|Geobra Brandsttter produces molded parts and tools for its various Playmobil toys, using ShopMill and Sinumerik CNC. |
Some tool and moldmaking operations program their machining functions offline, while others choose to do it directly on the machine tool. But, the manufacturers of the popular Playmobil toys have combined these approaches to give more creative flexibility to operators and encourage them to implement new product ideas.
Geobra Brandsttter GmbH & Co. KG introduced its toy molding system in 1974. Each part is produced as a sketch, then modeled, prototyped, and finally produced in an injection mold. Thousands of individual parts are produced annually, and about 600 new, individual designs are added every year. As such, creativity is needed throughout the process, from the development stage through to production.
It’s not uncommon for Brandsttter engineers to do some programming at the shop’s three and five-axis DMG () vertical machining centers. And, because the centers are guided by Siemens Sinumerik 840D CNC controls and ShopMill numerical control programming software, the designers say new products can be developed faster and with more flexibility.
The molded parts and production tools are made the same way as the finished items, using Pro/Engineer design programs. When programming is done offline, the NC programs are implemented using Work NC (Sescoi) and Esprit (DP Technology) translation programs.
SHOP FLOOR PROGRAMMING
Shop floor programming is done directly on the machines, which are equipped with Sinumerik 840D or Sinumerik 810D controls, depending on the axes and complexity of motion control required.
ShopMill, a “shop floororiented programming software” from Siemens, is installed on the Sinumerik 810D. This allows a trained operator to program simple contour modifications into the machine, which makes offline programming simpler and allows machinists to apply their expertise to the process.
Sinumerik controls are used in prototyping, too. Strictly speaking, the individual parts are completed using virtual methods (in-house design system, CAD/ CAM), but between these stages, actual models and prototypes are produced in hard foam or plastic.
For this step, Brandsttter engineers use a three-axis DMG DMU 35 machining center, where programs are created using ShopMill. “We introduced this combination about seven years ago and, in hindsight, this was a very good decision,” stated Michael Friedrich of the Playmobil development department. “ShopMill is simple to grasp and integrates into daily work flow without any problems.”
Siemens offers two versions of ShopMill – one for direct machine tool control and one for offline PC formatting. The latter enables NC programs to be created on the desktop to reduce machine downtime, and offers flexibility for machine tool utilization schemes.
The ShopMill user interface allows operators to access the CNC functions easily, and it can be operated without a high degree of programming or in-depth CNC knowledge (G-code). The standard work sequence (setup, programming and milling) is reproduced and optimally supported through the userfriendly representation of the tasks and graphical help.
According to Friedrich, this protocol works well in the shop. “The software is very intuitive and it guides you through everything. In theory, you can’t actually go wrong, since ShopMill only offers the options that are specifically useful for each command.”
The Brandsttter operators say that correct programs are produced quickly, and new inputs can be made without documentation because of the help screens.
Although the presentation and execution are simple, there are a large number of standard cycles available for processing and measuring tasks. For moldmaking, a text editor is offered specifically for large NC programs and simple programming of moldmaking functions with a high-speed setting cycle. The simulation possibilities of the programs with genuine tool data aid process security, and intuitive user guidance reduces machine setup time.