Colorometric study of polyamide-12 powder aging

The key point of 3D printing by selective laser sintering is the necessity of complete filling of the working chamber of the printer with a powder material. Since the powder is not completely consumed during the printing process, 25 – 30 wt.% of secondary (unused in the previous cycle) power is added to the primary material in each cycle. Repeated recirculation leads to degradation of the properties of the working powder mixture and increases the probability of rejects. We present the results of a colorimetric study of aging of polyamide-12 powder used in 3D printing by the method of selective laser sintering. Scanning and computer processing of digital images of primary and secondary polyamide powders obtained by colorimetry were performed using MathLab program package. Colorimetric analysis included the expression of the sample color using the parameters of color models applied in digital technologies for synthesizing colored images. The number of cycles before the onset of intensive destruction is no more than three, which is consistent with the practical experience in printing by selective laser sintering. The results characterizing change in the color of the secondary powder depending on the duration of thermal exposure and the gas medium are presented. It is shown that long-term storage of the powder for subsequent use is not advisable, since the initiators of destruction are already present in the material. Thermal oxidative destruction is shown to be a critical factor limiting the use of secondary powder along with changes in the crystallinity and fractional composition of particles. Computer processing of images of polymer powder obtained by the colorimetric method can be used to control the aging process of consumables and to predict the probability of rejections in 3D printing.

1. Khripushin V. V., Mokshina N. Ya., Pakhomova O. A. A method for assessing the quality of powder materials for 3d printing based on polyamide-12 / Zavod. Lab. Diagn. Mater. 2018. Vol. 84. N 5. P. 36 – 40. DOI: 10.26896/1028-6861-2018-84-5-36-40 [in Russian].

2. Davydov V. M., Morokov A. A. Laser processing of constructional polyamide low-power lasers / Uch. Zap. TOGU. 2016. Vol. 7. N 4. P. 445 – 448 [in Russian].

3. Borisovskaya E. M., Karmanova O. V., Shcherbakova M. S., Kalmikov V. V. The research physical-mechanical and optical properties of PMMA in with the addition secondary polymer / Vestn. VGUIT. 2017. Vol. 79. N 1. P. 264 – 270. DOI: 10.20914/2310-1202-2017-1-264-270 [in Russian].

4. Ivanov V. M., Kuznetsova O. V. Chemical chromaticity: potential of the method, application areas and future prospects / Usp. Khimii. 2001. Vol. 70. N 5. P. 357 – 372. DOI: 10.1070/RC2001v070n05ABEH000636 [in Russian].

5. Zyablov A. N., Zhibrova Yu. A., Selemenev V. F. Digital image processing. Advantages and disadvantages / Sorb. Khromatogr. Prots. 2006. Vol. 6. N 6. P. 1424 – 1429 [in Russian].

6. Sverdlova O. V. Electronic spectra in organic chemistry. — Leningrad, 1985 [in Russian].

7. Nelson W. E. Polyamide-based plastics technology. — Moscow: Khimiya, 1979. — 256 p. [Russian translation].

8. Petrushin S. I., Saprykin A. A., Valter A. V., Saprykina N. A. Layerwise synthesis technology of the products prototype by selective laser powders sintering / Tekhnol. Mashinostr. 2015. N 3. P. 42 – 45 [in Russian].

9. Griffiths C., Howarth J., De Almeida-Rowbotham G. A design of experiments approach for the optimisation of energy and waste during the production of parts manufactured by 3D printing / Journal of cleaner production. 2016. P. 74 – 85. DOI: 10.1016/j.Jclepro.2016.07.182.

10. Makarov V. G., Koptenarmusov V. B. Industrial thermoplastics. — Moscow: KolosS, 2003. — 208 p.

11. Lopez-Molinero A. et al. Chemometric interpretation of digital image colorimetry. Application for titanium determination in plastics / Microchemical J. 2010. Vol. 96. Issue 2. P. 380 – 385. DOI: 10.1016/j.microc.2010.06.013.

12. Oskolok K. V., Shultz E. V., Monogarova O. V., Chaplenko A. A. The optical molecular analysis of the pharmaceutical preparations using of the office flatbed scanner: colorimetry and photometry / Vopr. Biol. Med. Farm. Khim. 2017. Vol. 20. N 8. P. 22 – 27 [in Russian].

13. Shapiro L., Stockman J. Computer vision. — Moscow: BINOM. Lab. znanii, 2006. — 752 p. [Russian translation].

14. Monogarova O. V., Oskolok K. V., Apyari V. V. Colorimetry in Chemical Analysis / J. Analyt. Chem. 2018. Vol. 73. N 11. P. 1076 – 1084. DOI: 10.1134/S1061934818110060.

15. Shutilin Yu. F. Physicochemistry of polymers. — Voronezh, 2012. — 840 p. [in Russian].

16. Shutilin Yu. F., Shcherbakova M. S., Khripushin V. V., Borisova I. A. The study of characteristics of powders of polymers for 3D printing / Vestn. VGUIT. 2017. Vol. 79. N 4. P. 157 – 164. DOI: 10.20914/2310-1202-2017-4-157-164 [in Russian].