Another Büssing

[finescalerr]

Lawrence's little tutorial is worth its weight in gold. -- Russ

[Lawrence@NZFinescale]

I take it the check (cheque) is in the mail?

[finescalerr]

Sorry, Lawrence. Only an invitation to go stand in the corner is in the mail. -- Russ

[Ray Dunakin]

I love that prototype vehicle! It's so funky looking! Sort of looks like a truck body mounted on a tractor.

[Peter_T1958]

Thanks all for your contributions!

Lawrence's little tutorial is worth its weight in gold. -- Russ

@Lawrence
Indeed, you are a huge help! I hope I understood all right and I will separate all complex parts into own files.
In the meantime I tried to arrange the supports with reference to your suggestions in Chitubox. Already turning the wheel and omitting the wheel spruds reduces the number of the supports quite a bit (It has still enough of them). Now I can modify some and fix them into the right place. And I will divide the wheel in some smaller parts too!

With spruds...


Without spruds ...
 

Now I have to go back to  my workbench – there is much to do!!

Peter

[Lawrence@NZFinescale]

Hi Peter

Hopefully Russ forgives this esoteric digression (or provides actual gold for it :-))

Yep, what you have here looks about typical for the conventional wisdom and should work.  There is a calculation to get the angle optimal for surface quality but provided the layer height equals the pixel dimension the answer is 45 degrees.

Note however that the purpose of support is not only to eliminate islands, but also to provide sufficient mechanical stability to resist peeling forces and prevent distortions of the part.  This is rather hard to predict with any precision and is generally resolved by trial and error. If the part does move you'll end up with prominent layer lines at points where forces changed significantly.  These are particularly annoying when printing at an angle as they are more obvious than they would be if horizontal to the model.

The conventional wisdom, as far as I can see, is predicated on 'I have a model I need to print', rather than 'I want to create a model from print optimised parts'.

The attached water vat could have been done in 1 piece more or less as you have done the wheel.  However I separated out the base and printed it upside down (the detailed face here is the bottom of the vat) ie NO support.  Note that it has a chamfered base to counteract the widened 'foot' that occurs with layers attached to the build plate. This is hidden in the assembled model. The vat was printed flat as shown with what I call knife edge support (shown here in green).  The contact area with the part is continuous, but optimised to be as thin as possible. Note however that it is vented to avoid hydraulic issues. After printing it is easily removed and the edge trued on a sanding board (the only clean up needed).  The steel hoops are added from monofilament later and sit in the printed location grooves.

This is my preferred approach to 'engineering' subjects.  Advantages are:
* print time is minimised
* resin volume is minimised
* clean up time is minimised
* print quality is typically optimised.
* quality on similarly angled faces is uniform (not always the case with a tilted build)
* mechanical stability is generally good and easier to predict.

It doesn't always present the best solution, but generally does.

I would look to do your wheel in 3 parts if I were doing it.
1. The tire - done as the vat above
2. The hub, rim and spokes divided into 2 or 3 parts - inner and outer -done as per the tank base.

For the hub parts you would need supports, but the attachment of these would be inside the wheel so less visible.  As the wheel is in multiple parts clean up would be very much easier.

In short, I would be designing part breakdown to minimise supports and optimise printing right from the outset.  You can print more or less anything.  The quality of the result, cost to get there and effort for clean up can vary a LOT depending on the efficiency of part design.

I hope this helps.  Optimising supports and orientation is another skill set to learn.  Hopefully your print supplier will advise or do it for you.

[Peter_T1958]

Now it isn't just a little tutorial; I am currently studying my first semester of 3d engineering 
Lawrence, thank you very much in advance for your support! I don't know if I can put all this into practise, but it will help me a lot on my way to better results. And, may be, my future provider of the heart will learn something new too

Kind regards
Peter (From the opposite side of the globe...)

[Lawrence@NZFinescale]

My pleasure.

In your case, where you want to scale up later, minimising supports will save you a lot of trouble as supports do not scale well.

[Peter_T1958]

Last year I mentioned that a French producer showed interest in printing a small batch of my Büssing in SLA technique. In the meantime the cooperation has grown steadily. This also means that I had to redesign the major parts, as he can print much smaller details and designig a kit demands much more then doing that for my own.



I tried to transfer Lawrences suggestions and I will save all parts in seperate files. The producer will recommend what can and cannot be put together




The rear wheel in 3 parts:  tire, rim and spokes and hub.

The only negative aspect will be the usual scale 1/35. Initially I had planned to print the vehicle in 1/25 scale ...

Cheers, Peter

[Ray Dunakin]

That's cool. Couldn't you still print some in 1/25th for yourself?

[Peter_T1958]

Couldn't you still print some in 1/25th for yourself?

Ray, of course I would still like to do so and I did a lot of attempts in the past month. However I have already invested a lot of money with very sobering results. So first I will look forward tot he results of my 1/35 scale model!





Here the same wheel experimentally arranged in Chitubox. From my point of view, that's a real improvement; there are much less supports and they are all on the back side oft he wheel.



Cheers, Peter
P.S. Coincidentally, today a new parcel arrived with some simple sencils to paint the wheels of my other (limping) project. Absolutely unusable – it is almost cheek !!!

[Lawrence@NZFinescale]

Ray, of course I would still like to do so and I did a lot of attempts in the past month. However I have already invested a lot of money with very sobering results. So first I will look forward to the results of my 1/35 scale model!

Well done Peter.

Welcome to the world of finescale 3D printing.  There is always one more tweak or improvement one can make and most finished models pose on a mountain of test pieces, failures and early versions.  Experience tells you what should work, but even so there are surprises (good and bad) and resins, settings and hardware can have a large effect.

[Peter_T1958]

Welcome to the world of finescale 3D printing.

Oh dear, things get serious! But I have to get through this stage now and that's why I am working restlessly on my first commercial project – huh!
But now that I have researched more then thirty years on subjects like that, I thought it's time now to share the collected knowledge in any form. I was therefore very pleased about the offer from this French producer:



@ Lawrence
Thanks a lot for your hint! I did some trials in « Blender» to realize this curtain:

[Lawrence@NZFinescale]

Nice job on the curtain.

I'm not sure I understand the first part of the post - Is that the advance notice for your kit or somebody else's?

Hopefully yours - and, if so, well done!

[Peter_T1958]

You are right, this was not clearly formulated. To be more precise: That is my kit which is produced by that company - I couldn't lift that by myself ...