Nozzle changer benefits
- April 27, 2015
Set up your laser machine to reduce piercing times and increase throughput
In years past, it was common practice for laser operators to change nozzles manually when switching to different material or sheet thickness. Most laser systems now do this automatically with an optional nozzle changer increasing flexibility, quality and autonomy. A nozzle is a consumable made of copper, located on the bottom of the laser cutting head. It is responsible for focusing the assist gas onto the material being cut. The nozzle changer is a mechanical drawer that holds a capacity of 10 nozzle pockets. The operator can define which nozzle size/type is stored in each pocket. It is possible that multiple pockets will hold identical nozzle sizes/types when running longer productions in the same material and same thickness.
Nozzle condition is checked with the use of an integrated inspection camera. A necessary step, nozzle inspection verifies proper nozzle selection and confirms that nozzle installation is set in the correct pocket. Furthermore, frequent nozzle inspections will prevent the operator from using worn out nozzles, as they will have a negative impact on gas consumption and can produce inconsistencies on the edge quality of the laser cut part.
Integrated in the nozzle changer box is a rotatable nozzle cleaning brush that will clean the nozzle tip prior to placing it back into the pocket. The smallest debris on the bottom of the nozzle will have a negative impact on the “Stand of Distance” (SOD) and consequently on the position of the focal point. A mal position of the focal point will result in inconsistencies in the edge quality of the part being cut.
Most laser systems use a capacity sensor to maintain a constant SOD of 1.016 mm (0.040 in.) between nozzle and material. Nozzle calibration is essential for accurate SOD settings. This will ensure the machine is cutting with the best available efficiency and edge quality. Calibration is done each time a nozzle is changed.
Optimal piercing times
Optimal piercing times come from using the correct nozzle size for each material and thickness. In thick plate material, faster piercing times are obtained by using a smaller nozzle. The nozzle changer provides the operator with the flexibility to change the nozzle between piercing and cutting. To limit the number of nozzle changes, it is more practical to run the laser in “Separate Piercing” mode, allowing the operator to do all piercings first and then go back to do the cutting.
Optimal cutting gas consumption
Assist gas flow is determined by the nozzle size and can vary based on material and/or thickness. By using the nozzle changer, the operator can make sure each material and thickness used is provided with a nozzle that will use the most efficient and most economic gas consumption.
Optimal cutting speed
An important parameter for obtaining maximum cutting speed is the use of the correct size and type of nozzle based on your application. It is a fact that while cutting mild steel with oxygen, the smallest usable nozzle will always give you the fastest cutting speed.
With the arrival of the nozzle changer, operators no longer have to make compromises with piercing times, assist gas consumptions and cutting speeds. Adding a nozzle changer will have a positive impact on the overall efficiency and throughput
of your laser system. SMT
Stefan Colle is the laser product manager at LVD Strippit.