Shapeoko Laser Upgrade - Setting the Working Distance
One of the first things you ought to do once your Shapeoko Laser Upgrade is operational, is the appropriate Working Distance calibration.
Some engraving applications may require small focus spot, i.e. high-resolution engraving, detailed engraving. PLH3D-6W Series engraving laser has adjustable focal length and exchangeable lens. This future allows it to fulfill broad range of engraving applications. Shorter focal length of the engraving laser produces a smaller beam spot (higher power density).
You can adjust focus spot distance from the front of the engraving laser by rotating the lens clockwise or counterclockwise. Note: it is necessary to ensure that the mounted lens is sufficiently deep inside the laser head, so the lens does not move before powering on the unit.
Once you changed the position of the lens use your CNC machine to find where is the focus spot. Using the methods described above calibrate the engraving laser head's position.
- Coarse adjustment:
- Set current position as a zero position in your CNC software.
- Engrave “zero position” line on the engraving material. Hint: make this line longer compares to the next engraved line, it’s going to be easier to find “zero line”.
- Engrave (on the engraving material) 10 lines with step 1 mm in the positive direction of Z-axis and 3 mm step in X-axis.
- Go back to zero position.
- Engrave (on the engraving material) 10 lines with step 1 mm in the negative direction of Z-axis. and 3 mm step in X-axis.
- Inspect engraved lines, find the thinnest engraved line.
- Count how many lines away is the thinnest line from “zero line”, and in which direction it is placed. Let’s consider case when the thinnest line is located 5 lines from zero line and in positive direction of X-axis. In such a case calibration parameter is +5mm.
- In the CNC software, move “zero position” of the laser head by calibration parameter.
- Fine adjustment:
To obtain the highest power density, which results in the better engraving performance, we recommend making fine adjustments to the distance of the laser head and the engraving material. This adjustment should be done after performing coarse adjustment.
The process is similar to the coarse adjustment process expect steps in Z-axis, they are smaller to make adjustment precise.
- Set engraving laser head at a zero position, which must be calibrated by know.
- Engrave “zero position” line on the engraving material. Hint: make this line longer compares to the next engraved line, it’s going to be easier to find “zero line”.
- Engrave (on the engraving material) 10 lines with step 0.1mm in the positive direction of Z-axis and 3 mm step in X-axis. We recommend engraving lines with 50mm length, it is easier for eye to compare thickness of a line on longer range.
- Go back to “zero position”.
- Engrave (on the engraving material) 10 lines with step 0.1 mm in the negative direction of Z-axis. and 3 mm step in X-axis.
- Inspect engraved lines, find the thinnest engraved line.
- Count how many lines away is the thinnest line from “zero line”, and in which direction it is placed. Let’s consider case when the thinnest line is located 2 lines from zero line and in negative direction of X-axis. In such a case calibration parameter is -0.2 mm.
- In the CNC software, move “zero position” of the laser head by calibration parameter.