On May 26, 2020, Antarctic Bear learned from foreign media that researchers at Seoul National University in South Korea recently released a study investigating the effect of nozzle temperature on the emission rate of harmful particles during FFF 3D printing. The scientists tested four different common polymer wires and used direct-reading instruments to measure the particle concentration at different temperature intervals. This work proves that the nozzle temperature is a critical factor for the harmful particle emissions of the FFF system.
In fact, in 2018, a research institution did a similar study. The latest research: toxic particles and potential health risks from 3D printers.
Ultrafine particle emissions
Previous studies have determined that the emission levels of ultrafine particles, volatile organic compounds (VOCs) and aldehydes or carbonyl compounds are higher, especially at higher temperatures. If these emissions are inhaled, they will enter the lung area and transfer to the cardiovascular system, contaminating the blood.
In addition, temperature is not the only factor that affects the level of emissions during printing. The design of the print head and the polymer used may also be the main factors, so the manufacturer ’s warning should always be taken into consideration when operating the 3D printer.
Determination of emission rate
The research team first established a closed laboratory—printed here—to accurately measure the emissions produced. Each type of wire (PLA, ABS, wood and nylon) is used to produce 8 separate simple cube parts at different temperatures. The nozzle temperature is between 185 ° C and 290 ° C with an interval of 15 ° C. Each wire is weighed before and after printing, in order to later calculate the emission rate relative to the quality of the wire used.
Scientists use a scanning mobile particle analyzer and an optical particle spectrometer to monitor the emission rate at each temperature in real time every minute. Each experiment was repeated three times to calculate the number of particles per unit volume and the size distribution of the particles. From these values, researchers can determine the emission rate of each material at different temperatures.
The researchers found that in all four polymer types, every other temperature interval, the emission rate of harmful particles increases-this is a strong direct correlation. At the lowest temperature, the wire shows an emission rate of about 10 7th power-10 to 9th power particles / minute, but at the highest temperature it is 10 11th power particles / minute. Comparing the two, the emissivity at higher temperatures is 10,000 times higher than the emissivity at lower temperatures. Therefore, it is recommended that FFF printers operate at the lowest temperature of the materials used.
More detailed information about the study can be found in the paper entitled “Effect of nozzle temperature on the emission rate of ultrafine particles during 3D printing”. The authors of the paper are Haejoon Jeon, Jihoon Park, Sunju Kim, Kyungho Park and Chungsik Yoon.
Compiled from: 3dprintingindustry