Influence of Molecular Weight Average, Degree of Crystallinity, and Viscosity of Different Polyamide PA12 Powder Grades on the Microstructures of Laser Sintered Part

Way Yusoff,K Dotchev,Hanafi Ani,Dt Pham,J Zhou,H Gong

doi:10.1051/matecconf/20152603005

Way Yusoff, K Dotchev + Show 4 more

Open Access

https://doi.org/10.1051/matecconf/20152603005

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Abstract

Laser Sintering (LS) allows functional parts to be produced in a wide range of powdered materials using a dedicated machine, and is thus gaining popularity within the field of rapid prototyping. It offers the user the ability to optimise part design in order to meet customer requirements with few manufacturing restrictions. A problem with LS is that sometimes the surface of the parts produced displays a texture similar to that of the skin of an orange (the so-called “orange peel” texture). The main aim of this research is to develop a methodology of controlling the input material properties of PA12 powder that will ensure consistent and good quality of the fabricated parts. Melt Flow Rate (MFR) and Gel permeation chromatography (GPC) were employed to measure the flow viscosity and molecular weight distributions of Polyamide PA12 powder grades. The experimental results proved that recycle PA12 powder with higher melt viscosity polymer has a higher entanglement with a longer molecule chain causes a higher resistance to flow which cause poor and rough surface finished on laser sintered part.

Highlights

In manufacturing, many products need to undergo increasing customisation, and a shortening of the manufacturing cycle time
The objectives of this research are to improve the surface quality of parts produced by Laser Sintering (LS) and to reduce or eliminate the rough surface texture by investigating the Molecular weight average and viscosity of different Polyamide Polyamide 12 (PA12) powder grades in Laser Sintering process
The samples of “New PA2200” have larger degree of crystallinity and higher Melt Flow Rate (MFR) compared to the samples of the older or recycled powder

Summary

Introduction

Many products need to undergo increasing customisation, and a shortening of the manufacturing cycle time This makes the time needed to produce prototypes one of the most important contributors to product development cycles. Laser sintering (LS) is one of the most versatile Rapid Prototyping (RP) processes currently available.LS with Polyamide 12 (PA12) or Nylon 12 powders is a widely used technology for the rapid prototyping of functional parts and recently has become very attractive for the rapid manufacturing of small batches of plastic parts [2]. No tooling, fixing, and reorientation are required during the process [6]. In this technology, an object is created layer by layer from heat-fusible solid fine powdered materials with heat generated from a CO2 laser.

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