How to do color engraving with LP5?

Metal color engraving is a technique used to add vibrant colors to an engraved surface. One method involves natural coloration through oxidation. The process works by directing the laser onto the metal surface, where the intense heat causes the metal to oxidize and react with oxygen, forming an oxide film. This oxide film's varying thickness creates light interference, resulting in different colors. The variation in color intensity is closely related to laser parameters, such as power, depth, and frequency. In this article, we will introduce how to use the LP5 to achieve various color effects in metal engraving. (Users with LP4 can also follow this tutorial to achieve metal color engraving.)

1. Preparation for color laser engraving

1. Make sure the work surface and laser module are level. Use the level tool to check and adjust the laser module using the H2 hex key. This helps ensure the colors you engrave come out even and consistent.
2. Use stainless steel or titanium as engraving material.

For more details on how to adjust the laser module level, which applies to both LP4 and LP5.

2. Create Material Test Array

Step 1:

Connect the machine to LDS, open the canvas, and click the settings button in the top right corner to open the Mode Settings page. Find the [Experimental Features] settings and enable the Single-element Engraving Parameter and Single-element Transfer Engraving options:

Step 2:

Return to the canvas and open the [Material test array] function. To obtain as many color blocks as possible, set the number of rows and columns in the Material test array to 10. For other engraving parameters, please refer to the following settings:

• Minimum power: 10%, Maximum power: 100%;
• Minimum depth: 10%, Maximum depth: 80%;
• X columns: 10, Y rows: 10;
• Engraving layer: Fill;
• Laser type: 1064nm infrared, Frequency: 60 kHz;
• Resolution: 8K;

Increasing the maximum depth, the number of rows and columns, and the resolution in the [Material test array] will result in a longer engraving time.

The LP4 is equipped with a 2W 1064nm infrared laser and does not have the Frequency option.

Step 3:

After finishing all the parameter settings, click the confirm button in the top right corner. Adjust the size of the test array to fit the material and center the test array.

Step 4:

Place the engraving material on the cutting plate, click Preview, and adjust the focus.

Step 5:

There is a little trick called "Out-of-Focus" when using a fiber laser for color engraving. Typically, during engraving, we need to adjust the height of the laser module until the two red dots coincide (the optimal focal distance for the LP5 is 150mm).

However, for color engraving, you can slightly deviate from the optimal focal distance, such as 154mm. Through testing, we found that 154mm provides significantly better color results. But this is not fixed; you can also try 152mm, 153mm... until you find the focal distance that works best for your material. In this example, we adjust the focal distance to 154mm.

Step 6:

Position your material on the cutting plate according to the preview box, then click "Next" to begin engraving.

Step 7:

Below is the result of the engraving. If the test array is too small, the power and depth text may become unreadable. We can save the project file or take a screenshot to record the power and depth corresponding to different colors.

Step 8:

You may notice that at power levels below 10%, there’s hardly any visible color. Also, there’s limited variation at depths below 18%, and colors tend to look burnt at depths above 64%. To improve the results, let’s adjust the settings and run a second test array using the following ranges: Power: 20%–100%, Depth: 15%–65%.

Below is the new test array generated with these updated settings.

- After engraving is complete, the material temperature will be relatively high. Please wait for the material to cool down before taking it.

- If you feel the engraving colors are not vibrant enough, you can find the parameter range that produces the most varied colors based on the results and perform the [Material test array] again.

Step 9:

Similarly, we can adjust the parameter settings or choose the 450nm laser type to perform the [Material test array] again in order to obtain as many color blocks as possible. Below are the results of the test array conducted with different parameters and laser types. All materials shown in the images are made of stainless steel, with only the shapes differing.

LP5 Test Results

LP4 Test Results

3. Color engraving parameter setup

Step 1:

To achieve color engraving, different areas of the image require different engraving parameters. If the image consists of a single layer, it won’t be possible to apply distinct parameters to each area. Before importing the image, it needs to be pre-processed by separating the different colored areas into separate layers, then saving it as an SVG file before importing it into the LDS software.

Step 2:

Import the image into the software, then ungroup the image. By opening the layers panel, you will see that the image has been split into five layers.

Step 3:

Switch to the Engraving layer panel. Based on the recorded color-to-parameter mapping, click on the corresponding layer to adjust the processing type, laser type, resolution, Frequency, power, and depth parameters.

Step 4:

After setting the parameters for all layers, group the layers, adjust the image size, and center the image.

Step 5:

Place the engraving material on the cutting plate, preview the engraving, and then start the engraving process. Below is the result of the engraving.

4. Color engraving tips

1. For best results, use silver-colored stainless steel or titanium for color engraving. Different materials like mirror, brushed texture stainless steel will produce different effects.
2. The change of colors is determined by many variables, including air humidity, temperature, the attenuation level of the laser head, and the laser head's focal length.
3. Make sure your work surface and laser module are level. This helps prevent uneven color distribution.
4. Use the LDS app for color engraving, as the PC version currently does not support setting parameters for individual layers.
5. Clean the stainless steel surface before engraving. Avoid oil, fingerprints, or dust — any contamination can seriously affect the oxide layer formation.
6. Try experimenting with different focal distances and resolutions. Using different laser frequencies when selecting the 1064nm laser type, and adjusting the test array parameters to get more vibrant color blocks.

• LP5-color-engraving-1.jpg 2 MB
• LP5-color-engraving-5.jpg 2 MB