# Avoiding abrupt stop, blend radius not working? **URL:** \ **Category:** General Application Help: How do I?\ **Created:** [May 27, 2025, 8:48am UTC](https://forum.universal-robots.com/t/avoiding-abrupt-stop-blend-radius-not-working/39999 "2025-05-27T08:48:27Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![lars.mathias](https://avatars.discourse-cdn.com/v4/letter/l/2acd7d/32.png) [@lars.mathias](https://forum.universal-robots.com/u/lars.mathias)\ **Post date:** [May 27, 2025, 8:48am UTC](https://forum.universal-robots.com/t/avoiding-abrupt-stop-blend-radius-not-working/39999/1 "2025-05-27T08:48:28Z")
I have a UR5 robot that, during its cycle, has to reach down below its base and drop of a part into a basket. On every other stop this machine has, it stops smoothly and the radius blends just fine. On this particular stop however it jerk to a sudden stop every time. I added a “slowdown” waypoint with barely any speed to try and give it the chance to get there slowly and smoothly but it still jerks to a sudden standstill. Had to replace some joints for this robot due to this kind of issue. Anyone know how to make it slow down and stop gently? Its on a MoveJ movement, speed is 20 degrees/s before it reaches the stop. Radius is blended. Acceleration is also 20. I’ve heard someone mention a stopJ function but i havent found it anywhere. ---
**Author:** ![dpeva](https://avatars.discourse-cdn.com/v4/letter/d/b5ac83/32.png) [@dpeva](https://forum.universal-robots.com/u/dpeva)\ **Post date:** [May 27, 2025, 12:39pm UTC](https://forum.universal-robots.com/t/avoiding-abrupt-stop-blend-radius-not-working/39999/2 "2025-05-27T12:39:53Z")
Try turning off the blended radius. I’ve seen that cause the jerky motion before. ---
**Author:** ![efn](https://avatars.discourse-cdn.com/v4/letter/e/35a633/32.png) [@efn](https://forum.universal-robots.com/u/efn)\ **Post date:** [May 27, 2025, 12:59pm UTC](https://forum.universal-robots.com/t/avoiding-abrupt-stop-blend-radius-not-working/39999/3 "2025-05-27T12:59:18Z")
You shouldn’t have a blended waypoint before any type of stop/wait/delay. 🙂 That will indeed cause the abrubt stop and unwanted wear on the joints. ---
**Author:** ![dbarton](https://avatars.discourse-cdn.com/v4/letter/d/eb8c5e/32.png) [@dbarton](https://forum.universal-robots.com/u/dbarton)\ **Post date:** [May 27, 2025, 4:14pm UTC](https://forum.universal-robots.com/t/avoiding-abrupt-stop-blend-radius-not-working/39999/4 "2025-05-27T16:14:54Z")
not sure who your distributor is but if they are letting you buy new joints instead of helping analyze your program, i think it’s time for a new distributor… like efn said, if you have any type of decision making happening at that waypoint, you should not have a blend. also, if you are using subprograms, try not to blend the last waypoint in it as it will jerk like this when entering back into main program. ---
**Author:** ![lars.mathias](https://avatars.discourse-cdn.com/v4/letter/l/2acd7d/32.png) [@lars.mathias](https://forum.universal-robots.com/u/lars.mathias)\ **Post date:** [June 2, 2025, 9:06am UTC](https://forum.universal-robots.com/t/avoiding-abrupt-stop-blend-radius-not-working/39999/5 "2025-06-02T09:06:02Z")
They offered to do so, but you know how some management can be about slowing things down in production.. So i tried removing blends and it helped somewhat, so that seemed to be the issue. However, trying the exact same on a different robot running the same program did no difference at all. Same abrupt stop ---
**Author:** ![efn](https://avatars.discourse-cdn.com/v4/letter/e/35a633/32.png) [@efn](https://forum.universal-robots.com/u/efn)\ **Post date:** [June 2, 2025, 9:17am UTC](https://forum.universal-robots.com/t/avoiding-abrupt-stop-blend-radius-not-working/39999/6 "2025-06-02T09:17:42Z")
The UR will read its program sequentially. So whatever command is before the stop will be executed. I have never heard of it not doing this right. 🙂 Check the blend again. And the acceleration settings of the waypoint. If it’s a MoveJ, stay below 400 deg/s^2. If it’s a MoveL, stay below 2500mm/s^2. ---
**Author:** ![lars.mathias](https://avatars.discourse-cdn.com/v4/letter/l/2acd7d/32.png) [@lars.mathias](https://forum.universal-robots.com/u/lars.mathias)\ **Post date:** [June 2, 2025, 9:57am UTC](https://forum.universal-robots.com/t/avoiding-abrupt-stop-blend-radius-not-working/39999/7 "2025-06-02T09:57:57Z")
I added a new waypoint to the 2nd robot and it completely ignored it. After a reboot it read the program correctly, so something odd happened. The robots are fairly old so i am not surprised that some gremlins appear with age. Speed and acceleration is well within those values, i think it was 160 deg/s^2 and 250mm/s^2 at maximum, for both MoveJ and MoveL. I went ahead and sent the program to my distributor so we’ll see if he can figure it out. Thanks for the help!