from scratch

Hello everybody!
I've been following this project for a while since I like the design of this printer, it's simple, yet it gets high quality results.
Well done Sublime!
Now that I am fully determined to make this machine, I am putting together the necessary parts.
Although I have some experience with electronic and mechanical components, I am going to need a some help, and I wish you could point me in the right direction.
First, I want to make the machine a little bigger, so I can print some 250 (L) x 150 (W) x 150 (H) mm. Originally I wanted to use an old scanner glass, which is twice the surface, but perhaps this is a bit ambitious for a first attempt. So I will cut the glass in half.
The other issue is that I have several stepper motors that are different from this design requires. They looks like a NEMA23, but slightly different. The "front" surface is 56x56mm, 47x47mm between holes, 40mm deep. The shaft is 19mm long, 6mm diameter. I am attaching a couple of pictures for reference. Crouzet 89.908.001.
I'll have to change the whole section of the Z axis, and the motor support on the extruder. I don't see much problem with the gears or mounting on the wall of the cabinet.
What worries me is I have no detailed specifications, is that is 200 steps (1.8 degrees), I only know it is 1.68V and 0.7 Ohms per coil (which would give 2.4A). In tests I've done they show to have enough torque.
What I want to know is if they are appropriate for RAMPS + Pololu. As far as I understand, I should have no problems but I want to be sure.

I will appreciate your comments.

Thank you,

Biomech.

Biomech Wrote:
-------------------------------------------------------
> Hello everybody!
> I've been following this project for a while since
> I like the design of this printer, it's simple,
> yet it gets high quality results.
> Well done Sublime!
> Now that I am fully determined to make this
> machine, I am putting together the necessary
> parts.
> Although I have some experience with electronic
> and mechanical components, I am going to need a
> some help, and I wish you could point me in the
> right direction.
> First, I want to make the machine a little bigger,
> so I can print some 250 (L) x 150 (W) x 150 (H)
> mm.

You would be best to build it for 150 x 150 x 250 since warping occurs when we print wide objects but not when we print tall objects. (there is one being built 150 x 150 x 200 very soon)

Originally I wanted to use an old scanner
> glass, which is twice the surface, but perhaps
> this is a bit ambitious for a first attempt. So I
> will cut the glass in half.
> The other issue is that I have several stepper
> motors that are different from this design
> requires. They looks like a NEMA23, but slightly
> different. The "front" surface is 56x56mm, 47x47mm
> between holes, 40mm deep. The shaft is 19mm long,
> 6mm diameter. I am attaching a couple of pictures
> for reference.

You will run into some issue with the motor size since there is very little clearance around the motors. They will hit the bed and the Z motor will be too far from the back wall for the lead screw to be in the correct position. Both problems can be solved by not printing all the way to the limits of the carriages movement and by cutting a hole in the back panel to allow the Z motor to stick out the back but I would recommend buying motors. You can get used nema 17's on ebay for $9 each with delivery in north America if you buy 4-5 of them [shop.ebay.com] [shop.ebay.com]

> I'll have to change the whole section of the Z
> axis, and the motor support on the extruder. I
> don't see much problem with the gears or mounting
> on the wall of the cabinet.

You will have to space the extruder farther from the wall which will mean the bed will have to be smaller then possible otherwise.

> What worries me is I have no detailed
> specifications, is that is 200 steps (1.8
> degrees), I only know it is 1.68V and 0.7 Ohms per
> coil (which would give 2.4A). In tests I've done
> they show to have enough torque.
> What I want to know is if they are appropriate for
> RAMPS + Pololu. As far as I understand, I should
> have no problems but I want to be sure.

2.4A is a little high for a Pololu driver but will work. You will either not get the maximum torque or you will over heat the driver and need a lot of cooling.

Last thing is the cable drive will have a limit of how long the longest axis can be because it requires one wrap of cable around the shaft for every 25mm of travel. Right now it uses 10 wraps which does mean it can travel up to 250mm but that would leave no extra cable and I feel it should have two extra wraps in each direction. This would mean a total of 14 wraps for a 250mm travel machine and could have unforeseen issues.

---

FFF Settings Calculator	Gcode post processors	Geometric Object Deposition Tool Blog
Tantillus.org	Mini Printable Lathe	How NOT to install a Pololu driver

[...]
> > First, I want to make the machine a little
> bigger,
> > so I can print some 250 (L) x 150 (W) x 150 (H)
> > mm.
>
> You would be best to build it for 150 x 150 x 250
> since warping occurs when we print wide objects
> but not when we print tall objects. (there is one
> being built 150 x 150 x 200 very soon)
>

True. I was thinking of the possibility of printing more than one piece at a time.
is this a good idea or is it better to print each piece separately?

[...]
>
> You will run into some issue with the motor size
> since there is very little clearance around the
> motors. They will hit the bed and the Z motor will
> be too far from the back wall for the lead screw
> to be in the correct position. Both problems can
> be solved by not printing all the way to the
> limits of the carriages movement and by cutting a
> hole in the back panel to allow the Z motor to
> stick out the back but I would recommend buying
> motors. You can get used nema 17's on ebay for $9
> each with delivery in north America if you buy 4-5
> of them
> [shop.ebay.com]
> s=1&_from=&_ipg=25
> [shop.ebay.com]
> =1&_from=&_ipg=25

Well, yes. The matter is I'm in Scotland, so the shipment would increase the final price.
I had already bought these motors before knowing Tantillus.
I have to think about it. Anyway I'd rather spend that money on the RAMPS shield.

[...]
>
> You will have to space the extruder farther from
> the wall which will mean the bed will have to be
> smaller then possible otherwise.

I am afraid that the most significant change will have to be in this part.

[...]
>
> 2.4A is a little high for a Pololu driver but will
> work. You will either not get the maximum torque
> or you will over heat the driver and need a lot of
> cooling.

I was thinking of using two motors in parallel (mechanically) in each axis, connected in series (electrically), thereby increasing the resistance and decreasing amperes.

> Last thing is the cable drive will have a limit of
> how long the longest axis can be because it
> requires one wrap of cable around the shaft for
> every 25mm of travel. Right now it uses 10 wraps
> which does mean it can travel up to 250mm but that
> would leave no extra cable and I feel it should
> have two extra wraps in each direction. This would
> mean a total of 14 wraps for a 250mm travel
> machine and could have unforeseen issues.

Yes, I had thought of that. With a longer travel would have a lot of wraps. That's why I was thinking on using parallel motors and move the assembly with a pulley belt and not a cable.

I have been consulting with the pillow, and I think it's best to make the machine as it was designed, so, to avoid problems I will get the NEMA 17 motors.
thanks for the comments.

Sticking to the original sounds like a good plan until you understand the entire machine.

---

FFF Settings Calculator	Gcode post processors	Geometric Object Deposition Tool Blog
Tantillus.org	Mini Printable Lathe	How NOT to install a Pololu driver

Yes, I think I got it.
my problem is that I have different motors and I am impatient to start building my printer.
What if I put a resistor in series with the motor winding?
For example, 0.5 Ohm (5W), this would give ... 1.68V / (0.7R + 0.5R) = 1.4A
might it work?


Watching how Tantillus can "evolve" from the laser-cut version to the all-printed version, I was having the crazy idea of a printer that can actually print itself "from scratch"
Let's say you get a basic package:
hot-end head,
extruder,
motors,
electronics,
hardware (rods, bearings, bolts, etc)
+
start-up kit.
Then, with these basic parts you build a printer that can, barely, print every part for a Tantillus like laser-cut version. From here the all-printed Tantillus.
The start-up kit could be a very basic printer with the extruder and the electronics laying around, it don't need to be pretty nor fast, it don't need to be even durable.
Just is a crazy idea. Or maybe not?

Biomech Wrote:

> Watching how Tantillus can "evolve" from the
> laser-cut version to the all-printed version, I
> was having the crazy idea of a printer that can
> actually print itself "from scratch"

Not 'crazy' at all. It's the basic concept behind RepRap, if I understood your comment correctly.

---

----------------
Lem Fugitt
3D Printing Dreams
Robots Dreams
"The map is not the territory."

Well, yes and not. It's a RepRap concept at the end.
AFAIK, Tantillus is the only machine that actually can print itself entirely. with the exception of rods, bolts and bearings, all the parts can be printed in the same printer.
When I spoke of a basic kit, I mean something that just barely be able to print, from scratch, every part of the machine (with the exception of the extruder, that it is necessary to begin).
For example, a printer of cardboard, which lasts only a few times (alpha). Enough to print the gears, the supports and the corners of the box.
Then with these parts build Tantillus (beta). Finally, with this machine to print the whole box, or even Tantillus "plus".

Is the equivalent to compiling a compiler. In the begin you need to write a compiler in machine-code, then compile the basic compiler, and so on...

Maybe I am not explain well what I am trying to say.