The benefits of upgrading to a geared extruder? (Page 1 of 2)

So I suppose that begs the question... Anyone design a printable one for the solidoodle utilizing the stock direct drive components? Because if not I think I know my next design project.

Thanks!

Ian that does admittedly sound a lot simpler.  Not too mention $6 off ebay for the replacement driver (I have the Sanguino MB).  I'm ordering one right now I think.

Yeah I am not so sure the printer board was quite upgraded MB in someways.  Increased functionality, prettier package... at the cost of less flexible upgrade solutions... But then again for most users I am thinking it makes no difference. 

I have a feeling what I am doing with my doodle is turning it into a machine that outputs resolutions, and print qualities of which were never really intended by the original design.  Seeing as in many respects a stock solidoodle is a great printer in many respects.   

I am thinking motor needed to spin faster doesn't seem like an issue as long as you don't go with an aggressive gear ratio.  If a 1/32 micro stepper driver upgrade is enough to solve the issue, you ought to only need a 1:2 gear ratio to get rid of visible moire effect which is my main reason for wanting to upgrade.

Good to know about the 1/32.  And glad that I got in when Sanguino was the oem part.

What about just upgrading to a stronger Nema17 stepper?  Although I suppose why throw that money towards a new stepper when I could just put it towards a bulldog and be done with it all, and have an awesome surface finish.

I have plans to upgrade to an E3d hot end, and the Bulldog looks like the logical progression.

I'm keen to see a drop-in planetary box... Maybe keep the ratio something manageable - somewhere between 2 and 6?
Use those double helical gears that increase the tooth strength a fair bit and reduce backlash a touch... I'd love to see a double-helix ring gear. Sure that's possible!! Might get away with printed gears if you do that, otherwise it's looking a bit torquey to be reliable... The cost would be measured in c if we could print one, as opposed to $100's to buy a bulldog...

If you don't get around to it, I will.

It strikes me as very reasonable to do the gears out of 0.093" thick lexan, strong stuff and you could keep the profile down nicely with that.  Of course you wouldn't be printing that. 

But I have a laser cutter arriving in the mail on Monday:)

I am thinking it's very reasonable to produce a precise enough heard extruder with laser cut gears, and using metal rod's/bearings for any other important precision areas. 

I'll let you know what I come up with.

Well thanks for the heads up warning.  My laser cutter's home will be right next to my computer, and I'd rather not fumigate myself... Although a bit curious; i'm assuming your university's laser cutter has the required exhaust system, or does it just have a carbon filter and vent indoors? 

If so I will be venting via an exhaust tube to the great outdoors... my children can thank me later for contributing to the hole in the ozone.  Anyhow perhaps that will solve smell issues. 

Of course that still won't solve not being strong enough to handle the torque... Of course the one benefit to laser cut lexan over FDM ABS would be that the lexan would be at it's peak strength since it's not being put down in .1mm layers, and therefor no delimitation issues.

As far as cutting nylon, according to this it will, just melts badly--whatever that means--i'm guessing deformed edges which would be less then ideal for gears.  http://www.pololu.com/docs/0J24/3

Perhaps a better solution then fabricating our own transmission is harvesting one from an all metal transmission from an inexpensive DC geared motor. Perhaps one like this...http://www.ebay.com/itm/3-6V-DC-Small-M … 2c5f441e02

Or this is probably not going to have the acceleration we would need, but use this motor for a direct drive extruder, but since it's geared you get the resolution and hopefully enough torque to make an ultra compact extruder... I'm thinking it's not going to have the acceleration you'd want, but not wanting to track down the data sheet for it, I just ordered one to play with. for $4 it'll be a good toy to have around for some other project.  It has 64 steps per revolution. But with internal gear reduction included the equivalent of 4096 steps per revolution.  I am guessing it's plastic gearing inside... But maybe metal.  I'll find out in a few days;) Anyhow this strikes me as quite an elegant solution if it can meet the torque and acceleration requirements.  I am pretty confident it will meet the torque requirements, but speed not so sure. Of course backlash I am assuming will most definitely be an issue with such a stepper motor, but nothing our good old hysteresis firmware compensation won't handle with ease. http://www.ebay.com/itm/380803233237

My final thought is that the super cheap drills... Take it apart and harvest the gearing in that. I've done that for a few projects, and it turns out to be a wonderful source for a cheap (typically) all metal planetary transmission with in many cases built in adjustable over torque protection, not that you would want that in this case.

Yeah, going with a NEMA package would be easier to adapt, but the one I ordered up above was $4... So it was an easy impulse purchase. But I'll check out the NEMA package geared steppers and see what the price is on those guys.  I wonder why solidoodle moved away from them, just a higher cost, etc... ?

I suppose I'm pretty darn close to a bulldog xl extruder setup.  The main difference being I still have a tension arm. Although I am thinking I ought to take the opportunity to machine myself an Aluminum Mk5 variant.  I have enough scrap lying around...

Those are the specs with the Nema 17 motor they attached.  I will be using the solidoodle stock nema 17.  So I am not sure if it's weight will be comparable to the one they show, but fair point if it is.  Perhaps time to go to a bowden setup;)

As far as the length, again that's with their assumed motor.  After measuring the solidoodle motor I believe it comes in at about 40mm as opposed to 48mm.  Couldn't get a precise read, in the middle of printing some filawinder parts.  But the stock solidoodle fan assembly still may prove problematic interference wise.  However on the Solidoodle 4's I've noticed they got rid of the aluminum heat sink in favor of putting a fan to the side of the extruder up front.  Perhaps because of the new metal extruder, adequate heat dissipation?  So I suppose as I make that aluminum mk5 variant I talked about no problem following suit with my fan. 

But regardless, not quite the "no fuss" swap out I thought I had found, but pretty close, especially for the price.

I do have a bunch of PTFE tubing on it's way thought so I might just ditch the whole carriage mounted setup and convert to a Bowden.

the stock is 40mm, so if thats was the intention, then you've got an extra 8mm up your sleeve - BUT... according to the data sheet - the shaft is 8mm btw, not 5 - so wont be using the stock motor unless you turn up a collar ....

The front fan would work fine, mainly because the idea is to prevent the filament from softening whilst also cooling the motor as well - but this bit is kind of secondary. The motor is normally cooled so the stepper case can't radiate heat the filament causing it to soften and have feed issues - so if you active cool the filament then 'all is good' and you can forget the motor (within normal limits of course).

If you go bowden - then you can have 'easy to print' gears like a wades with herringbone cut gears quite easily - or yes do all manner of things with the planetary box... you just need to get some decent push-fit connectors (you can improvise with nyloc nuts et al - but they do come out, usually the middle of a print, where as quality push-fits correctly matched to the PTFE size will give you no troubles)