28 cm SKL/40 (E) Eisenbahngeschütz Bruno 3D printed

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EPOCH3
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28 cm SKL/40 (E) Eisenbahngeschütz Bruno 3D printed

Post by EPOCH3 » 19 Jun 2017 17:45

Hi - for anyone interested in 3D printing models....

Over the last 4 years, I have used shapeways to 3D print several very complex models. Just as I was investigating buying a 3D printer, Shapeways came onto the scene and offered a way to gain access to world class printers at a reasonable cost. That process allowed me to begin exploring complex 3D printing and making several projects that I had always dreamed about building (namely the Rheinmetall 35.5cm M1 and 24cm K3).

Just after I started to use shapeways, they increased their prices fairly dramatically to better align with material costs. I spent a huge amount of time tailoring my 3D models to reduce material (to make affordable). Shapeways has just recently readjusted their prices and for trivial /simple things the price has gone down a bit but for anything complex requiring support material - the price has again dramatically increased. What was an $11 part is now $9 but what was a $200 part is now like $450. Printing complex items through Shapeways has now become cost prohibitive for me.

Due to Shapeways increasing prices, which would force me to remodel everything to now reduce support material as well, I decided to take the plunge and buy a Formlabs Form 2 3D printer to see if I could find a viable alternative to using Shapeways as a service provider. After two weeks of use I can say it's not perfect but it does have a lot of capability and possibilities.

First project I printed was the US 14" Model E railway gun in 1/35th scale (just because it was ready to go) - I am including several photos just to show the gray resin which was used for the first prints. The carriage had to be sectioned into 5 parts (and the barrel assy into 3) but that proved to be fairly easy and straightforward. I did decide to do the walkway sections through Shapeways because they have a million little holes in them and I don't think the Form 2 will handle that type of part very well (I'll do a test later though).

My second project on the Form 2 will be a 28cm SKL/40 (E) Eisenbahngeschütz Bruno in 1/35th scale- I decided to try the black resin this time since the manufacturers specs suggest that it is better for greater detail. I noticed that print times do increase using this material though. I decided to section Bruno up a bit more so that if I have to do some of the smaller details through shapeways, I can still do that. I am not sure whether the Form 2 will be able to so those smaller parts like ladder and railings yet. Attached is a picture of the front section which just finished printing - still has the supports attached which will be removed.

I will upload photos of the various sections of Bruno as they get finished -

Regards and Happy Modeling
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EPOCH3
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Re: 28cm SKL/40 (E) Eisenbahngeschütz Bruno 3D printed

Post by EPOCH3 » 19 Jun 2017 20:13

Hi - here is a pic of the front end after removing most of the supports...
I've made the carriage sections in a way that the parts will lock together like a puzzle (or at least that is the plan).


Regards
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EPOCH3
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Re: 28cm SKL/40 (E) Eisenbahngeschütz Bruno 3D printed

Post by EPOCH3 » 20 Jun 2017 11:44

Tail section as printed - I decided to do the rear enclosure separately so that I could do both a WWI and WWII version.
Also shown is a portion of the walkway details which came out fairly nice.

Regards
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EPOCH3
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Re: 28cm SKL/40 (E) Eisenbahngeschütz Bruno 3D printed

Post by EPOCH3 » 21 Jun 2017 19:17

Wiege and Rohr

There are three quality levels/settings on the Form 2 - essentially you define a better print by reducing the layer thickness.
The Form 2 supports layers of .1mm, .05mm and .025mm. I ran several parts at .05mm and they took much longer than expected. For these parts I chose .1mm layers and reduced the build time by several hours but details were a bit softer than at the .05mm layer. I had to split the Barrel into several parts to fit - the carrier/mount was built as a single part. Layer lines are there but barely - any coat of paint will hide them pretty well. Parts shown as built prior to clean up.
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EPOCH3
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Re: 28cm SKL/40 (E) Eisenbahngeschütz Bruno 3D printed

Post by EPOCH3 » 22 Jun 2017 17:42

Hi - for anyone interested....
I thought modelers thinking about buying a Form 2 might like something of a simple comparison so I am just sharing a quick picture of a test I did recently printing the same part on the Form2 and again through shapeways (for what it's worth).

While the part is for my 14" RR gun above, I am trying to determine how best to make the detailed parts for Bruno - attach/integrate them into larger but fewer pieces or print them separately and optimize the details available on the shapeways prints. At present, it looks like the happy solution will be print "some" of the detailed parts through shapeways but print the larger and simpler assemblies using the Form 2. The larger structural parts done on a Form 2 are about 1/10 the cost of doing them through Shapeways. Shapeways however offers superior details on the smaller parts.

I was amazed that the Form 2 even got close to the quality of the shapeways part and it's actually fairly good. The shapeways part is near perfect and every gear tooth looks great - the Form 2 printed everything but it was a bit warped after soaking in alcohol to clean it and did not print completely straight and true. Note: I am told that if I mix several types of Formlabs resins to come up with a more custom mix I can get a superior part which I will be testing in future. For me, I can live with slightly less sharpness of detail but having to cut away the supports on a tiny part is problematic. Such small parts can easily facture when you try to cut off supports. This is not a problem with the shapeways parts because a wax substance is used for support material and then it is melted away leaving the clean part.

The shapeways part cost about $9 (for the qty 4 parts sprued together). It would have been about $6 just for one so I simply made a few more for a little more money. The Form 2 material cost for the part was less than $1.

Also note: The slight layering lines seen on the Form 2 were only present on the part that was printed horizontally. When I reprinted the part at the recommended angles (which needs slightly more support material to do) no visible lines were seen.

Hope these little snippets help those investigating model making using 3D printers...
Regards
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EPOCH3
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Re: 28cm SKL/40 (E) Eisenbahngeschütz Bruno 3D printed

Post by EPOCH3 » 23 Jun 2017 14:45

Hi - a few pictures of the rear and center front tunnion sections after first cleaning.

I also included a picture showing the barrel assy dry fit into the trunnions in the center front section showing how the front end is taking shape.

Regards
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Re: 28cm SKL/40 (E) Eisenbahngeschütz Bruno 3D printed

Post by Model Maniac » 24 Jun 2017 14:36

Nice to see a kit that's not available in plastic. Your 28cm gun is smaller and its barrel much shorter than the Leopold.

3D printers have come a long way. But for bigger project like 80cm Dora Rail Gun 1:35 I think it's easier and cheaper to buy plastic kit. I've got one:

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Andrzej Ditrich
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Re: 28cm SKL/40 (E) Eisenbahngeschütz Bruno 3D printed

Post by Andrzej Ditrich » 25 Jun 2017 13:07

Thanks Greg for very interesting photos.
Lokooing forward to seeing new photos-espiecially complete Bruno.

Why printed parts are in "angled" position? Easier to print?
Is there a possibility to make a macro photo to see quality of print?

Regards
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panzer67
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Re: 28cm SKL/40 (E) Eisenbahngeschütz Bruno 3D printed

Post by panzer67 » 26 Jun 2017 02:12

great work¡¡¡¡
i did in scratch german railguns and have some in progress.
how long time takes you to print it?
is possible to sell a copy of the printed pieces? i dont have this bruno railgun...
part of my work is in armorama as panzer67,

EPOCH3
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Re: 28cm SKL/40 (E) Eisenbahngeschütz Bruno 3D printed

Post by EPOCH3 » 26 Jun 2017 14:56

Hi - just a quick response to print times.... So far the parts I have printed have taken about 30 hours in total to print. That varies with respect to layer thickness. For example, a part printed at .1mm layers that takes about 3 hours might take 7 hours at .5mm. Most parts have been built separately but I could have saved quite a bit of time by printing several parts at a time (like the barrel parts). I am just going slowly until I learn more about any potential problems to look out for so I don't want to waste material. Also, so far all parts have been printed using one resin cartridge so total material cost so far is about $120 (but that includes support material that is thrown away).

Regards

EPOCH3
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Re: 28cm SKL/40 (E) Eisenbahngeschütz Bruno 3D printed

Post by EPOCH3 » 26 Jun 2017 15:28

Hi - As I finish up the test prints for the Bruno carriage project, I am evaluating the pros and cons of having used the standard Black resin material. Overall, I am generally beginning to prefer the gray resin over the black. The gray looks to actually print in higher detail and the print times are shorter. I also seems to clean up better/easier. I decided to run a test print the other day and print a part in gray that I had already printed in the black resin. Attached you will see the front end part that I chose. You can compare it to the one in black resin that I previously posted. While the print failed - It actually looks quite good. Unfortunately a support failed towards the end of the print. I am going to see if I can salvage the part and reprint the missing corner - just as this week's challenge :) I'll let you know if it works.

Note: just to compare project costs between using the Form 2 and sending to Shapeways to print - the carriage parts I have printed and shown so far have cost me about $120 in materials. The same parts printed through Shapeways (at their new, higher prices) would have been $474 for the carriage parts and about $185 for the barrel and holder... so... that is about $659 using Shapeways vs $120 on the Form 2. Sort of looking like a fairly good investment.


Regards
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Andrzej Ditrich
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Re: 28cm SKL/40 (E) Eisenbahngeschütz Bruno 3D printed

Post by Andrzej Ditrich » 27 Jun 2017 07:12

Great work and very interesting informations-thanks!

EPOCH3
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Re: 28cm SKL/40 (E) Eisenbahngeschütz Bruno 3D printed

Post by EPOCH3 » 27 Jun 2017 21:47

Last sections of the main carriage printed along with a quick picture of parts printed so far - starting to look like Bruno.
Regards
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EPOCH3
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Re: 28cm SKL/40 (E) Eisenbahngeschütz Bruno 3D printed

Post by EPOCH3 » 03 Jul 2017 15:39

Hi - just a quick test building the pivot assembly in a 3rd party resin.
Formlabs sells a line of their own resins which runs from $149 to $399 per liter.
Makejuice sells a compatible resin for the Form 2 which costs about $60 per liter.
I purchased a liter to run a test in order to determine if it was acceptable for use
in the Form 2. The Form 2 has something called "open mode" that allows you
to use 3rd party resins. Several operational features of the printer are turned off
when you use open mode but it did allow me to use the makerjuice resin.

I made a barrel for my US 14" Model E RR gun and I was amazed that it printed
it so cylindrical that it almost looked like it had been turned on a lathe. I decided
to try it on a slightly more detailed part.

The major parts of the pivot assy are basically made up of cast steel pieces so I decided
that super high accuracy was not needed and decided it was a good candidate to use the
Makerjuice resin with. The bottom line is that both the detail as well as physical stiffness
are a bit soft. Thin areas are extremely flexible and almost rubber like - this can be addressed
by exposing the part to UV light. The small handwheel also did not print perfectly but I will
just reprint that part in the other material and replace it saving the overall part.

For now, the 3rd part resin will be used for parts like barrels where details are nil. Its
easy to change materials and it will allow me to save quite a bit on parts where detail
is less important.

Happy Modeling
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EPOCH3
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Re: 28cm SKL/40 (E) Eisenbahngeschütz Bruno 3D printed

Post by EPOCH3 » 09 Jul 2017 13:30

Hi - I made a boo boo and printed out the wrong version of this part.
By accident I printed a version with most of the rivets missing so I decided
to reprint using a mixture of two Formlabs resins combined at an 80/20 ratio.
A couple of areas have issues but only because the geometery was very thin.
I'll thicken up those areas in the file so if I reprint again they will have better
results. All in all, the I really like the surface texture and the results are about the
closest to injection mold quality that I have seen generated from a desktop
3D printer.

You have to replace a resin tray approx. every 1-2 liters of resin which is
another consumable cost associated with printing beyond resin. For this print,
I calculated that cost to be about $3.42. Cost in resin material is approx. $8.60
so the part shown cost approx. $12.02 to produce

Have a great weekend
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