2.75" (CF38) Flanges
The BLT27S has the cantilever brackets (see drawing) bolted to the side of the flange. The advantage here is that the cantilever brackets leave 75% of the circumference of the flange unobstructed. This allows the translator to mount in very close quarters without interfering with other, nearby flanges.
The bottom (or fixed) flange of the BLT27S is available with an optional 12-hole pattern for further flexibility. Since the actuator cannot be repositioned relative to the bolt holes, the 12-hole feature allows the user more choices in mounting orientation. Despite its modest price, the BLT27S will provide years of trouble-free service, especially if simple maintenance is performed.
All MTS BLT lead screws use ball bearings. The lead screws and ball bearings are lubricated with high temperature grease for low friction and long life. All parts are field replaceable, including the bellows. All translators are also available with long strokes, motor drives, linear encoders, tapped flanges and special heights
The BLT27S needs only minimal maintenance. The linear bearings are self-lubricating and the guide rods and jacking screw need only be kept clean and free from dirt, dust and debris. The jacking screw and bearings do, however, need periodic lubrication.
As delivered, the screws are coated with lubricant. This coating will degrade over time, due to moisture in the atmosphere. After each bakeout, lightly relubricate the screws with the (provided) silicone-based molybdenum disulfide grease. Be especially careful not to use a hydrocarbon grease such as Felpro C100TM unless you periodically clean the oxidized residue from all load-bearing surfaces. The normal bakeout temperature is 150°C but higher temperatures can be used, if needed. For bakeouts between 150°C and 210°C, increase the frequency and thoroughness of lubrication.
To thoroughly re-lubricate the bearings while the translator is under vacuum,
- First move the translator to its fully extended position.
Place a spacer between the traveler and lower bracket. (Wood or metal work well.)
- Remove the bearing retainer flange on the lower bracket.
- Turn the knob counterclockwise to extract the bearings from the lower bracket.
- Work the factory-supplied grease into the bearing. Remember: a little goes a long way!
- Replace the bearing, retainer and screws.
- Remove the spacer.
- Do science.