Fabrication
Cost-Efficient Laser Depaneling
Machine and operational costs have shrunk over the past decade. by PATRICK STOCKBRUEGGER
For years, the word in the electronics industry has been laser depaneling is expensive. This may have been true for investments in laser machines a decade or more ago, but the situation looks different once operating expenses are accounted for, especially with newer systems. In fact, according to our data, depaneling with laser systems is the most efficient method for a range of applications, and the cutting results are excellent, which means quality standards are also met.

The trend in the price-to-performance ratio for current laser systems, especially with respect to production of rigid PCBs, is obvious: The cost of depaneling based on the effective cutting speed has fallen to approximately one-tenth of what it was a decade ago (FIGURE 1). This dramatic shift is based on three major factors, all based on the rapid advances in laser technology. First, capex cost for laser depaneling systems has decreased to almost 30% of what it used to be a decade ago. Second, overall throughput has improved more than seven times. Finally, the operational costs for energy and maintenance have noticeably decreased.

graph depicting changes in price-to-performance ratio for laser depaneling systems
FIGURE 1. Changes in price-to-performance ratio for laser depaneling systems, 2010 to 2020. Source: LPKF
This phenomenon has two main drivers. Material costs are much lower today than a few years ago, and the performance of laser systems has improved dramatically due to integration of more powerful lasers and more advanced process know-how.
Cutting Upstream Processes
Modern laser systems enable savings in terms of PCB material of more than 30% on average. This is made possible by utilizing a full-perimeter cut through the panels with the laser, rather than cutting tabs of pre-routed boards (FIGURE 2).

With a full-perimeter cut, PCBs can be spaced closely together for minimal material loss, taking full advantage of the narrow kerf width of a laser tool, which is typically around 20µm vs. a 1 to 2mm router bit. This eliminates the space otherwise occupied by pre-routing lanes around each PCB on the panel. Another advantage is the variable and precise laser guidance and the narrowest possible cut to accommodate intricate geometries for optimum material utilization. Through these factors, laser systems realize savings, especially for smaller PCBs.

illustration of typical distance for routing lanes
FIGURE 2. Typical distance for routing lanes with mechanical routers (left) and laser depaneling systems (right). Source: LPKF
In addition, the costs of upstream process steps are reduced, and users also profit from indirect savings because of the higher number of PCBs per panel. The handling time for the individual PCB is reduced, and human errors caused by manual handling are minimized.

Unlike with milling machines, there are no significant operating expenses. The laser as a tool has no mechanical wear, and the quality of the laser is constant. There is no need to replace saw blades or router bits, which eliminates related unproductive downtime and cost to replace such parts.

To maintain a constant MTBF and minimum downtime, the preventive maintenance work on laser systems is done at longer and planned intervals and is therefore less disruptive to day-to-day productivity. Common wear parts include laser diodes, which last two to three years and typically cost in the mid four-figures.

Error Minimization
For high volumes, laser machines integrated into production lines are often advantageous. Extensive automation often reduces manual errors.

Lasers in PCB depaneling operations eliminate dust and stress to the PCB, drastically improving production yield. Unlike traditional mechanical depaneling methods, laser depaneling machines do not generate milling dust, which can become airborne and cause quality issues anywhere in the plant, and may cause health problems for employees exposed to these airborne particulates. Lasers do not create the mechanical stresses that are imparted when using a dicing saw or router, which could jeopardize the functionality of sensitive components on the circuit board or even compromise the integrity of the board itself. In addition, laser depaneling systems create absolutely no burr and maintain a much higher tolerance of the board outline, which is particularly important for intricate-shaped circuit boards that must fit into tight spaces (e.g., wearables and sensors). PCB manufacturers achieve higher quality and better yield when laser depaneling systems are being used. These two factors together provide a significant advantage over traditional depaneling technologies.

Energy Efficiency
Even if it seemed at first the energy use for depaneling was negligible for many production facilities, this factor is often considered more carefully today. Over the years, laser performance has risen considerably, while its overall power consumption has dropped significantly. This translates into a sixfold increase in overall energy efficiency – a remarkable factor that can currently only be achieved by laser technology. A modern laser system is effectively depaneling seven times as many boards using the same amount of electrical power compared to a system from a decade ago (FIGURE 3).
graph depicting changes in energy efficiency
FIGURE 3. Changes in energy efficiency, 2010 to 2020. Source: LPKF
Conclusion
Modern laser machines for depaneling of rigid and flexible PCBs save on material costs and handling efforts, and improved production quality, which equates to higher yield. The return on this investment is easy math: Although today’s depaneling lasers can be 20 to 30% more expensive than a router in capital cost, they overcome this difference with higher productivity, especially for board thicknesses less than 0.62 mils (1.6mm) where lasers are substantially faster. In addition, laser systems capitalize on additional savings of up to 30% in overall board material cost by using full laser cut and eliminate the cost and downtime of permanent tool changes.
Ed.: For a look at how laser depanelers work, click here: https://vimeo.com/524306607.
PATRICK STOCKBRUEGGER is product manager SMT/PCB Production Systems at LPKF (lpkf.com); patrick.stockbruegger@lpkf.com.