I haven’t printed many things at that extremely high print speed because I didn’t want to put very much wear and tear on the machine. If you would like to see a specific part printed at high speed, let me know and I can print it. At the higher speed pass on the cube, I was under extruding a bit because the hot end couldn’t keep up, but there was no ringing or wobble present at all even at that speed.
The modifications I have made to my printer that have had the most effect on improving surface quality at speed are the following, in this order:
- The Openbuilds X axis
- The Openbuilds Y axis
- The Taller Extruder mount (eliminates forward nozzleflex)
- The reinforced extruder carriage (or the Taz 6 carriage)
- Reinforcing the corners with this bracket: (http://i-t-w.com/parts/brackets-misumi-hblfsnb5-series-5-aluminum) - stiffens the frame
- The Anti wobble modification
- The aluminum bed plate to main frame connector pieces sourced from Techsavvy34 in the forums here
- The Z axis openbuilds modification - does help, but it is a minimal amount (less than I was expecting actually) and the Anti wobble has a similar effect
The openbuilds X and Y make the most immediate and dramatic difference in printed part quality. The carriage modifications are incremental. The anti wobble can be pretty dramatic difference as well if your machine has wobble. if it does not have noticeable wobble, its less important than the other reinforcements. The corner frame reinforcement pieces are required for very high speed prints, as the frame will attempt to rack otherwise, but are less important for normal speed printing.
The Z axis doesn’t hurt anything, but it doesn’t help as much as I was expecting that it would. After giving it a lot of thought, I believe one of the biggest sources of offset in the x and y direction, which the Z axis should constrain, is actually flex in the Y bed rods. As the belt moves the bed in and out, it tends to exert a small but noticeable offset force on one side or the other. The X axis, being on stacked rods has a similar but less noticeable kick up of the nozzle. Since Z moves much slower and less frequently, the cheapest effective modification there is likely going to be replacing the bushings with a more precise set, and maybe hardened rods.
There are two other modifications that I also recommend strongly, that don’t necessarily improve surface quality. The Aluminum heated build plate to replace the glass plate allows for faster printing and much better ABS part adhesion to the bed. the glass bed is heavy and doesn’t spread heat as well as aluminum. The tricky part is finding a 12" x 12" aluminum plate that is 3/16" thick and not warped in any way by cutting.
The other modification I recommend is the Z axis endstop micrometer target modification. if you aren’t going to install auto leveling, it’s the best way to maintain a highly precise Z axis height
For the heat set inserts, it is possible to order them from one of the manufacturers in Germany. http://www.spirol.com appears to ship there. You want the series 14 tapered inserts, M3, and m5 (a couple M2 are also used but can be worked around.) Their minimum order quantity is 150 inserts, and I have no idea what the cost is, but that might be an option. They are also called ultrasonic weld inserts, so they may just be under another name auf deutsch.
One option, if you cant find the actual inserts, would be to modify an “acorn nut” or one of those nuts with the dome on one end. If you carve some grooves in the surface of the nut to rough it up a bit, then insert it like a heat set insert, it may hold.
Hope that helps!