3 D Printing 16mm models

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Trevor Thompson
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3 D Printing 16mm models

Post by Trevor Thompson » Wed Aug 19, 2020 10:05 pm

There seems to be very little on the forum about using 3 D printing as part of our hobby. Certainly there is nothing to encourage anyone to use it to make a significant impact on a garden railway.

Perhaps its time to change that.

I am currently creating a model of the Kerr Stuart 4415 diesel, (among other things) and I intend to explain the design and build process I am using.

Firstly let me explain what I have made using a fairly cheap printer since I persuaded my wife that it would be a good Christmas Present!

Everyone who buys a 3 D printer seems to make skip wagons downloaded from the internet. I certainly did. That left me wanting a typical contractors locomotive - and I didn't like what I found on line. So I started to work up my own design using 3 D modelling software (sketchup make which seems fairly universal in this context). Hence the model of the Kerr Stewart Wren:
IMG_0569.jpg
IMG_0584.jpg
Note that I produced the 3 D CAD files for this, converted it into printer code and printed it ( as well as making and painting it). Just to emphasise this - it isn't a kit.

So what else have I done.

Wooden Festiniog slate wagons based on a drawing in Vol 2 of Boyles book:
IMG_0615.jpg
Wooden Festiniog coal wagons based on the drawing in the 16mm Association guide to the Festiniog:

IMG_0614.jpg
Bolster wagons which appear in a photo in the same document: Note the slates are indifidual slates printed in a block - and they do fall apart into individual slates!

IMG_0617.jpg
And of course I could hardly forget to mention the model of Spooners Boat:
IMG_0618.jpg
I can't pretend to be an expert in CAD or anything else related to this, but I am satisfied with what I have been able to produce so far. On the other hand perhaps i have something worth sharing. So lets go back to the beginning and look at the process I am going through to create the model of the diesel Kerr Stuart 4415.

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Re: 3 D Printing 16mm models

Post by Trevor Thompson » Wed Aug 19, 2020 11:17 pm

So to the Kerr Stuart 4415.

The starting point was a set of drawings which are on line. The locomotive is currently under restoration in Boston Lodge - and there are blogs online and on Facebook.

There are plenty of videos on uTube which explain how to use Sketchup - but they all concentrate on making a simple house of an indeterminate size. They were of little help when I was learning. Bit by bit I hope to describe the things I wish I had known when I started!


Having the drawings you can import them into Sketchup, scale and orientate them correctly so that they almost form the outline of the model:


drawings.jpg
The big advantage of doing this is that you can trace the outline of the components on top of the drawing and it will automatically place the things you draw on top of the drawing. All drawing packages have tools for drawing lines, rectangles and circles. The trouble with a 3 D package is how to force the software to make the drawing in the plane you want it in. Doing it this way sorts that out. Anything drawn on the side view is aligned to the side face. Anything drawn on the end view is aligned to the end view. Of course so far we have something which is flat, 2 dimensional. There is a tool in Sketchup which allows the flat shape to be pulled or extruded into the third dimension. So a square becomes a cube. It becomes three dimensional. The whole model is built up from lines, rectangles, circles and the like, extruded and altered to fit what you want. Just as a taster, here is the finished CAD image of the finished model ready to be converted into print files.
Kerr Stuart 4415.jpg
Having created the extruded version of the part you want to make, you have to move it into the place where it is to go in the final model. To help with this you can create guide lines using a tape measure tool. You can control where the part moves by holding down the directional buttons on the keyboard, before moving the mouse.

There is a function in a menu called "instructor" - if you click on this it brings up a menu at the side of the screen which tells you how to use each command. I still use it when I need further guidance - but to begin with it was most helpful.

So looking at the locomotive again. Drawing over the side elevation I created an outline of the side of the footplate. My using the tape measure tool over the end view drawing I worked out how wide the footplate should be. Using the pulling tool that square was extruded into a box, by holding down the mouse button and scrolling. Letting go of the mouse, I typed in the width in mm and pressed enter. The box is automatically extruded to the correct width. In a similar way the sides of the footplate, perhaps better described as the frames, were created. They are formed from three rectangles, and some lines to make the angled edges. Unwanted parts of the boxes were then deleted. the shape was moved into the correct place:

frames.jpg
Another important point. Sketchup joins things together. If you draw two cubes and move one to the other it joins them together. If you then move one the whole thing distorts. The bits which touched "glued together". So its important to make "components - it is in the edit menue. So the footplate is one component. The frame side is another component. A secondary advantage of using components is that you can make a frame side once and use it twice. But you have to "flip" it - that is a sub menu under the components menu in the edit menu. (perhaps that is enough to help you locate it). Having created a component I can go back and edit it later. If a frame spacer needs to be 2 mm wider, I can edit the one component and every frame spacer will have the new width. Of course the frames then have to both be moved manually. Incidentally I did make the frame as a simple rectangle early on - and went back to edit the component a number of times later. The upstands were part of preparing the finished model for printing. Something to locate the body against.

You can see that I am cheating - I am hiding parts of the model and showing you relevant bits. So the footplate has a hole for the gearbox to poke through, and up stands to locate the bodywork, which have all been added later. There is also an image of the bearing on the front end of the frame. You can also see my standardised version of an early form of the chopper coupling used on the Festiniog. Yes I am printing chopper couplings, including the hook. I also make my own hooks for the slate wagon couplings in the last post. They seem quite strong enough to work on my railway (which has 1 in 60 inclines). I am standardising on using them on locomotives and coaches. I am also making all the wheels I use.

As an aside here is a photo of straight and curly spoked wagon wheels used on those wagons:
IMG_0619.jpg
More of this to follow!

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Re: 3 D Printing 16mm models

Post by philipy » Thu Aug 20, 2020 6:53 am

Nice post, thanks. Looking forward to the next one.

Interesting idea to use the 2D drawings as a template, I've never seen that concept described anywhere before, and certainly never tried it myself. Definitely food for thought. The curly spoke wgon wheels look very good as well.
However, I must take slight exception to your opening comment "There seems to be very little on the forum about using 3 D printing as part of our hobby. Certainly there is nothing to encourage anyone to use it to make a significant impact on a garden railway.". It depends on the definition of 'very little' of course, but quick search for "3 D Printing" brings up 373 references. There are at least half dozen members that I know of, who actively use a 3 D printer as a modelling tool and in my experience we are all more than willing to help and share info, either on the forum or privately.

Having said all that, it is a balancing act. For much of the membership there is little more than passing interest for various reasons from lack of money to a dedication to more traditional modelling/engineering techniques. So it's refreshing to see somebody such as yourself 'de-lurk' and wade in with new idea's. :D

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Re: 3 D Printing 16mm models

Post by ge_rik » Thu Aug 20, 2020 9:11 am

Hi Trevor
A fascinating thread. I struggled with SketchUp. I managed to use the draw tools and extrude the shapes into the third dimension but when I tried importing the drawings into my slicer program (Cura), I ran into myriad problems with reversed faces and non manifold shapes. Philip has been great in helping me sort out the issues but I seem to have a conceptual block when it comes to figuring out how to avoid making errors in SketchUp. I chickened out and have started using TinkerCAD, which is designed for kids to use and so seems to suit the way I think and learn.

I'll be interested in seeing how you overcame the sorts of problems I ran into.

Rik
Last edited by ge_rik on Thu Aug 20, 2020 9:26 am, edited 1 time in total.
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Re: 3 D Printing 16mm models

Post by ge_rik » Thu Aug 20, 2020 9:13 am

BTW What printer are you using? The quality of your prints suggests you are either using a good quality machine or you have set it up perfectly - or maybe it's a combination of both

Rik

PS Just re-read your first post and see you are using a cheap printer. Mine cost £80 but I've probably spent another £50 and more than a few hours trying to improve the quality of the prints it churns out. The prints are improving but nowhere near the quality of your wheels.
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Re: 3 D Printing 16mm models

Post by Trevor Thompson » Thu Aug 20, 2020 9:59 am

I suppose its appropriate to digress slightly and answer the question about printing.

Firstly what printer? I bought a Flashforge Adventurer 3. Its Chinese - and I would have preferred something made elsewhere. However I seem to have stumbled on a make which has a high reputation - particularly for its professional range of printers. When I said cheap - its relative - about £300.

Some details: it can print a model 150 mm x 150mm x 150mm. Not big enough but its all about price. I thought it better to spend as much as I could get away with rather than as much as I would have wanted to spend. The key features for me are that it has a heated build plate, which can heat to 100 C, and an extruder that works up to 230 C. It has an enclosure - so it holds heat in (and hopefully any smell of hot plastic). It also has a built in compartment for the roll of filament. All very neat.
Disadvantage of that is it is intended for 0.5 kg rolls - and its cheaper to buy it in 1 kg rolls. I just transfer it to a small reel with a lash up in a vice.

I am using ABS - and that needs a heated bed. Why? You can glue the parts together with Acetone. Just like we use solvent glues to fix plastic kits together. Incidentally I have found that they can be dismantled as will the same way!

This printer is what is referred to today by that horrible term "an entry level model", in real words it is straightforward. The build plate doesn't need levelling - it puts down a "raft" - a thick layer of plastic to create its own level area each time. More expensive in filament - but cheaper to make and less to go wrong. It has a replacement extruder as a complete unit - press a button it falls out and a new unit fits in. More expensive as a replacement part - but less hassle to get the replacement fitted correctly. The heated bed has a removable flexible plate on it - which has a "rough" surface to which the plastic sticks well - but can be made to come free without causing damage. That can also be replaced at a reasonable price. Adhesion to the bed when printing is a potential problem when printing with ABS. This printer handles ABS well.

It has its own slicing software which uses predefined settings. I can make changes, and have occasionally. However mostly it just works first time.

So I seem to have accidentally hit a good product for my use!

This is the main part of the footplate for the 4415 being printed. This part takes 3 hours to print. The other part almost 2 hours. This loco is over 200 mm long - and i am having to cut some of the components into two parts to print them. I suppose its worth adding that additive 3 D printing isn't seen as a production process. It is really only of use in industry as a prototyping technique. You can see why - it takes ages just to make the footplate!

IMG_0689.jpg
More Later!

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Re: 3 D Printing 16mm models

Post by Trevor Thompson » Thu Aug 20, 2020 11:23 am

Philip

I hope I have not caused offence anywhere. I struggled to know how to start this off.

Perhaps I should have said that I couldn't find what I was looking for on any forum or online. That doesn't mean I found everything that was there.

As far as modelling techniques go 3 D printing has many advantages.

Photo of a scratch built Ashbury 4 wheel coach with 2 printed ones. The hand built one is painted. I want to make Festiniog coach 16 to go alongside the scratch built coach 15. 15 took months to make, and repeating it has put me off for 2 years. I am now drawing the CAD files.
IMG_0690.jpg
Having drawn the Ashbury 1st coach the 3rd class was easy - delete 2 windows

It also augments traditional techniques. Tender inserts for holding the batteries and electronics in a steam model of Linda:

IMG_0691.jpg
The final top layer will cover the whole tender and have coal stuck on it.

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Re: 3 D Printing 16mm models

Post by philipy » Thu Aug 20, 2020 12:00 pm

Trevor Thompson wrote:
Thu Aug 20, 2020 11:23 am
Philip

I hope I have not caused offence anywhere. I struggled to know how to start this off.

Perhaps I should have said that I couldn't find what I was looking for on any forum or online.
No, not in the slightest as far as I am concerned. :D
What were you looking for, though, out of interest?

I just wondered whether you had looked at back threads. Not blowing my own trumpet but I've posted about printing everything from a waiting room fire, via an underground water manifold for a stream, to wagons and a modified Thingiverse diesel. Rik did a longish thread about his diesels and others have posted about bridges, loco's and other rolling stock and parts.
However your projects look extremely fine and I'm looking forward to more - those two coaches look very tasty.

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Re: 3 D Printing 16mm models

Post by ge_rik » Thu Aug 20, 2020 12:41 pm

Yes please, the more info about 3D printing the better as far as I'm concerned. I'm still feeling my way with this technology and so I am trying to read and absorb as much info as I can, particularly when it comes to drawing and printing my own creations.

Window frames and railcar seats are as far as I've got - though I did manage to draw and print the sides of a closed van. Unfortunately, when I tried drawing the ends of the van I got the dreaded "Not manifold" message, even though, as far as I could see, I drew the ends in exactly the same way I'd drawn the sides.

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Re: 3 D Printing 16mm models

Post by Trevor Thompson » Thu Aug 20, 2020 3:31 pm

What were you looking for, though, out of interest?

Well If I am honest I was looking for someone to tell me how to make coach sides with external panelling. Like this:
Ashbury 4 wheel  1st coach.jpg
Or locomotives like this:
Welsh Pony.jpg
I know it was unrealistic - but I just wanted something to point me in the right direction. To give me a starting point.

As for back threads I had found some - I had seen something from Rick on making seats for a railbus if I remember correctly. So you are correct and I will go looking for what I have missed.

I just wondered whether you had looked at back threads. Not blowing my own trumpet but I've posted about printing everything from a waiting room fire, via an underground water manifold for a stream, to wagons and a modified Thingiverse diesel. Rik did a longish thread about his diesels and others have posted about bridges, loco's and other rolling stock and parts.
However your projects look extremely fine and I'm looking forward to more - those two coaches look very tasty.
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Re: 3 D Printing 16mm models

Post by Trevor Thompson » Thu Aug 20, 2020 3:47 pm

Rick

I presume you were using Sketchup to draw the wagon?

I struggled for a month with sketchup to begin with. I even resorted to a trial copy of Autocad but that was just mind-blowing. I then did research on uTube, looking through all the instruction videos.

The key piece of information I got from an American source was to start off in 2 dimensions and ignore the third. The trick is to go to Camera, and select "top" from the "list of Standard views". Now you are looking down at the origin of the drawing. Everything you now draw will be a plan. You can pull and push it later into a 3 d object. You can do the same with the front view from the same place. Now you can draw the end of the wagon.

You can move it into the right place later.

However importing the drawings has changed all of that. as long as you spend time to scale them, and position them they make it all much easier.

There remains the issue of moving things accurately in Sketchup. It still takes me a while to get them where I want them. Even pressing the up arrow on the keyboard (which should constrain movement to up and down) doesn't always do that and the object just slides away to the side. The only solution I have found is to go to the appropriate camera view and move in the 2 dimensions that shows. Then change to a different view and move again. Takes a few attempts before it goes where I want and not where the software wants!

Scale is something that is rarely mentioned on uTube. My solution was to dimension everything (I mean add dimensions to every side) and change its size until it was the size I wanted. Tracing from the scaled drawing is much easier.

Trevor

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Re: 3 D Printing 16mm models

Post by metalmuncher » Thu Aug 20, 2020 4:32 pm

Importing scale drawings is an excellent tip. I did this for my Hudswell Clarke, it definitely sped up the modelling. Most modeling software will have some functionality to import images into the 3D space to trace off. I am using Fusion 360, their system is called "canvases," so if anyone trying Fusion wants to try modelling off drawings, that's the keyword to Google for more information.

While I haven't used Sketchup in a while, I seem to recall there was some system for aligning photographs to your sketchup model. With that, you could just trace over a photo to draw the model. I think it worked best with squarer objects like buildings.
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Re: 3 D Printing 16mm models

Post by philipy » Thu Aug 20, 2020 5:33 pm

Trevor Thompson wrote:
Thu Aug 20, 2020 3:47 pm


There remains the issue of moving things accurately in Sketchup. It still takes me a while to get them where I want them. Even pressing the up arrow on the keyboard (which should constrain movement to up and down) doesn't always do that and the object just slides away to the side.
I've found that positioning things can be a pain, as you say. I usually 'group' the item/object first, then draw a simple line, or two, aligned to where I want it to go and simply move it. It will normally align itself to that line, or intersection, without too much problem. The thing I REALLY struggle with is rotating an object, it can sometimes take me best part of half an hour to get what I want although it will always rotate to one of the other two planes that I don't want!
Trevor Thompson wrote:
Thu Aug 20, 2020 3:47 pm

Scale is something that is rarely mentioned on uTube. My solution was to dimension everything (I mean add dimensions to every side) and change its size until it was the size I wanted. Tracing from the scaled drawing is much easier.

Trevor
Scaling in SU is pretty easy IMO. It doesn't matter what scale you draw in as long as it's constant in all three dimensions. Then simply use the Tape Measure to reset one dimension to a known figure and it will ask if you want to resize the drawing, say yes and it changes all three dimensions in the same proportions. Alternatively, the Scale tool allows you to change the scale of the whole thing, or selectively in any direction.

BTW, thanks for the Camera --> Top, tip. I don't think I've ever used the Camera tab.

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Re: 3 D Printing 16mm models

Post by Trevor Thompson » Thu Aug 20, 2020 7:36 pm

The Hudswell `Clark loco looks very nice.

I suppose the issue of scaling was about making things to a consistent size - particularly to begin with. I agree that it is easy - when you know how. I just didn't know,

As far as rotating things the same Camera solution seems to help. It seems to tell it which plane you want to rotate in.

Trevor

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Re: 3 D Printing 16mm models

Post by Trevor Thompson » Thu Aug 20, 2020 8:00 pm

The idea if drawing on top of the imported drawing makes adding detail easy for example the side of the engine casing with its rivets and sandboxes.

Firstly I drew the basic outline of the side of the engine box, and pulled it to 2mm thick I made it into a component and moved it to where one of them should be. I copied it and pasted it. Then moved the second copy to where the other side goes.

I then went back to the imported drawing and created a circle the same size as one of the rivets. Zoomed in to make it big enough to work with. If its too small you get an error message not a circle. Say 1mm diameter, which means entering 0.5mm (radius) and pressing enter. I then pulled it 0.5mm. Saved it as side rivet. (I find it quicker to draw another rivet when you come to the end view and give it a different name) Now I can copy and past it on top of each rivet. If there are lots I copy the first 3 and past them 3 at a time. I built up the detail on the drawing until I was happy with it. At this stage it isn't connected with any other object and is easy to change.

When I was satisfied I selected all of the details and cut them. I then went to one of the sides I had made earlier and double clicked it which allows me to edit the component. I then "pasted in place" which added the detail into the component. I selected the second component ( the detail is on its inside face at the moment) and "flipped " it in the relevant plane. (I can never remember which plane it should be so I try one - undo if its wrong and try the next until the detail is on the other side).

So what I am creating has all of the detail - all of the rivets in the right place and it was easy to do - if a bit laborious.

Some thoughts on "Solid inspector" which Rick said he had problems with. I find it more successful to use it on individual components. It works best when the component is made up in the simplest way, and seems more likely to fail to sort issues when I have repeatedly altered the component.

The warning about "nested objects" seems to have no effect in the printed object so I ignore that one. My slicing software can repair models - and often seems to want to when solid inspector says they are "all shiny". Letting it repair models doesn't always repair anything it just changes things. For example filling the windows you spent ages drawing. So if in doubt I try printing the unrepared item.

Trevor

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