Automatic Dispensers Make Critical Deposits

Off-the-shelf bearings typically are lubricated with general-purpose oils or greases suitable for a wide range of applications. Many bearing users, however, prefer to specify both the type and amount of lubricant used with a particular bearing, in order to improve the bearing's performance and reliability in specific applications.

Intercontinental Bearing Supply Company (IBSCO) of Houston, TX, specializes in bearing relubrication. The company offers clients a wide selection of bearings and a choice of more than 600 different lubricants.

The relubrication process takes place in IBSCO's Class 10,000 white room lubrication center, where bearings are first carefully cleaned to remove the original lubricant, then placed on a precision scale to establish the starting weight. Using the customer's specifications, white room team leader Chris Kuhrt then calculates the amount of lubricant to be placed in each bearing pocket, taking into account the total volume of lubricant to be applied to the bearing. Since IBSCO measures lubricant weight down to 0.0001 grams, controlled application is critical.

IBSCO uses automatic dispensers from EFD, East Providence, RI, that use a timed air pulse to apply lubricant in precise, repeatable amounts. In timed-pulse dispensing, the size of the deposit is determined by a combination of three factors -- the amount of air pressure required to move the lubricant, the length of time air pressure is applied, and the gauge of the dispense tip. Changing any one of these parameters alters the deposit size.

Besides ensuring accuracy and repeatability, the dispensers adjust for different viscosities. For thin oils, low air pressures, short dispense times, and straight stainless steel tips are used. When heavier lubricants are dispensed, operators switch to higher pressures, longer times and tapered polypropylene tips that provide smooth, even flow of thicker materials. The dispensers also facilitate process control by making it possible to document the exact time, pressure and tip size used for a particular job, which greatly simplifies setup the next time that job is run.

IBSCO currently has four EFD dispensers in operation, and plans on adding more units once the latest addition to their facility is complete. The reason, according to Kuhrt, is simple: "They give us perfect deposits."

--RM

For more information, contact EFD, 977 Waterman Ave, East Providence, RI 02914. 401-434-1680. Circle 470.

IBSCO, 5811 Dierker Dr, Houston, TX 77041. 713-460-5300. Circle 471.