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9 Pound Naval Cannon (1786) by AON - 1:12 scale

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Thank you Hexnut.

Definitely looking at the option of printing vertically in sections.

What do you mean by "as a couple-layer flat"?

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Alan, I think hexnut was saying to print the emblem separately, sand it down to thickness required and apply to the barrel later after it’s cleaned up. 

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A question for people out there that have some expertise with 3D printing.

I have two sketches below.

One has the cannon divided into two pieces, almost equal halves, whereas the other has it divided into five unequal pieces.

 

What advantage or disadvantage is there to these divisions if presented as individual 3D vertical prints?

 

The first bad thing that comes to mind for me is that the ribbon of hot PLA plastic having no support at the bands when printed vertically... they may droop or simply fall away... even if they are rotated and printed upside down where possible.

 

The first possibly good thing is that the smaller sections allow larger detail in the 8Mb limited STL file.

 

Is there a better way to divide this?

vertical split - 2 pcs.JPG

vertical split - 5 pcs.JPG

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Update....

 

I received a PM from a forum member who took my file and attempted to print the small section at the insignia horizontally with his printer.  The results were similar.

 

He made many suggests: print vertically, 2 to 3" long sections; divide at an top or bottom of a ring not through it. Layer height no larger than 0.2mm. Infill of 20%. Wall thickness no less than 1mm (1.2 seems to be ideal without being overkill) Print with Brim of 5-8 lines (this will be a layer surrounding the parts that helps them adhere to the bed).  He concurred that printing the insignia separately and flat would likely result in better quality.

 

I have a considerable amount of info to discuss with the library staff.   Now I need to make smaller model sections.  This should be easier by reusing the original sketch.

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One advantage to the smaller pieces (more cuts) would be if one piece didn't print well, it would be quicker and easier to try different printing settings in an attempt to get a better print without having to reprint half the cannon. 

 

I honestly think either approach would work though.

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Had my meeting about 3D printing at the local Library this afternoon.  I brought in my list of suggestions supplied by one anonymous forum member (thank you again!) and it was very helpful.

 

Their machine is a 2 year old commercial printer.  I was told the 8 Mb file size limit is set by the Library's internet file transfer size limitation.  If I bring my files in on a thumb drive (stick) they can be any size I care to save them at.  By this logic I can split the gun into merely two pieces, a muzzle half and a breech half.  The split will be at the edge of the 2nd reinforcing ring just past the trunnion to keep the printing supports under the trunnion short.

 

We discussed printing the insignia flat as the wrapped version has a maximum offset of 0.01 inches (0.254mm) at 1:12 scale.  As the PLA filament diameter is  1.75mm (0.069"),  or x12 = 0.828 inches full size, this would be one layer of plastic on the machine bed.  They feel it would be very difficult to lift off without breaking it.  They asked if I could print it thicker (taller) part as two layers might be easier to "peel" off the bed.  I've just e-mailed them a couple more questions regarding this... trying to understand the difference between filament diameter (1.75mm) and layer height (0.15mm) as it relates to my build scale (1:12).

 

They also suggested I print a second breech end of the barrel with the insignia on.  They are not sure how this will turn out but they don't have any problem with trying.

 

So that is what I will do.  As Christmas is around the corner they are swamped with requests to print stocking stuffers.  I told them mine was not a Christmas present so I haven't any problem waiting.

 

Meanwhile (soon) I will cleanup the parts I have, acetone slovent weld them together and paint the insignia with my version of yellow ochre.  I am back to re-making frames for my 74 but won't be posting there until I have something worthwhile showing.

 

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Alan,

One of the suggestions earlier which may resolve the insignia issue, was to print the insignia flat, but thicker than required and sand it down to the desired thickness after you glue it on.

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I picked up my new 3D prints from the local library this afternoon.  This was extremely fast, they must have enjoyed the challenge.  It was different from the usual mundane items they print.

 

Two sections printed vertical (standing on end). One muzzle and two breeches with one version of the breech with the insignia.

This is what was on the note they sent me:

 

 In terms of the flat insignia, it didn't come out very clearly when we used the file's default thickness, but when we added another millimeter to its depth it came out much more clearly. You should be able to sand this thicker version down to get the look you want. The version of the breech with the insignia on it also looks surprisingly good.

All files were printed on the "Hyper" resolution setting with a layer height of 0.8mm. When printing the insignia, I slowed the print speed down to 20mm/s to ensure the details came out as precisely as possible.

 

They look a million times better than the earlier horizontally printed halves.

Judge for yourselves...

1 all pieces.png

2 barrel halves.png

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On 12/15/2018 at 4:18 PM, AON said:

I picked up my new 3D prints from the local library this afternoon.  This was extremely fast, they must have enjoyed the challenge.  It was different from the usual mundane items they print.

 

Two sections printed vertical (standing on end). One muzzle and two breeches with one version of the breech with the insignia.

This is what was on the note they sent me:

 

 In terms of the flat insignia, it didn't come out very clearly when we used the file's default thickness, but when we added another millimeter to its depth it came out much more clearly. You should be able to sand this thicker version down to get the look you want. The version of the breech with the insignia on it also looks surprisingly good.

All files were printed on the "Hyper" resolution setting with a layer height of 0.8mm. When printing the insignia, I slowed the print speed down to 20mm/s to ensure the details came out as precisely as possible.

 

They look a million times better than the earlier horizontally printed halves.

Judge for yourselves...

1 all pieces.png

2 barrel halves.png

Very nice.  From my 3d printing experience (MakerBot3), I would have done a couple of things differently.
For one, I would have made the trunion a separate item with a cast hole for it).
For another, I would have laid out the 3d model only semi-vertically about 5º skewed from the vertical, with all "appearance" items, crest, touch hole, etc., on the Positive Z face thus made (that to avoid issues with support structures).
Lastly, I would have set this up to fall on a suitable brass tube as an armature.  The brass tube could be blackened, but would provide rigidity and form to the construction. 

Come to think of it, I would have put a tapered overlap at the joins, too--but, I've also had problems with MakerBot not "respecting" model geometry dimensions.

 

But, that's just my 2¢

I think the texture turned out just fine.

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Alan

You are getting the hang of this! It becomes increasingly clear that this is not nearly as simple as just sending in an STL file. There is a major art to this, just like the art of understanding any other  tools like traditional lathes.

 

Mark

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