Waterjet Cutting System for High Flexibility and Accuracy
Tailor-made solutions designed specifically for individual conveying challenges is something Apullma Maschinenfabrik A. Pulsfort GmbH & Co. KG, Lutten, Lower Saxony, can appreciate. A metal processor for more than 100 years, the company began specializing in the development of conveying systems for various sectors of the food and farming industry a half-century ago, with approximately 90% to 95% of conveying systems being manufactured to order.
Over a year ago, the company acquired a waterjet cutting system from Flow International's European division, Flow Europe GmbH, for the production of individual conveying system components. The decision to introduce the system was made for several reasons.
"As we mainly manufacture to order, the number of personnel needed for an individual conveying system is much higher than the quantity of material required," said Dipl.-Ing. Peter Pulsfort, Managing Director of Apullma Maschinenfabrik. "It is therefore much more sensible not to save on material or material thickness for individual components, as this hardly makes a difference in terms of cost. However, this does have a significant influence on the quality of our systems."
Against this background, components were manufactured to an increasing extent which, due to the type or thickness of the material, could no longer be produced effectively using conventional methods such as turning or laser cutting.
Support in the introduction of new technologies
The experts for conveying systems had been outsourcing individual production orders to a contract manufacturer that was using waterjet cutting technology. "At that time, we were already fascinated by the flexibility of this technology which not only allows diverse contours, but also a wide range of materials to be processed. The material thicknesses we specified also posed no problem," said Pulsfort.
As the number of externally manufactured components steadily increased, the plant constructors decided to acquire a waterjet cutting system. They researched several leading manufacturers in the market and decided to purchase Flow's WMC-DWJ 3020 waterjet machining center from Flow Europe GmbH.
"This decision was naturally based on technical aspects," explained Pulsfort. "However, we were aware that a new technology could not just be simply introduced. We knew we would need reliable support in the initial months of use. To this end, we decided on a service-oriented company like Flow, which has proven to be the right decision."
In addition to helpful and reliable advice, the plant constructors were also impressed in particular by the efficient spare parts service. Wear parts are easy to remove and are delivered within the shortest time. "One call in the evening is all it takes and the ordered spare parts are delivered the next day," Pulsfort said. “This is extremely important, particularly in applications where long idle times cost money.”
Speed and precision
In addition to reliable support, the plant constructors are also impressed by the technology of the waterjet cutting system. Since their application involves high production speeds and precision, the system has the added benefit of the Dynamic Waterjet. While conventional waterjet cutting systems produce taper on the cut edge, in the case of thick materials in particular, this Dynamic Waterjet increases the level of accuracy thanks to three-dimensional tool orientation (cutting head).
Even with thick materials, tolerances of +/- 0.04 mm can be achieved at an increased cutting speed under certain conditions. The HyPlex 30 high-pressure pump delivers the required working pressure of 55,000 psi (3,800 bar). For cutting materials more quickly, the system can be used with the Hyper Jet intensifier pump to deliver a working pressure of 87,000 psi (6,000 bar).
Freedom of design
Since implementing the waterjet, the system has been working at full capacity. "Although we expected to use the system in a single-shift, the machine has been in use for two shifts a day, more or less from the outset," said Pulsfort. "This is because we greatly underestimated the possibilities offered by a machine of this type."
Like many other users of waterjet cutting systems, he is impressed by its flexibility. "It all starts with the design. Today, we provide solutions we would otherwise have thought inconceivable from design aspects, as we were unable to obtain the required components or could not process the necessary materials."
Where conveyor belts used to run along rotating rollers, the plant constructors have now developed an appropriate concept: Conveyor belts of food-safe material with good sliding properties now "slide" along fixed "half rollers" made of suitable plastic. This offers advantages, for example, in the food industry, which maintains strict hygiene requirements.
When rotating rollers are used, dirt gets lodged between the moving components. With the rigid concept by contrast, these problems are prevented at the outset due to the design, where undercuts are avoided. The required cyclical cleaning is also facilitated. "From design aspects, this solution would not have been conceivable without the waterjet cutting system.
For example, very hard Teflon material cannot be processed using conventional cutting methods," said Pulsfort. "The example shows that the waterjet cutting system gives us more freedom and flexibility in the development of design concepts."
Flexible contract production
For the most part, the conveying technology experts produce their own components using the waterjet cutting system; 20% to 30% also offer waterjet cutting services as contract manufacturers, where a whole range of materials including aluminium, bronze, high alloy stainless steels, PTFE, plastic, stone or wood are processed.
For these applications as well as small series production, easy setup of the water jet cutting system offers clear advantages. "What really fascinated me was how easy it was to program the system," said Pulsfort. "After entering the material type, thickness and the technical drawing, only the zero needs to be defined and cutting can begin. This allows us to respond quickly to requests from external customers, for example."
To ensure a smooth transition from the manufacture of one product to the next, an external programming workstation was provided, allowing the next process to be prepared while another product is processed. "Until now, we have not offered our services as a contract manufacturer to avoid restricting the flexibility of our own production," concluded Pulfort. "If we want to be more competitive, we will have to acquire an additional system in the near term."
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