Laser processing without damaging the protective coating: These dents must be avoided

In order to help users avoid damaging their products ’ protective coating in the laser processing process, the book covers key issues such as parameter adjustment, equipment selection and testing verification, to help users effectively protect the protective layer and increase the quality of processing.

Why is the rust-proof coating so easily damaged by lasers?

Many people may not have realized that the coating itself is very sensitive to heat.If the heat is not properly controlled during laser processing, the coating can burn or even fall off.In particular, the thickness and material of the rust-proofing layer on a metal surface can make an enormous difference in the material's tolerance of laser radiation.For instance, a galvanized coating can bubble up in seconds if it is exposed to a high-intensity laser.

Avoiding these three pitfalls makes it easier to protect the coating.

Blindly increasing power.

Some people think the more power the faster the coating will be applied, but the result is that the coating is carbonized.He suggests starting with a low-power model, such as a 500-W fiber laser, for a rust-proof coating on stainless steel.Remember to adjust the parameters and observe the results.

Ignoring the focus.

The focal point directly affects the heat-affected zone.If the focal length is too short, it will burn through the coating. If it is too long, the processing will not be thorough.I have a little trick to teach you: First draw a few different focal points on the waste material, and choose the best position to fix in place.

Forgetting to clean the surface.

Oil and dust may not seem like much, but they can cause secondary burning when exposed to laser light.Last week we had a customer who was caught out in this way. When we had finished processing the item, we discovered that the surface was covered with pockmarks.Rubbing the stone twice with alcohol before processing can save you a lot of trouble down the road.

The most effective techniques for protection.

The pulse mode is even more friendly.

Continuous lasers are prone to heat buildup, and using a pulse mode gives the coating a chance to dissipate heat.In particular, when handling aluminum anodizing, a 20 % duty cycle with high frequency pulse is very effective.

Don't choose the wrong auxiliary gas.

Nitrogen does indeed protect against oxidation, but it can also accelerate the peeling off of certain coatings.After many tests, it was found that zinc-based coatings were more suitable for compressed air. A pressure of 0.3-0.5MPa could just about remove the residue without damaging the surface.

After a sample is made, production is ramped up.

Don't rush to do the whole piece! First do a 5 cm x 5 cm test area on the edge of the workpiece.After observing the piece for two days to confirm that it is free of rust, the next step is to continue processing. This step reduces the risk of having to rework the piece by 90 %.

When problems arise, try these solutions.

If you spot a patch of paint peeling off, quickly use a low-temperature curing touch-up paint to repair it.If the damage is extensive, it is recommended that you sandblast the surface before applying the new paint. Don't just apply a new coat over the old--the adhesion will be greatly reduced.It is best to have some fast-drying rust preventative on hand for emergency use.