GentleLASE PRO Laser Rail Alignment Procedure
WARNING – SHOCK HAZARD!!!
The high voltage capacitor in the GentleLASE PRO laser retains LETHAL voltages and must be safely discharged, before working near the laser head or inside the HV section for any reason. This procedure must be performed only by those technicians who are familiar with the precautions required when working with high voltage specific to the GL PRO laser system, and those who have been trained on the GL PRO laser system and its particular hazards.
Residual voltages require stick discharging if access to the head or high voltage sections are necessary. This must be done using the discharge stick located in the HV section. Discharge all 3 capacitor terminals for several seconds each. Verify that the capacitor is discharged below 25 VDC using a DVM and a high voltage probe.
WARNING – LASER LIGHT!!!
During this procedure it is possible that the laser may perform a bleeder pulse, emitting laser radiation. Therefore safety eyewear must be worn at all times during these procedures. The eyewear must have an optical density of ≥ 5.8 at 745 – 765 NM for the Alex Head.
NOTE: If the OPHIR NOVA display is used, be sure the wavelength is set to “YAG, NIR or .8-6”, depending on the meter head being used.
LASER RAIL ALIGNMENT PROCEDURES:
- Remove side panels, top cover and laser rail dust covers and set aside, Remove fiber cable if installed.
- Remove the Head Detecotor and Beam Shutter and set aside leaving the shutter wires connected. Pleace assembly aside leaving the shutter wires connected. Place assembly out of beam path that allows the shutter to open/close without hitting anything.
- Turn laser on, allow for normal warm up. NOTE: Put on safety eyewear and leave eyewear on throughout this procedure.
- Enter Maintenance Mode (MM), select LASER CTRL screen, set Pulse Duration to 3ms and Rep Rate to 1Hz. NOTE: If the system will not stay in Ready to adjust the voltages for the fiber tool and burn plug, it may be necessary to install the fiber, or a fiber alignment tool to “reset” the system and then remove the fiber/tool to set the voltage correctly.
- Place/hold Ophir meter head in front of the fiber receptacle, Starting at 600V adjust HVRef to obtain 1-2J out of the fiber receptacle into the Ophir (no energy conversion factor needed). While adjusting voltages record the 1-2J voltage for fiber alignment procedure.
- Place/hold Ophir meter head in front of the fiber receptacle, Repeat “step 5” but adjust the HVRef voltage for 10J into the Ophir. Again, record this voltage for 10J for burn plug alignment procedure.
- Place black electrical tape on the alignment plug tool, P/N 7712-00-3363, and imprint the plug’s cross hair onto the tape with a ball point pen or tool. Install the plug into the fiber receptacle facing the laser head so the cross hair is oriented vertically and horizontally.
- Put a sheet of clear plastic in front of the plug, enter “Ready” and pulse the laser once to make a burn on the tape. Go to “Standby” and discharge the voltage from the capacitor using the HV discharge stick.
- Remove the plug, if the cross hair imprint gets burned off, re-mark it with a pen or tool. Inspect the centering of the burn on the cross hair, Do NOT reinstall the head detector at this time. • Figure 1 – Cross Hair Alignment Verification:
- Measure the centering of the burn with respect to the cross hair. It must be 0.7 mm or less vertically and horizontally. Be sure to divide by 2 if you measure the beam centering by measuring the difference between the distances from each beam edge to the cross hair. For example, if the top edge of the beam is 2.0 mm from the cross hair and the bottom edge of the beam is 2.5 mm from the cross hair, then the difference is 0.5 mm and the beam is off center vertically by half this, or 0.25 mm, See Figure 1.
- Verify the alignment of the fiber receptacle using the alignment tool P/N 7122-00-3362. Adjust the HVRef voltage to the same settings and voltage previously established in step 4, for 1-2J into the Ophir. Wait for the Sample voltage to drop below the HVRef. Most alignment tools are slightly de-centered, so this procedure also reduces the error caused by this de-center anomaly to a negligible value.
- Apply red or black “Sharpie” to the proximal end of the alignment tool. Insert alignment too in the fiber receptacle and mark the tool to indicate the “top” of the tool.
- Enter “Ready” and pulse the laser just “ONCE” and then enter “Standby”.
- Remove the tool and inspect the tool with an eye loupe or a magnifier, keeping the mark on the tool in the up or top position. The ink from the “Sharpie” should be gone where the beam hit the end of the fiber. • Figure 2 – Fiber Alignment Sharpie Burn:
- Rotate the fiber alignment tool so the mark is now facing “down” and repeat Steps 11-13, and be sure to look at the end of the fiber with the mark on the bottom this time.
- If the location of the burn has changed from the previous step, then the tool has a de-center error. The actual beam location is in the middle of the two beam locations. At the “actual” beam location, if the thickest “Sharpie” band is more than twice the thinnest band, then the receptacle must be aligned or replaced. See Figure 2.
- To align: First remove the 2 locking jam nuts on the fiber receptacle and screw in the vertical and horizontal set screws until they make firm contact with the lens housing. Then loosen the two inner (in the slotted holes) 4-40 socket head screws securing the lens housing assembly to the fiber receptacle block by ¾ turn each. Slightly adjust one of the two set screws, located on the top (vertical axis) and left (horizontal axis) sides of the fiber receptacle block (do not touch the ball plunger screw on the right side of the block). Adjust the set screw in the desired direction (ex: if burn spot is off to the left on the tool, adjust the lens housing towards the right [looking at the beam input side of the fiber receptacle]).
- Repeat the “Sharpie” burn and re-adjust until alignment is acceptable. See step 16.
- Tighten the two 4-40 screws evenly and perform the two “Sharpie” burns again to make sure nothing has shifted and the beam is still centered and aligned. Then unscrew the vertical and horizontal set screws and install the locking jam nuts.
- Install the head detector and beam shutter assembly and repeat the “Sharpie” burn again to make sure the beam alignment is still centered with HD re-installed.
- Clean the fiber alignment tool’s tip with a cotton applicator and solvent when finished and replace caps to both ends of the tool.
- Install the laser rail dust covers.