DrDuncan's 3D workbench

[drduncan]

So, having been inspired by many others working in 3D CAD I have decided to have a go...

 

As always there were several ulterior motives. First being cash poor, I couldn't commission someone to do the CAD for me.  Also, with a large and very young family, modelling time is at a premium, and often occurs times when sub optimal alertness and concentration levels were to be expected.  Now writing off one's one physical models due to trying to build expensive kits, or do not so straight forward OO to EM RTR conversions, while trying not to fall asleep on the superglue or soldering iron (lets not go there again) is bad enough, but doing it to other peoples that you are building/converting as a favour is far, far worse.  So those friends of mine, including some who I know will be reading this, who are patiently (probably) waiting for locos please read reason 2 and 3.  Second, CAD comes with a back or undo button, so I can avoid destroying hours of work in one careless moment - if only real life where the same!.  Third, my work uses CAD software (even if I don't for my job), so I could do some modelling in my lunch hour without causing snags, even if bringing in DrDuncan's patent portable workshop wasn't possible without a hernia and serious questions about what I thought I was employed for.

 

So what happened?  

 

Lets just say the less said about the first attempt the better.   Suffice to say Blender was not the right choice for me!

 

Fortunately, Mike Oxon was doing great things with Fusion 360 (- which, like Blender, is free -) so I downloaded it and had a go.  

 

This was much better (although that isn't actually saying much given the abysmal experience of trying to use blender).  I decided that a D0 parallel boiler and belpaire firebox for an Aberdare Goods (and probably one of my Dean Single stash) was a bit ambitious for a first attempt, let alone the Broad Gauge 3521 0-4-4t, Hawthorn class 2-4-0st, and  Vulcan 0-6-0t that I have a hankering for, or the N gauge Great Bear I've promised my boy for next Christmas (if any 2mm f/s chaps have a set of Farish china made GWR Castle wheels going spare do let me know).  So I did a GWR 1 plank wagon.  

 

 

 

Actually, I did three: an 18ft one, a 16ft and a 15ft 6 inch one.  Printing them was another steep learning curve.  I did the first set without solebars out of laziness and a desire to get printing.  Having admired the lovely banana shape that occurred, I redid them with solebars - which almost worked; certainly Kipford liked the version with solebars enough to prof one at the EMGS skills day just before the Covid 19 lock down for some ghastly LNWR purpose.  But there was still a slight bend so I thickened the solebars up (there's plenty of space) and they are awaiting their turn in the printer queue.

 

While I was waiting for a couple of lifetimes to get time to sneak away to the printer and then for the 1 planks to print I finished off the CADs for a Broad Gauge 6 wheels fish truck with barred sides, and then its standard gauge successor.

 

Here is the BG version.  CAD was a success - eventually (and I've just noticed I forgot the bolt heads on the inside of the doors) - but the print was a disaster as it warped in every direction and those middle posts for the bars are ****ing fragile.  A redesign to incorporate underfloor strengthening is in order.  That said I'm rather pleased with it so far and can't wait to see it on the wharf side of Nampara.  

 

At the same time, I did the S7 (below) and had exactly the same problems with warping when I printed out both it and the BG version at the same time.  The S7 has been doctored since and hopefully the next print will be satisfactory.  Now my eldest (6 year old) son is the proud owner of an N gauge train set and is after Daddy to make some wagons for him...the S7 might be shrunk down to N/2mm if I think I can make the brass bars work at 0.3mm diameter and not break the print.   

(See I remembered the bolt heads this time)

 

Since then (the middle of March) the following have reached the point where I think they are ready for the printer:

 

A BG fish truck with guards box to osL182

 

A BG fish truck without the guards box to osL182, showing the strengthening and fixing points for the as yet unfinished cleminson chassis and cosmetic solebars/axle irons (which due to very careful choosing of the prototypes will work for all the BG 6 w stock so far.

A BG fish truck to osL343.  It might look like the osL182, but the doors are smaller and in a different position, and the ends are different!

 

Finally, there is a BG 4 plank open wagon.  This will use etched normal w -irons (as will the S7).  Why 3d something that exists and is probably better material wise? - (and I've got quite a few in my bits box...)

.

 

In the works are the cleminson bits, a BG 3 plank wagon (which I'm hacking about the 4 plank CAD to do and making a mess of it the moment), a Cornwall Mineral Railways china clay tippler wagon and (gulps) a T51 brake 3rd 6 wheel coach... and of course all those lovely locos and boilers!

 

Thanks for looking - all advice and comments gratefully received!

 

DrDuncan

Edited March 31, 2020 by drduncan
too many typos

[monkeysarefun]

I found Blender pre-version 2.8 to be impenetrable, and I've had 40 years plus experience using some pretty involved software, firstly geoscience applications and now defence related packages.  However it all clicked into place when they released the 2.8 version, the interface suddenly worked for me.

 

That said, I'm a believer in horses for courses and think that for straight line non-organic engineering type modelling - rolling stock etc - Fusion360 or Solidworks is much more appropriate.

 

I've been concentrating on architectural modelling lately and for that I find Sketchup to be the most attuned to that particular task - purely a personal preference though..  Its just great that there's such a choice of  sophisticated software out there and its mostly free to use!

[kipford]

Duncan

Bit more experience and you will be able to do this: 

The full CAD model of the Aspinall (5" gauge live steam for those who don't know).

 

Thanks for the single plank body saved me the hassle of modelling one up. I have a nice new LNWR  chassis to go underneath.

[JimFin]

On 31/03/2020 at 09:34, drduncan said:

This will use etched normal w -irons (as will the S7).  Why 3d something that exists and is probably better material wise? - (and I've got quite a few in my bits box...)

.

 

Very sensible approach.

[drduncan]

4 hours ago, kipford said:

Duncan

Bit more experience and you will be able to do this: 

The full CAD model of the Aspinall (5" gauge live steam for those who don't know).

 

Thanks for the single plank body saved me the hassle of modelling one up. I have a nice new LNWR  chassis to go underneath.

Can you shrink it to 4mm?

[drduncan]

42 minutes ago, JimFin said:

 

Very sensible approach.

Just occasionally I manage to find one!

 

Yet I do model Broad Gauge....

[kipford]

Quote

Can you shrink it to 4mm?

Yes but you could never make it. Conversely I have been asked if I would be prepared to supply my CAD model and etch artwork of the LNWR shunting engine for a gauge 3 model, that's 2 1/2" gauge the smallest scale where it is possible to passenger haul. I declined as you would essentially need to redesign the whole model to achieve a reasonable representation of the prototype. I know by the way because I am part way through a 5" gauge version of it, when I am not sorting out 3D printing stuff for Matts new layout. Keep up the good work I find CAD work very therapeutic. 

[MikeOxon]

On 31/03/2020 at 20:02, monkeysarefun said:

 

.... That said, I'm a believer in horses for courses and think that for straight line non-organic engineering type modelling - rolling stock etc - Fusion360 or Solidworks is much more appropriate. ...

 

 

It's very useful to read that sort of comparison.  I rather stumbled across 'Fusion 360' because I've used other 'Autodesk' products and have a feel for their way of working.  It's worth remembering that 'Fusion 360' is only free for personal use and becomes quite expensive if you want to produce models for sale.  It's been great for me, as a retired 'lone' modeller, and I hope they will feel able to continue their present policy.

[drduncan]

So I managed to get some printing done.

 

Much has been leant but there are also some questions that need answers.

 

First, the strengthening of the osL181 fish wagon was partially successful. Most of the bending has been eradicated but where the Cleminson components will fit there is still a problem which will need a rethink. Also the solitary posts at the side mid point are just too vulnerable and break when you look at them, so some sort of removable reinforcement until the brass wire bars are fitted is needed...

 

 

The osL182 with guards box was another partial success.  The warping has been cured but the chassis needs tweaking as the cleminson parts don’t fit at each end.

 

 

However, it printed with a hole in the guards box.

 

 

what causes this?   I also had corners missing from the single plank wagons buffer beams...and the cleminson middle axle base too.

 

Suggestions and advice very welcome!

 

drduncan

 

[MikeOxon]

Warping is somewhat inevitable when there are structures on one side of a flat surface with no opposite 'balancers'  The fact that you also mention the sides being very fragile suggests that you need to make everything a bit thicker, to provide more strength and resistance to warping.  It's very easy, in 'Fusion 360', to add fillets at the right-angle corners to reduce stresses at such points and improve overall strength.  I usually add some chassis members under the floor to help rigidity - I say 'add' but, in practice, I make the floor thicker and then recess areas between what will be left as chassis members.

 

You can try placing the model on a warm surface ( e.g. a container of hot water) and weight it to remove the warp and de-stress the material

 

I have not experienced holes like those you show on the cabin side.  If you use 'Cura' to slice your model for printing, it is worth looking at it closely in 'layer preview' to check for any glitches.  I mention some of the things to look for in this blog post.  It may be that the panels are just too thin. Otherwise it looks as though there might be a feed problem with your filament.

Edited April 15, 2020 by MikeOxon
add extra thoughts

[drduncan]

Hi Mike,

 

Thanks for the advice. I use preform as the printer software and I’ll look closely at it.

 

Regards

 

Duncan

[regme]

What printer did you get?

[drduncan]

I have access to a Form Labs Form 2 resin printer.

[MikeOxon]

1 hour ago, drduncan said:

I have access to a Form Labs Form 2 resin printer.

That means my comment about filament was wide of the mark!  That's a rather sophisticated printer that you're using.  I still suspect that your walls may be too thin - hence the holes and weakness of the sides.

[drduncan]

I think you're right.  I'll try thickening the problem areas.

Duncan

[drduncan]

So I’ve been playing around with various drawings in the printer and slowly fine tuning how to place supports to irradiate distortion as well as some judicious tweeting of the drawings.  
 

I thought I was getting close to having something that didn’t end up with bits of red sharpie on it to highlight things that needed correction.  And then this....

I think the printer got Covid crossed with galloping plague that was then attacked by a passing flame thrower given the pustules that are covering everything and melted stuff everywhere.

 

The observant will notice the mass of supports on the middle without any sign of a wagon attached to them...

 

 

What I presume was this wagon was found (or at least the floor) was found on the floor of the resin tank.

 

I think the tank got contaminated somehow....

 

Anyway spare tank fitted, the dodgy one put aside for social enquires with a red hot poker, and we’ll see if anything useable emerges!

 

DrDuncan

[MikeOxon]

This reminds me of the scenery in KH1's blog Up the Line-1918

 

[drduncan]

Hmmmm

[simonmcp]

3 hours ago, drduncan said:

So I’ve been playing around with various drawings in the printer and slowly fine tuning how to place supports to irradiate distortion as well as some judicious tweeting of the drawings.  
 

I thought I was getting close to having something that didn’t end up with bits of red sharpie on it to highlight things that needed correction.  And then this....

I think the printer got Covid crossed with galloping plague that was then attacked by a passing flame thrower given the pustules that are covering everything and melted stuff everywhere.

 

The observant will notice the mass of supports on the middle without any sign of a wagon attached to them...

 

 

What I presume was this wagon was found (or at least the floor) was found on the floor of the resin tank.

 

I think the tank got contaminated somehow....

 

Anyway spare tank fitted, the dodgy one put aside for social enquires with a red hot poker, and we’ll see if anything useable emerges!

 

DrDuncan

On the open wagon nearest the camera on the first photo you can see clearly where the print 'went rogue' but not on the fish wagon, were they printed together? The result looks very like my first attempts with my Aldi additive printer.

 

Simon

[drduncan]

Yes. Three different wagons on the same build plate

[kipford]

Duncan

Welcome to the club. This was the first print with a new resin. An after market build head support plus some judicious milling, making sure the resin an ambient temperature was not to low, mods to the supports fixed the issue and revising the exposure times  eventually sorted it out. Now its dialled in it is printing ok.

[drduncan]

Well, the new tank has made a great difference and I’ve now got a pair of GWR broad gauge convertible wagons - a 3 plank and a 4 plank.

 

 

Here is the 3 plank and you can see it balanced on the etched w irons.

 

 

Here is the underside showing the recesses for the W irons and the relatively little cleaning up of the support stubs.

 

 

And finally the 4 plank with w irons dropped in, at which point I realised that although I’ve made a BG axle spacing jig I need to design and print a buffer height jig to make sure all my maths was right in the design stage.  Probably should have thought of that earlier!!!!

 

DrDuncan

Edited May 30, 2020 by drduncan

[drduncan]

The osL182 fish truck with guard’s box also came out well (as did the ordinary osL182 and 343 lot fish trucks but the photos go over the 10mb limit so I’ll upload them later).

You can see it sitting on the inside framed cleminson chassis but without the sole bars fitted.

Here you can see the cleminson and again I need a buffer height jig to check the maths!

DrD

[MikeOxon]

It's good to see you have solved your printing problem.  The wagons look good and I'm interested to see you have printed a Cleminson chassis - something I've been thinking of trying for my 6-wheelers.

[drduncan]

Hi Mike,

 

Thanks for the post.
 

The cleminson works well dry, but assuming the ride Height it ok the centre axle needs work - not the carrier itself but how it fits Into the main under frame; it needs a short guide piece on each side to stop it twisting out of alignment. 40 thou square strip styrene should do it on the current bodies but any new designs will get the modifications 

D