When marking surgical instruments the key requirements are that the process 

• must last the life of the instrument
• must not damage the instrument
• must not harm the patient

 Now see what the different processes can achieve with these requirements in mind.

1.  Laser Marking

If the laser mark is made with a low laser power so that it makes a really attractive black mark then what it has done is make a surface mark that is very thin and can easily be rubbed off or will gradually fade. This happens in the decontamination cycle from repeated imersions in the reverse osmosis rinse water and the effect of the clean steam in the steriliser. The mark will not last the life of the instrument. 

2.  Laser Etching

This sometimes called laser marking as well. This uses a higher powered laser beam and it burns through the protective oxide layer of the instrument. The instrument now requires an additional process to rebuild the oxide layer or the instrument will rust. Has this damaged the instrument?

3. Laser Bonding

This is yet another version of laser marking. In this method a new material is placed on the instrument and the laser beam is used to fuse the new material to the instrument. If there is contamionation on the instrument surface then the bond will not be complete and some material can become detached. This means the code will fail to read but more importantly the material may enter a patient. Could this harm the patient?

4.  Laser Marked Labels

In the sales literature for this product the life of the label is given as two years. This meand that labels must become detached from the instrument. This has two effects. One the history of the instrument is lost but more importantly the label could enter a patient. Could this harm the patient?