D ANDREA149General featuresU-CENTER148U-CENTER U-CENTER boring and facing heads are designed for use on machines with automatic tool change, thus essentially on machining centres. The feed movement of the toolholder slide and the tool position, even during rotation, is controlled by a U-DRIVE motor drive unit. This unit is managed directly by an axis, known as “U”, of the machining centre numerical control.A machining centre set up in this way allows to carry out a series of different tooling procedures such as inner and outer turning, cutting grooves, tapered bores (even variable), concave and convex spokes, cylindrical and tapered threading, phonographic spirals, etc.1. Power take-off 2. Servomotor 3. Transducer 4. Limit microswitches 5. Arbor 6. U-CENTER headCOMPONENTS 1. Stationary body 2. Rotating body 3. Tool slide 4. Interchangeable arbor 5. Counterweights 6. Toolholders with interchangeable head 7. Coolant outlets 8. Power take-off A; locking-release system ensures that the rotating body is secured to the fixed body when the U-CENTER is automatically removed from the spindle of the machining centre and placed in the tool magazine.BALANCING U-CENTER heads are designed with two counterweights (5) for automatic balancing, which move in the opposite direction to the slide (3) to allow to work at a high RPM without noticeable sways. The balanced heads are especially suited for precision tooling and to create diameters that require high rotation speed.General featuresKINEMATIC SYSTEM OF THE U-CENTER The kinematic system of all U-CENTERS is made up of a differential unit where one revolution of the power take- off “A” corresponds to one 0.25 mm radial shift of the slide. The maximum allowed rate of 2000 RPMat power take-off corresponds to a slide feed speed of 500 mm/min. The rated torque necessary for power take-off is 2 Nm. Between the servomotor mounted in the U-DRIVE unit and the toolholder slide of the U-CENTER is a radial reversal play of approximately 0.05 mm, thus in order to be precise positioning must take place in a single direction, and be included during programming.A51378246CNCUWZYX234165o+AD ANDREAAssembly151U-DRIVEU-CENTER150The U-DRIVE unit has to be properly mounted on the machines headstock to allow for a safe engagement with the U-CENTER head (fig.3). The U-DRIVE unit contains the U axis servomotor (1), a transducer (2), the end of stroke (3), zero reference proximity switches and the drive system to the U-CENTER head. The U-DRIVE can take different patterns according to the application on the machining centre; the most common are: angle (fig.4) or in line (fig.5)fig. 5fig. 443213421ASSEMBLY The manufacture and installation of the U-DRIVE must observe the measurements and tolerances indicated on the drawings.DATA 1. Spacer to adapt the U-DRIVE according to the measurement (X+0.5) mm 2. Preload spring (max load 20N) 3. Air intake for cleaning the power take-off 4. Wedge clutch axial stroke from 1 to 2 mm 5. Spring (max load 50 N) 6. Rotation lock disengage stroke 7. Lock-release lever 8.Reference peg 9. Positioning ringA. Distance between the taper reference line and the surface of the U-CENTER head H. Height of the U-CENTER power take-off+ 0.5023max 2000 RPM147 (X + 0.5)569786.58X AH8.56 0- 0.51750.02301530 46102324- 0.01 - 0.025 50 0.05 550 - 0.05 46+ 0.0300.5 - 1 H AU-DRIVEU-CENTER8.5fig. 3D ANDREA153SizesU-CENTER152Chip removal capacityDATA 1. Maximum overall dimensions of balancing weights 2. Measurements for hollows 3. Rotation lock disengage stroke 4. Coolant intake 5. Coolant outlet 6. Centre of gravityDATAUC 140 BHUC 160 BHUC 180 BHUC 200 BH A mm175200223275 B mm100116125200 C mm2022.52537.5 D mm12.512.51515 E mm10101212 F mm40405050 G (da N)11.71922.526.5 H mm50516363 I mm10101212 L mm2537.53060 M mmn 14 M 5x11 n 18 M 5x11 n 14 M 6x12 n 26 M 6x12 N mm40505050 O mm5567.567.567.5 P mm29.5353535 Q mm59.563.57373 R mm117133.5143143 S mm140160180200 T mm278288298298 U mm142162182182 Xmm55657485LD050100150200250050100150200250300400050100150200050100150L mmD mmU-CENTER 140/BHU-CENTER 160/BH - 180/BH - 200/BHU-CENTER 180/BH - 200/BHU-CENTER 140/BH -160/BHU-CENTER 140/BHU-CENTER 160/BHU-CENTER 180/BH U-CENTER 200/BH0.750.850.50.60.751These parameters are indicative for normal working conditions on steel with a hardness of 160-200 HB, positive insert and cutting speed of 120 m/min.U-CENTER 160/BH - 180/BH - 200/BHU-CENTER 140/BHD mm400300250200150100500250200150100500U-CENTER 140/BH -160/BHU-CENTER 180/BH - 200/BHL mm150100500150100500LDU-CENTER 140/BHU-CENTER 160/BHU-CENTER 180/BH U-CENTER 200/BH0.50.650.30.40.50.75 BCCD AR32155 180.010.01I+0.02 +0.04prof 2HF0.01M8.5223R49XQP S46T1750.0219.50.05 U 0.0582451.5O76G45(75)+0.02 +0.0460 -0.5+0.030E+0.10 70 -0.1 58-0.02 -0.06 550 -0.05 N-0.005 -0.008LLChip section in mm2Chip section in mm2D ANDREAToolholders and heads155SupplyU-CENTER154REF.CODESLUC 140 - 160/BHP 11043 35 50 32 095 03095 P