pesky corner rounding programs

[fanuc710]

Hello all,

We have a major issue with the fanuc robots at my job. The issue is when we teach nodes around an airfoil, the robot does not follow the exact path we have taught. It sort of swings by the nodes, and we lose precious time trying to dial in thickn,
ess, where it could be much easier if they operated like ABB programs.

I have heard that there is a setting in the karel programs that you can change, thus eliminating the corner rounding. Can anyone help me find this? Our programmer won't teach us anything to protect his job security, but he is bottlenecking us with this problem.

Thanks,

Fanuc 710

[ServiceTech]

1. Call Fanuc
2. Fire your programmer

Hello all,

We have a major issue with the fanuc robots at my job. The issue is when we teach nodes around an airfoil, the robot does not follow the exact path we have taught. It sort of swings by the nodes, and we lose precious time trying to dial in thickn,
ess, where it could be much easier if they operated like ABB programs.

I have heard that there is a setting in the karel programs that you can change, thus eliminating the corner rounding. Can anyone help me find this? Our programmer won't teach us anything to protect his job security, but he is bottlenecking us with this problem.

Thanks,

Fanuc 710

[fanuc710]

Well, I'm a peeon where I work haha. The programmer claims to have called fanuc...
If I knew hoe to write a program I could demonstrate it to the higher-ups. But I don't.

[djewell]

Change the last field in each movement instruction. The default value in this field for linear movement is FINE. In order to get smooth(er) or more precise movement, you make this value something between 0 and 100. The lower the value, the more closely the tool path should approach each node before changing orientation/direction. Higher values make smoother movements. Maybe someone else knows another setting, but this is how I do my programming.

Keep in mind that when you program, you have less load on the robot than when the gun is running. I have noticed this makes a difference in the points I record in my programs.

[kschewe]

Djewell is right.

There are different ways for a robot to figure out to get from point a to point b. The program is either done wrong by its moving point to point by not using linear movements, there is other movements. In the line of code for point there is a value for precision, might be called radius on fanuc. If you lower that value from 50 to 5 for fine it would help.

im sure if you sent a copy of the program to the tech support they would have it fixed and sent back the same day if you are customer. abb is like that.

[KevGarty]

I dont have any experience with Fanuc robots but with ABB if the TCP (Tool Centre Point) is not set correctly it will have similar effects to what you describe

As djewell mentioned I would check the zone designation

[Moat]

djewell is correct. Your Termination type and value will greatly affect how the robot "rounds" the corners of your path. A FINE value will direct the robot to come to a complete stop at each point and then accelerate to the next, while a value of 100 will completely miss the point and move on to the next. Be aware that the deceleration/acceleration of this setting will also affect your coating thickness.

[fanuc710]

Therein lies the problem. How does a programmer overcome that problem?

[djewell]

You have to use small numbers as your termination value to get very accurate movements. Don't change speeds from one instruction to the next. If you are spraying in a ladder pattern, you can also overshoot the ends of your part by 150-200 mm before changing direction. I know it goes without saying, but you should not be changing direction on your parts. You always need to overshoot the edges of the part so the robot has time to accelerate back to your desired speed before moving across the target again.

Also, make sure you are using the correct motion type - you probably want linear motion, not joint motion.

[fanuc710]

Linear might be the right answer, all the blades we do are done in either joint or world. Never linear