Switching to a new Computer Aided Manufacturing (CAM) system has enabled Merck KgaA (Darmstadt, Germany) to cut the time required to design, program and machine parts by 50 percent while at the same time greatly increasing the complexity of parts that the company can produce internally. This chemical and pharmaceutical firm previously programmed parts on the shop floor at the CNC control. This method was time-consuming, and it was impossible to program parts with 3D contours, so much of the company’s work had to be contracted to outside suppliers at a major expense. Having converted to a solids-based Computer Aided Design (CAD) system several years ago, the company decided to invest in a new CAM system that integrates tightly with its existing CAD system and provides a KnowledgeBase Engine to automatically select the best machining method for a specific workpiece. “The time required for programming has been reduced so significantly that it has cut the typical time to produce parts by about half,” says Achim Goettmann, CAD/CAM programmer for Merck. “Just as important is the fact that we have substantially reduced our expenses because we can now produce every part in-house that is needed by our manufacturing operations.”
Merck’s manufacturing facility in Darmstadt has thousands of pieces of production machinery that incorporate about 5,000 pumps, nearly 240 centrifuges and many other subsystems. The company maintains six different metalworking groups for the purpose of providing parts for special machines that are designed and built in-house and also to provide repair parts. The metalworking operations are also responsible for producing parts required to maintain the facility, such as for the elevators and climate control system.
The mix of work in these areas has changed substantially during the past 5 years. The majority of the work today is based on the design and manufacture of fixtures and components for special machines, while the production of repair parts has dropped considerably. This trend has greatly increased the complexity of the parts produced by the firm.
In order to address this issue, about 3 years ago Merck began designing components as solid models in a newly purchased Solid Edge CAD system. This switchover to a solids-based system improved the ability of the company to define the geometry of complicated 3D components, but an NC programming bottleneck made it impossible to produce components with anything other than the simplest contours. As a result, it became necessary to send more of the company’s machining workload out to suppliers at considerably higher cost than doing the job in-house.
Merck evaluated a number of different CAM systems and selected Esprit from DP Technology (Camarillo, California), primarily because it is the most tightly integrated with the company’s CAD system, Solid Edge. DP Technology provides push button transfer of Solid Edge part models into the Esprit CAM system. This push button transfer eliminates the need for a translator and a neutral file format that cause potential data loss, requiring extra time to correct. Another factor was Esprit’s associative connection to the company’s CAD system, which enables the CAM system to read part features such as holes, pockets and slots as well as their attributes, including height, depth and work plane orientation. The Esprit CAM system automatically recognizes the CAD attributes and then automatically creates the tool path necessary to machine the given feature, eliminating the time and potential for error involved in entering them manually.
Mr. Goettman provides an example of a part that the company could not have built in the past. The part, called a pill controller, is used to present pills at various angles so that they can be visually inspected. The grooves that the pills slide in are very complicated 3D contours. The part is excited, and the resulting vibrations move the pills along the slots. In the middle of grooves is a special form that automatically tilts the pills from one side to the other. The middle section has a unique shape that is controlled by the size and form of the pills that are being inspected. The creation of the CNC program for this part was the first job done with Esprit and was intended to determine whether or not the CAM system was the right choice. “Despite the complexity of the geometry, this part was very easy to program,” he says. “We defined the design of the part in the CAD system and pushed a button to move the geometry into Esprit. The CAM system recognized the standard features such as the holes and bosses. Then I defined the contoured slots as tool paths. The entire part took only a single day to design and program. Then we set the job up to run unattended on a machining center overnight and we had good parts the next morning.”
“The seamless interface between CAD and CAM has dramatically reduced the amount of time needed to make parts,” says Mr. Goettman. “Part complexity is no longer a criterion for manufacturing outside Merck so we have been able to dramatically reduce subcontracting expenses.”