Laser Maintenance Plan

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Laser maintenance

DO NOT perform any of the following maintenance activities without first disconnecting the Laser Cutter from the mains electricity supply!!!

Group Item Maintenance Task Maintenance Period
Optical Path Focal Lens Clean the lens Once a week
Mirror #3 Clean the Mirror Once a month
Mirror #2 Clean the Mirror Every 2 months
Mirror #1 Clean the Mirror Every 3 months
Laser Tube output Lens Clean the lens Every 3 months
Mechanical Linear Rails Clean and lubricate Once a month
Linear Bearings Lubricate Once a month
Stepper Motor Drive Belts Check tension and wear Once a month
Cooling Fans Check for dirt on blades Every 6 months
Jack Screws Lubrication Every 12 months
Jack Screw Belt Check tension and wear Every 12 months
Nuts and bolts Check Fasteners Every 6 months
Coolant System Laser Tube Water Jacket Follow the Coolant System check process Every 12 months
Water Hoses
Chiller Unit
Water Flow Cut Off Switch

Rabbit Laser Maintenance Schedule Document

Optical Path

Focal lens

This is the lens that is used to focus the laser beam. It is mounted inside the focal tube on the Y axis carriage.

This lens should be cleaned at least once per week.
It is not possible to clean the lens while it is mounted in the focal tube.
The laser beam alignment should be checked after cleaning is completed.
If there is any incident of fire or large issue of smoke/fumes, then it is advised to check the lens and clean it.
  • Use denatured alcohol and/or acetone as the cleaning solvent.
  • Use a lens tissue or cotton tipped swabs (Qtips) to apply the solvent.
  • Do not scrape the lens... Use the solvent to dissolve the dirt from the lens surface.
  • Only use a soft swirling motion when applying the solvent.
  • Use a dry swab in soft swirling motion while evaporating the solvent.
  • Use as many swabs as needed to result in a clean lens surface.
  • The lens surface should be somewhat difficult to see. Look at a reflection in the lens to help see dirt on the surface.
  • Make sure to clean the lens and not leave water marks or dirt smears.
The focal lens should be replaced if
  • it is cracked
  • the coating is scratched/pitted
  • the core material is darkened
  • the coating is delaminating
  • any other significant damage is found.

Some minor blemishes are acceptable, but any of the above problems waste power and will result in reduced laser power at the target material. Any dirt, contaminant or damage to the lens will cause the lens to become damaged faster.

Mirror #3

This mirror is located directly above the focal lens.

This mirror should be cleaned at least every one month.
It is possible to clean the mirror in its' mounting bracket. However it is strongly advised to remove the mirror from its mounted position and thoroughly clean it.
The laser beam alignment must be checked after cleaning is completed.
If there is any incident of fire or large issue of smoke/fumes, then it is advised to check the mirror and clean it.
  • Use denatured alcohol and/or acetone as the cleaning solvent.
  • Use a lens tissue or cotton tipped swabs (Qtips) to apply the solvent.
  • Do not scrape the mirror... Use the solvent to dissolve the dirt from the mirror surface.
  • Only use a soft swirling motion when applying the solvent.
  • Use a dry swab in soft swirling motion while evaporating the solvent.
  • Use as many swabs as needed to result in a clean mirror surface.
  • The mirror surface should be somewhat difficult to see. Look at a reflection in the mirror to help see dirt on the surface.
  • Make sure to clean the mirror and not leave water marks or dirt smears.
The mirror should be replaced if
  • it is pitted/scratched
  • it is rusted
  • it is discolored from heat damage
  • any other significant damage is found.

Some minor blemishes are acceptable, but any of the above problems waste power and will result in reduced laser power at the target material. Any dirt, contaminant or damage to the mirror will cause the mirror to become damaged faster.

Mirror #2

This mirror is located directly at the end of the gantry rail.

This mirror should be cleaned at least every two months.
Use the same directions as found for Mirror #3

Mirror #1

This mirror is located directly in front of the laser tube.

This mirror should be cleaned at least every three months.
Use the same directions as found for Mirror #3

Laser tube output coupler lens

This lens is located inside the output end of the laser tube.

This lens should be cleaned at least every three months.
You must be very careful when cleaning this lens.
This lens cannot be removed from the laser tube.
You can use a Q-tip for applying the acetone.
Be gentle!
The ideal situation is that you are only removing dust, film contamination from humidity or smoke fumes.
DO NOT scratch this lens.. It is not replaceable.

Mechanical Systems

Linear rails

The linear rails are the guiding rails along the left and right sides, and across the gantry.

The linear rails should be given some attention about every month.
These rails should be clean, without rust, and have a slight glaze coating of some oil.
The surfaces of the metal should always have oil on it such that it is wet to the touch.
The best way to see that you need to do some cleaning is to check the end of the rail near where the home switch is located. If you see a dirt line, then clean the rails off and apply fresh oil.

Linear bearings

The linear bearings are found under the gantry (to mount the gantry to the side rails) and under the focal head (to mount the focal head to the gantry).

The linear bearings should be given some attention about every month.
These bearings have grease fittings for pushing lubricant into the ball bearing areas.
You might not have a special grease pump to lubricate the bearings.
Try the cheap and easy approach.
  1. Remove the grease fitting
  2. Apply the grease to your finger
  3. Push the grease into the little hole
  4. Push more grease into the little hole
  5. Go to step #2 .....
  6. Put the grease fitting back on.

Rubber belts

The rubber belts are used to transfer drive from the stepper motors to the gantries.

The rubber belts should be checked for appropriate tension at least every six months.
You should expect the two side belts to be the same tension and should be tensioned at the same maintenance schedule.
The side belts work together to move the gantry from front to rear.
If one belt is tensioned more often than another, then that belt could become stretched more than the other.
It is difficult to describe how tight the belts should be, but there should not be a slack, sagging, or flapping.
If the belt appears to be worn on one side, check the bearing alignment or damage to the matching bearings.
There are many laser machine designs, but the method of changing the belt tension should not be too complex. It is usually a case loosening a locking nut, tightening a tensioning screw and then retightening the locking nut to lock the tensioning screw in place.

Fans

The cooling fans are used to force air over the electrical parts of the laser machine control system.

DO NOT CHECK THE FANS WHILE THE MACHINE IS CONNECTED TO THE ELECTRICITY SUPPLY!
If the fan blades get dirty, then the fans cannot move the air as quickly.
We need to check the fans to see if our laser environment is not as clean as we hoped.
If the fan blades are dirty
  • clean the blades with a mild soapy water solution applied by cotton buds and some paper towels.
  • The cotton buds should be damp, not dripping with solution.
  • DO NOT get soapy water in to any of the electronics!

Jack screws

The jack screws are threaded rods that are used to elevate the work platform.

Checkjack screw lubrication every 12 months.
The jack screws should be greased when assembled at the factory.
Additional grease can be applied if desired, but is not likely to be needed more than every few years.
The screws should be adjusted so that the bed is parallel to the plane of the gantry before the belt is tensioned.(below)

Jack screw belt

A belt is used to synchronize the turning of the jack screws.

The belt is woven from the Z-Axis shaft around a pulley on each of the jack screws.
Tension is adjusted by a sliding idler wheel on the base of the unit.

Nuts/bolts

Check all fasteners, screws, nuts and bolts on or around the lid and carriage are tight.

Cooling System

The Laser Cutter has a water coolant system to keep the Laser tube cool. Cooling the Laser tube greatly extends the life of the tube and protects it from thermal damage.

Coolant system Components

The coolant system comprises of 4 main parts

  • The Laser Tube Water Jacket
  • The Hoses
  • The Chiller Unit
  • The Water Flow Safety Cutout Switch

The Laser Tube Water Jacket

The Hoses

The Chiller Unit

Automotive antifreeze MUST NOT be used as a Laser coolant.
The best coolant is deionized water with a small amount of Milton sterilising solution, or similar, in it to reduce biological contamination build up.
  • In the absence of deionized water, distilled water can be used.
  • Tap water should only be used as a last resort.
The coolant should always be clean and clear.
It is a common problem for the coolant to become contaminated with mold, micro organisms or algae.
This often looks like a murky green water with snot building up on the inner walls of the hoses.

Coolant System Cleaning

The clean the coolant system please follow the following process

  1. Flush out the bad water.
    1. There is a drain plug on the front of the chiller unit.
    2. The whole system contains XX litres of water. Make sure you have a big enough container to receive all the old coolant.
    3. With you container below the drain plug, remove the plug an allow the water to drain completely.
    4. Once fully drained replace the drain plug.
  2. Add fresh water with 20 percent bleach through the filler cap on the top of the chiller.
  3. Cycle the bleach-water for 30 minutes.
  4. Flush this water out following the draining steps above.
  5. Switch the inlet and outlet hoses and flush with more water. This should dislodge any contamination from inside the laser tube.

The Water Flow Safety Cutout Switch

The flow safety sensor could also be full of contamination...

The best solution is to take it apart and clean with a soft brush or pipe cleaners. Make sure to re-assemble the sensor correctly and without leaks. It is possible that harsh cleaners could creep into the sensor electronics and cause permanent damage.

Spares

Maintenance Record

  • 09/2015 - Adjusted gantry orthogonality. (Was wrong when delivered). PAB
  • 09/2015 - Adjusted bed so that is was level, (jack screw sync). (Was wrong when delivered). PAB
  • 01/2016 - Cleaned all mirrors, and lens. Checked beam alignment (no change). PAB

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