March, 2012
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Page 57 Manual Handling of Delicate Parts By Tom Mealy, Virtual Industries, Inc., Colorado Springs, CO
Larger parts can be handled easily by hand without the assistance of any special tooling. Bus as parts become smaller and more fragile, specialized handling tools become more important. For many decades, the handling tool of choice has been the mechanical tweezer. The tool is simple to use and many people have tweezers at home used for such var- ied applications as removing splin- ters to plucking eyebrows. A disad- vantage of mechanical gripping, how- ever, is that fragile parts may be damaged or dropped during the han- dling process. Enter the age of high-technolo-
H
gy electronics and the need for man- ual tools that can handle parts rang- ing from 300mm to as small as 100µm. The ideal tool for handling parts without imparting contamina- tion, damage or dropping is the vacu- um-tweezer. The vacuum-tweezer typically consists of a pen or wand type device with a vacuum source and a pick-up tip. There is a wide variety of vacuum pens available depending on the particular handling application. There are self-contained
Proper handling of tiny or delicate components calls for something far more gentle and sophisti- cated than the age-old mechanical tweezer.
vacuum pens that are mechanically operated, tools that are battery pow- ered, compressed air-powered tools that have an internal venturi vacu- um generator, tools that connect to in-house vacuum sources and sys- tems with vacuum pumps that plug into standard electrical outlets. Each tool has advantages depending on the handling application. These tools are fabricated with materials that render them safe for cleanroom and static dissipative for ESD-sensitive applications.
Manual Vacuum Tweezer Let’s start with the manually
operated vacuum tweezers. These tools are ideal for handling parts that are a quarter inch in size up to sever- al inches. There are two basic styles, each requiring rubber vacuum tips for proper operation. First, the pen style PEN-VAC has a button on the side, an internal bulb and an inter- changeable rubber vacuum tip attached to the front of the tool. When the button is depressed air is forced out of the tool, the rubber tip is then placed on a flat surface of the part to be handled. Releasing the button draws the air back into the tool. A vacuum is created between the part and the vacuum cup and the part can now be handled. A second depression of the button releases the part. Operation is that simple. Next in line, there is the Bulb-
vac or Handi-vac style. The operation is very similar to the pen style. The bulb has a rubber vacuum tip attached to the front of the tool. When the bulb is squeezed air is forced out of the bulb, the rubber tip is then placed on a
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andling parts during assem- bly can entail the use of a variety of different tools.
flat surface of the part to be handled. The squeeze on the bulb is relaxed to draw the air back in and a vacuum is created between the part and the vac- uum cup. The part can now be han- dled. A second squeeze of the bulb releases the part. The Bulb-vac is especially suitable for placing today’s processor chips into sockets on com- puter boards.
Specialized Pickup Tips In addition to the different
Port-A-Wand handles ICs and wafers.
styles of vacuum pens there is a vari- Continued on page 61
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