3. Computer controlled cutting¶

This week we became familiar with the different types of laser cutter machines and their functions including the fiber laser cutting machine and the CO2 laser cutting machine. The one we will be mainly using in our lab, however, is going to be the CO2 laser cutting machine.

Fiber versus CO2 lasers¶

Fiber (solid-state)¶

How it works¶

A bank of diodes produces light. Fiber optic cables channel and amplify the photons to form a beam. Even though no optical mirrors are used, fiber lasers are 200% more efficient at light creation.

Advantages¶

The advantages to fiber lasers are plentiful. There are no moving parts or mirrors in a fiber laser which means nothing must be aligned. This results in a lower overall maintenance cost. The insensitivity of the machine leads to lower operating and maintenance cost.

Fiber lasers have excellent electrical efficiency when compared to CO2 lasers. This makes them more efficient than CO2 with the added benefits of lower running costs along with being environmentally friendly. Fiber lasers also have an advantage with regard to cutting thin materials.

They are close to three times faster at cutting on stainless steel with a 1 mm thickness than CO2 lasers. Finally, fiber lasers have the ability to cut reflective materials such as copper, brass, and aluminum.

Disadvantages¶

The main disadvantage to fiber lasers is apparent with thicker materials. When processing metals thicker than 5 mm, CO2 lasers produce faster, cleaner cuts.

CO2¶

How it works¶

Excited CO2 molecules release photons that are focused into a beam using optical mirrors and lenses.

Advantages¶

CO2 lasers also possess some advantages. As previously stated, CO2 lasers perform better on materials thicker than 5 mm. They leave a smoother finish than fiber laser and perform the cut more quickly. Additionally, CO2 lasers provide a smoother cut edge, especially in materials thicker than 3 mm.

Disadvantages¶

CO2 lasers are very sensitive machines. The mirrors that focus the laser require realignment if they get knocked out of place. The realignment must be done by a specialist, which can be an expensive ordeal. This leads to overall higher maintenance costs. Fiber lasers perform better on thin materials than CO2 lasers do. Finally, unlike fiber lasers, CO2 lasers cannot work with reflective metals. Back reflections could damage the machine irreparably.

Testing Your Material to Determine Laser Speed and Power Settings¶

As a group, we had to work on the assignment of testing the Laser Cutting Machine so that we can familiarize ourselves before actual use. The main purpose of this assignment is to test how the change in power and speed will alter the degree to which the material we are using is engraved.

A note to keep in mind is that the power and speed and the level of engraving is different from one material to another**