materials are based on polymers. It is for example an Acrylonitrile Butadiene Styrene (ABS), Nylon, Polycarbonate (PC), or composites based on different polymers. New devices designed for the production of a prototype models, based on Fused Deposition Modeling (FDM) are able to work with environmentally friendly and biodegradable materials as Polylactic acid (PLA). The aim of this paper is to show the possibility of using materials based on organic polymers whose properties are comparable to conventionally used polymers. Presented are measured and statistically evaluated data related to basic properties of PLA material.


2021 ◽  
Vol 11 (3) ◽  
pp. 1272
Author(s):  
Bartłomiej Podsiadły ◽  
Piotr Matuszewski ◽  
Andrzej Skalski ◽  
Marcin Słoma

In this publication, we describe the process of fabrication and the analysis of the properties of nanocomposite filaments based on carbon nanotubes and acrylonitrile butadiene styrene (ABS) polymer for fused deposition modeling (FDM) additive manufacturing. Polymer granulate was mixed and extruded with a filling fraction of 0.99, 1.96, 4.76, 9.09 wt.% of CNTs (carbon nanotubes) to fabricate composite filaments with a diameter of 1.75 mm. Detailed mechanical and electrical investigations of printed test samples were performed. The results demonstrate that CNT content has a significant influence on mechanical properties and electrical conductivity of printed samples. Printed samples obtained from high CNT content composites exhibited an improvement in the tensile strength by 12.6%. Measurements of nanocomposites’ electrical properties exhibited non-linear relation between the supply voltage and measured sample resistivity. This effect can be attributed to the semiconductor nature of the CNT functional phase and the occurrence of a tunnelling effect in percolation network. Detailed I–V characteristics related to the amount of CNTs in the composite and the supply voltage influence are also presented. At a constant voltage value, the average resistivity of the printed elements is 2.5 Ωm for 4.76 wt.% CNT and 0.15 Ωm for 9.09 wt.% CNT, respectively. These results demonstrate that ABS/CNT composites are a promising functional material for FDM additive fabrication of structural elements, but also structural electronics and sensors.


Author(s):  
Arash Alex Mazhari ◽  
Randall Ticknor ◽  
Sean Swei ◽  
Stanley Krzesniak ◽  
Mircea Teodorescu

AbstractThe sensitivity of additive manufacturing (AM) to the variability of feedstock quality, machine calibration, and accuracy drives the need for frequent characterization of fabricated objects for a robust material process. The constant testing is fiscally and logistically intensive, often requiring coupons that are manufactured and tested in independent facilities. As a step toward integrating testing and characterization into the AM process while reducing cost, we propose the automated testing and characterization of AM (ATCAM). ATCAM is configured for fused deposition modeling (FDM) and introduces the concept of dynamic coupons to generate large quantities of basic AM samples. An in situ actuator is printed on the build surface to deploy coupons through impact, which is sensed by a load cell system utilizing machine learning (ML) to correlate AM data. We test ATCAM’s ability to distinguish the quality of three PLA feedstock at differing price points by generating and comparing 3000 dynamic coupons in 10 repetitions of 100 coupon cycles per material. ATCAM correlated the quality of each feedstock and visualized fatigue of in situ actuators over each testing cycle. Three ML algorithms were then compared, with Gradient Boost regression demonstrating a 71% correlation of dynamic coupons to their parent feedstock and provided confidence for the quality of AM data ATCAM generates.


2021 ◽  
Vol 896 ◽  
pp. 29-37
Author(s):  
Ján Milde ◽  
František Jurina ◽  
Jozef Peterka ◽  
Patrik Dobrovszký ◽  
Jakub Hrbál ◽  
...  

The article focused on the influence of part orientation on the surface roughness of cuboid parts during the process of fabricating by FDM technology. The components, in this case, is simple cuboid part with the dimensions 15 mm x 15mm x 30 mm. A geometrical model is defined that considers the shape of the material filaments after deposition, to define a theoretical roughness profile, for a certain print orientation angle. Five different print orientations in the X-axis of the cuboid part were set: 0°, 30°, 45°, 60°, and 90°. According to previous research in the field of FDM technology by the author, the internal structure (infill) was set at the value of 70%. The method of 3D printing was the Fused Deposition Modeling (FDM) and the material used in this research was thermoplastic ABS (Acrylonitrile butadiene styrene). For each setting, there were five specimens (twenty five prints in total). Prints were fabricated on a Zortrax M200 3D printer. After the 3D printing, the surface “A” was investigated by portable surface roughness tester Mitutoyo SJ-210. Surface roughness in the article is shown in the form of graphs (Fig.7). Results show increase in part roughness with increasing degree of part orientation. When the direction of applied layers on the measured surface was horizontal, significant improvement in surface roughness was observed. Findings in this paper can be taken into consideration when designing parts, as they can contribute in achieving lower surface roughness values.


Author(s):  
SIVADASAN M ◽  
N.K SINGH ◽  
ANOOP KUMAR SOOD

Investment Castings (IC) is one of the most economical ways to produce intricate metallic parts when forging, forming and other casting processes tend to fail. However, high tooling cost and long lead time associated with the fabrication of metal moulds for producing IC wax (sacrificial) patterns result in cost justification problems for customized single casting or small-lot production. Generating pattern using rapid prototyping (RP) process may be one of the feasible alternatives. For this purpose present study assessed the suitability of the fused deposition modeling (FDM) process for creating sacrificial IC patterns by studying FDM fabricated part thermal response at various temperatures. A series of experiments with RP patterns are conducted and a set of test castings are also made in steel for establishing feasibility. The build material used is acrylonitrile butadiene styrene (ABS). As an annexe to this work a concurrent attempt is also made to quantify the risk in using Selective Laser Sintering patterns for Investment Castings. Authors hope this work might establish applicability of ABS in IC and also lead the investigations to theoretically tone down the shell cracking tendency with Selective Laser Sintering patterns when Proprietary Duraform is used as the build material.


2021 ◽  
Vol 338 ◽  
pp. 01005
Author(s):  
Damian Dzienniak ◽  
Jan Pawlik

Additive manufacturing has been gaining popularity and availability year by year, which has resulted in its dynamic development. The most common 3D printing method as of today, FDM (Fused Deposition Modeling), owing to its peculiarity, does not always guarantee producing objects with low surface roughness. The authors of the present article have taken on the analysis of the impact of FDM printing on the roughness of the filament thus processed. They also investigate the relationship between the roughness of the unprocessed filament (made of polycaprolactam, that is, polyamide 6 or PA6) with admixtures of other materials (carbon fiber, glass fiber) and the surface quality of the manufactured object. The main subject of the analysis is the side surfaces of 3D prints, as it is their quality that is usually directly dependent on many factors connected with the process of the laying of the consecutive layers. The authors check step by step whether there exists a pronounced relationship between the roughness of the original filament material and the roughness of the obtained surface.


2017 ◽  
Vol 23 (2) ◽  
pp. 414-422 ◽  
Author(s):  
Timothy J. Coogan ◽  
David Owen Kazmer

Purpose The purpose of this paper is to investigate the factors governing bond strength in fused deposition modeling (FDM) compared to strength in the fiber direction. Design/methodology/approach Acrylonitrile butadiene styrene (ABS) boxes with the thickness of a single fiber were made at different platform and nozzle temperatures, print speeds, fiber widths and layer heights to produce multiple specimens for measuring the strength. Findings Specimens produced with the fibers oriented in the tensile direction had 95 per cent of the strength of the constitutive filament. Bond strengths ranged from 40 to 85 per cent of the filament strength dependent on the FDM processing conditions. Diffusion, wetting and intimate contact all separately affect bond strength. Practical implications This study provides processing recommendations for producing the strongest FDM parts. The needs for higher nozzle temperatures and more robust feed motors are described; these recommendations can be useful for companies producing FDM products as well as companies designing FDM printers. Originality/value This is the first study that discusses wetting and intimate contact separately in FDM, and the results suggest that a fundamental, non-empirical model for predicting FDM bond strength can be developed based on healing models. Additionally, the role of equilibration time at the start of extrusion as well as a motor torque limitation while trying to print at high speeds are described.


Sign in / Sign up

Export Citation Format

Share Document