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Movement & Precision Mori Seiki launched its new NT series mill turn centre in a fittingly grand manner by inviting an international contingent of journalists to visit first its Iga campus and the Chiba facility where the NT is being manufactured. Goh Tz’en Long reports.
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ori Seiki’s NT series integ rated mill tur n cent re repre sent s a significant technological advance by combining cutting edge technology developed by Mori Seiki from the development of its NH series machining centres and NL series turning lathes. W i t h t y p i c a l fo r e s i g h t a n d vision that has ensured its market leadership position, Mori Seik i had anticipated and identified the demand for integrated mill turn centres in application niches such as aerospace parts, automotive prototype parts, energy industry parts, printing machines, die and mould and construction machine parts machining. While capabilities such as gear
Dr Masahiko Mori giving the opening address at the NT series press conference.
NT Series
Akihiro Mochizuki, Chiba Campus Chief & Senior Deputy Director explaining the NT series.
At the NT series press conference and official launch held at the Chiba Campus, Dr Masahiko Mori, President, Mori Seiki gave the opening address followed by an explanation of the NT series by Akihiro Mochizuki,
machining, grinding, machining of inclined surfaces are already de rigueur, the NT series surpasses customer’s expectations by providing more powerful OD cutting, drilling and milling. The new series allows complex workpieces to be machined in the most efficient manner in a single machine by combining an NC lathe with a high speed machining centre and 2-axis rotary table, allowing setup and machining time to be minimised. The NT series represents a logical progression from the development of the 2-axis lathe in the 80s to 4axis lathe with sub-spindle, vertical machining centre and automatic tool changer (ATC) development in the 90s, leading to the present amalgamation of technologies which has gone into the development of the NT series.
The Chiba Campus where the NT series is being manufactured.
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The basic structure of the NT series challenges conventional thinking of integrated machines by combining characteristics such as the high rigidity bed, built-in motor turret and symmetrical construction of an NL series lathe with ‘DCG’, ‘Box-in-Box’ and Octagonal Ram design of the NH series machining centre. The machine is impressively silent in operation and watching the smooth and fluid movements of the striking red tool spindle is akin to observing a balletic dance performance being conducted by a highly competent maestro.
Dr Masahiko Mori fielding questions from the press.
An international contingent of journalists was invited to the NT series press briefing.
the integrated mill turn centre was provided by Masayoshi Uneme, Manager, IT Design Section. MA PPS III allows fast processing and is equipped with a collision prevention function that monitors machine movements in real time. The conversational input function allows programming ease and convenience. As a result, high-speed canned cycles are strengthened, creating significant increases in programming speed.
Major Advances
Ch iba C a mpu s Ch ie f. According to Dr Mori, the machine tool company spends around 5 percent of turnover annually on R&D and it took 30 people working over a period of three years to develop the NT series. A pre se ntat ion on t h e M A PP S I I I ( M o r i Advanced Programming P r o d u c t i o n S y s t e m) op erat ing syste m for
The NT 4200 DCG is the first in a new line of integrated mill turn centres.
Among the significant advances are the increased machining area of the NT 4200 DCG compared to the previous model with X-, Y- and Z-axis travels of 750 mm, 420 mm and 1120 mm respectively. High speed rapid traverse can be achieved with Z-axis speed of 50 m/min, Y-axis speed of 30 m/min and X-axis speed of 50 m/min which is a significant improvement compared to conventional machining centres. equipment news October 2005 67
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DCG Theory
At the unveiling of the NT4200 DCG, the NT development team displays great humility despite their remarkable technical achievements.
The high speed rapid traverse lathe design allows rapid traverse of the lower turret: 30 m/min and subspindle: 30 m/min. This allows non-cutting time to be significantly reduced with the aid of the automatic tool changer (ATC).
B-Axis Design The B-axis design allows indexing to be carried out to 0.0001° and a maximum rotation speed of 100 rpm. A direct drive (DD) motor is used for the B-axis, which eliminates backlash and achieves high speed and precision. Machining time by simultaneous 5 -axis operation can be substantially reduced.
The NT series employs ‘DCG’ or ‘Driven at the Center of Gravity’ theory by pushing the structure at its centre of gravity using two ball screws for the X-axis and Z-axis drives. During movement, vibration is limited and high speed and high accuracy machining can be achieved. The machine with DCG generates little vibration at the beginning of acceleration, and is able to accelerate from the very start at maximum power. Rotational vibration, occurring at all acceleration start points, is reduced to an amount commensurate with the distance between the drive point and the centre of gravity, preventing deterioration in machined surface quality. Vibration accompanying changes in travel direction in conventional models is minimised by DCG. This significantly improves roundness in circle cutting.
Octagonal Ram The high rigidity octagonal ram construction was developed to retain maximal ram and cross rigidity within a constrained space. The opposing side length employed of 400 mm surpasses that of bridge-type machining centres such that even when using the maximum Y-axis travel, the centre of gravity does not protrude over the supported section, enabling high precision machining to be achieved. In addition, the V-shaped slideway creates superior rigidity.
structures. A decrease in sources of heat generation, together with the jacket cooling used with the built-in milling motor, effectively eliminates thermal effects. The ball screw core cooling system, circulating around the entire support bearing area, prevents heat from the motor transmitting to the main unit cast iron. In addition, coolant is circulated in the motor base, eliminating the problem of heat from the motor transmitting to the ball screws. The spindle lubrication system utilises an oil jacket placed in a spiral shape around the spindle unit to completely enclose it. As a result, spindle temperature rises are reduced. The cooling system minimises spindle oil amounts and frictional loss while dust infiltration is prevented. A spiral-shaped jacket enclosing the entire spindle housing effectively and evenly distributes heat from the spindle and lower turret, stabilising the spindle core and minimising thermal displacement.
The Iga Campus Amidst the rolling hills, rustic charm, serene and tranquil countryside and zen-like ambience of Iga in Mie, Japan, sits an advanced manufacturing facility that has led to the development of world class machine tools. Mori Seiki’s Iga Campus occupies a total area of 575,000 m2 with the Iga No. 1 plant taking up 60,700 m2 of floor space.
Hiroshi Mizuguchi, Iga Campus Chief explained the ‘auto-camp site’ assembly system.
Hiroshi Mizuguchi, Iga Campus Chief and Vice President, Development & Manufacturing HQ explained how the implementation of the cell production system has helped the Iga plant significantly reduce lead time before assembly from eight days to four. Time spent on individual tasks such as raising the machine column, piping, wiring, on-site adjustment, accuracy testing, mounting covers, product inspection and preparation for shipping could all be reduced. Operation time was also reduced from 2608 min to 1932 min.
The high rigidity octagonal ram construction was developed to retain maximal ram and cross rigidity within a constrained space.
The Iga No. 1 plant takes up 60,700 m2 of floor space.
A direct drive motor is used for the B-axis, which eliminates backlash and achieves high speed and precision.
A DD system motor was loaded into the B-axis (the axis that rotates the tool spindle) to take advantage of the structural benefit of being able to load a motor capable of creating enough torque for the ram. By utilising a DD system motor, a B-axis that is exceptionally quiet 68 equipment news October 2005
Thermal Control The NT series incorporates advanced thermal control measures and innovative design features such as the turret with built-in milling motor. The motor is located inside the turret, doing away with heat transmitting
The plant is equipped with some 384 machines consisting of NC lathes, 5 -axis machining centres, grinding machines, tool grinding machines and other NC machine tools. The plant is equipped with a high precision machining laboratory for R&D applications and a sheet metal plant which is equipped with a powdered automatic painting machine. It is staffed by some 280 employees consisting of engineers, skilled workers, machinists and employees in the general affairs, purchasing and other indirect divisions.
The ‘auto-camp site’ assembly system encourages total process ownership by entrusting the assembly of a machine to an individual skilled assembler.
The essential idea of the ‘auto-camp site’ assembly system is to encourage total process ownership by entrusting the assembly of a complete machine to an individual skilled assembler. The key concept was to bring the spare parts, raw materials and tooling for assembly to the skilled assembler and arrange it around him in an organised manner so the assembler can concentrate solely on the specialised task of machine assembly instead of having to waste time locating parts. equipment news October 2005 69
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SPECIALREPORT Heat Treatment Plant Mr Mizuguchi revealed that another development at the Iga plant was the setting up of a new heat treatment factory which occupies a total floor area of 924 m2. While Mori Seiki currently outsources its cast iron foundry operations, the setting up of the heat treatment facility would enable it to better handle the increase in demand, reduce lead time through in-house production and improve cast iron handling. Mori Seiki has plans to carry out research and development work at the heat treatment plant to better understand and improve the cast iron process, find ways of reducing processing costs as well as attain better quality of cast iron. The new foundry could also be used for the production of prototype components and is in line with Mori Seiki’s philosophy of achieving premium quality as well as customers’ request for quicker delivery, shorter lead time and faster development. With the foundry, Mori Seiki would also be able to manufacture and control the quality of its spindles and ball screws.
advanced machining equipment are used to a great extent throughout the production process. For example, two vertical ID/OD grinding machines for stator fixing flange and housing machining are used in combination with a robot handling system for work feeding and washing during the production process. In another instance, multi-axis grinding machines are used in combination with a loader system for loading, work feeding and washing during the spindle machining process. A high precision rotary forming surface grinder is used for spindle unit assembly machining of bearing spacer collars while multi-axis turning centres are utilised for gear/coupling machining.
data can be collected at every stage of the manufacturing process for quality control and audit. The flow of products and information is constantly tracked throughout the manufacturing process from cutting, pre-machining, hardening and tempering to finish machining, grinding, measurement and assembly. Final assembled products are then updated in the MRP system based on the instructions generated.
Spindle Production Spindle production at the Iga plant consists of a sequence of process steps which includes grinding of spindle taper, spindle and spindle case and the spindle machining line where the machining of spindle nose takes p l a ce . A f te r
In the event that a machine fault cannot be cleared by the end user, the Mori Seiki service centre is just a phone call away and is in operation 24 hours a day, 365 days a year. The call centre is manned by experienced service personnel who are on hand to offer troubleshooting advice. Service personnel are aided by a comprehensive knowledge base. The technical information search function is able to call up machine information cards, specifications and service histories. Service manuals, FAQs and troubleshooting tips can be accessed via Mori Seiki’s information network. Service personnel at the call centre also utilise a sophisticated CAPS-MONITOR which allows operators to remotely manipulate the M A PPS ( Mor i Adva nced P rog ra m m i n g
CAPS-NET Production System Production management is carried out with the help of the Computer Aided Production System (CAPS-NET) machine networking software which allows real-time monitoring of machine conditions, production record display and alarm notification. Alarm information can be statistically processed while production data can be visualised with a Gantt chart. The system allows alarm information and changes in machine utilisation over time to be statistically analysed which simplifies machine maintenance and inspection.
Automation Systems At the Iga plant, automated material handling and
Spindle testing and quality assurance.
Multi-axis grinding machines are used in combination with a loader system for loading, work feeding and washing.
The night time unmanned machining cell consists of three in-line horizontal machining centres with a linear pallet pool and tilting/turning setup station and a stocker consisting of 32 racks. This unmanned operation is capable of producing up to 324 workpieces/month with an average operating ratio of 72.6 percent. Operating status of each machine is monitored using the CAPSNET software which allows real time monitoring of the machines and production data. Alarm notifications are sent out automatically via email and to cell phones, indicating the alarm messages, machine name and date and time of occurrence.
Ball Screw Machining Mori Seiki employs an efficient Kanban Management System in its Ball Screw Machining Line so that in-process
production, spindle testing is carried out at the spindle unit operation bench as the la st proce ss of spindle unit assembly. The spindle unit operation bench is equipped with a measuring device that can automatically monitor up to 10 inspection devices. Here, spindle run-out, vibration amount, thermal displacement, heat generation and tool clamping force are examined. The spindle is also put through a run-in operation to detect errors early in the production cycle and ensure that only quality spindles are passed on to the subsequent process.
Service Excellence
A robot handling system for work feeding and washing during the production process. 68 equipment news October 2005
Ball screw manufacturing and assembly.
Mori Seiki offers extensive support to customers through its service and parts centres. The service centres handle breakdown repair maintenance while parts centres ensure spare parts are available and keeps track of parts inventory, order price and delivery.
Experienced staff and a comprehensive knowledge base ensure service excellence.
Production S y s t e m ) screen on the customer’s m a c h i n e to perform troubleshooting and machine restore services. Machines such as the NT series are equipped with the MAPS III alarm email send function. Detailed alarm information will be displayed upon pressing the message screen details button of the new MAPS III operating system. Additionally, pushing the E-mail Send button sends information about the alarm occurrence to a service centre by email. When necessity dictates, scheduling of on-site repair by service personnel and parts replacement can be arranged. A GPS map system allows efficient scheduling and dispatches service engineers based on their current locations. Centralised control of service personnel is achieved by introducing cell phones with GPS function. Mori Seiki has a global parts network with parts centres in Iga, Dallas, Stuttgart and Singapore and an efficient distribution system to better meet the requests of its valued customers. MEN equipment news October 2005 69