The recognition and funds are good. But do they attack an underlying issue?
Reading Dr. Hayao Nakahara’s annual accounting of the printed circuit board market (which ran on this site last month), it’s hard to believe Taiwan was once dependent on Japan for PCB knowledge.
Years ago, however, it wasn’t Taiwan and China battling it out for market dominance; it was Japan and the US. Yet long before China emerged as a player, Taiwan had already identified PCBs as a key area for development.
Shortsighted approaches lead to overspending.
Most air freight – including for printed circuit boards – is hauled in the cargo holds of passenger aircraft. While the number of available flights is slowly increasing as Covid restrictions lessen, the price is still high, and getting PCBs delivered on time and at a reasonable cost remains a significant challenge for buyers.
That’s why they should negotiate with suppliers for a “delivered” price.
PCB buyers often overlook fluctuating freight costs when considering total cost of ownership (TCO) of the offshore products they purchase.
Limiting PCB moisture absorption is the full responsibility of the supplier. How to pack boards right.
PCB suppliers who use good packaging methods are keeping their products safe from physical damage incurred during transit from the manufacturing facility to customers’ warehouses. Equally important, these packaging practices help ensure shelf-life expectancy by preventing moisture absorption.
To protect their orders, PCB buyers should require suppliers strictly follow corporate shipping specifications. Nothing is more frustrating than waiting for quality product to be built, only to have it damaged because of poor packaging practices. It’s just as frustrating when boards become useless while sitting on the shelf.
PCBs can be very heavy. Their sharp corners sometimes wreak havoc on the corrugated cardboard boxes in which they are shipped. A good freight spec should state boards are to be vacuum-packed with a bubble wrap base, with no more than 25 boards to a stack. When a board is oversized or heavier than normal, 10 to 15 pieces is the best option. Whatever number is used, the packaging should be consistent in count for a particular shipment.
Just like housing, a little extra size can cost a lot more.
Printed circuit boards in panel or array format increase the efficiency of the assembly operation, especially in volume applications. Takt time is greatly reduced, and handling of product is easier. However, rising material prices are cutting into that advantage because more material is required to produce those arrays.
PCB costs are based on the amount of raw material required to make a particular board. The metal finish, like ENIG or silver, plays a part in pricing, but it is the amount of fiberglass and copper needed that really determines the final cost.
The quoted price for most boards in panel or array format is based on a fabricator's desired panel price for a particular technology or quantity, divided by the number of arrays (or pieces) that fit on a standard 18 x 24" manufacturing panel. The more arrays or pieces that fit on the panel, the lower the cost.
Whether that price is dictated by the number of boards (arrays) that can fit on the standard manufacturing panel, or by the total square inches of the finished array, a quarter or half-inch too long in one direction may mean a double-digit price difference.
That price difference is a double-edged sword: Either the board eats into profits because it is costlier to buy, or it’s a missed sales opportunity because the board could have been quoted at a lower cost.
I have seen inefficiently panelized PCBs so many times. Sure, there is always some waste in manufacturing, but how much money is the contract manufacturer throwing away on every assembly?
Maybe that board does need a full inch of material railing on all four sides for it to be assembled, but it’s worth asking whether that was the original array when the assembly was still in its prototype stage. Could it be it was never optimized for production? Did anyone bother to ask?
Buyers who want better panelization pricing must ask:
“Do we have to have railing on all four sides?”
“Does the railing need to be that wide?”
“Can we score instead of route?”
FIGURE 1 shows a PCB placed in an array in one of three configurations, revealing the cost difference realized when the right questions are asked.
The tab-routed array on the left with a large railing on all four sides is the least cost-effective design, yielding only 12 arrays per manufacturing panel.
The design in the middle has a much thinner railing, but still on all four sides, with scored spacing in between the boards instead of the route. That half-inch difference in one dimension makes all the difference, permitting 25% more: 15 arrays total per panel.
The design on the right is the most cost-effective, where the PCBs are “butted” up against one another, and just two thin rails are needed along the longer edge. Eight more arrays (a 75% increase) are available from that same manufacturing panel compared to the routed array.
Depending on the board manufacturer, square inches of the finished product can also be used to calculate pricing, especially for larger volume orders, and this illustration holds true for that method as well. Fewer square inches mean a lower cost per array or piece.
Sometimes larger railing is needed, especially if a particular assembly requires something special. An example is a component that overhangs the edge of the board and requires extra spacing. In that case, the PCB buyer’s engineering department should let purchasing know of any special requirements prior to sending them to the fabricator for a quote.
Additionally, board buyers need to talk to their production and engineering departments and ask for a company standard for assembly criteria that can be incorporated into PCB fabrication specs.
Ensure your PCB suppliers have those specs in hand, so the quotes they submit meet your assembly criteria without adding unnecessary costs or delaying quote response times.
The wasted green I see on the production floor is not solder mask. It’s dollars. PCB buyers need to see that too.