PCB inside a parallel port cable case

Question

I designed a PCB to fit inside the case of a parallel port connector cable. It will be soldered, internally, to the pins of the cable connector. I already did a first version, I printed it on paper in order to better see the results. Below, there is a picture of it:

(click small image above for larger image)

But I'm afraid to design it to fit exactly into the case, because this way, it will fit only to the type of case that I measured and, maybe, it would not be a good choice. So, I was concerned about two points:

1. If it does not fit exactly, if it is smaller, it could swing inside the case and it can break the soldering between the PCB and the connector pins.

2. If it does fit exactly, I will be a "prisoner" of this case format. If, for some reason, this format of case became unavailable, I would need to redesign the PCB.

What do you think about it, does anyone have any advice?

Answer 1

To answer your first question about clearance, I wouldn't worry about making the PCB slightly smaller than your enclosure. To begin with, the solder joints between the DB25 and PCB will hold it securely; I would also recommend adding pads on your PCB for all of the pins that you can (even unused ones) to increase mechanical strength, and increase your trace widths to prevent any mechanical stress breakage.

Regarding your second question, component availability is always a concern. You can reduce some worry by designing around the most widely available, high-profile manufacturer's connector case as you can find, or, as others suggested, by purchasing several of these cases from different reputable manufacturers, and redesigning your PCB to fit as many of them as is feasible. If you find you have too much wiggle room with certain cases, you can always pad the case with foam or rubber, or a dab of hot glue.