Zero minutes for retooling
10 June 2018
Umnoe Proizvodstvo magazine, June 2018
Oleg SEMIASHKIN
Thanks to a Fastems flexible manufacturing system, Kempf CNC-Technik streamlined production and eliminated the sources of errors.
Norbert Kempf CNC-Technik, located at St. Ingbert (Germany), employs about 100 staff and manufactures simple to highly complex components in batches of 1 to 500, as well as prototypes for pneumatic and hydraulic systems used in various industries.
The company was founded in 1970 as a conventional turning shop, but it kept developing and supplemented its machine fleet with CNC machine-tools, so that by 2000 they had ten machining centres.
«At that point we realized that conventional growth just by purchasing machines has its limits”, says CEO Stefan Kempf. “Basically, the more machines we installed, the worse our productivity became. Qualified staff were hard to find and the surrounding organization and support processes were getting harder and harder for us to handle. The processes were just not stable. As a result, more and more errors were made, taking a lot of time, patience and expense to eliminate».
The company gave thought to how to carry out tasks without errors and, if possible, in parallel with other processes.
And arrived at the answer: maximizing automation. Before that, however, the key business processes had to be prepared.
«First, we purchased a tool data management system and invested a lot of time in developing continuous tool management”, went on Stefan Kempf. “In addition, we now could manufacture the machining pallets and workpiece clamping fixtures ourselves».
Tools as a limiting factor
Only then the company was ready to install a flexible manufacturing system from «Fastems».
In 2003, an existing machine was connected to the MLS (multi-level system) with a capacity of 12 machining pallets.. By 2011, the system had gradually grown to the maximum possible configuration with a total of four loading stations and 96 machining pallets on three levels. In addition to the existing machine, MLS was connected to five more Mori Seiki NH 4000 machining centres. «Right from the start, we made sure the tool interfaces were standardized, with each machine having a large tool storage with 180 tool spaces», — explained Mr. Kempf.
Storage becomes smart
For this reason, in 2013 Norbert Kempf CNC-Technik invested in another Fastems FMS, including construction of a new hall. The MLS-MD (medium duty) with a payload of 1 000 kilograms per pallet has space on four levels for a total of 156 pallets, half of which are machining pallets and the other half raw material pallets. The system integrating seven machining centres, has four loading/unloading stations for the machining and raw material pallets.
A peculiar feature of the system is the CTS central tool storage holding 2 500 tools and using a robot for transporting and replacing the tools in the machines. Since each machine also has its own tool magazine, the total access amounts to 3 200 tools. And this is from every machine, because a gantry system with the robot conveys the tools from the central storage to the appropriate machining centre as required. For unique tool identification by the robot’s reader, each individual, preset tool is equipped with an RFID chip.
Software plans production
Intellectual manufacturing management software (MMS) tackles the whole process of production planning and control in the FMS. This includes robot-aided tool transport from the central tool storage (CTS) to the machines. However, the software not only controls the logistics and plans the pallet order in the system, but it also manages all the CNC programs and tool data. Before each start of production, the MMS also carries out a resource check to verify, among other things, whether the required raw material is present in the system and that the tools required for a specific order have the necessary service life.
If the service life of a tool is no longer sufficient for machining, the tool presetting system automatically receives a message from the Fastems MMS about the necessity to replace.
One of the key considerations even before the commissioning of the FMS was that the preparations for production are crucially important for a reliable production process. «We initiate a process planning order for every new part or every change to a component. From the FMEA analysis, to the production control plan, to tool design and CNC programming, every single step is planned in advance, always with the focus on process reliability», — emphasized Mr. Kempf.
Fully automated retooling
Now, thanks to the FMS, the company is able to carry out any processing job on any machine, thus completely automating the retooling operations.
«Our retooling times are actually 0.0 minutes, which means that every component always has the same price for our customers, regardless of whether they order ten of them or a hundred», says Stefan Kempf.
The impressive numbers speak for themselves: around 1 000 tool transports and 500 pallet transports take place in the system each day. The average machine usage is between 95 and 98 percent.
«Despite such high levels of automation, we haven’t cut down on staff since FMS was installed, but have achieved an average annual growth of 15 percent since 2014 with the same workforce. The flexibility we gain by being able to process every workpiece on every machine in the FMS is so great that we want to continue with this approach», – communicated Mr. Kempf.
For all questions, please contact Pumori-North-West Ltd., phone +7 (812) 670-70-26