Feb 29, 2020
There are two types of AC-DC large modules that change from AC to DC and small DC-DC modules that change from DC to DC. In particular, the production and sales of DC-DC modules are huge, reaching tens of thousands per month. Marking content includes specifications, company logo, pin definition, etc. Laser marking technology came into being.
The material of the power module housing is mainly divided into:
1. Plastic (for civilian products, large quantity and thin thickness, suitable for cases where the shell does not generate heat, mostly using paper labels and PVC stickers)
2. Aluminum shell oxidation treatment (civilian product, multi-purpose screen printing)
3. Copper spray paint (military product, small amount and large benefit, multi-screen printing)
4. Copper-plated nickel and copper-plated hafnium (military, suitable for heating the shell, and with special requirements for shielding and grounding. Multi-screen printing, or heat-resistant adhesive)
Problems with the previous processing:
1. Although the paper label is cheap, it affects the module's heat dissipation. When the temperature rises, the paper label is easy to bulge, deform, and even fall off.
2. When the screen printing volume is large, it takes a lot of time and when there are many types, the layout changes are not flexible. Copper-nickel plating has a smooth appearance and is not easy to print.
3. There are many types of power modules, and the unit price of paper labels is very expensive when the printing volume is small.
4. Paper labels have been stored in the warehouse for a long time, and they are easy to be lifted.
5. A variety of types leads to error-prone workers and high labor intensity.
6. For individual varieties with a small amount, the cost of printing paper labels is high, so it can be directly printed on a printer and affixed, like laboratory products, without a grade.
Requirements for laser marking:
1. Plastic: The plastic composition is complex, and the laser marking machine produces very different results. It is recommended that module manufacturers ask their shell suppliers to change the plastic distribution ratio. Our company can cooperate with the test until a clear and beautiful mark is printed. It does not affect the protection of the enclosure.
2. Oxidation treatment of aluminum shell: The laser marking machine works well. The newly exposed aluminum gradually oxidizes and changes color, but there is still obvious contrast, especially for the black shell, the contrast color is more obvious. The relatively stable aluminum oxide does not affect the protective effect of the shell.
3. Copper spray paint: The laser marking machine can only remove the paint layer to reveal the copper background. Manufacturers are worried that the green copper rust will be affected by the appearance of copper for a long time. According to our company's process test results, there is no problem.
4, Copper-nickel plating, copper plating: copper plating has a thickness of 7-8U, 4U is required to avoid damage to the coating. The laser marking machine works well.
Do some modules work at temperatures as high as 100 ° C. Will the laser markings fail? Because laser marking is permanent, the marked character pattern will not fail.
For the traceability of supplier products, each module is required to have a different number, so the paper label and silkscreen are not flexible. And paper labels are easy to fall off and cannot be traced back. The military mandates that no labels be allowed. The silkscreen is easy to wipe off and difficult to trace. Coupled with military benefits, laser marking can basically be accepted. However, the amount of military products is small, and manufacturers may consider outsourcing laser marking processing.
The large quantity of civilian products has strict requirements on cost reduction, so even if only a small amount of cost is added to each module after laser marking, it is also a pressure on them. However, the cost of using a laser marking machine is similar to that of traditional paper labels and silk screen printing, and the logo is beautiful, which is conducive to the promotion of corporate brands.