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In Focus - Archives Août 2011
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01.08.2011 -
They appear to be unimposing - but they are located at a decisive interface in the chain of the metal cutting process. Between toolholder and workpiece, the intermediate sleeves influence reliability and precision of the clamping operation. The thin-walled, mostly slotted precision sleeves cover the difference between the clamping diameter of the toolholder, and the workpiece which has to be clamped. Functioning like reduction inserts, they multiply the fields of application of the toolholders or arbors, compensate tolerances, and ensure safe and gentle clamping of gear wheels. The newest sleeve design can do even more. Intermediate sleeves with nozzle effect extend the tool service life and increase the volume machining.
From the technical point of view, these flexible accessories have highly sophisticated features. They evenly transfer the clamping force via their whole wall, radial to the toolholder onto the workpiece, or onto the tool shank. Thereby the complete clamping force acts on them. Eroded slots in the wall provide the necessary flexibility to the intermediate sleeve, and leave enough space for the coolant supply. Since they are an additional interface, they have a great influence on the achievable run-out and repeat accuracy. In case of intermediate sleeves for precision toolholders, it is lower than 0.003 mm.
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The GZB-S intermediate sleeves from SCHUNK are universal in use on many conventional precision toolholders.
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Intermediate sleeves for tooholders
Intermediate sleeves are mainly used in toolholding systems for covering the clamping diameters. Various clamping diameters can be reliably clamped in one mounting, which increases the user‘s flexibility, and in turn, saves the user money. They can be used in hydraulic expansion toolholders, but also for tool mountings with polygonal clamping technology, or in toolholders with elastomer technology. There are two considerable restrictions: due to the thermal effects, intermediate sleeves cannot be used in heat shrinking toolholders, whereby the flexibility of the mountings is significantly reduced. However in collet chucks, mechanical collets are used. They also cover various clamping diameters and thus replace the intermediate sleeves. But their run-out accuracy is not efficient for most of the precision applications, which differentiates from toolholders where intermediate sleeves are used.
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The unique nozzle geometry of the GZB-S from SCHUNK, provides for optimum coolant supply of the tool’s cutting edge.
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GZB-S without nozzle effect
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Nozzle effect provides additional advantages
Depending on the type of coolant used, the intermediate sleeves are offered in two different versions. Coolant-proof sleeves are suitable for internal coolant supply via tools, none-coolant sleeves are used for peripheral cooling of the tools. For this purpose, SCHUNK, the competence leader for clamping technology and gripping systems has developed new intermediate sleeves, which are equipped with one nozzle geometry of the coolant slots. In case of peripheral cooling, they ensure that the tool’s cutting edge is optimally provided with coolant, the tool service life is increased, chips are specifically removed, and the workpiece quality increases. Since the intermediate sleeves with nozzle geometry are not completely slotted, they have an excellent stability. Compared with a direct clamping actuation, a 50% higher torque can be achieved with them. Higher cutting parameters, or feed rates, and thus higher volume machining is possible. The moveable intermediate piece of all SCHUNK GZB-S intermediate sleeves is also unique. It is used for flexible adjustment of the workpiece length. Particularly if multi-spindles are used, or in case of tool pre-adjustment, this serial adjustment possibility pays off very quickly.
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Intermediate sleeves for special hydraulic expansion toolholders from SCHUNK.
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Intermediate sleeves for tool grinding
Intermediate sleeves which are used for tool grinding play a special role. Since one thousandth of a millimeter can influence the quality of the machined tool’s cutting edge, the power-actuated hydraulic expansion toolholders have proven themselves in automated grinding processes. In contrast to collet chuck mountings, they have no openings or gaps which are susceptible to dirt, and are also maintenance-friendly. Their high run-out and repeat accuracy serves the cutting edge geometry well. Moreover, the hydraulic system of the mountings dampen the vibrations which occur during the grinding process, and provide an excellent surface quality. For automatic loading of the grinding machine, the tools are manually inserted into the intermediate sleeves, magazine, and then automatically exchanged in the hydraulic expansion toolholder on the machine spindle. Differences between the tool’s shank diameter and the clamping diameter of the grinding toolholder are compensated due to the use of intermediate sleeves. Particularly for production grinding, re-sharpening of individual pieces, and small batches, it pays off that due to the use of high-precision intermediate sleeves, various shank diameters can be clamped with one toolholder. Users profit from a uniform material removal and a high process reliability. The excellent grinding result also has an influence on the subsequent users of the tools: the excellent finish form and dimensional accuracy at the tool’s cutting edge increases the tool live by up to 75%.
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By using intermediate sleeves, gear wheels of three types can be clamped with one single hydraulic expansion arbor.
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With these intermediate sleeves workpieces for internal serration can be clamped gently and precisely.
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Intermediate sleeves for workpiece clamping
In the area of high-precision tool clamping, the use of intermediate sleeves has also proven to work well. Similar to clamping applications of shank tools, hydraulic expansion toolholders or arbors make a decisive contribution if various clamping diameters are clamped on one single base toolholder or arbor, and thus enlarge the field of application. Two decisive conditions have to be present: The intermediate sleeves fields of tolerance have to range within the admissible rate of expansion of 0.3% of the clamping diameter, and the wall thickness of the intermediate sleeves has to amount at least 2 mm.
Even for clamping gear wheels, intermediate sleeves have become indispensible: workpieces with internal or external toothing can be clamped via a cylindric intermediate sleeve on the tip diameter. Alternatively toothed intermediate sleeves are used for clamping of the root circle or the pitch circle diameter.
Intermediate sleeves take up an important function by clamping workpieces with an interrupted clamping surface, such as grooves or recesses. The same applies for asymmetrical clamping surfaces, where the tolerances cannot be covered by pure expansion technology. In both cases intermediate sleeves can prevent that an undefined progression of force will happen, and that the thin-walled expansion sleeves of the arbors will deform uncontrollably due to missing supports. Moreover, intermediate sleeves can protect hardened clamping diameters from wear, and thus extend life time of the high-quality toolholders.
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Leading supplier
SCHUNK the competence leader for clamping technology and gripping systems is one of the leading suppliers in tool and workpiece clamping. With more than 10000 standard products, the innovative family-owned company offers the world’s largest range of clamping technology. This includes standardized intermediate sleeves, which are known for their high precision and reliability. With a run-out accuracy of less than 0.003 mm, they are the world’s most precise intermediate sleeves.
In the field of special hydraulic expansion solutions SCHUNKoffers many solutions: The large-sized hydraulic expansion toolholders and arbors from SCHUNK are an efficient way to minimize set-up time at maximum precision, to increase process reliability, and to lower costs. At SCHUNK, intermediate sleeves for high-precision I.D. or O.D. clamping of workpieces are designed according to the customer’s requirements.
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12.2011
Clamping solutions for automated mass production
Efficient manufacturing means automated manufacturing. This particularly applies if large series are machined. This is when the clamping vises, which are the direct interface to the workpiece, playing an important role. In only a few seconds, they have to mount the components, safely and precisely align them, clamp them with-out deformation, and after machining they have to be reliably released. In view of the several million clamping cycles, which have to be carried out by many clamping vises being exposed to chips and coolant, process reliability is one of the decisive factors of success.
 Pour en savoir plus…
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11.2011
Modularity the factor of success
When designing gripping systems for handling and assembly applications, standardized modular systems will play an increasingly important role in the future. They reduce the necessary time for project planning and commissioning, and lower the investment costs. Due to the standardization, they offer optimum preconditions for stable processes. Since modular designed units can be flexibly modified and enlarged, they can be re-configurated for any changes that come up in the future.
Pour en savoir plus…
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10.2011
Producing more efficient
For a number of years, everybody was talking about the energy efficiency issue. Increasing energy costs, a growing environmental awareness, and the political guidance were all triggers for many companies to highlight the energy consumption of machines and components in their communication with the public. Efficiency is much more than simple energy efficiency now, especially when considering the
time- and cost aspects in regards to efficiency. When all these factors have been considered in a holistic way, the full potentials for modern machining and production become visible. The modern clamping devices and gripping systems make it clear how complex the possibilities are.
Pour en savoir plus…
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09.2011
Welding demanding materials crack- and pore-free
Laser welding technology is second-to-none, regardless of whether you are dealing with gears and injection molds or delicate and challenging welding works. When conventional cw lasers and many Nd:YAG-lasers reach their limits, modern process strategies can help to machine demanding welding metallurgies, different types of materials, or micro components process reliably and efficiently. Laser welding is particularly used if components have to be joined at a high welding speed, because slim welding seams, and a low thermal distortion are required. Compared with other welding techniques, the energy during laser welding fully penetrates into the material.
Pour en savoir plus…
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08.2011
More than a "Stopgap":
Intermediate sleeves ensure safe clamping and precision
They appear to be unimposing - but they are located at a decisive interface in the chain of the metal cutting process. Between toolholder and workpiece, the intermediate sleeves influence reliability and precision of the clamping operation. The thin-walled, mostly slotted precision sleeves cover the difference between the clamping diameter of the toolholder, and the workpiece which has to be clamped. Functioning like reduction inserts, they multiply the fields of application of the toolholders or arbors, compensate tolerances, and ensure safe and gentle clamping of gear wheels. The newest sleeve design can do even more. Intermediate sleeves with nozzle effect extend the tool service life and increase the volume machining.
Pour en savoir plus…
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07.2011
Changing, machining, compensating -
current trends in robot accessories
In dealing with industrial robot efficiency cycle rate and process reliabilty largely depend on their front ends, the grippers and other tools, but also from the effectors’ interfaces to the robot arm. Robot accessories have a great influence on the robot’s performance, flexibility and fields of application. Latest developments of quick-change systems, driven tools, compensation units, and power sensors show that the potentials of modern accessory components are enormous. Experts assume that their importance for handling, assembly and manufacturing will continuously increase.
Pour en savoir plus…
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06.2011
Deformation-free clamping:
From the plastic chuck jaw to the hybrid chuck
In case of rings, housings and other workpieces which are highly deformable dur-ing processing, conventional 3-jaw chucks quickly reach their limits. If the clamping forces are too low, there is no secure hold. If they are increased, workpieces de-form, and precision is reduced. A comparison shows the alternatives, the differ-ence between them, and how users can achieve an optimum result.
Pour en savoir plus…
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05.2011
Service robotics is the future key market
Insiders are convinced that golden times lie ahead for service robotics. Around the world companies and institutes have recognized the potential of robots as helpers for humans, and are working on everyday solutions. All different kinds of businesses are interested in service robotics, from large companies, to innovative startups, and also conventional manufacturers of industrial robots, electronic and automation components.
Pour en savoir plus…
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04.2011
Having set-up times under control
You cannot earn money with a turned off machine. However, in many companies the workpieces are still set-up in a complicated and time-consuming way on a grooved table while the plant is turned off. But solutions exist, which optimize the machine tool load. Modern quick-change pallet systems demonstrably accelerate the machining process, and at the same time, ramp up the precision and process reliability score. This leads to a reduction of set-up costs of up to 90%.
Pour en savoir plus…
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03.2011
Toolholders for micro cutting
Clamping tools used for micro cutting have their own rules. The subtle tools, the high spindle speeds, and the extreme precision requirements are a challenge for every tool manufacturer and user. Those who want to achieve continuously precise results, need mountings with a high run-out accuracy and balancing grade. Moreover, they should be as slim as possible and resistant to dirt. Furthermore, they have to assure that even small tools can be precisely adjusted and exchanged.
Pour en savoir plus…
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02.2011
Leight-weight design increases efficiency of Gripping Systems
Light-weight modules are now playing an increasing role in the area of gripping systems. Integrated into the system, they are saving energy at the same efficiency, or achieve a considerably higher efficiency at the indentical energy consumption. In both cases, the efficiency of the whole system is increasing. This is why the lightweights are so interesting for plant manufacturers, system integrators, and users. Since light-weight solutions had the reputation of being overly expensive in the past, recent developments now show that efficiency and cost control can go hand-in-hand. Modern designs, materials and techniques are paving the way to lighter solutions, which are rigid and robust, too. This also offer many more advantages.
Pour en savoir plus…
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In Focus - 2013
In Focus - Archives 2012
In Focus - Archives 2011
In Focus - Archives 2010
In Focus - Archives 2009
In Focus - Archives 2008
In Focus - Archives 2007
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