I figured out that it's nearly identical to the Bondtech Mini gears, since I completely overhauled an old extruder design (with the Bondtech Minis), used the Hobb Goblin in the new redesign, but never changed the settings, and it printed a calibration cube perfectly.
For those who find this topic later, the final answer is the effective diameter is 7.28mm
The teeth of the Hobb Goblin digs way deeper than the Bondtech, which is great for my 2.85mm filament, but it might be even a bit too deep for 1.75mm (only guessing, I can't test this since I don't have 1.75mm filament).
I'll put an adheisve magnetic sheet on top of the aluminium, the steel sheet will then stick to the magnet. Meanwhile ahesive PEI straight on the aluminium. Its good to 120C so hopefully it'll cover my needs for ABS and PETG for now.
With the bed being 120x120mm I only use about 70 watt or so, so I went with the small SSR modules with 2 channels, so I can add enclosure heater from the same heater wire. SSR only get up to 30C wihtout heatsink or active cooling at that load so it'll be fine as it is.
@alexander-mundy said in Delta arm length:
If I remember right from a long time ago in school, regardless of offsets in the below screen shot with the arms at 60 degrees isn't the hypotenuse (delta arm length) supposed to be 2 X the adjacent (delta radius) for a right triangle?
Why, yes, it should be! Let me take a look...
Edit: Now fixed.
However, I need to look at it again, however, because I changed this:
rodAngle[balln] = 180 - Math.cos(oppositeSide / DELTA_DIAGONAL_ROD) * 180;
rodAngle[balln] = Math.asin((oppositeSide * (Math.sin((Math.PI / 180) * 90)) / DELTA_DIAGONAL_ROD)) / (Math.PI / 180);
Which are just different methods of calculating the same thing... and verified in a debugger that the produce identical (numeric) results, yet the second one works and the first one does not... very bizarre.
I attempted a poly tower, but it ended up poorly because the slicer can only handle even numbers, so I had to print two shells and that kept the heat too close.
Normally I print that model with one shell.
Thanks, I will try again.
I used hair-spray and it helped, but I am so glad I haven't seen any cracking or warping issues, and the best part is parts seem to be 100% accurate, a 20x20 cube comes out at exactly 20x20.
That FilamentOne place was fast as hell to get it out to me, ordered Saturday, got it Monday!
I have suspicions it's made by Filimentium, same reel design, and the company used to sell that brand.
Going to re-print my cooling duct since the one I have now is a rough mess- $9 glow in the dark ABS on ebay gets you $9 quality.
Thanks for the information. Extrapolating (yea I know) the line it appears to fall inside but right at the edge of the area. I don't know if it will make any real world difference but I think I'm going to try the SS-01E which is a low force model.
Re Linear Rails
Yes, I have modified my Prusa to linear rails mounted on 3030 extrusion. It has made the printer bed far more stable. Improvement to print quality is minimal but there is a big improvement to repeat-ability. The only calibration I really need to do now on a regular basis, is to level the Z axis.
The original 8mm diameter rails and bearing arrangement is easy to build and probably just about adequate and cost effective for the loads involved but not good engineering practice IMO.
The linear rails do need precise alignment and setting up, but once done, the bed runs smoothly and stays in alignment.
For two aluminum 1/4 inch plates, I am getting a $450 price quote.
The tolerances quoted are not great.
As you can see I have staggered holes to accommodate different geometries.
The real kicker is that if you go up to 25 parts the price goes down from $200 each to $80-$100 each.
It would be great if this could be cost-shared in some way.
@tletourneau said in Need advice on new heated bed aluminium plate:
Does anyone think the additional weight of going with a 14lb (3/8") plate over a 12.2lb (5/16") plate would have a detrimental effect on the Z axis?
BTW I've replied to the other thread that you've started with more or less the same topic.
@vwegert I kind or forgot but I actually made a video of my purge bucket in action. If it's any use, check it out here https://www.youtube.com/watch?v=zNNmZCXErYY&lc=z234cfh4dkylhh4ra04t1aokgl1ownrihxxz0fiwil5xrk0h00410
@wilriker said in Must pulley and idler sizes match?:
@dougal1957 Thanks for confirming.
Just to be totally sure I got it right this time another diagram with a totally crazy and exaggerated belt path. I believe it is still correct, isn't it?
P.S.: Only one of these is supposed to be driven by a motor.
Yes, that's what i was trying to convey.
65 is pretty hot (at least to me it is).
PEI is awesome. Try dropping to 60 or 58.
I got an MK3 recently. Love it. I try PETG recently on the MK3, Love it.
I used it to re-print some parts on my dimond hotend mini kossel Duet Wifi.. Lovin it.
I swear the more extruders, the more problems. lol
And yes I use the same model for both fan and temp. It's a decent model because it has bridges, overhangs, sharp corners and curves.
@john-sinclair203 I'm pretty sure that only the polypropylene inner layer flexes, the aluminum is cut out on both sides. At least that's my understanding of Hylite. https://www.display.3acomposites.com/hylite.html
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