WO2011124188A2

WO2011124188A2 - Method of replication of surface structures

Info

Publication number: WO2011124188A2
Application number: PCT/CZ2011/000028
Authority: WO
Inventors: Vladimir Pata; David Manas; Jaroslav Maloch; Miroslav Manas; Michal Stanek
Original assignee: Tomas Bata University In Zlin
Priority date: 2010-04-09
Filing date: 2011-04-05
Publication date: 2011-10-13
Also published as: WO2011124188A3; CZ302594B6; EP2567296A2; CZ2010278A3

Abstract

First the surface of the respective part is covered with a non-transparent mask with a rectangular hole, whose edges correspond to the size of the replicated part of the surface. After that follows the optical scanning of coordinates of this part of the surface, saving coordinates in the form of three- dimensional matrix x, y, z and creating an enlarged replication of the surface by transferring data of the three-dimensional matrix to an enclosed area without gaps with subsequent print-out by 3D print and/or import of the data to the CAD system with automatic generating of the respective tool trajectories for production of an enlarged surface model by means of the CNC machining technology.

Description

Method of Replication of Surface Structures

Field of invention

The invention relates to method of surface structure replication, creation of an enlarged image or model of surface of technical parts made of metal and non-metal materials.

State of the art

For these purposes the principle of optical scanning and subsequent evaluation of quality of surfaces is more likely being used. Many producers deal with production of single- purpose devices, which carry out scanning or subsequent evaluation of quality of surfaces according to the respective ISO standards in the field of 2D and 3D. The outputs of the scanning include cither numeric parameters of surface quality or graphic presentation.

However, this can be, for a technician who does not particularly deal with evaluating surface quality; very complicated for proper practical interpretation. Another insufficiency is also the fact that it is very difficult to reach repeatability or reproducibility in the field of the evaluation of surface quality. Today the display of the scanned surface is possible only by means of single-purpose programmes shipped with individual devices, which are usually not mutually compatible.

Regarding the so far known methods of surface replication, they currently consist mainly in applying sufficiently plastic material on the tested surface, reinforcing this material into form of a compact layer and removing the replica in form of the surface negative. Within solutions according to USA patent application no. 2008173078, this principle is being used for evaluation of unacceptable surface defects of the sample. Thermoplastic melt is being applied on the sample- surface and, alter its cooling,' the created foil which represents the negative replica of the sample surface is being removed; -By comparing the replica with the standard the actual evaluation of sample surface quality is being carried out.

Another method of surface replication on a nanostructure scale according to the USA patent application no. 2003228418 rests in applying a thin film on the replicated substrate surface; the film is based primarily on cellulose acetate, which after application of softening agent-namely acetone- occupies conformation which exactly copies the surface. After reinforcing and removing the foil in this conformation a thin layer of suitable material; such as gold, platinum, ferrum or carbon, is being applied on the negative established on its surface. This way the replica with nanostructures consistent with the original substrate surface is being produced.

It is obvious that the above described well-known methods of replication are rather exacting, expensive and they bring many limitations from an application point of view.

Nature of invention

The method of surface structure replication according to the invention contributes to the removal of the above mentioned imperfections of the state of art to a great extent. The nature of invention consists in that the surface of the respective part is first covered with a non- transparent mask with a rectangular hole, edges of which correspond to the size of the replicated part of the surface. After that follows the optical scanning of coordinates of this part of the surface, saving coordinates in the form of three-dimensional matrix x, y, z and creating an enlarged replication of the surface by transferring data of the three-dimensional matrix to an enclosed area without gaps with subsequent print-out by 3D print and/or import of the data to the CAD system with automatic generating of the respective tool trajectories for production of an enlarged surface model by means of the CNC machining technology.

The non-transparent mask is advantageously a mask made of non-transparent thin and elastic material, based mainly on paper or plastic material provided with an adhesive layer.

The enclosed area without gaps for print-out by 3D print is advantageously generated in standard STL format (stereolitography) with the possibility to set the individual scale for particular x, y, z axes.

Method of replication according to the invention is particularly convenient when it is necessary to create a replica of the evaluated surface which is interesting from the tribologic point of view. In such case it is possible to display in arbitrary scale a space on which the scanning of surface texture in 2D and 3D, according to relevant ISO standards, was performed. Further it is possible to replicate in arbitrary scale various defects as scratches, fissures or cracks, which occur on the surface of samples and thereby also decrease their quality. List of Drawings

The enclosed drawings serve to clarify the nature of the invention more closely:

Fig. 1 - schematic representation of the principle of surface replication according to the invention,

Fig. 2 - example of a sample of microhardness evaluation prepared to serve as a model surface replication with a mask applied,

Fig. 3 - 3D image of the enlarged replica of sample surface from microhardness evaluation, Fig. 4 - space enlarged surface replica of the sample from microhardness evaluation (replica created by rapid prototyping technique),

Fig. 5 - 3D image of the enlarged surface replica of the steel sample surface made of steel machined by face milling technique,

Fig. 6 - space enlarged replica of the surface of sample made of steel machined by face milling technique (replica made by rapid prototyping technique).

Examples of Invention Implementation Example 1

On the basis of an example of a microhardness evaluation of a polymethylacrylate sample the practical applicability of the way of replication as per the invention was verified. A typical (im)print of the measuring pyramid remains in the tested material after measurement of microhardness. The pyramid diagonals are 0,020 mm and its height is 0,015 mm.

As a result of material sample relaxation the (im)print deforms; these deformations must be displayed and subsequently evaluated. (Note: From current visualisation methods only the use of electrone microscope applied, such as SEM).

During application according to the invention (see fig.l and 2) the sample surface 1 was covered by a paper mask 2 with a limiting opening of a square shape with 0,6 mm edges. The area 1 defined by the mask opening 2 was subsequently scanned by a 3D scanner (such as Tailor Hobson with a CLA scanner), in specific distance in x and y axes 0,025 - figure 1 presents scanning in the direction from x to y, or in the y to x direction from the starting point A to the end point Z - as suggested by arrows 3. The resolution in the axis was left to maximum, namely 1 nm. After the actual scanning a three-dimensional matrix of x,y,z coordinates was transferred to a closed area without gaps and was subsequently printed as an enlarged replication of the sample surface through a rapid prototyping technique (see fig. 4).

Fig. 4 presents a well visible replication of the surface sample with a typical imprint of the measuring, already after relaxation.

It is also possible to import data into the CAD system with an automatic generating of corresponding instrumental trajectories for a production of an enlarged model of the surface through the CNC tooling technology.

Example 2

Replication of the 12020 steel sample surface made according to the invention presents another practical example of application. The sample was tooled by a technique of face milling. The scanned surface size for 4mm x 2mm; the remaining process and 3D scanning parameters were identical with Example 1.

In Fig. 5 a 3D image of the surface sample can.be seen which was gained with help of Talymap commercial programme; in Fig.6 can be seen a space replication of the surface which was achieved by the rapid prototyping technique.

Claims

1. Method of replication of surface structures, technical parts made of metal and non- metal materials in particular, characterized in that the surface of the respective component part is being covered with a non-transparent mask with a rectangular hole, edges of which correspond to the size of the replicated part of the surface, and this process is followed by the optical scanning of coordinates of this part of the surface, saving coordinates in the form of three-dimensional matrix x, y, z and creating an enlarged replication of the surface by transferring data of the three-dimensional matrix to an enclosed area without gaps with subsequent print-out by 3D print and/or import of the data to the CAD system with automatic generating of the respective tool trajectories for production of the enlarged model by means of the CNC machining technology.

2. Method according to claim 1, characterized in that a mask is made from thin and elastic material, mainly based on paper or plastic material provided with an adhesive layer.

3. Method according to claim 1, characterized in that the enclosed area without gaps for print-out by 3D print is generated in standard STL format (stereolitography) with the possibility to set individual scale for particular axes x, y, z.