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Snappy v3.0 released.

Posted by RevarBat 
Snappy v3.0 released.
February 02, 2018 04:27PM
I just released Snappy v3 as a working design, and added a Snappy 3 page to the Reprap Wiki. I patterned the page on the one for the original Snappy.

[reprap.org]

The main improvements of the Snappy 3 over the old Snappy 1.1 are:

- Replaced the old metal lifter rod vitamins with printed equivalents.
- Bed leveling is now adjustable.
- Z axis homing is now towards Z-min.
- The herringbone gears and racks should be smoother and cause less print artifacting.
- The extrusion bridge is now lighter.
- Tightening the extrusion idler is now done with a printed adjustment screw.
Re: Snappy v3.0 released.
February 13, 2018 06:06AM
That looks pretty neat in the assembly manual.

But how long does it take to print all the parts on a 200x200x200 machine at 50-60mm/s ?

Wasnt there a calibration check print too in (v1 or 2)? So one would be sure that the parts would actually snap together.

So far I never been able to get parts I printed to fit together well, not your parts, parts I made or downloaded.

I like it tho. Great work.

Edited 1 time(s). Last edit at 02/13/2018 06:06AM by orbitalair.
Re: Snappy v3.0 released.
February 14, 2018 10:45AM
It takes about a week of continuous printing. Maybe more.

The STLs/slop_calibrator_parts.stl model still exists for slop calibration.

Edited 2 time(s). Last edit at 02/14/2018 10:52AM by RevarBat.
Re: Snappy v3.0 released.
February 19, 2018 11:48AM
So I noticed in the BOM it states that no supports are required.

How are all the large prints with overhangs kept from getting drizzle down?

I'm going to be printing this on an ultimaker at my uni.
Re: Snappy v3.0 released.
February 19, 2018 12:00PM
Bridging gaps are kept to less than about 25mm. If you have reasonable bridging settings in your slicer, it should make good parts. Even if you get some bridging sag, those are not a critical problem for this design.
Re: Snappy v3.0 released.
February 19, 2018 12:32PM
Just got into 3D printing a month ago (Qidi Tech I) and I'm starting to print parts for this. Not exactly because I expect it's the best route toward another printer for me, but it's too interesting not to smiling smiley

I've diverged from the instructions a little and made the two drive_gear_parts in Taulman Nylon 645 which was an adventure (hairspray on glass bed and a large brim or else it would come loose due to the forces of the part cooling trying to bow out the bottom.) The rest I plan to do in PLA -- rail_xy_motor_segment_parts is printing currently.
Re: Snappy v3.0 released.
February 19, 2018 08:44PM
Well, that phrase "bridge settings" really opened up google to a solution. Thanks. I kind of assumed that using the fans and a low speed would make it work; though I'm never sure what atrocities will occur on the school printers. The student workers, for example, all told me that old cob web looking "triangular" infill was perfectly normal. I suppose I'll try out the bridging test from YouMagine.

On another note, how do you use the slope calibrator? I just assumed that since the peg only fit in the 0.2 slot I should set the horizontal expansion to -0.2, but if everything is off by 0.2 does it really matter?

I'm super excited about this project (especially since I don't have to pay for the filament winking smiley ).

Edited 1 time(s). Last edit at 02/19/2018 08:45PM by livingfractal.
Re: Snappy v3.0 released.
February 20, 2018 12:31AM
Regarding the slop calibrator:

1. find the smallest hole that it you can insert and remove the plug from without having to use a lot of force.

2. Take the value of that hole and set the printer_slop variable in config.scad to it.

3. Regenerate all the STL model files by opening each *_parts.scad file in OpenSCAD, use F-6 to render the parts, then export to STL.

4. Print from the new STL files.

5. Test the fit of the parts.

-Revar
Re: Snappy v3.0 released.
February 20, 2018 11:11AM
I'm using the newest version of Cura and an utlimaker. When I open the the described file in OPENscad the prescribed variable is already set to the value that first time I printed the slope calibrator the block fit into.

I suppose I should just make a new thread to discuss ideal settings for printing snappy 3.0 with cura & ultimaker.

Thank you.
Re: Snappy v3.0 released.
February 21, 2018 01:26PM
Just to clarify, so if I find my printer slop is 0.20 mm, there's no need to regenerate the files in the STLs directory and I can slice and print them as they are?
Re: Snappy v3.0 released.
February 21, 2018 03:16PM
Correct. You do not need to regenerate the STL models if the printer slop is already correct.
Re: Snappy v3.0 released.
February 22, 2018 08:12AM
So, we are learning about modes of failure in my intro to materials science course. Obviously, that means I have just enough knowledge to make an ass out of myself.

Would there be any benefit to rounding the corners, such as the internal corner between the beams and walls on the x-y motor segment, to reduce stress concentrations?
Re: Snappy v3.0 released.
February 22, 2018 01:28PM
Quote
livingfractal
Would there be any benefit to rounding the corners, such as the internal corner between the beams and walls on the x-y motor segment, to reduce stress concentrations?

Maybe? Probably? Have to be careful what you round out, though. Rounding out overhang corners can cause bridging issues. Adding lots vertexes too close together in an arc can cause shudders and slowdowns in printing, which can add blobs and ripples to the parts as well.
Re: Snappy v3.0 released.
February 22, 2018 02:46PM
Quote
RevarBat
Adding lots vertexes too close together in an arc can cause shudders and slowdowns in printing, which can add blobs and ripples to the parts as well.

Can you elaborate on that?

Edited 1 time(s). Last edit at 02/22/2018 02:47PM by livingfractal.
Re: Snappy v3.0 released.
February 22, 2018 03:07PM
Quote
livingfractal
Quote
RevarBat
Adding lots vertexes too close together in an arc can cause shudders and slowdowns in printing, which can add blobs and ripples to the parts as well.

Can you elaborate on that?

Because STL files are all flat triangle faces, models made with them translate arcs into small consecutive facets. Slicers translate these into short line segments in the g-code output. When the printer tries to process several consecutive short moves, say less than a millimeter each, it can take longer to send the g-code lines over the serial line to the controller, confirm receipt, and decode them, than it takes to do the motion. This will tend to cause the motion buffer in the firmware to drain of moves, causing the printer to stop moving until the next motion is received and decoded. This can cause rapid fast stop-starts that can cause excess extruder blobbing where it stops, and it can cause the printer to vibrate excessively.
Re: Snappy v3.0 released.
February 23, 2018 11:16AM
What you say it's possible but magnitude of the issue varies greatly from firmware to firmware.

Edited 1 time(s). Last edit at 02/23/2018 11:21AM by newbob.
Re: Snappy v3.0 released.
February 23, 2018 05:25PM
It happens commonly enough that I try to keep it in mind when designing parts.
Re: Snappy v3.0 released.
March 30, 2018 05:40AM
Any news on a completed build?

What issues did you run into?
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