More on the Topic of Interchangeable Nozzles

In previous posts there have been examples of things that I am doing with my new 0.25mm nozzles on my Ultimaker 2's and the Olson Block from 3DSolex (now being sold in the UK by GoodTube.   Two great examples are both 1:100 models that are part of my bling collection that I developed for the Flames of War community.

The Bailey Bridge is a particularly good use of interchangeable nozzles as the road part of the bridge is printed using 0.15mm layers from a 0.4mm nozzle and the detailed parts at 0.125mm layer height using the 0.25mm nozzle.  In the former case the extrusion width was default and in the latter case I forced it from the default of 0.3mm to 0.25mm.

The question is...knowing that you can force an extrusion width, though this is not optimal, what exactly would it mean in terms of print quality?  The answer can be seen below.

The lesson is obvious.  You can force the extrusion width down but you are going to lose quality.  This clearly makes sense when you think about plastic squirting out of the nozzle but I still wanted to see a picture.  Technically I should be using my 0.15mm nozzle instead of forcing the 0.25mm nozzle but that nozzle is a little too fussy for running as much as I run the 0.25mm nozzles.

Bailey Bridge Design Background

Once I decided to do the Bailey bridge I hit Google and look to for pictures and plans if possible. There was actually more than I expected to find. The challenge was finding any two that seem to agree with each other in terms of assembly. Given how long this general design has been around I guess this is understandable.

I decided to make my own hybrid to some extent in an attempt to meet my goals of making it 3D printable, as close as possible to the real thing, and easy (sort of) to assemble at 1:100 scale.  Obviously there are a number of compromises in the design to make this possible!

This illustration shows the key elements of the bridge.  There are a number of them that got lost on the way to 1:100 scale such as the End Post, Sway Brace, and the rest of the smaller parts.  The Raker got translated into Braces that support the Panel and are large enough to print and handle.  The Stringer left the building when I wisely decided to print a one piece road bed rather than one built from components (honest, I did think about it)!

These are various configurations that can be built from the basic building blocks.  I can support the Single-Single and Double-Single but the others would require some additional work and/or parts.

 My Base Plate vaguely resembles this one!

The Walk Way does not appear in that many of the diagrams but does in pictures.  I liked this one.

Transition from the first build to the second looks pretty good.  Am not sure what to do about the ramp to the walk way but that is the only issue remaining in terms of design change.  A little construction boo-boo in that one corner is a little higher than the others!

 First build...

...second build.  In the image viewer you can go back and forth between them... :-o

 Detail on the ramp we need to do something with.

 Note the Base Plate.  Looks just like the full scale version (not)!

 Detail on the road bed.

Thats it until the build instructions and then this model will be on sale.

Flames of War, 3D Printed, Bailey Bridge

I have had a long term interest in building models, from the typical airplanes and tanks of a young me, to radio controlled planes and boats as an older me.  The stuff that I have been doing for Flames of War is another avenue of that interest.  At the moment I am working on designing a 1:100 scale version of the famous Bailey Bridge of World War Two.

From Wikipedia:

• The Bailey bridge is a type of portable, pre-fabricated, truss bridge. It was developed by the British during World War II for military use and saw extensive use by British, Canadian and the American military engineering units.
• A Bailey bridge had the advantages of requiring no special tools or heavy equipment to assemble. The wood and steel bridge elements were small and light enough to be carried in trucks and lifted into place by hand, without requiring the use of a crane. The bridges were strong enough to carry tanks. Bailey bridges continue to be extensively used in civil engineering construction projects and to provide temporary crossings for foot and vehicle traffic.

I am doing the design in Sketchup from images of plans that I have found on the Internet.  I am trying to be as accurate as possible in terms of following the famous design, but I am obviously having to make allowances for the scale such that it be assemble-able, for the fact that I am 3D Printing the parts, and finally, that I want to minimize print time as much as possible.

I am at the point now where I have an initial design and have done a first complete assembly.  There are, obviously, some fit issues but you can still see where I am going with this model.  The bridge as I have chosen to construct this version, is neither fish nor fowl.  The original Baley Bridge would have been in one of several configurations, Single-Single, which I have chosen for one side, and Double Single which I have chosen for the other side!  I am not doing a Triple version though one could use the parts for a Double Single to create a Double Double.....!

Anyway, the bridge that I have constructed consists of two bridge segments which were 10 feet long making the bridge 20 feet (or 6.096 meters or in 1:100 scale a 60 millimeters).  Obviously we are talking assembly by tweezers here!

Once complete the bridge will be available, as a kit, on eBay with the other "bling" that I have created for the game Flames of War (which I don't even play)!

Flames Of War Bling - 3D Printed to Order

				Flames Of War Bling - 3D Printed to Order Flames Of War Bling - 3D Printed to Order in Toys & Games, Wargames & Role-Playing, Table Top/ Historical | eBay
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Here are some more images of this project.  In later posts I will talk more to the design and also how to assemble the model once I make it available.

More on this project:

Background

Flavors of the Bridge

Someone Said Field Kitchen?

Yes, why yes they did and so I designed and printed one!  This has really pushed the limit for what my printer can do with the 0.25mm nozzle upgrade that I installed from 3DSolex.

The entire set consists of the following items:

• Field kitchen trailer.  Based on a couple of pictures that Google provided when I searched for WW2 Field Kitchen.   Not intended to be based on something historically accurate!  It does have an oven and four burners though.
• Two gas bottles for the above (Google says that many of these portable kitchens were gas fired).
• Two jerry cans for fueling some warmers at the serving tables (no, I did not print warmers and the only reason these are here is because I had them but not used anywhere)
• Tent for serving the repast (Could be longer but took too long to print as it is).
• Four large tables for serving or dining (officers anyway).
• Four chairs for the officers.
• Assortment of crates (six or so).
• Two cabinets subdivided for storage.
• Two small tables or large shelves (depending on how they are placed)..
• Two trays of fresh bread.
• Four trays of Christmas Lunch (two of turkey and two of some huge fish that is native to FoW land).
• Four large pots with lids on.
• Four large pots with lids off (and two loose lids).

This collection has been listed on eBay and will be available on Thiniverse soon.

Flames Of War Bling - 3D Printed to Order

				Flames Of War Bling - 3D Printed to Order Flames Of War Bling - 3D Printed to Order in Toys & Games, Wargames & Role-Playing, Table Top/ Historical | eBay
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3D Printing in Air

One of the harder things to understand, or visualize, about how a 3D printer works is how it prints in air.  Or rather the fact that a 3D Printer (of my type, a fused filament fabrication (FFF) printer) has to employ some special techniques in order to print structures that would require it to print in the air.

An FFF based printer works by laying down layer after layer of plastic in little strands of plastic that are extruded following the plan calculated by a slicing program.  In a way you can think of building in bricks as being somewhat similar.  Each line of bricks representing a line of plastic.  Consider three types of structural elements:

• An overhang.  An overhang can be built using bricks as long as each course of bricks that extends into the overhang is only projected into that overhang a little beyond the previous course.  The next course of bricks will then keep the first course from falling.  Allowing the concrete to set before going to high is a good idea.   The same principal applies for building an overhang from extruded plastic.  A little at a time with active cooling so the plastic sets.
• An square opening (e.g. for a window or door).  In this case the brick layer has to use a support above the opening on which the courses of bricks are layed.  An FFF printer is capable of building it's own support by something called bridging.  The slicer knows that it needs to string threads of plastic across the opening and that is exactly what it does (using various tune-able settings to make it work).  Subsequent layers of plastic are then layered on top of the bridge.
• An arch.  For this type of shape a supporting structure must be built on which the brickwork is layed in a pattern where once the mortar has set the structure will be stable and the support removed.  An FFF printer can also print support structures that allow for complex shapes to be printed without concern for building layers or bridging a square opening.  There are a number of downsides to this approach however.  It takes a lot of extra time and plastic and all that extra plastic has to be removed...often leaving blemishes on the model being printed.

Here is a good article on the topic of designing for 3D Printing.

3D Printed Tank Related Bling (Flames of War) for Sale!

What started as a way to experiment with my new 0.25mm nozzles ended with having a selection of Flames of War bling for sale.   Note that there is now a minimum order of 20 quid for this bling due to the effort involved with small orders.  All proceeds benefit the MS Society. (except for the Bailey Bridge which will be at 50% until it renews).

The first of these eBay sales allows you to select a custom assortment of bling that will be printed to order:

Flames Of War Bling - 3D Printed to Order

				Flames Of War Bling - 3D Printed to Order Flames Of War Bling - 3D Printed to Order in Toys & Games, Wargames & Role-Playing, Table Top/ Historical | eBay
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An outhouse was added to the original collection....and a collection of fences and gates...and a finally a field kitchen!

Horse Drawn Wagon

Here is a another new addition to the collection.  It is a kit for a Horse Drawn Supply Wagon that is loosely based on one used by the Germans in WWII.  It is available for sale here on eBay  and for download here from Thingiverse.

Bailey Bridge

This is a relatively new, and large (read more expensive than the rest), addition to the collection.  It is a kit for a Bailey Bridge that is discussed here on this blog and is available for sale here on eBay.

More About the Bling Collection

The bling collection consists of over 20 different selections that can be mixed or matched.  Once I get an order the bling will be printed for that order.  Below is a table that details what is available (see eBay for costs)

Original Collection of Assorted Bling - Page 1 of 4
Name	Contains	Printed Items
Road Signs	3, 4, 5, 6 arrows + 2 extra leaves, 4 bases	10
Field HQ	Large table, crate, cab, radio, typewriter, 6 chairs	11
Tools	4 each of shovel, pick, axe, sledge	16
Barrels	8 barrels	8
Arty ammo crates	2 open /w lids, stack, 2 individual	7
Dragons teeth	12 whole, 6 broken	18
Crates	2 stacks, 4 singles (mixed large/small)	6
Belgian gates	2 gates	2
Antitank	4 Panzerfaust, 4 bazooka, 4 ammo	12
Czech hedgehogs	Discontinued	--
Utility poles	4 poles, 4 bases	8
Outhouse Addition - Page 2 of 4
Outhouse	Two outhouses (one open), burn barrel, shovel	4
Fences and Gates Addition - Page 3 of 4
Picket Fence	Three fence segments, one gate	4
Horizontal Fence	Four fence segments	4
Horizontal Fence Extras	Four short fence segments, two large gates	6
Vertical Fence	Three fence segments, one gate	4
Stone Wall	Two walls (front/back), one corner, small gate	5
Stone Wall Extras	Two short walls (front/back), two large gates	6
Field Kitchen Addition - Page 4 of 4
Field Kitchen	Trailer and accessories	29
Field Kitchen Extras	Tent and additional accessories	6
Field Kitchen All	Both of the above	35

These are not very profitable items to sell as they take a while to print and the price point competition seems to be for injection molded plastic...with which a 3D Printer can not compete.  That said I would like to see someone put some of the bling to work (and maybe share some pictures)!

Comments on Pricing

When I first listed these things I offered free shipping thinking that an order for just one item would be rare.   That turned out to not be the case as there have been a lot of single item orders.  Since I practically have to pay to sell these things by the ones I tried adding postage but offering a rebate in terms of good for orders of two or more items.   Well two of two buyers either did not understand the offer or did not want to take advantage of it.   Given that one of these buyers was for a single item I do still feel vindicated in taking some kind of action.  What I have decided to do, however, is simply increase all prices by a little to cover shipping but offer these items with "free shipping".  Trust me when I say that I am glad this is a hobby not a business!  Besides, half of anything sold goes to the MS Society, a charity for a disease that is close to me.

Shipment Costs
	< 5 GBP	> 5 < 15 GBP	> 15 GBP
United Kingdom	Free	Free	Free
Europe	1.5	0.5	Free
North America	2.5	1.5	Free
Australia/New Zealand	2.5	1.5	Free
South America	2.5	1.5	Free
Africa	2.5	1.5	Free
Asia	2.5	1.5	Free

Interchangeable Nozzles Still the Cat's Meow

I am still appreciating the hot end upgrade that I did on my two Ultimaker 2 printers.

The 3DSolex heater block makes changing nozzles a matter of seconds.   It makes it easy to switch between materials but I am finding it even more useful to be able to choose a nozzle size based on what I am printing.   One of the standard 0.4mm nozzles can usually be found on the printers but I love being able to switch to the 0.8mm or 0.6mm nozzles when I want to print a draft at 0.4mm or even higher or maybe a case or box for which a layer height of 0.3mm is just fine (like the one shown below).

I have started to collect nozzles so had to print myself a box for storage.  The little plastic squares remind me what nozzle is on what printer.

The top row are reserved for PLA and descend in size from left to right (1.0, 0.8, 0.6, 0.4, 0.25, 0.15mm).  The bottom row are the same sizes reserved for ABS but for the lower left which is a steel nozzle for carbon fiber reinforced filament.

My only complaint is that there is not a reseller in the UK.  I have an order in flight from the source in Norway but we are having some shipping problems (with stuff having gone astray) and I think that Carl is tired of me!   Hopefully we can get this sorted out as I want to complete my nozzle inventory primarily with additional PLA nozzles (0.25, 0.6, 0.8) so I can print the same size on both machines at the same time.

Speaking of 3DSolex.  It is not just the heater block and nozzles that I have purchased from them.  I also upgraded the newest of my printers with their steel coupler, I2K insulator to help protect the teflon coupler, and their bowden tube.  I have no way of measuring the effectiveness of these last products but based on how well the nozzles perform I am willing to go on faith!