151 Reply by Claghorn

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Re: DIY Aluminium 3D-Printer, build 2 (page 4)

toobyaas wrote:

Do you think that smoothieboard website is a bit unclear..?

Well, I'm certainly always challenged when I'm trying to find stuff on it :-).

Thanks for the info about the display (though I always have my print next to my computer, so adding a display is a long way in the future, if ever :-).

Claghorn's Website

152 Reply by 11b30b4

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Re: DIY Aluminium 3D-Printer, build 2 (page 4)

Toobyaas, very impressive.

153 Reply by aleksi

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Re: DIY Aluminium 3D-Printer, build 2 (page 4)

Quite nice build! smile Overkill, but nice! Then again, what's worth doing it, is worth overdoing it, right? wink

I would expect a frame like this be able to go much much faster than 150mm/s - the belts are probably the limiting factor.
I achieved that kind of speeds reliably on a heavily modified Prusa V1 at high accelerations (i think 3-5k, cannot remember) without severe loss of quality and no ringing.

Your limiting factor on speed will eventually be the drivers & voltage, you'll need 24VDC after a certain point - that's basicly where i got stuck with RAMPS 1.4 last time around. But there's now easy solution on RAMPS board smile
For Smoothie you need put headers in and use external, afaik it cannot take separate supply for the drivers sad Which is such a shame as digital current control is sweet!

Before you get to that point, add heatsinks & cooling fan for the onboard drivers, heatsinks for all the steppers and basicly just run them at the highest current you can make them reliably work, find the spot where they start failing and come back 20% smile
Cooling affects that most heavily.

Voltage as i understood is the ultimate limiter of speed due to back EMF, eventually the back EMF generated by the steppers when decelerating will be too large and eventually the voltage difference from back EMF to supply vanishes and you'll miss steps.

My next build is going to have 36VDC driver supply voltage with 4.6A Nema23 stepper motors which are 3N-m or 425Oz-in, so a bit above 4 times the torque the Nema 17s linked on this thread.

Because all steppers are basicly wound for the same speed, which translates to about 1200rpm with half steps (measured in PPS), eventually no matter how much larger motors are put in, you can't get more speed unless you sacrifice resolution sad
Precision is largely determined by how sturdy the frame & drivetrain is.

Knowing what i know now, it still amazes me how i managed to drive so much performance out of the Prusa V1 design, which has wobbly X axis and super strong Y axis, esp without lateral supports!

With Nylon i got out flawless prints at 180mm/s print speed (tho design was round) with straight cylinders snap fitting together so well that people didn't know they are snapped together unless i showed it to them smile

154 Reply by toobyaas

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Re: DIY Aluminium 3D-Printer, build 2 (page 4)

Thanks! This is overbuilt mainly because I didn't have certain machines in use such as milling machine so I needed to design parts that can be made with 3-axis lathe smile

Yes you are correct, frame isn't limiting factor in speed. I'm running rapid moves at 250mm/s and could do higher but there is lot of moving mass and printer is waving my work table! I have printed with faster speeds, but print quality is always weaker then. When printing fast the start of extrusion looks ugly and some ringing is showing. Main reasons to ringing are wavy printbed, moderate quality linear bearings(they weren't as good as I thought), non supported rails and rubber belts. Even though I have 12mm chromed rods, I can bend them pretty easily just by pressing it down by hand and that isn't good thing.

Nowdays I can't machine parts by myself so I need to get along with these problems and I usually print around 50-60mm/s and I'm pretty happy with it. Print quality is good and I don't need to tweak calibrations at all!

As far as I know, Smoothieboard can handle 24VDC, so it wouldn't be a problem! At this point I still don't need upgrade for higher voltage.

Do you have any information of your printers online? They sound interesrting! I might also have one bigger printer project coming. If it begins, printer will have over 300x300 build area and I'm planning to use nema 23 steppers also.