Previously we discussed how Dynamic Stock Models can make your cutterpaths more efficient on the milling machine, and how that efficiency actually extended tool life (safety). Today, we will take a look at how utilizing a dynamic stock model can increase safety, and a side benefit of the increased safety is increased efficiency.
As a refresher, the difference between a Dynamic and Static Stock Model is that in a static stock model, the CAM software algorithms only know the condition of the stock at the beginning and end of calculations, not during, as is the case with a Dynamic Stock Model .
Dynamic Stock Models and Tool Safety
When calculating with a dynamic stock model, the cusps (stairsteps) are known at all times. All cutting movements, repositioning moves and retracts can be done with the condition of the stock known at that moment of time, just as if the machine were really running. This increases safety because all collision avoidance (and remember avoidance is better than detection) is done automatically, during the calculation process, increasing safety and user confidence.
Let’s take a look at an example where the dynamic stock model and automatic avoidance can be used. One thing that cutting tool companies, and most advanced machinists advocate time and time again, is cutting with the shortest tool possible. This allows for a sturdier tool/holder combination with fewer vibrations (for safety and extended tool life) and this also means the milling machine does not need to be run at a slower feedrate to accommodate the longer tool, for efficiency.
Depending on the actual design, to mill an entire part may require a fairly long tool. As is often the case, one can usually remove the majority of material with a short tool, and use the long tool in the small percentage where it is necessary. Utilizing a Dynamic Stock Model makes this much easier to program.
In the headlight part below, we will actually remove 87% of the material with the very short tool. The remaining material can be removed with a longer tool, or a different tool, or sometimes the same tool at a different angle. This is done completely automatically, with automatic tool holder collision avoidance of the holder to the material already removed.
Dynamic Stock Model utilizing short tools
Knowing the condition of the stock dynamically allows for cutterpaths that are reliable and safe to run without the need for running them through a NC verification program.
Tool Safety Leads to Efficiency
With the inherent safety of the quality cutterpaths that can be produced utilizing a Dynamic Stock Model, many shops find that they can run their mills unattended more often. Being able to run your milling machines 24/7, often unattended, or even having one person run several mills, increases productivity and allows the fastest return on the capital investment of the milling machine.
In conclusion, use short tools more often in an environment where the machine runs reliably and you sleep well at night. Dynamic stock models make that possible. There are other benefits, that we will save for the next installment. Until then, comment on what benefits you see from a stock models and dynamic stock models.
