Laser Marking Experiment | MBB6: Laser Material Processing | | FACULTY OF MECHANICAL ENGINEEERING |

Exercise 1: Familiarisation of Machine and Laser Parameters
Learning Objectives: * Familiarise with machine * Familiarise with the software: * Trumpf CAD Editor * TruTops Mark * Observe the relations/influence of the various parameters: * Pulse Rate * Velocity * Power * Defocus

Part 1: Familiarisation of machine

In this section, you will learn the basic buttons and switches on the machine.

On/Off Switch
This switch turns the machine on/off. It is located on the right hand side of the machine.

Movement of machine table These buttons moves the table of the machines and z-axis of the laser head.
Movement of Laser Head
Movement of Table (X-axis)

Movement of Table (Y-axis)
Movement of Laser Head
Movement of Table (X-axis)

Movement of Table (Y-axis)

Emergency Stop Button This button immediately stops the machining process.

Part 2: Familiarisation of software

In this section, it gives an idea of how to use the two software that are required to operate the laser marking machine.

6
1
2
3
4
5
7 1. New file 2. Laser Parameters Administration 3. Drop Down Menu for Parameters 4. Align to centre (Y-axis) 5. Align to centre (X-axis) 6. Insert Text 7. Insert/Import Photo

Basic Features: 1. New File 2. Laser Parameter Administration * Enables editing and inserting of new laser parameters 3. Drop Down Menu for Parameters * Shows the list of available parameters which can be assigned 4. Align to centre (Y-axis) * Position Text/ Pictures to the centre of the Y-axis 5. Align to centre (X-axis) * Position Text/ Pictures to the centre of the X-axis 6. Insert Text 7. Insert/ Import Photo
6
1
2
3
4
5
7
8. New file 9. Laser Parameters Administration 10. Drop Down Menu for Parameters 11. Align to centre (Y-axis) 12. Align to centre (X-axis) 13. Insert Text 14. Insert/Import Photo

Basic Features: 8. New File 9. Laser Parameter Administration * Enables editing and inserting of new laser parameters 10. Drop Down Menu for Parameters * Shows the list of available parameters which can be assigned 11. Align to centre (Y-axis) * Position Text/ Pictures to the centre of the Y-axis 12. Align to centre (X-axis) * Position Text/ Pictures to the centre of the X-axis 13. Insert Text 14. Insert/ Import Photo
Trumpf CAD Editor

TruTops Mark4
4

2
3
6
5
7
1
2
4
Basic Features: 1. Key in desired absolute coordinates of individual axes: * Position of workpiece (X and Y axis) * Thickness of workpiece (Z axis) 2. To move the individual axis after keying in the desired coordinates 3. To switch on Laser 4. To load marking job into the software 5. To start marking of the workpiece (Note: Do not click on this if the workpiece has not been positioned) 6. To close machine door 7. To identify where the boundaries of the marking are on the workpiece 8. To open CAD editor
8
2
3
6
5
7
1
2
4
Basic Features: 9. Key in desired absolute coordinates of individual axes: * Position of workpiece (X and Y axis) * Thickness of workpiece (Z axis) 10. To move the individual axis after keying in the desired coordinates 11. To switch on Laser 12. To load marking job into the software 13. To start marking of the workpiece (Note: Do not click on this if the workpiece has not been positioned) 14. To close machine door 15. To identify where the boundaries of the marking are on the workpiece 16. To open CAD editor
8

Part 3: Familiarisation of Laser Parameters

In this section you will learn and test the various parameters of the laser: * Pulse Rate * Velocity * Power * Defocus

These parameters will produce different results on the marked workpiece and will be observed as you input different set of values. But before doing the experiment you must first be aware which of the individual parameters listed above affects the laser operation. What effect do you notice e.g. by increasing or lowering the pulse rate? Please fill in your answers in the table below. Parameters | Effects | Pulse Rate | | Velocity | | Power | | Defocus | |

Table1.1: Effects of setting parameters on the laser operation

Before starting on the experiment, a “Checkerboard” pattern has to be loaded onto the Trumpf CAD Editor, and the individual parameters have to be adjusted and then marked depending on the desired shade.

Part 3A: Preparation of file

1. Create new folder on the desktop and rename it with your group. 2. Copy and transfer all the files that can be found in the folder “Laser Material Processing Lab” into the folder. 3. Start-up “Trumpf CAD Editor” either through the icon on the desktop or through “TruTops Mark”. 4. Once inside the editor, go to “File” then “Open” and navigate to your folder to open the file “Checkerboard.VLF”.

Part 3B: Assigning of Parameters
Each square of the pattern will get its own set of parameters. Before assigning the pattern with the parameters in the computer, you are required to write down a different combination of parameters in the table below. Try to get a combination where you will get a shaded checkerboard pattern that gets increasingly brighter to the right and to the bottom. Don’t worry if you don’t get the combination right for the first time. There is a certain system behind the parameters to which you should get after some attempts.
To keep it a little bit more simple please vary the parameters only inside the following ranges. * Pulse rate (Hz): 10 000 - 60 000 * Velocity (mm/s): 500 – 5000 * Power(%): 60 – 95 * Defocus: +/- 0.5mm
Hints:
Parameters | Checkerboard pattern | | A1 | A2 | A3 | B1 | B2 | B3 | C1 | C2 | C3 | Pulse Rate(kHz) | | | | | | | | | | Velocity(mm/s) | | | | | | | | | | Power(%) | | | | | | | | | | Defocus(mm) | | | | | | | | | | Table 1.2: Parameter setting for checkerboard pattern
Once the table is completed you can now assign the parameters to each square accordingly.
Steps:
1. Assign every square the parameter name suggested by Figure 1.3 ,by choosing the parameter set in the dropdown menu. 2. Once successful, the colour of the square will change to black. 3. Open the parameter administration, Figure 1.4, by double clicking a square. Here you can change to the desired value based on the table 1.2 above. 4. Repeat Step 3 on all the remaining squares. 5. Save your file after you are done.

Figure 1.3 Checkboard

Figure 1.4 Main parameter setting

Part 3C: Marking of Workpiece
For this exercise, we will use a 1mm thick sheet of steel.
Steps:
1. Load your file in “TruTops Mark”. 2. Turn on the laser by clicking “Laser” button or pressing F2. 3. Set the Z axis with the thickness of the workpiece which is 1mm and click “Move”. 4. Display marking area by clicking “Pilot Laser On” or pressing F4. 5. Position the workpiece so that it is within the area of the laser. 6. Check the preview of the mark in “TruTops Mark”. 7. Switch off the display marking area by clicking “Pilot Laser Off” or pressing F4. 8. Start marking procedure by clicking “Marking” or F12.
After a period of time the checkerboard pattern will be marked on the surface of the workpiece and you can clearly see the difference with varying parameters.
Part 3D: Marking on Plastics
For this section, it will be shown that laser marking system can be used on plastics and you will receive a piece of plastic sheet (grey). Repeat the steps as in Part C and start the marking process. (Note: Please change the Z axis accordingly based on the thickness of the plastic)
Answer:

Answer:

After the marking is completed, compare the patterns on both the plastic and metal surfaces. What differences do you observe?

Experiment 2: Annealing
Introduction:
Annealing marking is when an oxide layer is created on ferrous metals (iron, steel, high-grade steel) and titanium through localized heating. This creates oxide layers on the surface whose composition determines the coloured appearance.
Generally, the oxide layer is black, but it can also have other annealing colours (such as yellow, red and green). The colour depends on the temperature of the heated layers. The material surface remains even during annealing because nothing is removed from it; the colour change is achieved through localized material heating only.
Learning Objectives: * Understand and observe how different parameters affect the colour of the marked shapes on the workpiece.

Part A: Preparation of file
In the editor, go to “File” then “Open” and navigate to your folder to open the file “Annealing.VLF”.
Part B: Assigning of Parameters
Once you have opened the file, you are required to fill the following boxes with the different parameters that are listed below. You are allowed to choose any of the following parameters below (Colours below may not reflect the actual colour on the workpiece). Assigning of parameters is similar to Experiment 1, so repeat the steps found in Experiment 1: Part 3B.
A: Pulse Width, B: Defocus (mm), C: Pulse Frequency (kHz), D: Velocity (mm/s)
C
D
B
A
A: Pulse Width, B: Defocus (mm), C: Pulse Frequency (kHz), D: Velocity (mm/s)
C
D
B
A
Note: If pulse width parameters does not appear in the Administrate Laser Parameters click on the Pulse icon located at the bottom left.

Part C: Marking on Workpiece
For this experiment, please use a 1mm thick sheet of steel.
Steps:
1. Load your file in “TruTops Mark”. 2. Turn on the laser by clicking “Laser” button or pressing F2. 3. Set the Z-axis according to the thickness of the workpiece which is 1mm and click “Move”. 4. Display marking area by clicking “Pilot Laser On” or pressing F4. 5. Position the workpiece so that it is within the area of the laser. 6. Check the preview of the mark in “TruTops Mark”. 7. Switch off the display marking area by clicking “Pilot Laser Off” or pressing F4. 8. Start marking procedure by clicking “Marking” or F12.
Part D: Anneal on Aluminium
For this section, we will see whether we can anneal on Aluminium.
Steps:
1. In the editor, go to “File” then “Open” and navigate to your folder to open the file “Annealing Alumnium.VLF”. 2. Assign your favourite colour parameter for the square. 3. Continue with the Annealing process which is similar to Part C.

Answer:
Answer:
After the annealing is completed, what do you observed? Why do you think the outcome of the annealing process is like that?

Exercise 3: Engraving
Introduction:
Metal, ceramics and several plastics can be engraved with the laser. The power density of the laser beam is so high that the material evaporates partly during processing. A colorless indentation results in the material – the engraving. Oxides sometimes form in the engraving, the color of which make the mark even clearer.
Learning Objectives:
Create an engraving on a metal work piece by using the marking laser.
Part 1: Engraving
In this part of the exercise, we will observe several engravings using pre-programmed laser parameters.
By now you should be familiar with operating the laser marking machine and the use of the "CAD Editor" and "TruTops Mark" software.
For this exercise, we will use a 1mm thick sheet of aluminium.
Steps:
1. Open the file "DeepEngraving.VLF" using "TruTops Mark".

2. Start the laser process. (Remember to measure the thickness of the workpiece and adjust the Z-axis) 3. Decide which of the six engravings has the best optical quality and durability against abrasion. (You may use sandpaper to scratch the surface)
Part 2: Engraving Sequence
In the second part of the exercise, you will learn how to set up a "Sequence" parameter so that the same engraving cycle is repeated, producing a deeper engraving.
For this exercise, we will use a 1mm thick sheet of aluminium.
Steps:
1. Open the CAD editor and create a new file called "EngravingSequence.VLF". (Arrow 1) 2. Click the symbol "Variable data object" (Arrow 2) to create a Text Box. Select "Text properties". Insert the text "Engraving Sequence". Click "OK" and "Place" your Text Box.
2

2

1

1

3. You can center your Text Box both vertically and horizontally. (Arrow 3)
3
3

4. Click on "Global laser parameters" (Arrow 4) and choose "Insert new parameter". Name it "Engraving".
4
4

5. Click on the newly created parameter and click "Copy parameter". Rename the new parameter as "Engraving Seq". 6. Transfer your choice of the best parameter set (G1 - G6) from the last marking job into the new parameter "Engraving". 7. Click on the parameter "Engraving Seq" and click on the "Sequence" Tab above. Here you can choose the previously defined parameters and add a sequence (repetition). Under the "Available parameters" column, highlight the desired parameter and shift it to the "Used parameters" column. Change the Sequencing Number to "100". Click "OK".
5
5

8. Assign the parameter set "Engraving Sequence" to the Text by selecting the Text Box and selecting the desired parameter from the drop-down box. (Arrow 5)

More repetitions of the engraving sequence will produce a deeper engraving but this will increase the process time. Please optimize the parameters for the text "Engraving Sequence" to meet the following requirements: * Process time < 10s * Good visibility
After each change of the parameters, save the file in "CAD Editor" and open the updated file with "TruTops Mark" so that the new settings are loaded. Please stop this exercise after the third try, so that you have enough time for the remaining exercises.

Exercise 4: Line Width
Learning Objectives:
Familiarise with changing the line width of the laser marking to enhance the visual quality of the engraving.
Steps:
By now you should be familiar with operating the laser marking machine and the use of the "CAD Editor" and "TruTops Mark" software.
For this exercise, we will use a 1mm thick sheet of aluminium. 1. Open the file "Linewidth.VLF" in the CAD Editor

2. Now assign the following filling parameters to each letter as shown beneath:
S = simple line
P = parallel line (Width 0.300mm, Number 5)
W = wobbled line (Width 0.300mm, Sequence 0.200mm) 3. Open "Global laser parameters" and click on the "Width" Tab. Now select the appropriate setting for each of the letters.

4. Load the file in TruTops Mark and start the laser process. (Remember to measure the thickness of the workpiece and adjust the Z-axis)

Answer:
Answer:
Change the settings of the Parallel line (Width 0.800mm, Number 5) and repeat the marking process. Next change the settings again (Number 10). What are the effects of these changes?

Answer:
Answer:
Change the settings of the Wobbled line (Width 0.500mm, Sequence 0.300mm) and repeat the marking process. Next, change the settings again (Width 0.500mm, Sequence 0.500mm). What are the effects of these changes?

Exercise 5: Making a Bookmark
Introduction:
CAD-editor supports some common picture formats like bitmap(bmp.), vectorgraphic(DXF), jepg , TIFF and so on. Bitmap and DXF are the two frequently used for company logo and label marking. Bipmap is featured by occupying certain bits to form a picture. DXF is made of vectors, i.e. starting points and directions. The advantage of DXF over bitmap is that the resolution does not lose when a picture enlarged. Therefore DXF files is more suitable for company logos or labels marking because their sizes are usually altered for different products.
Firgure 3: Zoom in a bitmap by 4 times
Firgure 3: Zoom in a bitmap by 4 times Figure 1: Original picture Figure2: Zoom in a DXF by 4 times Illustration: original picture in Bitmap or DXF(Figure 1) after zooming in by 4times, there is obvious qualitz loss for bitmap. You can create ,edit and convert vectorgraphic pictures in INKSCAPE.

Learning Objectives: * Understand the differences of bitmap and other importable picture formats and learn how to adjust the imprted pictures in the CAD editor. * Add texts and QR-code

Part 1: Loading bitmap
For this exercise, please use a 1mm thick sheet of aluminium.
Steps:
1. Open file “Bookmark.VLF” in CAD-editor, the template of bookmark 2. Import bitmap
In this step, click the icon "Bitmap" (Arrow 1) and select the file "HS-Esslingen.bmp" from the folder “Import” on the desktop. 3. Adjust the picture.
A window named "Size and location of bitmaps" should appear. Do not change anything and click “OK”.
Place the picture on the intended spot. In the “image resolution” window set the fixed factor to be 1. (the lower the factor, the lower resolution and picture quality, but the marking time decreases)
You may center your picture both vertically and horizontally.

Part 2: Inserting QR-codes
Steps:
Now, the QR-code will be added to the bookmark. 1. To add a QR-Code, click icon “Variable data object” (Arrow 2) inside the “CAD-Editor”, select “As barcode” and click on "Barcode properties".

2. Under "Barcode type", select “QR-Code” and type “www.hs-esslingen.de” or anything else you like into the "Text" field. Everything else remains unchanged.

3. You may add text such as your name, faculty, etc. (Please refer to previous exercise) 4. Finally, save the file and load it into "TruTops Mark" to begin the laser making process. 5. Remember to set the z-axis of the machine according to the thickness of the workpiece (In this experiment it is 1mm).