GENERAL INFORMATION

Table type (TT) and T type (with column moving perpendicular to the table travel) boring and milling Machines with horizontal spindle are intended for machining prismatic parts made of cast iron, steel, aluminium and other materials, of dimensions and weights within the machine processing capacity.

MAIN OPERATIONS

The operations available with these machines are: boring, milling, drilling, threading or tapping, counter boring, both in roughing and finishing modes. Through one setting of the work piece, four or five surfaces of it may be machined. The various special accessories available with such machines increase their machining capacity and productivity.

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MACHINE STRUCTURE

Structurally, such a TT type machine is designed with a bed along which the saddle supporting the cross slide and rotary table is moving longitudinally, describing the Z axis. The cross slide and rotary table assembly move transversally along the saddle guideways, describing the X axis. On the bed end, a fixed column is located. Along the column guideways, the headstock moves on the vertical direction (Y axis). Inside the headstock the milling spindle is supported, having inside its bore the boring spindle that moves as W axis.

The T series structure features two beds: one bed along which the cross slide and rotary table assembly is moving (X axis) and one bed, perpendicular to this, along which the column saddle and column assembly is moving (Z axis). Along the column guideways, the headstock moves on the vertical direction (Y axis). Inside the headstock the milling spindle is supported, having inside its bore the boring spindle that moves as W axis.

The main cinematic linkage consists of a gear box with two mechanical steps, connected to the spindle by a timing belt transmission. The gear box is driven by a stepless adjustable speed motor.

The feed mechanisms are driven by stepless adjustable speed servomotors. Each of the 5 moving axes of the machine has independent feed mechanisms and limit switches for travel limitation. The rotary motion coming from the feed boxes is transformed into translation motion by means of a preloaded ball screw-nut mechanism. The machine is endowed with auxiliary cinematic linkages that provide the locking of the movable assemblies as well as the tool clamping/unclamping.

The motion measurement of the movable assemblies is performed through linear scales and rotary encoders compatible with the electrical equipment. The machine controls are centralized on a control panel that may be of pendant or swivelling type. The machine is available for accommodating several special accessories that increase its machining capacity and productivity. The bed guide ways are protected by telescopic covers.

•  X axis – the rotary table cross motion;
•  Z axis – the rotary table longitudinal motion;
•  B axis – the table rotation;
•  Y axis – the headstock travel along the column guideways;
•  W axis – the boring spindle axial motion.

•  X axis – the rotary table cross motion;
•  Z axis – the column saddle motion;
•  B axis – the table rotation;
•  Y axis – the headstock travel along the column guideways;
•  W axis – the boring spindle axial motion.

The bed is made of high quality cast iron and has a heavily ribbed structure. Its top surface features the guide ways for longitudinal motion of the saddle, cross slide and rotary table assembly (Z axis). These guide ways are coated with hardened and ground steel plates (55 HRC and Ra=0.4). On the bed end, a fixed column is located. It is fixed to the bed by means of special bolts and dowel pins for alignment. Along the column guideways, the headstock moves on the vertical direction (Y axis). The bed is fixed to the foundation by means of levelling blocks and special foundation bolts. Oil collecting ducts are fixed to the bed, for collecting the guideway lubrication oil.

This assembly is composed of the saddle that supports the guideways along which cross slide and rotary table assembly are moving.

The saddle is made of special cast iron and is strongly ribbed for a proper rigidity. On its lower surface the counter guideways are located, through which it moves along the bed longitudinal guideways, describing Z axis. This motion is supported on both sides by outriggers that slide along two side guideways, rail type. On the top surface of the saddle the guideways designed for the cross motion (X axis) of the cross slide and table assembly are located. These guideways are coated with steel inserts, hardened and ground (55 HRC and Ra=0.4).

The cross slide is made of special cast iron and is strongly ribbed for a proper rigidity. On its lower surface the counter guideways are located, through which it moves along the saddle guideways, describing X axis. Its top surface features the table rotation (B axis) guiding surface (the matching surface) coated with antifriction material. On the cross slide the table rotation mechanism (servomotor, feed box, wormed gear) is located, as well as the table clamping and indexing systems.

T series machines have two beds: a cross bed, along whose guideways the saddle, cross slide and rotary table assembly moves, by describing X axis and a longitudinal guideway along whose guideways the column saddle and column assembly moves, by describing Z axis. Both beds, made of special cast iron, have strongly ribbed construction that gives them outstanding rigidity.

The top surface of the beds the guideways for the motion of the two moving assemblies are located, related to the X and X axes respectively. These guideways are coated with steel inserts, hardened and ground (55 HRC and Ra=0.4). Beds are fixed to the foundation through levelling blocks and special foundation bolts.

To the beds collecting troughs for the lubrication oil are mounted and guideways are protected with telescopic covers.

The column saddle is a cast iron component sustaining the column and headstock assemblies as well as other equipment and mechanisms.

The column saddle moves along the bed guideways. It contains the hydraulic installation ensuring the Z axis guideway lubrication and lubrication of the Z axis feed reducer. To the saddle there are fixed the guide ways covers, cable carrier, the encoder of the Z axis measurement system etc. The column saddle feed motion is generated by an A.C. stepless servomotor and a planetary reducer /gearbox. The bed guide ways are protected with telescopic covers distributed on both sides of the column saddle.

The feed movements on all axes are driven by gears transmission via planetary speed reducers by servo motors with step less variation of the speed. The rotary motion coming from the feed box is transformed into translation motion by means of a preloaded ball screw-nut mechanism.

The double wall, ribbed cast iron column supports the headstock that travels along its two vertical guide ways (Y axis). The column guideways are provided with hardened and ground steel plate inserts.

A counterweight, to balance the headstock, is guided inside the column. On TT series, the column is mounted on a bed end through special bolts and dowel pins for alignment. On T series, the column is mounted to the column saddle.

The headstock is a heavily ribbed cast iron structure designed to withstand the extensive forces generated by the main motor. The headstock houses the spindle assembly and slides along the vertical guide ways of the column. The headstock guide ways are lined with anti-friction material. The spindle is driven by an A.C. stepless spindle motor through a precision ZF gear box, electrically shifted and a timing belt transmission that connects the ZF output shaft directly to the spindle.

The sleeve-type spindle assembly is composed of the milling spindle and boring spindle. Its bearings feature high precision angular grease lubricated ball bearings: four in the front and two in the rear. Cooling is achieved by a closed circuit oil refrigerating system inside the outer spindle sleeve.

The boring spindle is guided inside the milling spindle by nitrated bushings. The ISO 50 taper allows automatic clamping and unclamping by the mechanical-hydraulic system inside the boring spindle. Both its outer surface and the ISO 50 taper are nitrated. The rear side bearing consists of four radial-axial ball bearings, mounted within the special cast iron bearing of the ram. This one is actuated by the ball screw nut which creates the W-axis feed motion. The main shaft is provided with internal coolant system of 20bar work pressure and 60 lpm flow.

The tool clamping/unclamping is located inside the boring spindle and the back bearing body. Tool clamping is mechanically performed by a disk springs package. Tool unclamping is achieved hydraulically.

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