This document identifies and organises important information for the VHS Laser Cutter Lenses. It is a combination of a product description document and a how-to guide.

1. Trained VHS laser cutter users.
2. Laser experience levels can range from new users to sporadic users to very experienced users.

1. How to perform basic laser cutter operations. I.e. logging in, turning on the laser, starting Lightburn, loading laser files, setting power and speed levels and performing laser cuts, general cleanup and putting away all laser related material after completing laser session.
2. How to set the lens focus height for a specific operation (ie engraving vs cutting) and material thickness using a focusing guide.

Learning about the different types of VHS laser cutter lenses will open up exciting new laser project possibilities, add to learners capabilities as well as allowing for more efficient use of the laser cutter.

VHS currently has three laser lenses that live in a storage box on the shelf on the laser bench.

1. one 2.5 inch (standard) lens. (green tape)
2. one 4 inch lens. (orange tape)
3. one compound engraving lens. (blue tape)

This is the lens that any user should find on the laser cutter when starting their session. The usual power, speed settings and focus guides work as expected with the standard lens. All trained laser users should have no issues with using the standard lens as they normally have.

This lens is used for cutting thick materials from ⅜” up to ¾” plywood/softwood and perhaps up to ½” hardwood or engraving into deep recessed pockets.

This lens is used for fine detail photo engraving. This lens when properly focused and using proper speed and power settings should be capable of producing 0.1mm dots.

Lenses are installed in the head assembly by sliding them into the lower tube and securing by snuggly tightening the lower knob and then attaching the blue air assist tube to the lens. Below is that head assembly and air assist tube without a lens installed.

1. Position the laser head lens over a gap between the bed grates.
2. Detach the air assist line from the lens.
3. While holding the laser lens with one hand loosen the knurled knob and gently slide out the lens from the head assembly.

1. Slide the lens into the head assembly and gently snug the knurled knob. Do not over-tighten.
2. Attach the air assist line to the lens

The standard and 4 inch lens have a simple push to insert and push to detach system while the engraving lens has a small diameter tube that is inserted inside of the air assist line.

Laser lens with blue air assist tube attached

Push down on outer ring to release and gently pull the blue air assist tube from lens

The laser engraving lens has a smaller diameter tube that is permanently attached to the lens. Just slide this inside the larger diameter air assist hose.

Smaller diameter air assist hose inside of larger diameter air assist hose.

Each lens requires its own settings for focal length, speed and power settings, number of passes for each specific material and operation type (i.e. cutting vs engraving). Basic starting parameters are given here for various operations. All laser users are expected to experiment and find the optimum settings for their own projects and to share these findings with the wider community.

The usual Lightburn speed, power settings and focusing guide may be used with the standard lens and materials.

Note air assist is absolutely required for cuts with this lens.

• ½” hardwood - focus height 2mm, speed of X and Power of Y with Z passes
• ¾” Birch ply - focus height 1mm, speed of X and Power of Y with Z passes

See laser-cutter-7-16-maple-hardwood for an example of some power and speed settings to cut 7/16” maple.

When your laser cuts are deep It is extremely important to keep a fire watch on your cut at all times. This means not walking away from the laser or using your computer or engaging with other tasks while the laser is actively performing deep cuts.

This compound lens was designed by YouTuber RDWorks. They have a very nice video outlining in depth information about engraving using this compound lens. https://youtu.be/ZG5KsMw8fJY?si=mj3bWv7gRNXFy1x2

The current documentation calls for 10.5mm focus height but testing at VHS shows 11mm works better.

After you have completed your laser session please do the following

1. Inspect the laser lens by looking through the end of the tube. If the lens appears dirty then please alert the Laser Cutter Committee so that they may perform laser lens maintenance. Do not use a dirty lens as this will cause dirt to be baked onto the lens and permanently damage it.
2. Ensure that the 2.5 inch standard(green tape) lens is left on the laser cutter for the next person. Return the 4 inch (orange tape) or compound engraving lens (blue tape) to the lens storage box.

Look through lens to see if it is dirty and report to LCC.

These lenses were purchased from Cloudray Laser

Compound Engraving Lens (blue tape)

The 2.5 inch standard lens (green tape) uses position 3 and the 4 inch lens (orange) tape uses position 4 in the following Focal Length Adaptation diagram.