Re: [Emc-users] ender 3 and low quality sprockets

[andy pugh]

On Thu, 12 Nov 2020 at 02:22, Chris Albertson  wrote:

> A better approach is to create a slicer that can work with .STEP files
> directly.

Or slice inside the CAD software itself, where 100% of the design data
is available.

This isn't as hard as it sounds, I have even done it, using the
built-in API of Autodesk Inventor:
https://youtu.be/hefY46fyVvU

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] ender 3 and low quality sprockets

[Gene Heskett]

On Wednesday 11 November 2020 21:20:48 Chris Albertson wrote:

> The information is gone.  There is no way to automatically reconstruct
> a curve from a sequence of straight lines.  A human can do this
> because he can see what was intended.
>
> A better approach is to create a slicer that can work with .STEP files
> directly.   The trouble with that is the mathematics gets hard.   If
> you remember basic algebra, it is easy to find where two lines
> intersect if you have the equations for each of them.  There is no
> need to guess, you get an exact solution in one shot.  It is easy
> enough that they can even teach this to 13-year-old kids.But just
> try and find the intersection of a line and a curve.  Except for
> special cases, you are forced to solve it numerically which is very
> slow and a slicer needs to do this many millions of times.  Slow,
> but in theory, it could be done.
>
> So the practical solution, what we all use is to create STL files that
> have a specified maximum deviation from the ideal surface.   You can
> set this to 1/10,000 inch if you like and then any error is
> undetectable.   Slicing a file like that would be slow but slicing a
> STEP file would be way-slower.
>
> The OTHER thing we can do to make better 3D prints and I suspect if
> you found a good design, this was done, is to design around the
> capabilities of the printer.  Use simple ideas like filets and wall
> thicknesses that are multiples of the nozzle diameter.  It is not hard
> and if you are designing from scratch you can make a wall 1.60 mm
> thick rather than 1.5 mm and it will come out better if using a 0.4 mm
> nozzle.  There are probably a dozen more tricks like that.
>
> On Wed, Nov 11, 2020 at 5:41 PM Gregg Eshelman via Emc-users <
>
> emc-users@lists.sourceforge.net> wrote:
> > Since it looks like there's little or no progress on an update to
> > the STL format, there is work going on for 3D printer G-code post
> > processing to refine and smooth curves or even convert curves
> > defined by a series of straights to real arcs for printers that have
> > hardware and firmware capable of doing real arcs.
> >Supposedly units are arbitrary in STL. There's nothing in the
> > file format (unless with a proprietary command that only specific
> > printers understand) for indicating what unit or scale to use.
> > Assume 1 unit = 1mm and design accordingly. In the 3D software I
> > use, for STL export it makes a meter, centimeter, or millimeter all
> > equal 1mm. I use the different model and world unit settings to best
> > fit whatever I'm doing on the screen. Design tiny stuff in Meters in
> > a Centimeter world and big stuff in Centimeters in a Meter world.
> > Working in US units produces STLs that aren't the expected size.
> > It's all the fault of 3D Systems. When they created STL they were
> > only thinking of millimeters because their early stereo lithography
> > printers that scanned a LASER across the top of a tank of resin only
> > made rather small parts. One of the first products prototyped with
> > those was the roller clamp used on IV fluid lines and that was a
> > pretty large 3D print in its day.
> > A little bit of foresight and they would have made STL able to
> > support many types of units. Just a simple UNITS= line at the start
> > and have the printer software able to read that and adapt the
> > movements. On Wednesday, November 11, 2020, 09:47:14 AM MST, Chris
> > Albertson < albertson.ch...@gmail.com> wrote:
> >  Remember the workflow.  You start with a 3D model where the
> > resolution is literally "perfect" as the curves are defined by
> > mathematical functions. Then you convert the 3D model to an STL and
> > an STL can contain only straight lines.  No circles, no curves. 
> > When you make the STL you get to specify a maximum error but small
> > errors mean big files.
> >
> > So when you look for a gear or sprocket ALWAYS look to see if you
> > can get the 3D CAD file and not just the STL.  The best places are
> > the big resellers like Boston Gear, McMaster Carr, SPD,..  they all
> > have "perfect" 3D CAD models, usually.STEP file type.

And freecad-19 can load that.  But can it export the .stl's?

> > If you do download an STL then you are accepting some other random
> > person's idea of what is a good error tolerance without even knowing
> > what he specified.

And this obviously is a major PITA for someone like me, looking for a 
usable bit of code. 

> > *So make the STL file yourself. * I usually go overboard with
> > resolution in the STL and specify something like 0.001 mm or less
> > allowed error.

Which will result in huge .stl and .gcode files. And therein lies another 
problem.  Re-slicing after changing filaments, like from PLA to PETG, 
which changes all the temps, and using a root copy of mc to overwrite 
the files that are changed by this on the sd card, I find the file on 
the sd card is NOT changed by the overwrite, so I have to yet again 
change the TF card, 

Re: [Emc-users] ender 3 and low quality sprockets

[Chris Albertson]

The information is gone.  There is no way to automatically reconstruct a
curve from a sequence of straight lines.  A human can do this because he
can see what was intended.

A better approach is to create a slicer that can work with .STEP files
directly.   The trouble with that is the mathematics gets hard.   If you
remember basic algebra, it is easy to find where two lines intersect if you
have the equations for each of them.  There is no need to guess, you get an
exact solution in one shot.  It is easy enough that they can even teach
this to 13-year-old kids.But just try and find the intersection of a
line and a curve.  Except for special cases, you are forced to solve it
numerically which is very slow and a slicer needs to do this many millions
of times.  Slow, but in theory, it could be done.

So the practical solution, what we all use is to create STL files that have
a specified maximum deviation from the ideal surface.   You can set this to
1/10,000 inch if you like and then any error is undetectable.   Slicing a
file like that would be slow but slicing a STEP file would be way-slower.

The OTHER thing we can do to make better 3D prints and I suspect if you
found a good design, this was done, is to design around the capabilities of
the printer.  Use simple ideas like filets and wall thicknesses that are
multiples of the nozzle diameter.  It is not hard and if you are designing
from scratch you can make a wall 1.60 mm thick rather than 1.5 mm and it
will come out better if using a 0.4 mm nozzle.  There are probably a dozen
more tricks like that.

On Wed, Nov 11, 2020 at 5:41 PM Gregg Eshelman via Emc-users <
emc-users@lists.sourceforge.net> wrote:

> Since it looks like there's little or no progress on an update to the STL
> format, there is work going on for 3D printer G-code post processing to
> refine and smooth curves or even convert curves defined by a series of
> straights to real arcs for printers that have hardware and firmware capable
> of doing real arcs.
>Supposedly units are arbitrary in STL. There's nothing in the file
> format (unless with a proprietary command that only specific printers
> understand) for indicating what unit or scale to use. Assume 1 unit = 1mm
> and design accordingly. In the 3D software I use, for STL export it makes a
> meter, centimeter, or millimeter all equal 1mm. I use the different model
> and world unit settings to best fit whatever I'm doing on the screen.
> Design tiny stuff in Meters in a Centimeter world and big stuff in
> Centimeters in a Meter world. Working in US units produces STLs that aren't
> the expected size.
> It's all the fault of 3D Systems. When they created STL they were only
> thinking of millimeters because their early stereo lithography printers
> that scanned a LASER across the top of a tank of resin only made rather
> small parts. One of the first products prototyped with those was the roller
> clamp used on IV fluid lines and that was a pretty large 3D print in its
> day.
> A little bit of foresight and they would have made STL able to support
> many types of units. Just a simple UNITS= line at the start and have the
> printer software able to read that and adapt the movements.
>  On Wednesday, November 11, 2020, 09:47:14 AM MST, Chris Albertson <
> albertson.ch...@gmail.com> wrote:
>  Remember the workflow.  You start with a 3D model where the resolution is
> literally "perfect" as the curves are defined by mathematical functions.
>  Then you convert the 3D model to an STL and an STL can contain only
> straight lines.  No circles, no curves.  When you make the STL you get to
> specify a maximum error but small errors mean big files.
>
> So when you look for a gear or sprocket ALWAYS look to see if you can get
> the 3D CAD file and not just the STL.  The best places are the big
> resellers like Boston Gear, McMaster Carr, SPD,..  they all have "perfect"
> 3D CAD models, usually.STEP file type.
>
> If you do download an STL then you are accepting some other random person's
> idea of what is a good error tolerance without even knowing what he
> specified.
>
> *So make the STL file yourself. * I usually go overboard with resolution in
> the STL and specify something like 0.001 mm or less allowed error.
>
> The next step is manufacturing where you get to specify how it is sliced
> and printed or how the file is cut on a mill.
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>


-- 

Chris Albertson
Redondo Beach, California

___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] ender 3 and low quality sprockets

[Gregg Eshelman via Emc-users]

Since it looks like there's little or no progress on an update to the STL 
format, there is work going on for 3D printer G-code post processing to refine 
and smooth curves or even convert curves defined by a series of straights to 
real arcs for printers that have hardware and firmware capable of doing real 
arcs.
   Supposedly units are arbitrary in STL. There's nothing in the file format 
(unless with a proprietary command that only specific printers understand) for 
indicating what unit or scale to use. Assume 1 unit = 1mm and design 
accordingly. In the 3D software I use, for STL export it makes a meter, 
centimeter, or millimeter all equal 1mm. I use the different model and world 
unit settings to best fit whatever I'm doing on the screen. Design tiny stuff 
in Meters in a Centimeter world and big stuff in Centimeters in a Meter world. 
Working in US units produces STLs that aren't the expected size.
It's all the fault of 3D Systems. When they created STL they were only thinking 
of millimeters because their early stereo lithography printers that scanned a 
LASER across the top of a tank of resin only made rather small parts. One of 
the first products prototyped with those was the roller clamp used on IV fluid 
lines and that was a pretty large 3D print in its day.
A little bit of foresight and they would have made STL able to support many 
types of units. Just a simple UNITS= line at the start and have the printer 
software able to read that and adapt the movements.
 On Wednesday, November 11, 2020, 09:47:14 AM MST, Chris Albertson 
 wrote:  
 Remember the workflow.  You start with a 3D model where the resolution is
literally "perfect" as the curves are defined by mathematical functions.
 Then you convert the 3D model to an STL and an STL can contain only
straight lines.  No circles, no curves.  When you make the STL you get to
specify a maximum error but small errors mean big files.

So when you look for a gear or sprocket ALWAYS look to see if you can get
the 3D CAD file and not just the STL.  The best places are the big
resellers like Boston Gear, McMaster Carr, SPD,..  they all have "perfect"
3D CAD models, usually.STEP file type.

If you do download an STL then you are accepting some other random person's
idea of what is a good error tolerance without even knowing what he
specified.

*So make the STL file yourself. * I usually go overboard with resolution in
the STL and specify something like 0.001 mm or less allowed error.

The next step is manufacturing where you get to specify how it is sliced
and printed or how the file is cut on a mill.  
___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] ender 3 and low quality sprockets

[Gene Heskett]

On Wednesday 11 November 2020 14:50:29 Gene Heskett wrote:

> On Wednesday 11 November 2020 13:10:38 grumpy--- via Emc-users wrote:
> > On Wed, 11 Nov 2020, Gene Heskett wrote:
> > > Greetings 3d printer X-spurts;
> > >
> > > I just downloaded the .stl kit for a nema 17 powered, gt2 belt
> > > driven reduction gear.
> >
> > if i may ask, what did you download
> >
> >search u-tube for Emilostuff, final version

The zip has one bad file, when he did the sliders for belt tension 
adjustments, he did 2 copies, but the 2nd copy is 29+mm up in the air, 
equals huge ball of filament following the head around.

Even a single copy is nearly 90k LOC. I'm decent at editing gcode, so I 
just deleted the second copy's gcode, the up in the air copy, its 
identical but upside down. Give me your PM address and I'll send you the 
fixed copy, but the temps are set for PETG, way too hot @ 240/70 for 
PLA. Some printers may not be able to get that hot.

Take care now, we need all the grumpy's we have.  When you get to be my 
age, grumpy comes naturally.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] ender 3 and low quality sprockets

[Gene Heskett]

On Wednesday 11 November 2020 13:10:38 grumpy--- via Emc-users wrote:

> On Wed, 11 Nov 2020, Gene Heskett wrote:
> > Greetings 3d printer X-spurts;
> >
> > I just downloaded the .stl kit for a nema 17 powered, gt2 belt
> > driven reduction gear.
>
> if i may ask, what did you download
>
>search u-tube for Emilostuff, final version
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users


Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] ender 3 and low quality sprockets

[grumpy--- via Emc-users]

On Wed, 11 Nov 2020, Gene Heskett wrote:


Greetings 3d printer X-spurts;

I just downloaded the .stl kit for a nema 17 powered, gt2 belt driven
reduction gear.


if i may ask, what did you download


___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] ender 3 and low quality sprockets

[Gene Heskett]

On Wednesday 11 November 2020 11:43:37 Chris Albertson wrote:

> Remember the workflow.  You start with a 3D model where the resolution
> is literally "perfect" as the curves are defined by mathematical
> functions. Then you convert the 3D model to an STL and an STL can
> contain only straight lines.  No circles, no curves.   When you make
> the STL you get to specify a maximum error but small errors mean big
> files.
>
> So when you look for a gear or sprocket ALWAYS look to see if you can
> get the 3D CAD file and not just the STL.  The best places are the big
> resellers like Boston Gear, McMaster Carr, SPD,..  they all have
> "perfect" 3D CAD models, usually.STEP file type.
>
> If you do download an STL then you are accepting some other random
> person's idea of what is a good error tolerance without even knowing
> what he specified.
>
> *So make the STL file yourself. * I usually go overboard with
> resolution in the STL and specify something like 0.001 mm or less
> allowed error.
>
> The next step is manufacturing where you get to specify how it is
> sliced and printed or how the file is cut on a mill.
>
> On Tue, Nov 10, 2020 at 9:15 PM Gene Heskett  
wrote:
> > Greetings 3d printer X-spurts;
> >
> > I just downloaded the .stl kit for a nema 17 powered, gt2 belt
> > driven reduction gear.  I thought I see how it rendered since I had
> > such poor luck with that previous harmonic drive. so I update cura
> > to 4.8.0, loaded up the teeny little gt2 belt sprocket that fits the
> > motor shaft.

I have now rendered all the pulley's in PLA, and am starting on the 
smaller box bits in PETG. I'm still impressed. This stuff has sharp 
corners etc, and just screams precision like I have never seen this 
printer do before. I haven't adjusted any of the printers scales as they 
were last set for a good fit of the bearings that the harmonic drives 
used. I may be able to salvage the bigger ones from those but I think 
they are bigger.

I found on his latest video, a BOM of sorts, he didn't count or spec the 
lengths or numbers of the 3 and 4mm bolts and nuts. I generally buy that 
stuff by the bag anyway, but I'll have to render the whole box before 
I'll have a good idea how long the bolts are.  The big box is about a 28 
hour render. By then I may have to switch colors of PETG as I've used 
over half a spool of candy red, and have 2 spools of kelly green left.

I'm even dreaming of it having the cajones to drive the bs-1 as I think 
my nema-17's are longer than what he used in the video.. The rear of the 
motor is going to stick out around 2" above the top of the bs-1 when its 
facing horizontal as its the only way to make it clear when tipped up to 
vertical. Sticking out to the side means it will hang out a good 4" but 
that's in the air where its not going to hit anything, not even the 
choker straps I pick it up with.  Since the encoders index will be a 
home switch on the bs-1, I wouldn't need the index hall effect this one 
can have.

I enjoy playing what if? :)  A good winter project. But you likely had 
that figured out already. ;-)  Where this could best be used is on the A 
axis of the 6040. With more geardown than it has ATM. With a teeny 
little nema-23, & my drivers from the micromill, it can do about 50 
rpms.

Take care & stay well, Chris.


> > I noted that cura was lifting the head and moving it off about 2cm
> > to about half a cm above, I assume to give that small a part a
> > chance to cool between layers. But it still finished in about the 15
> > minutes it said it will take when cura sliced it. And the print is
> > easily 5x sharper, a quite usable gt2 rendering where before, an xl
> > pulley was just barely usable with a belt tight enough to satisfy
> > Jack Benny!
> >
> > So I've come to the conclusion that quite a bit of what you can
> > download as .stl's, are intended to be very low resolution so as not
> > to compete with the same you-toobers commercial offerings.  And my
> > printer isn't the piece of crap I turned off in disgust 6 weeks
> > back.  I am impressed.
> >
> > Cheers, Gene Heskett
> > --
> > "There are four boxes to be used in defense of liberty:
> >  soap, ballot, jury, and ammo. Please use in that order."
> > -Ed Howdershelt (Author)
> > If we desire respect for the law, we must first make the law
> > respectable. - Louis D. Brandeis
> > Genes Web page 
> >
> >
> > ___
> > Emc-users mailing list
> > Emc-users@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/emc-users


Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


___
Emc-users mailing list

Re: [Emc-users] ender 3 and low quality sprockets

[Chris Albertson]

Remember the workflow.  You start with a 3D model where the resolution is
literally "perfect" as the curves are defined by mathematical functions.
 Then you convert the 3D model to an STL and an STL can contain only
straight lines.  No circles, no curves.   When you make the STL you get to
specify a maximum error but small errors mean big files.

So when you look for a gear or sprocket ALWAYS look to see if you can get
the 3D CAD file and not just the STL.  The best places are the big
resellers like Boston Gear, McMaster Carr, SPD,..  they all have "perfect"
3D CAD models, usually.STEP file type.

If you do download an STL then you are accepting some other random person's
idea of what is a good error tolerance without even knowing what he
specified.

*So make the STL file yourself. * I usually go overboard with resolution in
the STL and specify something like 0.001 mm or less allowed error.

The next step is manufacturing where you get to specify how it is sliced
and printed or how the file is cut on a mill.

On Tue, Nov 10, 2020 at 9:15 PM Gene Heskett  wrote:

> Greetings 3d printer X-spurts;
>
> I just downloaded the .stl kit for a nema 17 powered, gt2 belt driven
> reduction gear.  I thought I see how it rendered since I had such poor
> luck with that previous harmonic drive. so I update cura to 4.8.0,
> loaded up the teeny little gt2 belt sprocket that fits the motor shaft.
>
> I noted that cura was lifting the head and moving it off about 2cm to
> about half a cm above, I assume to give that small a part a chance to
> cool between layers. But it still finished in about the 15 minutes it
> said it will take when cura sliced it. And the print is easily 5x
> sharper, a quite usable gt2 rendering where before, an xl pulley was
> just barely usable with a belt tight enough to satisfy Jack Benny!
>
> So I've come to the conclusion that quite a bit of what you can download
> as .stl's, are intended to be very low resolution so as not to compete
> with the same you-toobers commercial offerings.  And my printer isn't
> the piece of crap I turned off in disgust 6 weeks back.  I am impressed.
>
> Cheers, Gene Heskett
> --
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> If we desire respect for the law, we must first make the law respectable.
>  - Louis D. Brandeis
> Genes Web page 
>
>
> ___
> Emc-users mailing list
> Emc-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/emc-users
>


-- 

Chris Albertson
Redondo Beach, California

___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] ender 3 and low quality sprockets

[Gene Heskett]

On Wednesday 11 November 2020 02:44:09 
marcus.bow...@visible.eclipse.co.uk wrote:

> On 2020-11-11 05:12, Gene Heskett wrote:
> > Greetings 3d printer X-spurts;
> >
> > So I've come to the conclusion that quite a bit of what you can
> > download
> > as .stl's, are intended to be very low resolution so as not to
> > compete with the same you-toobers commercial offerings.
>
> I don't know if that is the reason, but I have certainly found that
> only a small percentage of the Thingiverse stls are worth using.
> That's mostly because I have issues with the design of the parts,
> rather than the printed output, but your thought adds an interesting
> dimension to the argument. I don't know how print quality is related
> to an stl file, becuase I had assumed most of the quality of
> interpretation lies in the slicer. But maybe not.
>
> What nozzle size and layer thickness did you use? 
box stock, .4mm nozzle. micro-swiss feeder conversion but has OEM hot-end 
mounted because the micro-swiss hot end is AFAIAC, a defective design 
prone to freezing up. I can put a small washer under the upper tubing 
fitting to compress the tube solidly against the rear of the nozzle so 
the filament never touches the hot end metal until it is inside the 
nozzle. One MUST prevent the liquid plastic from being able to migrate 
up into the fan cooled upper heat sink portion of the hot end. This 
limited contact only in the nozzle limits the maximum flow rate, so feed 
speeds need to be a bit lower but that's a very small price to pay for a 
hot end that doesn't freeze up. The output sprocket currently being made 
has the extruder feed set at 86% as I am still fine tuning that feed. 
Currantly set at about 5x the factory setting.  That made a cat the is 
too light to weigh on my powder scale, and which I can read a newspaper 
thru.

> I assume it was much 
> the same as for the harmonic drive, but I certainly find the
> difference between, say, o.2mm and 0.1mm layer height makes a huge
> difference to the quality.

Currently set at .12, as low as cura offers for this printer.

> I tend to stick with 0.4mm nozzle size, but 
> I know from friends that a move to a smaller nozzle can improve
> quality even further - even if print times do become rather extended
> for larger jobs. I am using a cheap Anet A8 printer, which is
> essentially a copy of the Ender i3.
>
> > And my printer isn't
> > the piece of crap I turned off in disgust 6 weeks back.  I am
> > impressed.
>
> No; low price does not necessarily mean low quality prints. It does
> mean the printer will probably require some fettling and mollycoddling
> to give of its best, but there are no surprises there.

True.  TANSTAAFL principle.  My fight with hot ends is a prime example.

> I note that the recent models of the Anet and Ender feature more rigid
> metal frames (Anet is plastic) - although they are still a bit flimsy
> if you ask me.
> As with machine tools, rigidity is (nearly) everything.

And the ender 3 pro's all metal frame seems more than adequate. I had 
visions to seeing the added weight of the extruder motor, but have not 
seen any adverse effects on the ballistics that I can discover. The 
table its on is a very nervous fold-up design, but as long as it rocks 
and rolls as a unit its not bothering me because it moves as a single 
unit. I cannot see any advantage to adding the 20 some lb concrete 
18x1.5" paver under it because that added mass under it only stresses 
the frame more. I think it it was hung from the ceiling with 2 wires, it 
would still work just as well. 

OTOH, I've been known to think outside the box. ;-) 

The only thing missing from the zip of this device is the BOM.

> Marcus

Thanks Marcus.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] ender 3 and low quality sprockets

[andy pugh]

On Wed, 11 Nov 2020 at 05:15, Gene Heskett  wrote:

> So I've come to the conclusion that quite a bit of what you can download
> as .stl's, are intended to be very low resolution so as not to compete
> with the same you-toobers commercial offerings.

You are free to conclude what you want, of course. and to assume evil
intent if you wish.

But the preview on Thingiverse is generated from the STL, so what you
see in the rendering should be what you get.

The _only_ thing in the STL is a lot of little triangles. If there are
enough triangles to render the shape well in the Thingiverse preview
then there should be enough triangles to make a decent part.

The rest is all in the slixer settings and the printer.

-- 
atp
"A motorcycle is a bicycle with a pandemonium attachment and is
designed for the especial use of mechanical geniuses, daredevils and
lunatics."
— George Fitch, Atlanta Constitution Newspaper, 1912


___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

Re: [Emc-users] ender 3 and low quality sprockets

[marcus . bowman]

On 2020-11-11 05:12, Gene Heskett wrote:

Greetings 3d printer X-spurts;

So I've come to the conclusion that quite a bit of what you can 
download

as .stl's, are intended to be very low resolution so as not to compete
with the same you-toobers commercial offerings.


I don't know if that is the reason, but I have certainly found that only 
a small percentage of the Thingiverse stls are worth using. That's 
mostly because I have issues with the design of the parts, rather than 
the printed output, but your thought adds an interesting dimension to 
the argument. I don't know how print quality is related to an stl file, 
becuase I had assumed most of the quality of interpretation lies in the 
slicer. But maybe not.


What nozzle size and layer thickness did you use? I assume it was much 
the same as for the harmonic drive, but I certainly find the difference 
between, say, o.2mm and 0.1mm layer height makes a huge difference to 
the quality. I tend to stick with 0.4mm nozzle size, but I know from 
friends that a move to a smaller nozzle can improve quality even further 
- even if print times do become rather extended for larger jobs.
I am using a cheap Anet A8 printer, which is essentially a copy of the 
Ender i3.





And my printer isn't
the piece of crap I turned off in disgust 6 weeks back.  I am 
impressed.




No; low price does not necessarily mean low quality prints. It does mean 
the printer will probably require some fettling and mollycoddling to 
give of its best, but there are no surprises there.
I note that the recent models of the Anet and Ender feature more rigid 
metal frames (Anet is plastic) - although they are still a bit flimsy if 
you ask me.

As with machine tools, rigidity is (nearly) everything.

Marcus


___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users

[Emc-users] ender 3 and low quality sprockets

[Gene Heskett]

Greetings 3d printer X-spurts;

I just downloaded the .stl kit for a nema 17 powered, gt2 belt driven 
reduction gear.  I thought I see how it rendered since I had such poor 
luck with that previous harmonic drive. so I update cura to 4.8.0, 
loaded up the teeny little gt2 belt sprocket that fits the motor shaft.

I noted that cura was lifting the head and moving it off about 2cm to 
about half a cm above, I assume to give that small a part a chance to 
cool between layers. But it still finished in about the 15 minutes it 
said it will take when cura sliced it. And the print is easily 5x 
sharper, a quite usable gt2 rendering where before, an xl pulley was 
just barely usable with a belt tight enough to satisfy Jack Benny!

So I've come to the conclusion that quite a bit of what you can download 
as .stl's, are intended to be very low resolution so as not to compete 
with the same you-toobers commercial offerings.  And my printer isn't 
the piece of crap I turned off in disgust 6 weeks back.  I am impressed.

Cheers, Gene Heskett
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
If we desire respect for the law, we must first make the law respectable.
 - Louis D. Brandeis
Genes Web page 


___
Emc-users mailing list
Emc-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/emc-users