I did change my belts (GT2) to prosper quality that is soft and fiber reinforced.
Also swapped my bearings to, toothed pulleys. That did bring ringing and distortion quite a bit.
A Bowden setup, also improved the prints. Still not perfect. But I will try to change some 8 mm rods to better ones.
+ quality bearings.
Improved frame rigidity. Small improvement there too..
Think there is many small steps to get to the goal..
But, core xy is the best option..
I am thinking of a CoreXY Build myself... But that was just a small footnote
Back on the topic, I would almost conclude that the weight on the Y carriage has little to no effect. I used to have a small 200x200 PCB heatbed and had the same issue nonetheless. Now I am utilizing a 250x320mm silicone heater glued to a 6mm machined cast aluminum plate. I even used to have a glass on top of it which is a total weight gain of 3kg. But this didn't make the rippling any worse than it already was. I got rid of the glass (1.3 kg) but there was no effect.
I suspect that the key contributer to our ripple problem is the X axis.
I switched from a greg wade's extruder with a huge Nema 17 motor to e3d titan with the small motor they supply with it. Maybe I could use a pancake motor instead but shy of that I have one inductive sensor, two 40mm fans and the classic e3d hot end attached to the X carriage. No extreme weight.
I guess I should try geared idlers. I would furthermore think how to stabilize the X carriage. It is not the weight itself that causes the ripples but the freedom the nozzle has to vibrate. So a more rigid construction should be able to take that freedom away...
First way to improve:
Get 0.9 degree steppers, instead of 1.8 degree steppers.
Get some Panucatt SD6128 drivers. They are amazing.
Third way: Get a Duet board that does segment less movements.
The explanation for the ripples involves the way that RAMPS firmware segment travel moves into discrete segments, and the way that those segments don't often line up with whole microsteps. It's tricky. I'm seeing the light after going down the same rabbit hole.
Okay maybe I'm being slightly pessimistic but Marlin is frequently quoted as only being able to generate 40khz step pulses from a mega/ramps board. So you're using repetier? I've little experience with it, but to do the moves you quoted that's 75khz step pulses, so that seems reasonable from what I'm told it's code is more efficient.
But on a delta is a pure z move really a good test? Whilst moving up/down is the worst case in terms of maximum step pulses to be generated, the processing requirements to calculate the movement are very little, all motors move by the same amount to achieve pure z movement. Any other movements require a lot of square root calculations which load the processor . How fast can that same machine (on a dry run) do a circular spiral vase, this is a more useful test, given that you almost never do a large pure z move when printing?
Is the choice of 20t pulleys just to lower the steps/mm to give the 8bit controller a chance? Surely mechanically improving your resolution 25% by just using smaller pulleys is a no-brainer. Would you run 20t pulleys on a 32bit controller? If so, why?
Glad you're liking the SD6128 drivers, might buy some, but can you comment on how they compare to TMC2100's?
There is no real 3D Printing news, it's all Fake.
When was the last time a reporter came to you for the Real Story.
Ok Maybe Mutley & Pursa get a few inquiries?