Wear of the PG-CP4 coating applied by plasma to 40H13 steel and subjected to laser treatment

This paper discusses the wear of PG-CP4 powder coating deposited by plasma on 40H13 steel and treated by laser. A multi-factor model was established that relates the absolute wear of the PG-CP4 coating to independent factors of the laser processing process and allows you to reduce the coating wear. The longitudinal feed Spr of the laser beam and distance L from the protective glass of the laser head to the processed surface have the greatest and approximately equal influence on the absolute wear of the coating, and the radiation power W -a minimum influence. The research of 40H13 steel coated (the first option) and uncoated steel (the second option), showed that of all the samples that provide reliable adhesion of the coating to the substrate and the greatest reduction in absolute wear (from 80 to 22 micrometers, by 72.5 %) was achieved in the first case at the mode: W = 3 kW, Spr = 10 mm/s and L = 60 mm. The results of the research are recommended for use in enterprises that implement the processes of plasma and laser processing of materials, as well as in design organizations that develop modern technological laser systems.

Modification of Laser Marking Ability and Properties of Polypropylene Using Silica Waste as a Filler

Polypropylene (PP) belongs to the group of polymers characterized by low susceptibility to absorption of electromagnetic radiation in the infrared range (λ = 1064 nm). This research consisted of assessing the possibility of using silica waste from the metallurgic industry as an additive for PP laser marking. The modifier was introduced into the polymer matrix in the range from 1 to 10 wt%. The effects of laser radiation were assessed based on colorimetric tests and microscopic surface analysis. The mechanical properties of the composites were determined during the static tensile tests. The thermal properties were investigated via differential scanning calorimetry. It was found that the introduction of silica waste into polypropylene allows for the effective marking of sample surfaces with the use of a laser beam. The greatest contrast between the graphic symbol and the background was obtained for silica contents of 3 and 5 wt%, with the use of a low-speed laser head and a strong concentration of the laser beam. The application of silica caused an increase in the modulus of elasticity and the tensile strength of the composite samples. Increases in the crystallization temperature and the degree of crystallinity of the polymer matrix were also observed. It was found that silica waste can act as multifunctional additive for polypropylene.

Laser Cutting Defect Recognition Using Conversion of Processing Light Information into Spectrogram Images – Spectroscopic Measurements in Multiple Work Surface Conditions and Extraction of Spectral Data Features Based on Processing Principle –

At urban production sites, laser cutting is an essential technology for high-speed flexible sheet-metal processing. This study aims to detect defective cuts by sensing laser-cutting-induced light emission and elucidate meaningful features for processing-based detection. The proposed method comprises three steps. In the first step, the sensors installed in the laser head acquire the spectra of light generated during processing, and data analysis software converts the spectral data into spectrograms and stacked-graph images. In the second step, image processing software extracts the edges of both images and emphasizes the periodic features in normal laser cutting. In the final step, a one-class support vector machine recognizes defective cuts from the extracted features. Verification tests using multiple normal and abnormal cut data confirmed that the proposed method accurately detected defective cuts.

Hardness of the Powder Coating PG-CP4 Applied to Steel 40H13 and Subjected Laser Treatment

The article examines the hardness of the coating made of PG-CP4 powder. Plasma powder deposition was performed to samples made of 40H13 steel and then the samples treated with a laser beam. A multi-factor model was established that relates the hardness of the protective coating to the radiation power W, the longitudinal feed Spr of the laser beam, and the distance L from the protective casing of the laser head to the treated surface. Depending on the laser treatment modes, coating was in a state of complete, partial reflow or its absence. Full reflow is characterized by the adhesion of the filler material to the substrate, by maximum hardness of HRC 51.2–56.6 and no defects. In the absence of reflow, gas sinks, transverse microcracks, detachments, and other defects were found in the coating material, and the hardness decreased to HB 125–212. An increase in W and a decrease in Spr lead to increases the hardness of the treated coating, which is explained by an increase in the specific heat flux supplied to the coating per unit time, and a high rate of heat removal deep into the surface layer of 40H13 steel. The thickness of the surface layer with increased hardness ranged from 0.1 to 1.5 mm. Based on the multi-factor model, laser processing modes are controlled to ensure the required values of the protective coating hardness. The research results are recommended for use in enterprises that implement laser technologies and develop modern laser systems.

Friction Coefficient of the Coating PG-CP4 Sprayed to 40H13 Steel by Plasma and Processed by Laser

This article deals with laser treatment of plasma spraying of PG-CP4 powder on steel 40H13. A multi-factor model is obtained that relates the friction coefficient of the coating to the radiation power W, the longitudinal feed of the laser beam Spr, and the distance L from the protective glass of the laser head to the sample’s surface. The model allows you to control the modes of laser processing, in order to reduce the friction coefficient of the coating. The greatest influence on the friction coefficient is exerted by the longitudinal feed Spr of the laser beam, followed by the radiation power W and the distance L. A multi-factor model of the friction coefficient of uncoated 40H13 steel treated under the same conditions as coated 40H13 steel is also established. Comparison of the two variants showed that of all the samples providing reliable adhesion of the coating to the substrate, the greatest reduction in the friction coefficient (by 30.2 %) was achieved at W = 5 kW, Spr = 25 mm/s and L = 85 mm. The results of the research are recommended for use in enterprises that implement the processes of plasma and laser processing of materials, as well as in design organizations that develop modern laser systems.

Estimating the Accuracy of Mandible Anatomical Models Manufactured Using Material Extrusion Methods

The development of new solutions in craniofacial surgery brings the need to increase the accuracy of 3D printing models. The accuracy of the manufactured models is most often verified using optical coordinate measuring systems. However, so far, no decision has been taken regarding which type of system would allow for a reliable estimation of the geometrical accuracy of the anatomical models. Three types of optical measurement systems (Atos III Triple Scan, articulated arm (MCA-II) with a laser head (MMD × 100), and Benchtop CT160Xi) were used to verify the accuracy of 12 polymer anatomical models of the left side of the mandible. The models were manufactured using fused deposition modeling (FDM), melted and extruded modeling (MEM), and fused filament fabrication (FFF) techniques. The obtained results indicate that the Atos III Triple Scan allows for the most accurate estimation of errors in model manufacturing. Using the FDM technique obtained the best accuracy in models manufactured (0.008 ± 0.118 mm for ABS0-M30 and 0.016 ± 0.178 mm for PC-10 material). A very similar value of the standard deviation of PLA and PET material was observed (about 0.180 mm). The worst results were observed in the MEM technique (0.012 mm ± 0.308 mm). The knowledge regarding the precisely evaluated errors in manufactured models within the mandibular area will help in the controlled preparation of templates regarding the expected accuracy of surgical operations.