Increase automation, reduce production times, cut costs – Kaltenbach steel and plate processing technology has the edge
Sometimes, you find yourself in a situation where everything comes at once. When this happens, you need to find a solution as quickly as possible which addresses all the issues. C + P Stahlbau GmbH & Co. KG from Breidenbach in Germany was faced with just such a situation not so very long ago. The steel fabrication specialist from Hesse, which is part of the CHRISTMANN & PFEIFER Group, not only had to respond to changing market conditions; it also had to reshape its own technical parameters to meet future challenges. In other words, far-reaching decisions had to be made.
Plate and steel products for the construction industry have always been at the heart of Christmann, Pfeifer & Co’s operations. Established in 1925, the company soon acquired an excellent reputation based on quality and proficiency, with the following years marked by a period of expansion. When a devastating fire destroyed the business in 1962, the company rose from the ashes determined to rebuild bigger and better. Production systems were completely overhauled and restructured, new business areas developed and additional production facilities and sites established. With a modern structure based on stand-alone business divisions covering different production and service areas, CHRISTMANN & PFEIFER has created an excellent network of specialists for industrial construction projects spanning all levels of completion.
Changes take their toll
The steel fabrication division at CHRISTMANN & PFEIFER operates three production plants covering a total area of around 250,000 m², which between them manufacture 30,000 tonnes of steel a year. The 300-strong workforce mainly fabricates steel components with unit weights of up to 150 tonnes for use in industrial and commercial buildings, bridges and power plants. C + P Stahlbau GmbH & Co. KG in Breidenbach, with a steel production capacity of 12,000 tonnes a year and a production area covering 16,500 m², is one of the three production plants. The company employs some 45 skilled workers who produce conventional steel structures for industrial and commercial buildings alongside large structures such as bridge girders, crane girders, roof trusses and preflex girders. Components like these can reach lengths of up to 45 metres and weigh as much as 80 tonnes. The company's guiding principle is to offer turnkey solutions from a single source; from project consultancy, design and manufacturing to assembly and post-completion supervision.
The wide variety of work calls for engineering expertise as well as state-of-the-art steel and plate processing machines capable of implementing the construction plans with precision and quality. It needs durable equipment that holds its value. A company that has been in the steel fabrication business for almost one hundred years understands the importance of maintaining consistent quality standards. This long-term commitment to quality, while indicative of the company's ethos, requires regular investment in replacement plant and machinery – which has not been necessary since the last restructuring in the 1990s. On top of that, a changing and expanding order book requiring a greater diversity of materials called for a higher level of automation and more flexibility. Ultimately, a tough competitive environment has made it necessary to speed up throughput times and cut costs. And last but not least, the new machines had to be integrated into the existing production line on a footprint determined by existing plant and current production. Quite a tall order!
Faced with this situation, the technology of the 1990s simply didn't measure up. What was state-of-the-art at the time was now outdated, making new investment inevitable. When it came to the question of a suitable supplier, the company was quick to reach a decision. It was to be Kaltenbach, the internationally renowned machine-tool manufacturer from Lörrach in Germany. The metal fabricator had already made initial contact with the company regarding cutting equipment. But what swung the decision in Kaltenbach’s favour was their problem-solving expertise and commitment to quality, reflected in skillful engineering and intelligent machine design. The fact that the machines are made in Germany and that the company uses reputable manufacturers for components such as control units were further plus points.
A bundle was put together to meet C + P’s diverse requirements, comprising a KDM 1015 high-performance profile drilling machine and KBS 1051 DG precision saw, combined with an M 151 G measuring carriage. A Sprint 1504 shotblasting system was also included for preparatory blasting operations.
Drilling and cutting with power and precision – true to the values of C+P
Kaltenbach’s KDM drilling machine series has long had a worldwide reputation for power, speed and precision. This is due among other things to the high drive power, automated tool change, mechanical drill infeed with ball screw and press-fit, zero-play drill holder. In combination, these attributes enable capacities to be increased significantly and processes rationalised. The KDM 1015 features robust construction and state-of-the-art engineering as well as a fully automated linear tool change system with five tools on each of the three drill axes. Carbide drills significantly increase production output. Another key factor that persuaded C + P to purchase the KDM was its ability to mill precise slots on all three drilling axes – an operation which is particularly relevant to the company’s order scope. Furthermore, the use of customised CNC programming to automate individual operations supports flexible order processing and saves time.
The additional material marking function, which uses a special high-speed contour marking tool, has since proved indispensable. This technology relies on a milling tool mounted on the drilling axis to inscribe programmed instructions and references on the material that is to be machined. These inscriptions greatly facilitate downstream machining processes; for example, the subsequent welding of parts to a steel girder. At C + P this has resulted in savings of up to 40 percent in the downstream 'final assembly' stage. Marking data is transferred accurately and without errors in DSTV format.
This compact solution, which takes up considerably less floor space than the individual machines, houses the drilling machine in conjunction with the Kaltenbach KBS 1051 DG bandsaw with mitre unit. This well-engineered machine is regarded internationally as one of the fastest in its class. It features a powerful drive motor to deliver the high speed, a ball screw to ensure smooth running and constantly reproducible feed rates to reduce wear. Auto Feed Control (AFC) automatically controls and adjusts the saw band angle to suit the changing profile cross-section. This has enabled the company to significantly reduce the time required for certain operations. The bandsaw is designed for use with carbide saw bands and produces excellent results, especially when machining profiles. Easy-to-use and flexible, it facilitates everyday tasks for employees dealing with very wide ranging order specifications. Thanks to the high level of automation, operators can now take on additional tasks which they were unable to do when operating two separate machines.
Automation reduces errors
The saw-drill combination works in conjunction with the M 151 G sliding measuring carriage with one gripper. This system prevents measurements from being subsequently changed once they have been made, which is a great advantage when precision is key. As a result, error rates have been significantly reduced during the processing of long steel girders, which in C + P’s case can reach lengths of up to 24m. The M 151 G also creates the precise conditions required for the KHS 1000 marking unit mounted between the drilling and sawing machine. This ultra-rapid marking system enables letters and numerals to be applied as part of the fully automated machining process – information which greatly assists with the final assembly of the individual parts. The marking unit can also travel in the direction of material flow, allowing up to 21 characters to be applied without having to move the material sideways.
Sprint 1504 shotblasting system removes undesirable surface contaminants
Before steel plates and profiles can be further processed, they usually require shotblasting to remove rust, mill scale and other impurities. C + P opted for the Sprint 1504 shotblasting system, which has a working range of 1600 × 650mm. The abrasive media is propelled at optimum speeds by four powerful 11kW turbines. These are mounted vertically at right angles to the feed-through direction to achieve perfect shotblasting results. A clever arrangement which ensures that the abrasive media reaches all surfaces to be shotblasted, regardless of the material. Virtually all the used abrasive material is recovered, thereby protecting the environment and conserving resources. The shotblasting system is designed with high material throughput to boost machine efficiency and cost effectiveness.
The switch from individual machines to a compact saw-drill combination and associated increase in automation has reduced through-feed times and increased productivity. Profiles are now transported automatically between the shotblasting system and the cutting/drilling machine in an unmanned operation. Furthermore, the error rate typically associated with manual work has fallen. The facility to mark parts for further processing automatically with speed and precision has resulted in enormous time savings in the downstream assembly shop. The objectives laid down by the company when they initially planned to renew the machine pool have been achieved in a sustainable manner. Daniel Pfeifer, project manager at C + P Stahlbau GmbH & Co. KG, sees this as confirmation that Kaltenbach was the right choice: “With Kaltenbach's new plant concept we are now able to process up to ten completely different orders in parallel. The high level of automation achieved has sustainably boosted our productivity and at the same time dramatically reduced the manual workload for our employees. This not only reduces the error rate, but also frees up staff for additional tasks. We have even managed to further enhance the three elements of steel processing that are of central importance to us – quality, speed and precision. A fact which is constantly borne out in discussions with our customers. We have rediscovered Kaltenbach’s broad spectrum of services and sustainable approach to customer care – and this guiding principle has helped shape our own success. I believe this is a good basis for future cooperation."