Current situation and market analysis of composite processing machine tools

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In the face of fierce market competition, the company's way of survival is to give more value to products, which means producing more sophisticated and complex products. At the same time, a company must reduce the amount of capital tied up when seeking to increase its product range. This has promoted the development of multifunctional composite machine tools.

The changing concept of a multi-processing machine

Today's manufacturing industry, especially the machining site, has the following characteristics: multi-variety, small batch production; Shorter delivery times; Require cost reduction; Products with complex shapes have been added along with lighter weight and composite performance; Lack of skilled operators and excellent technicians. To adapt to this status quo and win in the fierce market competition, an enterprise needs new technologies and machine tools, and then the composite processing machine tool as the "trump card" will comply with the market demand.

We call a machine tool

that has the ability to process complex workpieces in several processes and in different ways a composite machining machine. In order to achieve the same purpose of improving production efficiency and adding value of machine tools by process integration methods, there are also technical solutions to multi-axis machine tool control coordinates, expand processing functions, and make them multi-functional. Here, we refer to the former's machine tools that realize different varieties of processing in one machine and the latter's multi-coordinate control machine tools, both of which are collectively referred to as composite processing machine tools.

The functions of composite machining machine tools change with the times. In the past, there was a period when the machining center was called a composite processing machine tool, but because the variety of tool exchange processing was limited, and it could not go out of the field of cutting processing, the general machining center is no longer called a composite processing machine tool.

The development and production of multi-machining machine tools is advancing in the

market demand, especially recently, the number of sales of machine tools with combined turning and rotary cutting functions has increased rapidly, and it is expected that the production and sales scale will be comparable to that of machining centers in the future.

Current status of composite machining machine tools

Composite machining machines generally have these characteristics: fewer settings, sometimes even disposable; Complex workpieces do not need to be machined on multiple machines; Reduce the number of clamping times of the workpiece; The number of machine tools on the machining site is reduced, and there is no need to invest a lot in the site.

Machine tool manufacturers are adapting to an expanding market in two ways. One is that they designed the machine to perform more than one machining process. Some machines now offer milling, drilling, tapping, turning, grinding, welding and leveling. Another multifunctional and obvious way is to achieve high machine output by accelerating the workpiece clamping speed, mainly by adding robots or workholding mechanisms in a single machine or cell. Another factor of interest for multifunctional machines is that most automation and aerospace manufacturers are now tending to reduce their own machining scales and require suppliers to deliver assembly-ready modules directly. Analysts see that large companies are facing many problems such as quality assurance and aging equipment that cannot process high-precision workpieces in large quantities, so some high-volume workpieces are now broken down into small batches and subcontracted to multiple suppliers. All this provides a place for composite machining machines to display their talents.

Machine tools consist of functional unit components

The American company Makino is a company specializing in the development of grinding technology. Initially, they supplied electroplated CBN grinding wheels for conventional machining centers. Now they have greatly expanded this technology, developing a composite grinding machining center with ceramic grinding wheels in addition to electroplated CBN grinding. Nowadays, whenever it processes hard-nickel alloy materials, grinding has become a primary roughing process in addition to the traditional final finishing. This is a remarkable reform that enables flexible manufacturing that can be both machined and ground on one machine.

Makino uses a standard machining center platform and offers a unique grinding option package. In addition to electroplated CBN grinding wheels, the company now offers grinding option packages using ceramic grinding wheels. In addition, Makino has added special cooling circuits and wheel grinding capabilities to support the grinding function. The second axis of the machine comes with a diamond grinding roller to support continuous grinding, which includes continuous and intermittent grinding systems fixed in the machine work area. This continuous grinding capability greatly improves productivity and quality because the sharp abrasive grains are continuously exposed and the grinding wheels have a very good shape retention ability. The change of the grinding wheel profile can be done by calling up the different grinding rollers and grinding wheels in the tool magazine, which is similar to how machining centers change tools.

An important control factor in the process is the use of coolant. If too much coolant is used, just like a seaplane, the workpiece tool contact is not good; Using too little coolant not only reduces the cutting speed but also risks burning the workpiece. So the machine has another set of nozzles for milling, plus spindle coolant if needed.

Makino installed a set of high-pressure nozzles around the grinding wheel 360?, using this programmable nozzle to inject high-pressure coolant into a porous wheel in front of the grinding wheel, centrifugal force pushes the liquid out of the wheel, enough liquid will flush the grinding debris out of the wheel, thus keeping the workpiece cool.

Module design is key

EMAG is unique in that it has many basic machine platforms that can be modified to meet specific user requirements, so most of its machine tools are customized by users and use the method of adding modules. For example, there is a vertical machining center that is popular with EMAG users, which can be turned, hobbing, grinding, hardening, assembly and laser welding.

After receiving the order, the designer first finds a solution from the user's production conditions and then creates a machine or machine line that can complete the task. This may be a single-function machine (grinding, milling, etc.), but often requires a versatile design, including milling, drilling, turning, grinding, wire tuning, hobbing, boring, welding, measuring and leveling of the workpiece.

The main design features of EMAG machine tools: short stroke, that is, short travel between the workpiece and the cutting tool; ambient cooling, where the machine is kept at ambient temperature and not at arbitrary values; The best results can be achieved when the workpiece and the machine tool are at the same temperature; Internal system circulation cools all heat sources within the machine, including motors and bearings; With minimal vibration, the foundations and columns are made of advanced polymeric granite components known as Mineralit. Compared to conventional materials, Mineralit's low vibration results in good surface quality and longer tool life. In addition, all power units are not in the work area, but are mounted on top of a rigid box structure on the machine, and a ribbon fluid unit is also surrounded by the spindle, which reduces spindle deviation during vibration and loading.

Manufacturers in the automotive and transportation industries use VSC lathes and gears? Hobbing centers for turning blanks, down-sequence high-speed gear hobbing and burr repair. VSC composite machines can also be converted from machining soft blanks to machining hard basic machine components. For example, VSC machines automatically perform soft turning to machine cast steel pistons, followed by hard turning, drilling, milling and finishing grinding with CBN or emery wheels.

Another unique feature of VSC machines is the welding cell. This is an increasingly important application in laser welding in the manufacturing industry of transport structures. Many mechanisms, such as transmission wheels and clutches, are often machined individually before being assembled and welded. At the welding station, the assembled workpiece is clamped and the weld seam is generated. The teeth of the two workpieces should also be protected to prevent solder fluid from splashing on the tooth surface of the workpiece. The welding station has two axes, one for clamping the workpiece during the welding process, and the other shaft for unloading the welded components and carrying the workpiece that is installed next. Installed components are stacked on the conveyor and removed manually or automatically.

EMAG's VSC series machining centers are considered to be the world's leading lathe design, where the workpiece moves and the machine tool does not move. This design is the basis of most multifunctional machining centers, so that different machining operations can be completed with a series of tools on the same machine, thus realizing the transition from "simple" vertical lathes to multifunctional composite machining machines. EMAG has delivered more than 5,000 of these machines.

Expanding markets and changing needs

Monarch Machine Tool has assembled a VTL platform on the bridge frame of its machining center, which enables the machining center to achieve 5-axis functionality. The bridge frame controls the X, Y, and Z axes, a 150 cm, 60 kW turning/positioning table, a replaceable spindle head clamping tool or a 50° spine shank tool plus a single-axis tiltable spindle head as the 5th axis. This enables 5-axis machining, typical of which are large valves and components for aero-engines. Monarch Machine Tool Company is bullish on the multi-function machine tool market and hopes that it will continue to expand. Monarch Machine Tool is redesigning existing machines and some new design work to make its vertical machines have spindle-like functions similar to horizontal machines.

Fuji Machine Tool America originally manufactured machine tools mainly for mass production, often machining more than 100,000 workpieces, under such production efficiency, you can not expect to use lathes for milling or drilling processing. Today, the demand for small batches and more complex workpieces is even more prominent. Some large manufacturers are trying to get rid of the finishing process, they want to assemble modules, and their suppliers have had to replace old equipment and reduce scrap rates. To reduce costs, these companies need simple machines that offer a wide range of functions.

A machine tool company to meet these new requirements of customers, machine tools that can quickly replace functions are the solution, for example: running for 1 or 2 days to complete one job, changing the function to another machine tool to run half a day to complete another workpiece, and so on. To meet this demand, the mill-turn series and TN line were born, which are mainly designed for multifunctional automated manufacturing in small and medium-sized plants. This is a conservative design based on one or two axes that enables milling, drilling or tapping. With the extensive use of mill-turn centers, 5-axis machining machines have also been widely used to meet the needs of the multifunctional market. Mikron offers machines from three to five axes with spindle speeds of up to 60,000 r/min and accelerations of more than 1 g. One of the latest products is the UCP600Vario, with a power of 16kW, a spindle speed of 20,000r/min, and a rotary/tilt table for five-axis, five-sided machining. To ensure accuracy, the machine is also equipped with vibration monitoring and intelligent temperature control modules.

The UCP600Vario five-axis unit from Mikron can meet many versatile requirements

Composite machines require more robots to match

The American company Motoman believes that the application of robots with independent devices outside the machine tool and robots enclosed inside the machine tool will become more and more popular. They have key mechanism technology that seals to prevent lubricant or coolant from entering the robot. In addition to conventional loading and unloading, robots can now transport workpieces to the measuring area, to the grinding process or to visual inspection systems. The biggest advancement in robotics is the simplified programming and operation of controls, for example, the operator can call up the intuitive diagram to confirm whether the workpiece held by the robot is the one that should be machined.

System 3R also believes that when a robot can serve many single-function machine tools, it can greatly improve the versatility of manufacturing. The less time a human hand has to touch the workpiece, the better, and robots should play more of a role in improving the versatility of machine tools.

The main unit provided by System 3R in the United States is a robot called a "workmaster". This pick-and-drop robot serves three machines, and most of the action is to place the workpiece tray from one machine to another without additional setup. The biggest difference between the devices is the software part. 75% of the robot's job is to serve a machine tool, that is, the machine program signals the robot to tell it when to move. In some more complex applications, the robot's program can control the machine tool. Using a piece of software called WorkShopManager, the robot's program becomes the cell controller. Feature chips on each fixture and tool changer view and start the work cycle. For example, robot programs tell machines what workpieces they are machining and check the configuration.

Fanuc Robotics said that the robot can not only be used for simple loading and unloading, but also for certain operations after processing, such as measurement and workpiece calibration. In terms of the ability to assist machine tool processing, intelligent robots have added new functions. They have increased force sensing and visualization capabilities, which can realize the handling of workpieces of different sizes; They are not limited to one specific way of grasping workpieces, but can also handle different sizes or handling a group of workpieces, and when gripping workpieces, the force sensor can adjust the gripping force according to different conditions, rather than using the set force; The robots can also precisely position the workpiece or perform machine adjustments such as changing the size of the chuck through programmed settings, so they can eliminate or reduce manual labor. The key to all this is the connection of the robot program to the machine or machine cell