Feet for the Prusa MK3s should do three things:
- Not wobble, be firmly connected, and support the printer
- Isolate and eliminate vibrations to improve print quality
- Dampen noise caused by those vibrations to improve quality of life
In addition, if you are using an LACK enclosure, not see it move.
Although OK, the stock feet do none of these really well.
The only material that is truly designed to do the latter two is Sorbothane. Read about its properties here: https://www.sorbothane.com/material-properties.aspx This is a scientifically proven anti-vibration anti-noise material, that is similar in feel to a gummy bear, and used to soften vibrations in electronic and industrial equipment, such as a 3D printer.
This simple but strong printed foot design when used with Sorbothane domes should maximize the reduction of vibrations. The only way to firmly attach feet to the printer is with slide in frame brackets, using screws. The feet also need to be printed at 100% infill to pass any vibrations on to the sorbothane. Each foot is attached solidly to the frame by two M3 12mm screws to framebrackets that slide into the frame channel groove. You do need to remove the frame ends but that is easier then fiddling with drop in framebrackets, and these are sturdier. The feet provide a round flat area to stick the adhesive backed Sorbothane 1 inch 50 duro domes.
EDIT - I CAN CONFIRM THESE WORK, ESPECIALLY WITH SIX!! JUST INSTALLED!!
When the Sorbothane dome is compressed it works best. Too large or stiff a dome and it isn't doing its job. If it is too small or too compressed it can't handle the vibrations. You want to pick a set of specific domes so that the weight supported falls in the middle of the load rating for the Sorbothane, so the domes have optimal compression.
The combination of dome size (1,1.25,1.5 inch) and duro rating (20,30,50,70) tell you how many you need for a particular vibration load (weight). For the printer we can use either four or six. It weighs about 17 pounds with a spool.
After matching 17 pounds to the various combinations of size and compression, using six of this type is the best combination to support 17 pounds:
- 1 inch 50 duro, supports 2-4 pounds each, so six of them support 12-24 pounds
- 17 pound printer weight falls squarely in the middle of this 12-24 range (this is ideal)
All the other combinations of duro ratings, sizes, and quantities gave load ranges that were mostly above or below 17 pounds:
- 1 inch 70 duro support 4-8 pounds so four support 16-32 pounds
- 1.25 inch 50 duro support 5-10 pounds so four support 20-40 pounds
- 1.25 inch 30 duro support 2-4 pounds so six support 12-24 (same as 1 inch but would require larger feet and longer print time)
- 1.5 inch 30 duro supports 4-7 pounds and four support 16-28 pounds
Therefore we need to print six feet using 1 inch 50 duro domes!
To understand further read:
Here they are on Amazon. I got mine for $10 for 4 with free shipping/Prime - make sure to get 50 duro ones! (these come in packs of 4 so buy two packs)
You will need six feet exactly. For each foot you need:
1 Sorboholder printed
2 Framebrackets printed
1 Sorbothane 1 inch 50 duro dome
2 M3 12mm screws
2 M3 hex nuts
(optional)1 Woodprotectpad printed (2 sizes included)
Print everything at 100% infill because you need the printer vibrations to carry through them completely to the Sorbothane domes. PETG is preferred due to the constant weight on the part.
The woodprotect pads serve three functions. There are two sizes of these. Pick which one you like. You might print them if any of these apply:
- Sorbothane can stain some surfaces like wood and you have a wood surface.
- Sorbothan is sticky and you don't want them to stick to your table but the pads instead.
- You want to slide the printer around on your table/desk easily.
My mod that moves the LCD to the left or right side of the printer with a bracket::
Now you can mount a Logitech or any camera with a screw mount securely to the front frame, as well as place you Pi there for Octolapse: https://www.thingiverse.com/thing:3518161
You might also want to make this so the LCD cable is held better: https://www.thingiverse.com/thing:3485143
My favorite mod replaces just your Einsy door with an integrated Z-axis brace so your printer has virtually no Z wobble:
Instructions with pics below.
Fusion 360 file included for remixing.
The goal is here is not to have to re-calibrate the axis. The frames should always be resting on the original Prusa feet while we slide in the new feet. Note that only in the final step do we remove the old feet and attach the new adhesive Sorbothane domes.
- Print out four 'sorboholder' feet, and eight 'framebracket2'
- (see pic) Lightly sand the 'framebracket2' and then insert an M3 hex nut into the back of each. Push them in fully. Make sure they are flush or below the surface.
- (see pic) Screw two 'framebracket2' to each sorboholder feet with two m3 12mm screws. Don't fully tighten them. Don't attach the adhesive parts (sorbothane, etc) yet
Repeat for each end of the frame:
- Slightly lift one frame end and then slide the stock/gray/existing Prusa feet towards the middle of the frame four inches from each end, and do not remove them
- Slightly loosen one end of the frame plate by loosening the eight large screws. Once they are all loose remove them fully.
- (see pic) Lift the frame up and slide in the assembled sorboholder/framebracket2 assembly for the both feet on that end of the frame. Loosen the M3 12mm screws if needed
- (see pic) leave the old feet in for now
Once they are in reattach the eight frame screws and screw them back in to reattach the frame end
- (see pic) Slide the new feet into the desired position, and screw in the new feet into the frame.
When all are in:
- (see pic) Finally, attach the new adhesive Sorbotane domes and remove the old Prusa rubber feet.
Lightly sand the 'framebracket2' and then insert an M3 hex nut into the back of each. Push them in fully. Make sure they are flush or below the surface.
Screw two 'framebracket2' to each sorboholder feet with two m3 12mm screws.
Lift the frame up and slide in the assembled sorboholder/framebracket2 assembly for the both feet on that end of the frame.
leave the old feet in for now
Slide the new feet into the desired position, and screw in the new feet into the frame. (Correction - You will need 6 not 4 feet.)
Finally, attach the new adhesive Sorbotane domes and remove the old Prusa rubber feet. (Correction - You will need 6 not 4 feet, and spread them out more than this pic shows.)