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> You 14/144 pair nicely shows where an undercut would be necessary. That's yet another story ;-)
I dont think it is undercut problem. Wrong involute profile curve. The second screenshot
proves it to me at least;-)
by
khiraly
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General
Looks like it is not the right solution. Here is a screenshot demonstrating it:
magenta: 14 teeth gear (m=2)
white: 144 teeth gear without DB=DR modification (m=2)
yellow: 144 teeth gear with DB=DR modification (m=2)
So it is clear, that the correct method would be finding the intersection
mathematically, and trim each involute profile curve by DR.
I gave up here. I think i just wait a coupl
by
khiraly
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General
I semi-fixed the tooth issue. Now the tooth and gap has the same width at the pitch diameter.
Also when the Root diameter is bigger then the base diameter, I made the two diameter equal.
Is is almost good. Here is a screenshot:
However the bigger gear is 144 teeth version, and the involute profile seems a bit too straight to me.
Laszlo
by
khiraly
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General
Traumflug Wrote:
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>> > Base circle diameter = number of teeth * module
>> * cos(20deg)
>>
>> This is not correct either. It is the root circle
>> diameter.
>
> Base circle is the circle your convolution is
> perpendicular on, right? No mistake on this one on
> my side.
Yepp, you are right. From
by
khiraly
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General
Also seems like the formulas Im using matches with this example:
python arcolgears.py -n 24 -m 3.0
N: 24 m: 3.0 a: 3.0 b: 3.75 PA: 20.00 deg
DR: 64.5 DB: 67.6578686966 D: 72.0 DO: 78.0
Or this pdf:
Or this:
Where even explain the pitch diameter and circular pitch:
pitch diameter = N * m
circular pitch = m * pi
The problem is, there are number of teeths, where these formulas are simply d
by
khiraly
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General
> You want tooth thickness and tooth gap to be the same at the pitch circle, not at the base circle.
Correct, you are right. My mistake.
> Pitch circle diameter = number of teeth * module / pi
It is wrong. If you look at the 9 teeth gear, the outside diameter is 22mm, the root diameter is 13mm.
If we solve your equaton: P = 9*2/pi = 18/3.14 = 5.7 mm
The pitch diameter cant be smaller t
by
khiraly
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General
Hi,
Im studying spur gears since two days already. I have some math questions about gears.
Im seeing many spur gears with 67, 127 teeths, and Im unable to generate it.
There are basically two standard for gears: metric and US. The metric is basically
defined with module , number of teeth and pressure angle .
The US version is defined using diametral pitch instead of module.
For nomenclature
by
khiraly
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General
> Besides, I doubt it's possible to get repeatable results without a
> lathe, but the big advantage of this design is that you don't need a
> lathe.
I have tried to machine in a CNC shop. So we had everything (lathe, cnc, etc).
Im also playing with the idea, of having different gears (different tooth number), and mark a number on the screw. Just we need a very precise measuring tool.
by
khiraly
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For Sale
Wade Wrote:
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> Hey, neat-o! Glad you guys like my design!
>
> Wade
I have machined 10 bolts too Wade, but none of them has the exact same diameter, which affects seriously the extruded filament length.
We have built the two bearings setup, like on this thingiverse:
But the bearings and the bolt has some play, so we could not cr
by
khiraly
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For Sale
I do believe it would be better to name this machine as "Mendel-like repstrap".
It has no RP parts after all...
Best regards,
Laszlo
by
khiraly
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For Sale
I have done a detailed analys, and wrote an article:
Ruttmeister:
Is the filament reliable for you?
Do you get some blockage from times to times?
Best regards,
Laszlo
by
khiraly
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For Sale
I would discourage "extruded" PMMA/plexi, because they are very brittle.
I will make mine out of PVC.
Best regards,
Laszlo
by
khiraly
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Mechanics
> The plastic itself costs ~$20 for a whole machine, and time spent printing
I do believe 1kg of plastic is required for a set of Mendel, its 40-45GPB +shipping from bitsfrombytes.com.
Also you can buy cheap plastic from elsewhere (like 5kg in a spool), but there is a chance it has an oval shape, and worse quality.
I did this, and broke my extruder (the ptfe tube), so I have a little exper
by
khiraly
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For Sale
Looks like I have sold this Mendel.
If you are still interested, send an email to order (at) arcol (dot) hu, if the buyer steps back, I could offer to the next one. OR, if there are more people buying this kit, I could decide to print more sets or not.
Best regards,
Laszlo
by
khiraly
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For Sale
> Again I say, giving someone $300 when they haven't even printed with
> the prototype... That's brave.
I dont really believe the official Mendel extruder is reliable for ABS in the first place.
So I think some modification will be required in the Mendel design itself.
Also the cartesian bot is quite awesome, so buying this part is not a bad idea.
And keep in mind, that everybody who h
by
khiraly
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For Sale
> I guess that takes care of the mechanical parts kits that you were
> going to offer. confused smiley
When I offered the mechanical kit first, I didnt had my mounted Mendel.
So I could not be 100% sure, if I include everything or not.
So I wanted to build a Mendel myself to verify it.
Now it is done, so I can offer the mechanical parts only, if somebody wants it. (I have enough mater
by
khiraly
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For Sale
> You should probably state if this is a metric or an imperial mendel.
> winking smiley
I strictly followed the official building manual:
So everything is metric. I used M4 nuts, M8 threaded rods, etc, etc.
Best regards,
Laszlo
by
khiraly
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For Sale
Hi!
Im thinking of selling my (semi-)completed Mendel.
The reason for selling is, that I need to work on the electronics before, so basically this Mendel wont print/finished for at least a month.
And Im currently working on heated bed (http://blog.arcol.hu/?p=589) right now, so when I could finally print with this machine, until then i will be able to print an another Mendel.
The machine is t
by
khiraly
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For Sale
khiraly Wrote:
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> I should really create a summary blog about all
> this.
Here is an extensible writeup about this Dremel holder:
Best regards,
Laszlo
by
khiraly
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General
VDX Wrote:
> Your setup is a good idea, but i think this
> grinding-discs will reduce in diameter after some
> way, so you have to adjust regularly or your
> surface will get wedge-shaped ...
Im milling two full days already. Like 30hours in total, and Im not done yet. Im using the 5. disks now.
I think the best method is going end-to-end the y direction, and 0.4mm after each turn
by
khiraly
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General
I dont see a point for heated room either. But we could use some kind of hat around the nozzle to prevent the heat going further up.
Its not exactly a heated room because it has no walls;-) and open, but I think it would create more uniform heat.
Also the heated bed looks awesome and enough.
by
khiraly
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General
> 150x150x15 were 15€ on a local shop
So 330x330 piece would cost 72.6+ EUR. Aluminium is not cheap at all.
So 100EUR for the whole thing seems pretty good deal to me. (if I can really make it that low). (and I need to machine it also, which is expensive)
> But there is a hope!! The Raftless pulgin for Skeinforge let's us
> define a head speed and extrusion speed, so we can make the
by
khiraly
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General
Here is a video, how Im milling it flat:
by
khiraly
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General
> When the layer height is only 0.25 to 0.4mm 0.1mm is quite a big error
> when printing without a raft.
With my current bed, I could only print using raft, and in that case I needed to be around when it started, because I have must to level the bed using the three nuts while it started to print the raft.
I hope I can avoid at least this issue.
However the dremel is already running 12
by
khiraly
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General
For printing, I think 0.1mm flatness error is perfectly fine. But I will report anyway how it will turn out the whole story.
The current flatness error is about 1-1.5mm.
by
khiraly
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General
Oh, and Im actually milling steel/iron. Its still the first prototype.
I would expect aluminium is much easier.
by
khiraly
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General
> ... milling an Aluminium-sheet really flat with a dremel should be
> nearly impossible
Seems to work fine for me.
Im using a dremel, a dremel right angle attachment 575:
And 1mm thick cutting disks (420).
It is noisy as hell, but works fine.
And also I designed a dremel holder for my machine too.
I will publish a blogpost about it at the weekend with some nice photos.
by
khiraly
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General
> It's a bit expensive, I think
The bfb bed is 330x330mm, it is more than four times bigger, then your 150x150 aluminium sheet...
How much was your aluminium sheet?
(Im just curious no offense at all)
by
khiraly
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General
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Pages: 12345