Optimization of Surface Cleaning and Painting Methods for DIC Measurements on Automotive and Railway Aluminum Materials

Round 1

Reviewer 1 Report

This paper focuses on the suitable surface preparation, cleaning materials and spray paints for Digital Image Correlation measurement of aluminum materials. Twelve surface cleaners, eleven paints, and five pieces of aluminum sheet material are tested. Here are some comments and suggestions for the authors:

1.    The introduction should focus more on research developments relevant to this paper, and Section 1.2 could be moved into the introduction.

2.    “DIC is a technique that can detect the 3-dimensional position,….”in line 32: Actually, 2D-DIC only provides 2D in-plane measurement, 3D-DIC detects 3D position and deformation. “Using CCD cameras….” in line 35: In addition to CCD cameras, there are also CMOS cameras. “ … with 1024-1280 pixels” in line 133: As far as I know, cameras commonly used in DIC today have a resolution of more than 1024-1280 pixels.

3.    This paper only does experiments with a variety of paints, but no explanations about the principles of paint adhesion are included.

4.    The parameter and its unit in Figure 6 are missing. The unit for vertical coordinate of Figure 7 is also missing.

5.    The conclusions could be improved.

Author Response

See attached PDF file.

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper deals with optimizing surface cleaning and painting methods for DIC measurements on automotive and railway aluminum materials. The authors have employed standard methods (wet paint thickness test, touch test, print-free test, cross-cut test, bending test, and Erichsen cupping test) to investigate and assess the performance of the Digital Image Correlation measurement technique (DIC). Twelve cleaning agents, eleven paint materials (sprays), and five aluminum sheets were examined in the laboratory tests. The paper discusses the relevance of the DIC measurements' preparation work, as the quality of the primer and speckle pattern mainly influences the quality and confidence of the laboratory tests conducted and validated with the optimal measurement system. If the dyes' quality is not appropriate, the measured deformation results will be inaccurate; thus, the results will be unsatisfactory and very uncertain. The hardening and drying of the paint(s) are dependent on the cleaning agents used and the paint(s) directly. There is one more major influence: the baseplates' type. The study delivers timely and exciting results on this issue. The paper unequivocally corresponds to the scope of the Infrastructures (MDPI) and its Special Issue, "Land Transport, Vehicle and Railway Engineering. The work is original.

I have noticed that this submission is also related to another one recently submitted to the same journal (infrastructures-2187972 – title: “Optimization of surface preparation and painting processes for railway and automotive steel sheets”), which I have also reviewed. Should the submission infrastructures-2187972 be accepted for publishing, it would be appropriate to cite it in this one.

The reviewer recommends the below-mentioned modifications:

•        The figures of the applied cleaning products and paints should be removed, as it looks more like a commercial and there is no need for that. Tables 1 and 2 are absolutely sufficient and the figures provide no additional information compared to those tables.

•        Please, correct the title of Figure 3. The current title reads: “Photos of inadequate cleaning procedures”. Those photos do not show procedures but the consequences of inadequate procedures, which is not the same.

•        Add the missing DOI numbers to the references (where missing);

•        A paragraph may be added at the end of the "Introduction" section related to the structure of the article;

•        A "List of abbreviations" would be useful at the end of the paper containing all of the abbreviations applied in the manuscript (assuming the ;

•        The introduction part may also be improved by adding some relevant and up-to-date papers.

•        Why were the considered types of aluminum chosen for the tests? Also the rolling dates of the aluminum sheets shouldbe provded, as those can affect the behavior the products.

Author Response

See attached PDF file.

Author Response File: Author Response.pdf