Hello, I have the same Issue on my P3Steel with a Duet WiFi, so I thought I'd share my experiences. For me, they're more noticeable along the Y-Axis (maybe a problem with the bed?) than along the X-Axis, but it's still there on both.
I too have an e3d Titan Extruder (with a 0.9° Stepper) and played around with the extrusion, but it didn't change much.
I tried various acceleration, jerk and speed settings. Also I don't seem to be getting those ripples on curved surfaces.
I also tried printing without any fan running on the Printer (Had to unclog my Hotend after that…) but it didn't help.
Another thing I tried was putting astrosyn dampeners on all motors, but that also didn't help.
Then I tried something "just for fun" and replaced the duet WiFi with an Ultimachine RAMBo 1.3, running the latest Marlin Firmware with the same Motion settings that I settled on in the Duet Firmware. Now it's still happening but its much less noticeable. On the Duet print I could easily feel the ripples when running over the surface with my fingernail, and on the RAMBo print I can't.
Very odd. Are you sure you were using the same motor currents on both controllers? What motors are you using?
Yes, 800mA. I was using These Nema 17s from Robotdigg:https://www.robotdigg.com/m/product/1137/42HS40-1704-58-oz.in-stepper-motor#
I generally had good experiences with robotdigg Motors and I've used them in a different Duet equipped Machine before, and didn't have a Problem. Maybe it was just a coincidence that it came out better on the RAMBo, I didn't really do any further Testing on it because I couldn't directly compare everything in the Firmware since I only know enough about Firmware to configure it for a Printer and not much more.
I can easily install the RAMBo again with different Settings if that helps.
While searching around I found this thread in the reprap forum:http://forums.reprap.org/read.php?246,702962,723107 it's in German but they're having the Same problem, and their Solution was to have the left End of the X-Rods fixed and the other End slightly loose in the right End (Like fixed/floating bearings), so my Right x-end might be too tight. I'll try printing a new one with a looser fit, and I'm going to drill out one side of the y-rod holders in the frame.