Innovative manufacturing strategies in Tool, Pattern and Mould Making
1A information for manufacturing – from machines and tool clamping to machining tools and manufacturing strategies for the future - presented in impulse lectures at 5-minute intervals: Short, compact and to-the-point!
Robust market players
That the German machine and tool construction industry is under severe economic pressure can be seen in the numbers below: The return on sales in tool making has fallen by 47% from 2016 to 2019. The production utilisation rate in machine construction fell by 17% in 2020 alone. Three quarters of all enterprises plan to reduce their workforce by 5 to 15%.
Dr.-Ing. Kristian Arntz knows these numbers well. He is responsible at the Aachener Werkzeugbau Akademie (Aachen Toolmaking Academy) for research topics concerning the technological aspects and asks how tool making can develop further: „What comes after automation?” The trend seems quite clear, and it forces the tool making industry to adapt. Good products as a differentiating feature do not suffice any more. In order to return to calmer waters again and become a robust market player, enterprises have to adapt new technologies from the field of digitalisation: “We can observe that data usage is starting to play a role, nevertheless the use and interpretation of data has to be utilised to a considerably greater extent in future”, says Arntz.
This applies to resilience, for example: How can entrepreneurs make their delivery chains more stable? For the answer, it is essential to leave the domain of highly variable products, plants and challenges. “We need an adaptivity that allows us to make changes to the machines or the process steps ideally up to the moment the component is in production”, he proposes. To do this now, we have too few data, too little information and resulting from that not the necessary forecasting capacity to know how long certain process steps are going to take. This is a major task for further development.
Sebastian Guggenmos of Kern Microtechnik GmbH asks the question: „How robust are our enterprises?“ He also provides approaches for higher resilience in future through more differentiation in the market. Smart machining shall lead to more varied and robust processes and above all to a more differentiated product range. In his opinion, it is not enough to look at the machines alone but consider all influencing factors. These include the materials with their varied properties, different cooling lubricants, and the respective tool with its clamp. Further factors are variability in design and in the CAM area as well the individuality of the machine operator.
Guggenmos identified one common denominator in variability, though: Temperature. This key feature influences all other factors and stands responsible for 70% of inaccuracies in automated high precision processing. This is the starting point for the corporate philosophy of his company to provide constant quality. „The machine learns a behaviour that can be fed back later to correct processing steps during the course of the manufacturing in an automated way“, Guggenmos states.
“Even today, we can control quite well what is going on in our machine and can react to changes in an automated way. In future, it will be important to include the surrounding factors in this intelligence. Our objective, though, is to develop a self-learning machine. We will reach a state then that an old machine ‘knows and can do’ more than a new one”, he ads smiling.
In many industrial applications, wear-resistant steels are favoured in order to maximise the service time of system components and tools. These steels though, with their combination of strength and toughness, are giving the very tools that should shape them a hard time, too.
Andreas Jenter of hard-metal tool manufacturer Paul Horn knows the problem and presents a new cutting tool designed especially for the demanding tool and mould production. In a performance test at the Technikum, a cavity was processed with the new HPC cutting tool. „Due to the new geometry of our tool, we can sink it in aggressively into the workpiece; up to 10° are possible. This saves a lot of time in the processing”, Jenter explains.
According to him, the ratio between core and outer diameter during chip removal is also stable. This means that the tool has a very stable core and can thus be exposed to strong radial pressures. The combination of chip space and chip outlets ensures that the chips are discharged continuously and in an orderly manner, even at lower entry angles.
The new cutters will be available as standard stock from July 2021. “If you are not sure yet, you are welcome to some test cutting with us. We can even work out a new processing strategy together”, Jenter invites.
Robust manufacturing strategy
Graphite materials pose a challenge to many users. Whether in terms of dimensional accuracy or surface quality, there are surely materials that are easier to process. As they are a fixture in tool and mould making, the right strategies just have to be developed for this group of materials.
Application expert Andreas Weck and his colleagues of Zecha Hartmetall-Werkzeugfabrikation have made it their goal to realise a machining process that is easy to reproduce and highly accurate. The new tool series focusses on machining fine grained graphite varieties resulting in extremely strong and wear-intensive processing. Cavities in workpieces have become deeper over time and the corresponding tools longer. The produced electrodes should also become thinner and more filigree, Weck explains the challenges.
The Zecha team replied to this with the Torus graphite cutter with a blade length of 1 x d and an additional short finishing blade of 0.5 x d resulting in a new series of tools with short finishing and long roughing blades.
The workpieces processed with it possess high surface quality, good dimensional and shape accuracy due to low-vibration cutting, and a precise concentricity. The low cutting forces also reduce deflection and the targeted homogenisation of the cutting edges improves the coating adhesion in the cutting zone, says Weck. „These advantages together result in a robust manufacturing strategy with long service times and a high degree of process safety when processing fine-grain graphite“, Weck is convinced.
Concerning innovative manufacturing strategies, Magnus Hoyer, Manager of the OSG Academy, concentrates on roughing and the possible time savings therein. For him, the key is not in the roughing but in the pre-machining. In order to demonstrate how to make the process quicker, he compared two tool concepts.
In his experience, many users employ wide-angle or Torus cutters. Obvious advantages of wide-angle cutting are that due to its about 10° front cutting, the tool need not sink too deeply into the workpiece and - as long as the height of the incline is not exceeded - that the reaction force is always applied in the same direction to the centre of the spindle or axially. A disadvantage of the Torus cutter: The deeper it sinks in, the larger the resulting radial forces and the less perfect the chip. In addition, the feed rate is limited.
„The new WXS-CRE Torus cutter can level these disadvantages. It has not only a theoretical radius but also a precisely defined corner geometry. Thus, it is clear from the beginning how much material remains to be removed after processing”, Hoyer says. The crowned cutting edge is very robust, produces a soft cut and can be run at high feed rates, he adds.
“We achieve radius tolerances of +/- 5 micrometres and thus have the opportunity in the roughing to work very precisely along the contour from the pre-machining on. Here, we have to allow a little more time, but we save total processing time because one step is completely omitted”, Hoyer says.
Robust clamping techniques
Manuel Nau of clamping technology manufacturer Andreas Maier GmbH & Co. KG has made it his goal to boost productivity in the plants with the AMF zero-point clamping technology. The keyword is standardisation. In this case, though, not in the machining process itself but in the periphery. To this end, he presents a special AMF clamping system. The zero-point clamping system is typically used for fixture changes in series and single part machining, but also for vise and jaw chuck changes.
On the example of direct workpiece clamping he demonstrates how machine run times have improved. “Direct workpiece clamping can best be realised in a modular zero-point clamping system”, he is convinced. In a modular system, several clamping bolts are located directly in the workpiece, which are then locked in the zero-point clamping system. Workpiece size and geometry are flexible and the gauge can also be freely selected.
Fitting applications according to Nau would be in tool and mould making as here complex workpieces clamped in very individual systems are processed on a regular basis. Direct clamping of the workpiece is a way to standardise processes in an enterprise. The same system is employed on different machines and by changing users. “This does not only improve reproducibility but also machine run times considerably - in the case of one customer with 22 machines, the increase was a whopping 75%” Nau says.
Automation and digitalisation also gain more and more importance in the traditional tool and mould making industry and open a multitude of options for comprehensive improvements of their productivity to enterprises of every size.
Markus Piber, Divisional Board Member Sales and Technology Excellence at DMG Mori, counsels enterprises to tap the added value of their own transformation step by step. Special potential for him lies in the planning. “With a lot of our customers, we still see project planning slips or display boards with planning statuses and we observe necessary changes in the existing planning as part of everyday work life”, says Piber. In order to cover the overall planning flow 100% and to be able to react even to short notice sourcing scenarios, digital planning tools are useful. Without local installation or IT structure, the capacity of machine tools, measuring equipment or injection moulding machines can be planned and controlled digitally with cloud based ISTOS solutions, for example. Lead times, capacities and utilisation become transparent - from order to delivery. With digital optimisation, planning times can be reduced by up to 80% and utilisation improved by up to 25%.
With regard to manufacturing strategies, Piber explains the fascinating possibilities of the digital twin. “With the digital representation of our machine tools, customers can easily optimise their production. The time to the start of production can be reduced by up to 40%, costs by up to 30%, and in addition, a 100% collision free machining is ensured.” Piber states - effects of a possible automatisation not included. For tool and mould making alone, DMG MORI provides a portfolio of more than 30 machine and over 20 automatisation solutions. “Eventually, nothing is more efficient and sustainable than a machine that runs 24/7” Piber underlines.
In the case that a problem does occur and even brings the machine to a standstill, the company has the appropriate service tools in the digital tool-box. “Via service camera and a highly secure remote connection, our experts have the opportunity to eliminate the error in a dialogue with the machine operator or even with other colleagues in a multi-chat.” describes Piber the functionality.
DMG MORI also extended its digital services: Via the customer portal, service processes are being optimised and become quicker and more transparent - from first contact to the delivery of spare parts.
- Sebastian Guggenmos, Kern Microtechnik GmbH
>> Kern Smart Machining – Multi-variant and robust processes
- Andreas Jenter, Hartmetall-Werkzeugfabrik Paul Horn GmbH
>> HPC Milling – HORN Performance Cutting
- Andreas Weck, ZECHA Hartmetall-Werkzeugfabrikation GmbH
>> Innovations in machining graphite materials
- Magnus Hoyer, OSG GmbH
>> AE-H Milling cutter series for high-strength, hardened materials
- Manuel Nau, ANDREAS MAIER GmbH & Co. KG
>> Give your productivity a boost with AMF zero-point clamping technology
- Markus Piber, DMG MORI
>> We strengthen you with integrated manufacturing strategies from DMG MORI
- Dr.-Ing. Kristian Arntz, WBA Aachener Werkzeugbau Akademie GmbH
>> Manufacturing in toolmaking - what comes after automation?
- Markus Heseding, VDMA
- Dr.-Ing. Christoph Kelzenberg, WBA Aachener Werkzeugbau Akademie GmbH