First prints off my new solidoodle 3 after just leveling the bed and adjusting the Z-stop! I dont mnow if solidoodle changed something with the bed heater, but it heats up remarkably fast, almost as fast as the hotend.
There seems to be some artifacts with the hearts, one of them was printed at .3 and the other at .1mm. The toothpaste squisher on the other hand shit the bed, and I have no idea why. What are some settings I should adjust to get started on tuning in my printer?
Extruder calibration. Check how much filament is going through your extruder. Is 100 mm really 100 mm. then go from there.
What’s the Z steps/mm on the Solidoodle 3? It looks like they’re not using a metric pitch.
2268 and not metric, 5/16
Yep, turns out the extruder was over extruding by 31.7mm per 100mm, I’ll be fixing that tomorrow.
I figured as much. When I say that the solidoodle cuts so many corners that it’s likely to roll off the table, this is the kind of stuff I’m talking about.
The non-metric pitch is the cause of your Z axis banding. Your layer height needs to be a multiple of the full-step length to avoid rounding errors. There are two ways to calculate your full-step length, you can find the pitch of the screw (either 1/18" or 1/24" for 5/16 diameter, I forget which is more common), convert to mm and divide by 200, or you can look up your steps/mm setting, divide by the denominator of your microstepping ratio (probably 1/16), and take the reciprocal to convert steps/mm to mm/step. Any multiple of this full-step length will be a position you can hit accurately each step, though most of the options will probably have long decimal components that will have to be rounded-off and may re-introduce error.
Oh, just realized that the 2268 was the answer to my steps/mm question, so that would be a 1/18" thread pitch at 1/8 microstepping with about a .5% error in the steps/mm setting. Beautiful.
@Whosa_whatsis
Or, you can use the Tantillus calculator http://www.tantillus.org/Intermediate_calc.php
Enter your steps per mm at the bottom and a rough layer height at the top, click calculate and it gives you a table with a variety of layer heights to 3dp and the associated rounding errors.
@Whosa_whatsis My AO-100 has 3/8-12 ACME leadscrews. I did try to adjust layer height with the Prusa Calculator but to my eye it made absolutely no change to Z banding. In any case I’ve been thinking of changing them to M5 rods… right now they’re beefier than my smooth rods which are 8mm and I’m guessing this must not help with Z wobble.
I actually was going to change my Z to a 3mm stainless threaded rod and a long brass nut. That is a really fine pitch.
I bought all the parts but haven’t done it yet.
For the most Z accuracy, you should change that to 20320/9 (let the firmware do the math so that it can store the value with as much precision as possible), and use layer heights that are muliples of 63.5 microns. 1/24" pitch would make things a little easier, but I would recommend switching to an M8 rod and nut and then use layer heights in multiples of 6.25 microns.
Sorry @Whosa_whatsis was that a reply to Wayne or to me? I should learn not to hijack other people’s posts…
@Normand_Chamberland I’m realizing that even with a properly-calculated layer height, there can still be rounding errors in the steps/mm setting that will introduce error. I HIGHLY recommend using M6 rods with a 1mm pitch (.5mm full-step length) to avoid rounding errors.
@Wayne_Friedt An M3 rod (.5mm pitch) should have similar benefits, but I don’t think it’s going to be stiff enough to be reliable.
@Normand_Chamberland , that comment was still replying to @Wayne_Friedt 's previous comment. Left the comment half-written while I was trying different variations on the math to figure out that 20320/9 thing.
@Whosa_whatsis Sorry I meant M8 rather than M5. So M6 would be stiff enough for a Prusa Mendel sized MM1.5-variant machine? I gather I am right in assuming the leadscrew should not be bigger than the smooth rod?
Correct. M6 is my recommendation, and it’s what we use on the Bukobot.
@Tim_Rastall I hadn’t seen that calculator, but @Josef_Prusa has one with similar features. I’m realizing now that the calculations won’t work unless they factor-in the need to round-off the steps/mm setting, making it essentially impossible to avoid rounding errors that will cause print artifacts entirely when using non-metric leadscrews.
There is people using the 3mm and it does seem very small but they say it doesn’t bend like you think it would. Just what i have read.
@Whosa_whatsis Many thanks for the info.
@Whosa_whatsis true, but if you insert a Layer height to 3dp, the rounding errors are so small they become imperceptible. For instance, I use 1/4 acmes on my ex-mendelmax and use a layer height of 0.140mm (+/- 19nm error) and get no discernable banding. The key is keeping those decimal places in.
