Planning Ongoing Reliability for Electronic Components

Here is a few lessons that I have learned with electronics

1. The higher the current, the faster it will fail
2. The more moving parts, the more likely it will fail
3. The closer to design specifications, the faster it will fail. Most engineers design 20% over the specifications. The larger this percent, the longer it will last.
4. The lack of use of static straps while handling electronics = guaranteed short life of electronics.
5. Digital electronics are suseptible to EMP. A well grounded shield will guarantee a long life.
6. Magnetic media will dissipate its information over time, CDs and DVDs get scratched. Bubble memory is best
7. Surge suppressors are worth the price of what they are connected to.
8. Cooling fans fail due to dust build-up, the resulting heat build-up can be catastrophic to electronics.
9. Some people mistakenly think that removing a cover will improve air circulation.

And your question being?

To add to Techno's advice:

1. Heat kills components. Air filters that clog choke off cooling air and components rapidly degrade. Need big air filters that plainly show when they are clogged.

2. Dead fans kill components. Need sealed ball bearing fans with long service life. Try to design without fans if possible.

3. Batteries always fail. Avoid using them.

4. Heat sink everything that gets warm. Can not overdo heatsinking and cooling.

5. Vibration shakes things loose and intermittent. Make everything sturdy and tight.

6. Do not use chip carrier plug-ins. Solder directly into boards. Chips back out of carriers with heat cycling and vibration and cause intermittents.

7. Avoid using complicated mechanicals and precise mechanical alignments. Electronics people tend not to know how to perform mechanical tasks.

8. Do use clear marking. It is bad when you adjust the wrong thing.

9. Use strain relief on cables. Anchor wires. Pot vibration sensitive components.

10. Design cases for easy access and use only captive fasteners, so they won't get lost in the works and short something out.

11. Put fuses, batteries, and adjustments in plain sight on the outside or under an access cover. You want to keep people out of the insides as much as possible.

This should get you started. These are the common causes of failure in the medical equipment that I work with.

Dave Meador