Die and mould

Simulation optimizes the die & mold sector

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While moldmakers benefit from significantly fewer required setups, the chance for collisions among machine components, tools and parts is very high. Complex machine tools typically involve many moving parts—often moving simultaneously, in a small space, at very high speeds, very close to an expensive workpiece. Additionally, the machine parts themselves are expensive and sometimes have a long lead time if they need to be replaced owing to a collision. Wrecking a high-speed spindle can ruin more than just a moldmakers day, but the effort required to manually validate a NC program that drives a highly complex machine is impractical. Significant software enhancements are necessary to support these complex machines during their early introduction into the industry.

Simulation saves the day

No one wants to spend time simulating a machining process. However, simulation is a necessary engineering step because of today’s complex and fast-paced manufacturing environment. The faster the simulation can return results, the better. The overall simulation time is an important consideration in every software purchase. Simulation software must be constantly evaluated, and the software developer must regularly invent and implement new algorithms to improve speed.

Additionally, no one wants to spend time setting up a simulation session. To further simplify setting up a session, tool libraries should be created by importing CAD solid models of inserts and holders. This makes it simple to specify which parts of the CAD model file correspond with which holders, cutters or inserts.

Developers have spent thousands of hours optimizing simulation methods, thereby creating the fastest, most efficient motion simulation to date. As a result, the moldmaker can spend less time setting up and running simulations, and more time making molds.

With advances in cutting tools, tool materials and CAM software, it is increasingly critical to use the right feed rate for each and every cut. However, many CAM systems use machining strategies and cut patterns that are not efficient for common operations such as open boundaries, roughing cuts on complex shapes, complex pocketing or planar roughing.

Some software packages can detect and machine excess material, un-machined areas and surface blend areas, but for this useful automation, efficiency is usually sacrificed. Therefore, a lot of time is wasted cutting air and feeding slowly across the part’s surface. Additionally, the tool path may plunge the cutter into material at an incorrect or inefficient angle. Poor feed rates contribute to excessive cycle times, bad workpiece finishes, increased cutter wear and broken tools.

Optimization at the design stage

Software that enables programmers to automatically optimize NC toolpath programs is essential. This software can read the NC program file (G-code program or direct CAM system output) and automatically divide the tool motion into a number of smaller segments (determined by user-defined settings in the software). The software will then assign the best feed rate based on the amount of material removed in each segment.

Light cuts at extremely high feed rates and spindle speeds are common in today’s high-speed machining centers. Under such conditions, the manner in which each cutter tooth contacts the material is critical. Too low a feed rate produces chatter, vibration and work hardening, leading to poor surface finishes and premature cutter failure. Too high a feed rate causes excessive cutter loads and unsafe conditions that can lead to catastrophic failure of the tool, spindle, fixture and machine. Feed rate optimization solves the problem by ensuring that all cutting operations maintain a constant chip thickness. This technique works especially well in high-speed finishing operations.

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Manufacturing software has made tasks achievable that were practically impossible or extremely difficult and time-consuming a decade ago. These software innovations change the way NC machining is performed while saving time, money and resources, and each year, advancements in the technology make optimization software an increasingly powerful and intuitive productivity tool.

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