Limitations of Laser Cut Parts

Laser cutting is a very popular option in manufacturing parts. A major reason for this is the accuracy of reproduction. In addition, the fact that laser cutting doesn’t create any physical contact with the final piece(s) and the ability to cut a wide variety of materials lend to so many projects being turned to laser cutting. Despite laser cuttings popularity and versatility, it is not always the perfect fit for a project and has some limitations.

Delicacy

Laser cutting is a delicate process. A number of pieces of the machine require proper and accurate settings. The distance of the laser from the material, the heat of the laser, and the focus of the laser all need to be set for each piece of material that is used and can take time. A small mistake in these settings can cause the material to burn unexpectedly. This also means that the process is susceptible to being disturbed by the surrounding environment. A small bump or the laser cutter could cause the laser to be jostled and cut outside the design specifications.

In addition, the rate of production is also delicate meaning it is inconsistent. Each material and thickness of that material is going to take a different amount of time to cut. Changes in material and the cutting time will also affect the cost of cutting. This definitely has to be considered when deciding whether or not to use laser cutting instead of another manufacturing technique.

Materials

Materials are also a big consideration with laser cutting. While laser cutting is able to be used on a wide variety of materials such as wood, plastics, and some metals, it does not work with all materials. For instance, when it comes to metals, some cannot be laser cut. The amount of light a metal reflects is a big factor in whether or not it can be laser cut. For instance, aluminum reflects so much light that laser cutting is not efficient or effective. The same is true copper. In addition, metals that are too thick may not be able to be cut by a laser as well. Advances in technology are decreasing the limitations on thickness, but it is not irrelevant yet.

Outside of certain metals, other materials cannot be cut with a laser. Brittle materials or materials that are easily warped do not make good candidates for laser cutting machines as the heat produced by the laser can compromise the cut. Transparent materials also tend to create issues with laser cutting as the majority of the light passes through the material instead of absorbing the heat of the laser and getting cut.

Any design being cut using a laser must also take into account that laser cutting is done using intense, focused heat which affects the material along the cut. One known effect is the possible formations of microfissures along the cut.  If the material is likely to be made brittle or the effect of heating can cause complications for the final application, such as some aeronautical applications, it might be best to consider a different method for cutting. This can also affect materials that are extremely thin as they may be more susceptible to warping and bending than a thicker piece of the same material.

Design considerations

There are a number of things that must be considered in the design if laser cutting is the preferred method of production for a piece:

  • Part shape
  • Laser taper
  • Laser thickness

The shape of a piece can have a big effect on the effectiveness and efficiency of laser cutting. When it comes to sharp corners, such as 90-degree corners, a laser cutter must slow down as it approaches the corner in able to adjust to make the sharp turn. This obviously affects the amount of time it takes for a piece to be cut, but larger issues can occur. While it can slow its motion, a laser cutter cannot adjust the heat going toward the corner or it will not be able to cut the material. As the laser slows, stops, and changes direction, the heat from the laser continues to cut. This can cause issues with the corner such as warping, charring, or in the worse case, completely burning out the corner. It is suggested that designers use the greatest arc possible to avoid any overheating caused by the laser needing to slow to make any cuts.

Despite common belief, as the laser is not perfectly straight but is actually shaped more like a cone or hourglass. This usually gives a taper of as much as 2°. For thin materials, this may be insignificant, but it starts to be noticeable in materials as thin as 0.5-inches or 1.25 cm. If this taper could be an issue, it should be compensated and planned for during the design and application planning stage.

For parts that have pieces that are thin or come to a sharp point, the thickness of the laser needs to be accounted for. In most cases, the laser is about 1/100th of an inch thick or 1/4 of a millimeter. This may seem small, but when accuracy is a primary component in deciding to use laser cutting, this small amount can be important. In the case of an extremely thin product, the laser may need to be designed to cut just outside the allowance of its thickness. If a part comes to a point, it’s possible the laser will sheer off this point. A design may need to be adjusted or a different method considered to avoid wasting resources.

Laser cutting is an amazing technology that continues to develop, but it is not without its limitations. If you have a project, talk to the experts are at Engineered Mechanical Systems. Their experts can help you determine if laser cutting is what is best for your project and if not, which resources and method might be best for completing your manufacturing with their state of the art facilities, machinery, and knowledge.