2018cnc2-3

46 www.CNC-West.com CNC WEST February/March 2018 CAD/CAM/CNC Perspective By: Tim Paul Customer Success Manager Fusion360 CAM Tim.Paul@Autodesk.com Instagram: OneEarTim Do smoothing and tolerance settings really matter? smoother arc movement when the G-Code is output in tiny segments. These machines generally make nicer parts with very tiny line segments. Machines that are limited to how many lines of code they can process handle arc movement smoother with G2 and G3 G-Code. These machines generally make nicer parts when you find a good tolerance and smoothing combination that suites the machine and part. A good example of code processing and look ahead is with the Haas High Speed Machining setting. This is a paid feature that we decided to turn on and off during our testing to see the true difference. With one part we made, the cycle changed from 12 minutes without the High Speed Machining turned on to 8 minutes with High Speed Machining turned on. I’ll share more time stats later in this article. Controller Highspeed Machining and smoothing: Different companies have different names for this. In summary, these are the settings that balance accel- eration and deceleration with accuracy and rounding corners. My racer mind thinks of this like a school bus needing to slow down more than a Porsche to make the hair pin turn on a race track. If you make the race track wider each vehicle can go faster through the corner. The same principles apply to your CNC Machine. If you let the path it has to travel to be less “ How much does smoothing and tolerance settings really matter?”, “What are the good settings for smoothing and tolerance?”. These are questions I get asked often. Unfortunately, there is no one good answer for every machine and every part. But, like most things in the machining trade, my favorite overused saying, “the devil is in the details” fits perfectly for this topic. I realized the topic was worth digging into deeper after a friend of mine called to talk through a surface finish problem he was having with a part that was designed with splines. So, I found a day to spend cutting some test parts at the Autodesk Pier 9 Work shop on our Haas VF2SS. I could have easily spent a couple days making chips and documenting all the data but for the time I had I collected enough data worth sharing. In this article I’ll share some interesting things on machine settings, part design, tolerance settings and smoothing settings. Machine/Controller: In all my years in the machining industry the one thing that rings true more than most is that knowing your tools is paramount to producing good parts. Just like different model four flute end mills require different pa- rameters to perform at their best, machines and their machine controls require different things to perform at their best. Code processing: Some machines are limited by how many blocks of code they can process per second (BPS) while other machines handle virtually limitless blocks of code well. Another term you will find with different machines is the number of lines of look ahead. Look ahead essentially looks ahead a certain number of blocks and helps accurately control acceleration and deceleration. Depending on the part geometry, the look ahead can slow a machine down more than the blocks per second the control can pro- cess. Machines that can process a lot of code often produce Photos: Marti Deans