Make it Stop – Quickly!

The long established Leader/Hainbuch collaboration offers users, who have implemented SPANNTOP a ‘must have’ accessory -Quick-Change End-Stops – that save time and money. VarioPart and VarioQuick, the two variable end-stop systems ensure significantly more flexibility, and to a great extent make bespoke end-stop design unnecessary. The days of cost-intensive and complex end-stop designs are basically gone forever. Now VarioPart and VarioQuick, the standardized work piece end tops are available. The basic end-stop plates are provided as standard equipment with Leader’s Hainbuch clamping devices, we have extended and enhanced this and now you save valuable time in work preparation, you are significantly more flexible and you always have the required clamping length close at hand. Start now with one of our sets, which we deliver in a practical storage box.

Two systems for even greater flexibility

Using standardised workpiece end-stops, valuable time can be saved in work preparation, set-up times are drastically reduced, and the user always has the suitable end-stop at the ready. Leader recommends the VarioPart system for precise and rigid clamping. It functions on the same principle as a gauge block box and can be height-adjusted in 1 mm increments with precision ground plates. With a face run out of < 0.02 mm on the portion of the end-stop that contacts the workpiece. VarioPart is ideal for finished part machining.

The VarioQuick variant is designed for fast, flexible clamping. It works with a precision trapezoidal thread that allows fast adjustment of the clamping length. A half turn corresponds axially to 1 mm. In addition, Leader also offers end-stop blanks for workpiece end-stops or front end-stops.

Mini-mum effort provides maximum rewards

The TOPlus Mini range features significant real-world benefits. Available from Leader Chuck Systems, the chuck features a mass reduction of 38 per cent, is one third shorter and one third smaller in diameter. This means reduced energy consumption during operation and better cutting tool accessibility.

Thanks to the reduced mass and size the choice of suitable tools is much broader. Also, the tools used can be shorter and therefore more stable – for both the main and sub-spindles. This is particularly key where installation space is limited and in batch production operations where part-to-part consistency is vital. TOPlus Mini is ideal for lowering energy consumption, providing dynamic spindle acceleration and shorter cycle times to lower the cost per workpiece.

Managing Director, Mark Jones, states: “A typical CNC lathe has a 20 to 30 kW spindle motor, which costs around £1,000 per month to run. By reducing the mass of the chuck you can directly reduce the power drawn, which will result in ongoing energy savings. With industrial electricity costs only going up, every step you take towards energy efficiency is rewarded within the business profits. The TOPlus Mini range supports these business goals.”

The TOPlus Mini is available in two variants; pull-back and deadlength. The pull-back TOPlus Mini features a Vulcanized clamping head with pull-back and hexagonal geometry for optimum chuck sealing and a 25 per cent higher clamping force. The fixed base end-stop for clamping with pull-back effect, or central mounting thread for component-specific end-stops makes it perfect for clamping workpieces with shorter collars or shoulders. Additionally, this can be removed when necessary to facilitate a through-bore for bar work. A bespoke mounting thread for drawtube connection is also provided.

For radial clamping without axial movement of the clamping head the deadlength TOPlus Mini is suitable for component transfer between spindles such as horizontally opposed twin spindle lathes, also known as kissing-spindle lathes, and for vertical turning pick-up spindles. Again, the chuck can be used for through-bore work with bar fed raw material.

Providing a concentricity of 0.025 mm there are five TOPlus Mini deadlength chucks in the range, 26, 40, 52, 65 and 100, the figure denoting the maximum workpiece diameter. The smallest chuck is rated up to 10,000 rpm and a radial clamping force of 35 kN. The Mini 40 and 52 are rated to 7,000 rpm, and offer radial clamping forces of 103 kN and 108 kN and axial compression force of 33 kN and 40 kN respectively. The rotational mass of much larger workpiece capacity of the TOPLus Mini 65 and 100 means these chucks are rated at 6,000 rpm and 5,000 rpm, and accordingly the clamping forces have also been increased. The 65 has a radial clamping forces of 120 kN and an axial compression force of 45 kN, while the largest chuck in the range has a radial clamping forces of 172 kN and an axial compression force of 65 kN.

Covering the same five workpiece diameter ranges, with equivalent speed ratings, radial and compression forces, the TOPlus Mini pull-back chuck range increases concentricity to 0.015 mm.

Get a grip and TESTit

For a safe, precise and productive manufacturing process a regular check of the actual clamping force being achieved is indispensable. To address this demand, Hainbuch launched the extremely capable and easy to use TESTit clamping force gauge. Capable of measuring clamping forces greater than 200kN the TESTit is the only device currently capable of measuring internal and external workholding systems, such as mandrels and manual/powered jaw or collet chucks.

Manufacturing process security often requires the maximum permissible holding force of any clamping device be applied during the mechanical machining of any components, whether turning, milling or grinding. While this is straightforward for solid workpieces, where the clamping force should be as high as possible to minimise any centrifugal force losses, an increasing number of thin-walled and sensitive workpieces are being manufactured that can easily be deformed if too much clamping force is applied.

Says Mark Jones, managing director of Hainbuch’s UK agent, Leader Chuck Systems: “Design necessity and optimum material selection means that some components require lighter clamping forces, or manufacturers risk damaging the part. However, if it not clamped securely the machining operation will be compromised. With the margin between clamping too tightly and not tight enough being so narrow it is vital that the actual clamping force is known. Using the TESTit gauge the clamping force can then be calibrated to exactly match the process requirements.”

In operation, the TESTit gauge is completely wireless with all the clamping force values transmitted via Bluetooth to a display device, such as a smart phone, desktop or tablet PC, or PDA with the appropriate software installed. Featuring automatic sensor recognition and a Li-ion rechargeable battery for more than 5 hours of operating time, the TESTit clamping force gauge can be used to measure stationary or rotating holding forces both internally and externally.

“In the face of global competition manufacturers have to optimise every machining process. Using the TESTit clamping force gauge the efficiency of any fixturing will be maximised. If you cannot measure something, you cannot control it – so specific clamping measurement data should be demanded by industry,” concludes Mark Jones.

A balanced approach

Everything can be improved upon, which is why the creative team of engineers at Hainbuch has developed a generation of Spanntop chucks. Leader Chuck Systems now offers this versatile range of fixturing solutions for lathe and turning centre users in the UK.

The Spanntop Nova range from Hainbuch includes the Combi pull-back, Combi dead-length and Modular versions. Its introduction heralds a design with better functionality, increased versatility and an improved geometric form. This design avoids the need to chose between bar fed stock or billet workpieces – via mandrel or jaws – because it can accept both.

Representing over two decades of experience and exploiting all the advantages of the latest CNC lathes and turning centres, Spanntop Nova chucks offer secure and reliable workpiece fixturing. With intelligent internal workings Spanntop Nova chucks feature a standardised chuck body so the same components can be used in the pull-back and dead-length variants.

The standardised chuck body means the easy-to-change Spanntop adapter Mando Adapt can be used both with the Modular chuck and the Combi pull-back variant, and the Jaw Adapt can be used with the Combi pull-back chuck.


Due to the increased distance between the front face of the chuck and the end-stop, longer workpieces can be clamped more rigidly. The longer clamping length also reduces the protruding length, producing optimum conditions for accurate machining. Previously, extended guides cause a slip-stick effect. Hainbuch has negated this with high precision extended guides; these prevent ‘wobbling’ to ensure that the component moves smoothly and achieves a concentric precision of better than 1 micron.

Offering operational speeds up to 8000 rpm, the fine balancing of the Nova chuck range is vital to both component accuracy and spindle bearing longevity. Balancing can be achieved in two planes without disassembling the chuck. As well as the usual balancing points on the front face of the chuck, the threaded holes in the spindle flange serve as a fixture for balance weights.

Leader Chuck’s managing director, Mark Jones, says: “Hainbuch has a well deserved reputation for innovation and quality. Its Spanntop Nova range has been designed for maximum parallel holding force at high rpm, and offers extreme rigidity and precision. Offering functionality and flexibility without any compromise on quality the new Spanntop Nova chuck range can improve efficiency for any company using high speed turning equipment.”

An emphasis on revision prosthetics

Based in Germany, Peter Brehm GmbH, develops, manufacturers, and sells medical implants for primary and revision joint supply. The strength of the company is in the area of revision prosthetics for large joints such as hip, knee, and spinal column. Here, a carbon fibre workholding solution from Hainbuch, available from Tamworth-based workholding specialist, Leader Chuck Systems, addressed exacting production demands.

Every year in Germany around 400,000 people receive artificial hip and knee joints. The main endoprosthesis (an artificial device to replace a missing bodily part that is placed inside the body) operations can be defined as 210,000 hip joints and 165,000 knee joints. If, after a number of years, the prostheses requires replacement the primary joints fitted often cannot be re-implanted due to physiological changes of the patient. In these cases, revision joints are necessary. The modular character of these joints offers more variation possibilities in the structure to create different bone grip situations or size variations.

Located in Weisendorf, Germany, Peter Brehm is a full-service provider and one of the company’s core strengths is revision prosthetics for large joints for hip, knee, and the spinal column. So, hip endoprosthesis or spine fixators are important products in its portfolio. The product line also includes special implants that are used if the patient’s bone defects are so extensive that they can no longer be covered with standard implants. Supporting the industry fully the company also manufactures the instruments necessary for the implantation.

Customers for all of these products are clinics – particularly those clinics that specialise in the difficult revision operations. With few exceptions, all university hospitals in Germany belong to the customer base of the company. The company also supplies many international customers, with around 40 per cent of its production being exported.

Peter Brehm only uses high-quality materials, such as titanium, cobalt-base alloy, and ceramics that are particularly bio-compatible, strong, and low-wearing to manufacture the implants and instruments. All semi-finished materials are forged so that the possibility of imperfections and fatigue failures are almost completely excluded. “The titanium material we frequently work with is the alloy TiAl6V4 that has established itself in the field of medical technology,” explains Production Manager, Gerd Kirsch. “For example, we use pure, grade 1 titanium for hip sockets, and cobalt-base alloys in the knee area due to the excellent polish ability and high strength.”

For implants the batch sizes extend from five to a hundred parts, depending upon the product. “The trend is downward,” admits Gerd Kirsch. “This development also applies for smaller parts, like screws, which we formerly manufactured in either lots of 500 or 1,000. Today it is 200 or 300 pieces.” However, the instrument sets the company produces in five to twenty-fold types can include 3,000 individual parts. So the quantity is low and the variation is high.

Machining of the implants and instruments is carried out in the prefabrication department. Here the emphasis is on turning and milling with the objective of increasingly complete machining is consistently pursued. “Fixed and sliding headstock lathes can cover everything that is customary in the turning area”, emphasizes Gerd Kirsch. “Now we are prepared and set-up for every application in the field of medical technology. We invested in four C30 machines that are configured for simultaneous 5-axis machining. We have automated one so we can manufacture unmanned with even shorter cycle times.”

Milling Technician, Walter Kloha, adds: “We decided on pallet automation so we can manufacture either batches or just a single part in any sequence, unmanned. We have integrated a pallet changer that has more than 24 pallet positions, and that can handle pallet weights up to 60 kg.”

The automated C30 is currently operated by Marco Horny and Stephan Stahl, who alternately program the machine and run the parts, in order to handle the high volume of work. They clamp round material with nine manual Manok CFK stationary chucks from Hainbuch purchased to meet very exacting requirements.

Chucks from a competitor, used prior to automating, did not have a construction height sufficient to move the loading station into the machine. The company was also dissatisfied with the shape of these clamping devices and the resulting swarf ingress. In the subsequent search for an alternative, these and other criteria, for example, the new stationary clamping device should also be able to accommodate bars that are as long as possible; have a low construction height to avoid waste material, and should be easily accessible, were the crucial factors.

“With these requirements we sought out different manufacturers and selected Hainbuch,” explains Gerd Kirsch. “Preliminary discussions with Hainbuch had shown that our idea of obtaining a steel clamping device with as smooth a surface for diameters to 65 mm were achievable. We decided on the Manok that is made from carbon fibre.”

The carbon version is as much as 70 per cent lighter and at the same time is extremely rigid because they are equipped with hexagon Toplus clamping heads that offer a positive locking of the clamping head and clamping device. Unlike the round clamping heads, the hexagon model prevents radial displacements to the taper of the clamping device. Therefore, the chips cannot penetrate into the Manok. This is particularly important when milling as chips often fall over and into the clamping device.

Currently, a wide range of parts are milled from solid material using the CKF Manok system. The clamping devices have repeatedly proven their capability for lot sizes of 30, 50 or 150 pieces. Stephan Stahl highlights an example: “We had a situation that required the machining of residual material, and we only had 6 mm to clamp. So we tried it, and it was rock solid. Compared with a conventional three-jaw chuck that needs at least 2O mm, of course there is significantly less material scrap with the Manok.”

The high holding forces and the high rigidity also have positive effects on the surface quality of the manufactured implants and instruments. “ln addition to functionality, the appearance of our components also plays a very important role,” Walter Kloha comments.

“Previously, we could produce parts with the same quality. However, the effort was significantly higher. We simply had more rework. Moreover, we were by no means able to run the cutting parameters that we are running today. Formerly, two stagess were required. Today it is often just one step.”

“However, the advantages of the Manok system also include user friendly set-up, built-in vibration dampening, and lower weight. These Manoks also combine to reduce the formation of chatter marks, and it is also very easy to quickly change something in the machine,” reports Marco Horny.

The components are machined using coolant on the Hermle C30 so a wash program is applied after milling. This removes all the chips from the parts as well as the clamping heads. “With open chucks, the chips fall through in the middle and stay at the bottom on the zero position clamping system,” is how Walter Kloha describes his experiences. “Then if the pallets are changed automatically at night, eventually they will be placed on the chips. This cannot happen with the Manoks System.”