How will the heat generated by a laser beam affect my board and components during depaneling? Will it melt edge components into an ugly heap? Or demolish thin flex materials into an unrecognizable blob? We get these worst case scenario questions all the time from PCB designers and manufacturers who have relied on mechanical routers, manual cutters, and other traditional depaneling machines throughout their careers. So it is no wonder that there’s an ongoing concern about a laser’s heat affective zone (HAZ), and the thermal effect on edge components in particular.
That concern is certainly valid when it comes to CO2 lasers with 50+ watts of power designed to cut thick boards quickly. The good news is that HAZ is not an issue at all when using UV laser depaneling systems. And we have scientific proof.
LPKF’s affiliate in Germany conducted an independent study of the HAZ generated by a UV laser during depaneling. The study emphasized the laser’s effects on the HAZ near components at the edge of the board, which have a higher risk of being damaged during the depaneling process. In other words, to what degree does the UV laser alter the area or zone around the cutting channel, and does the heat from the laser beam damage the edge components?
The study found that, even in the worst case scenario, the temperature reached only a maximum of 100 degrees Celsius when cutting a rigid 1 mm thick board with edge components at the UV laser’s full power of 15 watts. That is half the maximum temperature generated by the SMT soldering process that every PCB goes through. It’s clear that UV laser depaneling causes no damage to edge components or board materials in the HAZ. Further research on the effects of HAZ will be forthcoming, but now we know that optimizing the UV laser’s parameters for different types of materials can control the HAZ temperature.
More HAZ control with UV lasers
Unlike CO2 lasers, UV laser depaneling machines use less energy in general – a max of 15 watts versus 50 watts for CO2. In addition, the parameters of our UV laser machines are very easy to change. You can go from 15 watts for thick boards to as low as 1 to 3 watts when processing thin flex materials. But what makes UV lasers shine is their ability to be programmed for cooling delays during depaneling. When processing flex materials or certain types of plastics that require multiple passes of the laser, you can add a microseconds-long delay between passes to reduce the amount of heat applied to the material at one time. As a result, the HAZ is reduced and edge components are protected. Furthermore, you can even change the laser parameters for just one section of your PCB panel to further protect edge components.
So, is UV laser depaneling right for your application? Don’t guess. Partner with a vendor who can help you match the right depaneling method with your specific application for the best results. That’s how we work with our customers every day at LPKF. Questions? Give us a call.