Fiber cutter tips #1 Stainless steel
Learning how to identify the issue through visual images is one of the easiest ways I have managed to solve a multitude of issues in a short period – Retaining visual knowledge helps mainly with a photographic memory.
The majority of the work we deal with in Quick Supports, Tickets, and Installations entails visual images and knowledge from experience.
Here are some images and important information to consider when cutting stainless steel.
1.) Strips of slag at the bottom of the stainless steel (Picture 1) The reasons for this issue can be as follows:
1.1) Focus position set too high : lower the focus position.
1.2) Cutting pressure is set too low : adjust the cutting pressure according to the settings parameter specified and try again (Recommended pressure minimum 9 BAR, maximum 22 BAR).
1.3) Cutting speed is slightly too fast (just enough to cut through but not enough to allow for a smooth and even cut : follow the recommended specified settings and adjust from there to get the best results.
2.) Layers on the cutting edge of the stainless steel (Picture 2) The reasons for this can be as follows:
2.1) Focus position set too high : lower the focus position.
2.2) Nozzle height is set too low : raise the nozzle height.
2.3) Auxilary gas pressure is set too high : lower the pressure.
3.) Slight burn around the bottom edge of the cut (Picture 3) The reasons for this can be as follows:
3.1) Using compressed air to cut stainless steel.
3.2) Lower the focus position if using Nitrogen.
4.) Goldish cutting edge (Picture 4) The reasons for this can be as follows:
4.1) Nitrogen being used is contaminated.
4.2) The grade of Nitrogen is not the correct purity.
5.) Droplet-like tiny burrs on the bottom side of the stainless steel (Picture 5) The reasons for this can be as follows:
5.1) Cutting speed too high : reducing cutting speed slightly will improve the results.
5.2) The focus position is set slightly too low and needs to be raised up.
6.) A wide cutting gap is visible on the top side of the cut. The reasons for this can be as follows:
6.1) Check the lower protective lens for contamination or damage : replace the lens and try cutting again. (Normally only occurs when cutting mild steel)
7.) Rough or jagged edges along the cut edge of the material (Picture 6) The reasons for this can be as follows:
7.1) The focus is set too low and needs to be raised up accordingly.
7.2) The cutting speed is too fast and needs to be slowed down until the edge is even and smooth.
7.3) The start point is not set in a good position and using an arc lead-in will help – along with ticking the slow start option on the layers parameter to reduce the acceleration when starting the cut.
8.) One side of the cut is good but the other side is bad (Picture 7) The reasons for this can be as follows:
8.1) The nozzle could be damaged, in poor condition, warped, or have particles stuck inside.
8.2) The protective lens needs cleaning – either due to oil, moisture, or dust/particles – If there are signs of damage or contamination it needs to be replaced.
8.3) The laser beam is not coming out of the nozzle perfectly centre. Alignment will need to be completed to correct this issue.
9.) Goldish trim halfway through the cutting edge (Picture 8) The reasons for this can be from the following:
9.1) Make sure the Nitrogen is 99.999% pure this should not occur with laser-grade Nitrogen.
9.2) Make sure there is no air or oxygen in the Nitrogen line and that the correct gas is selected in the layers parameter.
9.3) Check for leaks in the Nitrogen piping or regulator.
9.4) Make sure the gas delay is set correctly in the layers parameter under the global parameters.
Finding similarities in materials:
Most of the issues and problems that come with cutting stainless steel can also be found when cutting aluminium alloys and brass so these solutions should work for most thicknesses of aluminium alloy and brass but it is very important to keep in mind that they are not identical and only show similarities.
Supplier warning:
Brass and aluminum alloy have much higher reflectivity compared to stainless steel so the cutting speed will be slower along with the lead-in speed (Always make sure to check the recommended settings before trying to cut these materials as they can cause damage to the power source and the supplier will not give a warranty on negligence) YOU HAVE BEEN WARNED!
It is recommended that when cutting brass >3mm using Oxygen is a better option over Nitrogen as it will yield better results.
*Key point to note*
Please see the diagram for focus position, 0 focus being the bottom of the nozzle. In accordance with this news article when I refer to lowering the focus it means going further down into the negative and raising the focus means raising it up closer to 0.