4th axis and fusion 360 problem

Having real problems with my 4th axis . Can any one help. IV just installed it and made a small model in fusion this is my first time using the 4th . When I run I code it runs ok for the most but the the 4th (A) slows down to almost a stop . It crawls along at about 1mm a minute . Then after it gets to where it's going all speeds up again. It does this 2 or 3 times in the operation . IV run it 5-6 times and it happens at the same place every time. I'm scratching my head not knowing if it's the post processing or fusion or my new 4th axis or my stepper. iv added some videoAny help would be cool





Attachment 24862https://www.youtube.com/watch?v=ppOQ...ature=youtu.behttps://www.youtube.com/watch?v=DsJY_yiks64&feature=youtu.be

stops at 490 line every time here

What speeds and feeds have you selected in the F360 CAM settings tab? In your screen shot, the machine speed drops right down at the line marked, where there is a significant move in A.

Attachment 24863

iv changed nothing from this

I'm probably talking the proverbial... but 490?, your Mach3 installation is licensed?

Yes it's I'm running some more code and it's still doing the same thing but at line 234

been trying to get this working for over a week now . almost giving up on it

Both examples that you show freeze with very slow feed rates (F554/F373) compared to the preceeding gcode - can you confirm that these lines do indeed have the lowest feed rates upto that point in the gcode?

If so, add a zero (x10) and try an air-cut, see if the behaviour is the same

this is some more code im running and it is doing the same thing what do you think

X-16.223 A24.234 F8759.5091
X-16.233 A23.903 F20792.2569
X-16.242 A23.465 F17076.7648
X-16.247 A23.027 F18351.0809
X-16.248 A-2.375 F346.9053 <------- stops at this line every time and runs really really slow
X-16.24 A-3.806 F5889.3929
X-16.22 A-5.243 F5463.8838
X-16.187 A-6.724 F4964.8767
X-16.139 A-8.234 F4565.2459
X-16.077 A-9.76 F4244.1414

The gcode is telling it to run really slowly. That's about a sixtieth of the speed in the previous line. It appears to be happening when there is a much larger movement in A than in previous lines. Suggests something happening at the CAM toolpath generation stage, which I why I wondered about the feed settings. At this point, it doesn't look like a Mach3 or machine issue.

i think you're on the right track I changed the gcode line where it slows down f346 to F646 and i moves faster. I just need to work out why now. But I'm a lot happier than I was this time this morning. Slowly getting to the bottom of it