So you might not get the regular CNC junkie to drop down and give you 20, but besides physical shape, I dare to say that a day in the shoes of a machinist can be just about as exciting.
First off it is noisy; some places you might even have to operate half in the dark, and night vision is not standard gear in most shops. Then there is the equipment: if you don’t think that the thrill of a F-15 compares*, you have never pressed the green cycle- start button on a multi-axis machining center that rapids at 1200 inches per minute and does Tool-to-Tool change in under 3 seconds. It can be scary, but awesome!
Tom Cruise made it look easy in Top Gun, but besides reflective sunglasses and leather jackets, there are rules and best practices in preparing for a dogfight.
Have you ever seen a pilot take a walk around and inspect the outside of an airplane? or how about the notorious checklist performed between pilot and co-pilot? Flaps, check – fuel, check – landing gear, check. It must make them almost roll their eyes of boredom every time. But would you ever take off in a plane where you knew they hadn’t done that test? Here is the lesson we can learn from fighter pilots: Just like we are expecting the best performance from pilots and their dedication to do the checklist prior to takeoff, we should do the same before hitting the green cycle-start button on our CNC machines.
CNC Operators Pre-flight check list. Take the time to walk around the machine to assure that all safety equipment such as guards are intact and doors are closed. This might also be a good time to make sure there are no oil spills on the floor or objects blocking the path around the machine. What about maintenance? Coolant and way-oil levels should be topped off if needed.
Just like pilots, follow the checklist in the same order every time, and you will most likely have a safe landing in the end. With the machine powered up, we can prepare for operation.
Always start with the tooling. Why? because if you always start at the same beginning, and follow the checklist, chances are you will not forget an item that will cause a crash. We do not have any parachute for this trip. Gather all the tooling needed for the job prior to installing in the machine, and take the time to inspect it carefully. A magnifying glass might be a handy tool to inspect cutting flutes on endmills.
Insert tooling into clean tool holders, and input measurements into tool length and tool diameter offset pages in the machine control. Remember to stay focused; this is not the time to dance to the latest iTunes or eat a sandwich. It is many times at this early stage where people get distracted and insert a value in the wrong column.
Work holding. Indicate and secure vise or fixture…”Check!”.
Insert stock into vise or fixture. Make sure everything is wiped clean of dirt and chips, and then pay extra attention that everything is secured and located against stops. We do not want to see anything come flying out of here.
Work offset is important. G54-G55 is standard, but if you did not write the g-code, or did not double check the code, this could be a mission-critical error. Now go ahead and pick up the part. Double check, and then check again before saying “Check!”.
Now you can go ahead and load the program into the control. Here is an important step many people decide to skip. Most controls have a graphic simulation option, and though it is not as pretty as in your CAM system, it is not a waste of your time. At least make sure you have an updated setup sheet, and an idea about what this program is about to do. If in doubt, I order you do the next step.
This step is up to the guy who is hitting the green button. If there is a crash, you can assure that the boss will ask if this step was done. You can a) dry-run the program safe above the part, or b) use single-block command and reduced rapids.
Take a step back. One deep breath. Circle back to the beginning and run through the checklist one more time in your head. Did you remember everything? Now tighten that seat belt, put on those cool reflective sunglasses, and press that green cycle-start button for blast off!
I challenge you… I challenge you to print this article (including the cool images) and hang it at the machine or leave it in the break room. If your CNC Superstar does not know how to stay focused and follow a checklist, he is not Top Gun.
*Honestly, I cannot compare, but if someone can arrange for me to get a trip in a F-15, I’m in.