FIELD OF THE INVENTION
This invention relates to a compact, vertical, high-speed production center. This vertical machining center has an unique configuration of side mounted tool magazine and high productivity features.
BACKGROUND
Demand for compact vertical machining centre with better productivity features such as high spindle speeds, higher rapid traverse rates and faster tool change is increasing in manufacturing sectors for smaller components of auto sector. This is gaining importance to reduce the cost of floor space and for multiple machines operation by single operator.
DISCUSSION OF PRIOR ART
U.S patent 5,927,463 discloses a vertical machining center with a vertical pallet capable of clamping a horizontal pallet. U.S. Patent 5,885,199 talks about a compact machining center for multifunction, having to do with a metal cutting machine tool. Both of these inventions do no have the re-arrangement of the ATC atop the machining center and other features to ensure compactness, that are a part of this invention.
There have been a number of vertical machining certers described and claimed in various patents throughout the world. However, the need to devise a compact machining center, which has, not only better features but also reduces the need for large floor area required for installation and which will avoid multiple operations to save time and energy.
SUMMARY OF THE INVENTION
It is an object of the present invention to develop a compact vertical machining center with a special automatic tool changer (ATC), which occupies minimum space without sacrificing the faster tool change by use of twin arm ATC. The machine is designed optimally for minimum width keeping enough space for maintenance.

In the proposed system, all the elements and sub systems are mounted on the machine to facilitate lifting of machine as single unit.
Further the use of high speed ATC (Refer Fig 4 - Numeral 6) with 1.3 sec tool to tool change time along with faster clamping and de-clamping of tool by use of high-pressure hydraulic booster system, higher rapid traverse rates, to achieve faster chip-to-chip time.
Advantages of this machine:
The compact high speed-machining centre combined with high productivity features provides the required advantage for lean manufacturing solution wherein single operator can handle multiple machines. This is possible due to compact design and also feasibility of machines arrangement with minimum space between them. The gap to be maintained between the machines arranged in the concept can be minimized as the chip disposal system is also arranged on the rear side of the machine, thereby maintaining minimum line length.
BRIEF DESCRIPTION OF DRAWINGS
Fig. 1 illustrates the known standard vertical machining centre;
Fig. 2 illustrates the side-view from side A (hereby referred to as View A) of the known standard vertical machining centre;
Fig. 3 illustrates the plan-view from side B (hereby referred to as View B) of the known standard vertical machining centre;
Fig. 4 illustrates the vertical machining centre proposed by the present invention;
Fig. 5 illustrates the side-view from side C of Fig. 4 (hereby referred to as View C) of the vertical machining centre proposed by the present invention;
Fig. 6 illustrates the plan-view from side D of Fig. 4 (hereby referred to as View D) of the vertical machining centre proposed by the present invention and

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
In figures 1, 2 and 3, the preferred embodiment of the known standard vertical machining centers is shown, comprising of the following subsystems:
• A machine bed Fig.l, part 1, with a fixed column concept Fig. 2, part 2.
• A milling head shown in Fig. 1, part 3.
• The spindle subsystem shown in Fig. 1, part 4.
• A table capable of moving in two directions, shown in Fig. 1, part 5.
• Tool magazine mounted on the side of column with twin arm, shown in Fig. 3, part 6.
• A coolant tank below the machine guard and projected sidewise, shown in Fig. 2, part 7.
• A machine guard, shown in Fig. 1, part 8.
• The operator's control panel in front of the machine, shown in Fig. 3, part 9.
• An electrical cabinet mounted on the side of the column, shown in Fig. 3, part 10.
• For tool change operations, the tools are tilted by 90 degrees, shown in Fig. 1, part 11, to make the tool axis parallel to spindle axis.
The standard machines come with three axes servo systems, with all the axes elements being protected by telescopic covers. As a standard, the machines are available with side mounted disc type tool magazine where the tools are arranged in a horizontal axis configuration.
The compact high-speed vertical machining center of the present invention, is
designed keeping in view of market requirement of compact machine with width of 1400 mm. This preferred embodiment is depicted in figures 4, 5,6 and 7.

The machine is developed with following subsystems:
• A machine bed , shown in Fig. 5, part 12, with fixed column concept, shown in
Fig. 5, part 13.
• A milling head shown in Fig. 4, part 14.
• A # 40 taper Spindle with 3.7/5.5 kW power and speed of 6000 RPM, shown in Fig. 4, part 15.
• A table capable of moving in two directions, shown in Fig. 5, part 16.
• Tool magazine mounted on the side of column with twin arm ATC, shown in Fig. 4, part 17, with a 1.3 sec tool change time. The tool magazine is capable of holding  75/  125 mm diameter, 200 mm long and maximum of 4 kg tool weight at every tool location.
• A chip disposal system, shown in Fig. 6, part 18, is interfaced with the machine at the rear end.
• A machine guard, shown in Fig. 4, part 19.
• An operator control panel in front of machine, shown in Fig. 4, part 20.
• An electrical cabinet mounted on the rear of column, shown in Fig. 5, part 21.
• For tool change operations, the tools are tilted by 30 degrees, shown in Fig. 4, part 21, to make the tool axis parallel to spindle axis.
Three axes servo system with traverses of 350/300/350 mm in X/Y/Z axes and rapid traverse rate of 48 m/min with IG acceleration. All axes are protected by telescopic covers. In order to maintain compactness, these subsystems are innovatively arrangement such that machine width is maintained within 1400 mm for this size of machine with telescopic cover protection for all axes. This is possible due to newly developed side mounted special twin arm 12 tools ATC that occupies minimum space, as shown in Fig. 4, part 6. The tools are arranged at an angle of 30 degree to vertical position, as shown in Fig. 4, part 11 instead of standard 90 degree as in case of standard machines. During tool change the tool is tilted by 30 degree to make the tool axis

parallel to spindle axis. This unique arrangement provided advantage of compactness in machine width.
This machine is also provided with spindle speed option up to 20000 RPM. In order to maintain the compactness, the chip disposal system, shown in Fig. 6, part 7, is interfaced with the machine at the rear end. The machine is provided with world class guarding concept for aesthetics and ergonomics.
The machine construction of the present invention, the CHPC 30V, is described below:
This machine consists of well ribbed and stress relieved structure like machine base, column, cross slide, milling head and table etc., with sufficient slopes for easy disposal of chips and coolant. The other units like coolant tank and Electrical cabinet etc., are placed at the rear end of the machine base in convenient positions. The machine mainly consists of the following units:
MILLING HEAD:
Milling head is mounted on LM block, which in turn slides on LM rail mounted on column. Milling head houses the spindle cartridge. AC spindle motor drives the spindle through timer belt drive. Belt tension can be adjusted by sliding the motor mounting plate through hexagon screw provided on top of milling head. The spindle BT 40 taper is mounted on precise angular contact ball bearings. The bearings are life lubricated by ISOFLEX grease. The tool is clamped by set of disc springs and automatically de-clamped by hydraulic cylinder through de-clamp shaft. The milling head with spindle is moved up and down (Z-direction) by ball lead screw & nut driven by AC servomotor through coupling.
COLUMN:
Column is mounted on machine base top, which is fitted with LM rail on its front side, over which the milling head is mounted. Milling head carries the spindle, which moves up and down in 'Z' direction.

TABLE:
Worktable having X-axis movement is mounted on cross slide. LM block is mounted on bottom of table slide, which in turn is guided by LM rail mounted on cross slide top. The guide ways are lubricated by oil through centralized lubrication CENLUB unit. T-slots are provided on top of table to mount fixture. The table moves in X-direction by ball lead screw and nut, driven by AC servomotor through coupling and well supported by ball screw support bearings.
CROSS SLIDE:
The cross slide carries LM rail for X-axis movement of table on top. Bottom side of cross slide, LM blocks for Y-axis are mounted to guide LM rail (Guide way) which is mounted on topside of the machine bed. The guide ways are lubricated by oil througji centralized auto lubrication CENLUB unit. The cross slide moves in Y-direction by ball lead screw & nut driven by AC servomotor through coupling and well supported by ball screw support bearings.
AUTOMATIC TOOL CHANGER (ATC):
A bracket with tenon mounted on left side of the column, which carries the tool magazine. The tool magazine capacity is 12 tools. The tools required for operation is mounted on tool pocket. Transfer of tools from tool pocket to spindle is done by Automatic tool changer arm.
COOLANT TANK AND CHIP DISPOSAL SYSTEM:
The chips produced by machining fall on the machine base slopping on the rear side of the machine. The chip tray is provided with wire mesh and filters the coolant retaining the chips at the top. The chips collected at the top are to be manually cleared. The chip tray is provided on the rear side of the machine.
A centrifugal coolant pump is mounted on the coolant tank, which delivers coolant through nozzles arranged around the spindle for cutting. Y-Strainer is provided in nozzle coolant line for filteration purpose. Bed wash pump is provided to flush out chips falling on machine base.

PNEUMATICS:
Pneumatic system is provided for tool pot tilting operation of tool magazine and spindle taper cleaning during tool change.
CENTRALISED AUTOMATIC LUBRICATION UNIT:
Centralized lubrication pump provides metered lubrication for table slide, cross slide and vertical slide and ball screws at preset time intervals. An oil level indicator is provided for maintaining the oil levels regularly. The 'OIL LEVEL LOW signal appears on control panel through the float switch mounted on the lubrication unit. In addition, a pressure switch is also provided for checking the pump to build set pressure.
CNC CABINET & ELECTRICALS:
Machine is controlled by a 'FANUC Oi/MB' system, which is fixed on pendent box. The cabinet is fitted behind the machine on a platform. The temperature inside the cabinet is regulated by an air conditioner mounted on the left cabinet door.
MACHINE GUARDS:
Sheet metal enclosure / guards are provided around the basic machine for safety and to protect against dust and other foreign particles entering into the machine, which may cause damage to accuracy of the machine.

WE CLAIM:
1. A compact, vertical, high-speed production center with a width of 1400mm
comprising a machine bed, table, three axes servo system, milling head and
spindle cartridge, tool magazine, electrical cabinet, operator control panel and
coolant tank characterized in that an automatic tool changer with twin arms and
a tool magazine is mounted on the side, the tools in the tool magazine being
arranged at an angle of 30 degree to vertical position such that during tool
change the tools are tilted by 30 degree to make the tool axis parallel to spindle
axis, a hydraulic booster system for clamping and de-clamping of tool, the chip
tray and coolant tank being provided at the rear of the machine.
2. The compact, vertical, high-speed production center as claimed in claim 1,
wherein the spindle speed varies between 6000 to 20000 RPM.
3. The compact, vertical, high-speed production center as claimed in claim 1 or 2,
wherein the operator control panel is mounted in the front and an electrical
cabinet is mounted on the rear of a column mounted on machine base top
DATED THIS 28™ DAY OF NOVEMBER 2005.