Turnkey system for a flexible and integrated machining line  

October 12, 2021 5:27 pm

WFL Millturn Technologies has taken a step towards intelligent, automated production. Manufacturing is carried out with a central turnkey system, to which four complete machining centres are attached.

Automated and flexible systems are now playing a crucial role in the production of work-pieces. From articulated robots to gantry loaders, every system combined with a MILLTURN brings a high-tech element and a breath of fresh air into production halls. The acquisition of FRAI Elektromaschinenbau GmbH in 2018 represents another step towards innovation in complete machining, paving the way for a digital future. 

Autonomous production methods have long been used by automotive manufacturers, the aerospace industry and, above all, mould construction companies to produce equipment for machine tools. Other sectors with less of a focus on automation are nonetheless showing increased interest in this area, above all due to the possibility of introducing autonomous night and weekend shifts. WFL Millturn Technologies works with different automation variants such as gantry loaders and articulated robots for automated workpiece loading and unloading, depending on each customer’s requirements. Peripheral transport and storage systems for work-pieces, tools and clamping devices can be combined as desired. This brings some key advantages for the user, such as continuous productivity with minimal operating effort. Automated machines are also ideally suited to repetitive tasks. However, robots are not only used in large-scale series production; there are also many advantages to automation for small batch sizes, when used in combination with easy-to-program software. Customer-specific options, such as unloading samples, inscribing, cleaning, measuring blank parts, or even additional processing tasks performed by the robot like deburring, provide optimal conditions for automation. 

Fit for the future 

An automation solution recently implemented by WFL has been specially developed for flexible batch production and is designed for the automation of four machine tools for handling different shafts. The 6-axis robot with a 500 kg payload is mounted on a 7th axis. An automatic gripper exchange system has also been attached so that a wide variety of grippers can be connected and disconnected fully automatically as required when the system is operating in automatic mode. An integrated drip tray collects coolant and chips. Because of the fully automatic quick-change gripper system and gripper warehouse, five different grippers are used in specific applications: servo grippers for workpieces and shafts, grippers for prismatic tools (such as long boring bars), grippers for tailstock tips and grippers for three different inner and outer jaws. The prismatic tools that are inserted into the machine have a prismatic tool accommodation with a very narrow tolerance range. Before the new tool is inserted into the machine, the robot moves with the exposed guide to a special station in which the guide is blown off to clean it and then coated with oil. This creates the optimum conditions for correct installation. 

Smart tool handling 

The jaws can be changed over fully automatically in the automated solution by means of a special chuck. The tailstock tips can also be changed over automatically using a special gripper. Another special gripper is able to automatically change the long prismatic tools (boring bars up to 2,500 mm long and 250 kg in weight). By using two separate set-up stations for workpieces and tools, tools can be set up and new work-pieces can be loaded parallel to machining time and without restricting automation. In the warehouse, 20 different sets of jaws, 6 different tailstock tips, 12 individual prismatic tools and up to 10 work-pieces are stored. The gripper station, for the five different grippers, has also been integrated into the warehouse. 

The system has three control levels: the KUKA KRC robot, the Siemens PLC sequence control and safety technology, and the host computer for cell logic and logistics. The host computer – which manages the CNC programmes centrally and makes machines available – as well as tool management and material flow planning optimise machine utilisation, minimise downtimes and enable autonomous or low-personnel manufacturing. Automatic changeover of jaws, tailstock tips and prismatic tools in conjunction with a servomotor gripper (diameter and length plausibility), which covers an extremely wide product range, allows for set-up-free operation of the machines and automation solution. 

Advantages at a glance 

• Set-up-free operation of machines and automation. 
• The warehouse serves as a “lung” and the host computer as the “brain”, meaning that the production plant manufactures both small series and batch sizes of 1 without restriction. 
• Higher numbers of units through high degree of utilisation. 
• More affordable unit costs through reduced staff. 
• The high degree of flexibility offered by automation allows four different shafts to be produced on the four machines at the same time. 

“The major challenge today in the field of automation is the intelligent combination of a very wide range of technical solutions. You cannot invent or develop everything yourself and this is also not necessary, as there are excellent solutions in a wide range of different areas. Combining these solutions with your own experience and successfully implementing customer projects is a fine art. Although a modular concept has often been spoken of in the past, I use the term “Expert modular system”, which FRAI is improving on a daily basis together with WFL and expanding with every exciting project,” mentions, Andreas Bitzyk, Sales Manager at FRAI Robotic Technologies.