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The 9 most common Engineering Queries we see and how to address them?
Every year our Technical Department solve thousands of Engineering Queries (EQs), assisting our customers in the process of developing their PCBs to various projects and industries. Here we have collected 9 of the most recurring ones.
What is the issue? What is the solution? What damage can it cause if not discovered or solved?
Some EQs are easier than others to handle and answer, but after solving these for several decades, we know that having an experienced partner onboard in the process, decreases the risk of failures on the finished printed circuits.
Issue: Mechanical drawing not according to Gerber/drill files.
Solution: Designer needs to control this and make sure they are aligned.
Damage: Received PCB can not be used – new boards must be ordered.
Issue: Copper pads in design for non-plated holes.
Solution: This is many times on purpose – very difficult to make a general rule.
Damage: Does not have to be a problem – can get exposed copper – but 99% of times handled in EQ.
Issue: Copper features too close to the PCB edge.
Solution: To avoid this issue please try to use 0.3mm for routing and 0.5mm for v-cut.
Damage: Exposed copper – damage depends on customer application – not necessarily a problem
Issue: Opening in solder mask for via holes specified as filled/plugged.
Solution: Close the opening in the solder mask – designer needs to be made aware of this problem and correct it.
Damage: If not detected in EQ, the holes will remain open and may cause a problem for customer in circuit testing or even in final application.
Issue: Finished hole tolerance of +/-0
Solution: The best tolerance we can offer is +/-0.075mm for plated holes, and +/-0.05mm for non-plated holes.
Damage: PCB cannot be used because customer have specified an impossible tolerance. If EQ is not seen and tolerances understood, the boards cannot be used.
Issue: Gerber / Drill and ODB++ in the same file package.
Solution: Inform which one to follow. We have experienced situations where there are deviations between them. This is why it’s crucial to inform which one is the correct one.
Damage: Worst scenario, PCB cannot be used.
Issue: Specified with no silkscreen, but with silkscreen files in the package.
Solution: Make sure to inform which one to follow, specification or Gerber Files.
Damage: Probably just cosmetic, but can lead to PCB needing to be remade.
Issue: Text in copper with smaller line width than 0.2mm and lower height than 1.0mm
Solution: Small text is not possible to etch out, move it to the silkscreen layer.
Damage: Text illegible – if text is used for service or final application, it may lead to wrong use of application.
Issue: Text in solder mask over copper.
Solution: Copper will be exposed on the finished PCB, make sure text is placed outside copper.
Damage: Probably only cosmetic, but may lead to soldering problems and short circuits.