How do I alter my Prusa i3 to print micro parts with accuracy

I built the DIY prusa i3. I have printed larger things and they came out crappy.. now I want to print micro parts that have wall thicknesses of .005" with some degree of precision and quality. I assume I need to alter the default settings. Would I need to buy a smaller extruder? Can someone who is doing smaller precise prints copy and paste their settings? Thank you!

wall thicknesses of 0.127mm is not easily achievable... and defiantly not via software magic. you would need a phisical nozzle with a hole of a little less than that diameter

To force plastic threw that tiny hole you would need and extruder with a lot of torque (ie a geared extruder, preferable strong metal gears) Direct extruders are a joke for this sort of thing.

You will also need patience, everything is going to take approximately 64x longer than a .4mm nozzle (4 times as long in each dimension so 4*4*4)

Then there is your frame, the smaller you go the more issues a wobbly frame will cause

As fro X.Y and Z resolution most of these are already fine for this sort of accuracy.

I would gradually reduce things.. try a 0.25 nozzle first, as they are available.. get that working well first

Edited 1 time(s). Last edit at 01/27/2017 10:31PM by Dust.

Ignoring the potential extrusion issues, a wall thickness of 127 um implies a nozzle diameter of maybe 100 um which in turn implies maximum print layer thickness of 50-75 um which implies a really flat print bed, really stiff guide rails with high precision bearings and a very rigid frame. Since your larger prints come out crappy, your machine is probably not built to the sort of tolerances that would be required to print really tiny things.

In general, it is best to scale the size of the printer to the size of the objects being printed. Since you're talking about printing in such tiny dimensions you'e probably wanting to print small objects otherwise the print time will become astronomical. It is much more difficult, and usually more expensive, to make a large printer with tight tolerances than a small, high precision printer.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

The easy answer is you can't make a prusa i3 print to those tolerances unless you have an unlimited budget. The better answer is you need to change to a print technology that will print to those tolerances. SLS would be one such technology.

Thank you all for the feedback. What about getting a higher print quality in general? I printed larger things with 1mm wall thicknesses and the wall was still flimsy/porous. What settings can I change to produce a denser wall? And what do I change them to?

Change the infill % in the slicer settings.
I normally print my ABS with about 20-60% infill because I print parts that are used.

Thank you Floyd I will try that

Infill settings don't change the wall density. For this type of question, it's best to post photos of the prints and then as much of the print settings as you can recall. Nozzle diameter is good to know, too.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Lancedrg, printing quality prints were the layers are stacked exactly on top of each other (no difference in XY direction from layer to layer) and where each layer is exactly the same height is a really hard thing to do with these printers. To achieve the highest level of accuracy you have to do a lot of tweaking on your machine. Don't expect to just throw one of these machines together and get perfect prints. You have to print, observe, tweak, and repeat over and over until you've got the best you can get. It's all about limiting how much undesired movement the printer does and having smooth plastic flow. Eventually you run up against limitations of the printers design.

Step #1, buy a quality filament to start out with. I have tried many different brands of filament and the most consistent for me has been Ultimachine. It's really the only "high end" filament I have tired. All the rest have been ones priced under this point. Use something like this to take the filament itself mostly out of the equation.I also recommend you start out with PLA. ABS introduces more variables that you don't need when tweaking. You'll need a fan blowing on your work and I recommend using a heated bed with a plate of glass on top. Run it about 60 degrees for the first couple of layers then drop it to 40 after that. Use hairspray on the glass to help the PLA stick. I do about three thin coats allowing each to dry between applications. Rinse it all off between prints with hot tap water. Make sure there isn't any oil or dirt on your glass before reapplying. Use binder clips to hold the glass onto the bed.

Step #2, get your be level. Either add an auto leveling system (with software compensation) or do it the manual way of using a feeler gauge between the end of a clean nozzle and the bed glass. I use a piece of card stock that is just a little thinner than my later thickness. Manually run the nozzle to each corner and keep homing it on that corner until the feeler drags the same on each. When it does, your bed is pretty much level.

Step #3, make a test model that has one layer thick and wide snake going from one end of the bed to the other. Print this over and over again and adjust on your extruder until you get an even flow. These adjustments take the form of adjusting the tension of all the nuts and bolts on it, making sure the filament feeds smoothly in and out of it, and isn't dragging on anything between the spool and the exturder. You shouldn't have to torque anything down ridiculously tight. Differences in how much the extruder grips the filament will produce drastic results in my experience. Lube the extruder gears. Print, observe, tweak, and repeat until the height of every part of the snake looks as uniform as you can get it. Still having issues, you may need to repeat step #2. Check your bed leveling every so often.

Step #4, lube you Z rods and screws lightly. Reduce z screw wobble. I use fish tank air hose to connect my Z screws to my motors so all the flex goes here instead of moving my X axis so much.

Step #5, Belts, belts, belts. No one I have seen has a way to do this exactly, but adjust the tension, print, observe, tweak, and repeat. Stick to one speed during this test and don't try to make it mach 3. Run the thing at a reasonable rate. Slower = less jerk. You will need different belt tensions for different speeds; however, too much or to little tension can effect things. Like too much tension can bend the printer itself causing binding. If your belt is as tight as the low string on a guitar, it's probably to tight. If you can't find a good tension that eliminates jerk when changing directions and such, then you might just have junk belts.

Going through these steps should deliver some results. I find two an three to deliver the most. Belt tension on my Y axis to the last of the wobble out of my layers. You'll see that to, Oh, they are only uneven on the Y sides. That's your clue that you need to do adjustments on that axis. After this start looking for things that can move in your printer that shouldn't and find a way to secure them without binding the printer. It's an iterative process, hang in there. Persistence will pay.