Watch Error-Proofing Your Production Manufacturing Operation This MMS inMotion presentation from Makino explains how Error-proofing your process can maximize throughput and speed up your entire operation.
For More Information ...visit Makino's MMS Online Showroom, or select the MMS Direct icon at right.
	Link a Friend to This Page Via E-mail
	Print this article

The other thing we do in this particular example is part seat detection, which validates the setup. That’s the use of the air sensing system that I mentioned before that can detect if this part is properly up against its locators and not miss-set to the fixture so it will be machined properly by the machine tool and the NC program.  Again, eliminating an error before it can occur. If it’s not properly seated, the machine or the control will flag an alarm to the operator to stop the process and correct it before you move forward. 

Another piece in this particular fixture is part presence detect. It’s a little bit different than Part C detection, because it asks, is the part even there? This is typically done with sensors. What we’ve used a lot is are Balluff inductive type sensors, where we can locate that sensor on the fixture and it can detect if the part is there or not, because in an automated type of situation where a human may not be loading the part something can occur where the part didn’t make it to the fixture or it came off the fixture it was not located properly.  Again, the process can be stopped before an error can occur.

Finally, there is coolant through fixture locators.  This particular fixture has some of the locating positions and that’s to eliminate the risk of chips or any kind of contamination affecting the placement of the next part onto the fixture once you load the finished parts. Again, it’s eliminating errors before the errors ever occur. 

My next slide is a little bit unusual and I've got to be careful how I approach this slide because this slide possesses Poka-yoke techniques, but it also possesses issues that can still allow errors to occur. So this is really kind of an example to prevent errors; on the other hand, it can also allow errors. This part is located up on the fixture correctly. There are guideposts in this particular fixture. The purpose of the guidepost is a Poka-yoke method to make sure you can only put the part on there correctly. The guidepost is there so you don’t skew the part or something

The other Poka-yoke process on this fixture is shown on my slide as an actual silhouette or diagram of the shape of that part up against the fixture, so that as an operator you can kind of look at that and engage and know that you're putting the part on there in a correct orientation. This is all good. It will prevent errors. However, in my own little test, I went out and took the part and I loaded it incorrectly, so this part in this particular example can be loaded incorrectly. There could’ve been stronger methods applied in this particular case. It’s a good approach to eliminate errors and it will be effective but it won't be 100 percent effective.