Mounting a thermocouple in a hole under a BGA pad can be a complicated task. Roger Saunders, president of Saunders Technology (Hollis, NH), explains some of the techniques currently in use:
One elaborate but effective method starts with removing the BGA. Once accomplished, drill a hole in the board at a center pad, insert a fine-gauge thermocouple into the hole, solder the thermocouple to the pad, (keeping the junction 0.002 to 0.004 inch above the pad), epoxy the wire into the hole, and then replace the BGA.
An easier but less reliable method is to drill a hole through the bottom of the board into one of the center pads and use a high-temperature adhesive to secure the thermocouple to the pad. The risk here is that inaccurate readings can result if the thermocouple lifts off the pad slightly during adhesive cure.
A disadvantage of both of these techniques is that it is necessary to retain the instrumented test board and re-profile it whenever the profile must be checked.
A postcard or post card is a rectangular piece of thick paper or thin cardboard intended for writing and mailing without an envelope. There are novelty exceptions, such as wood postcards, made of thin wood, and copper postcards sold in the Copper Country of the U.S. state of Michigan, and coconut "postcards" from tropical islands.
In some places, it is possible to send them for a lower fee than for a letter. Stamp collectors distinguish between postcards (which require a stamp) and postal cards (which have the postage pre-printed on them). While a postcard is usually printed by a private company, individual or organization, a postal card is issued by the relevant postal authority.
Some cars are more reliable than others, but even the vehicles at the bottom of this year’s Consumer Reports reliability survey are vastly better than those of 20 years ago in the key areas of powertrain and hardware, experts said this week.
Many of the materials in this slideshow are resins or elastomers, plus reinforced materials, styrenics, and PLA masterbatches. Applications range from automotive and aerospace to industrial, consumer electronics and wearables, consumer goods, medical and healthcare, as well as sporting goods, and materials for protecting food and beverages.
While many larger companies are still reluctant to rely on wireless networks to transmit important information in industrial settings, there is an increasing acceptance rate of the newer, more robust wireless options that are now available.
Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.