yet another Ferrari 1/8th F40 Engine

[Pouln]

Looking very nice, Nick. Put the valves in, run water through the block, get the pistons in and let it purr (or roar, but in scale).

[Pascal]

The parts that you made are really amazing.

 

It's hard to tell the difference between your parts and 1/1 scale parts (and that says a lot !)

 

 

[nick]

I wonder if I'll ever reach the stage where I DON'T underestimate how long these bloody CAD drawings take?

 

 

Cracking on and printing first block test print even though its not finished yet.

 

Nick

[nick]

Time for me to eat my words, I said yesterday I often print things flat, here is a classic example of why you don't:-

 

 

Physics always wins!

 

I know a few people are dipping a toe in the water (resin?) with this form of 3D printing so a quick explanation for them, the rest of you saner folk can talk amongst yourselves for a bit!

 

what happened here is suction, the build plate/last layer is way more sticky the FEP plate (the transparent tank bottom the UV/image comes through to expose the resin layer) so when the plate lifts it tears from the FEP not the plate/last layer - in theory!

 

and it generally does.

 

It still requires force to pull it away due to the very  slight stickyness of the FEP, but mostly suction, this is why printing closed cylinders or boxes is bad as you're effectively making a syringe full of resin that you need to pull away every layer.

 

So my failure above - the model is connected as little as possible by the build structure - think sprue, so you always want as few contact points as possible for cleanup afterwards. but this means the actually surface area connecting the model to the build structure and ultimately the build plate is very small indeed overall.

 

So when I printed the large, flat top surface of the the crankcase, this is relatively a very large surface in one layer, compared to the very small surface of all the contact points combined (the tips of the sticky out bits of the failed support structure) so the suction force required to pull this big flat surface off the FEP plate (I now know!) exceeded the mechanical strength of all the little contact points, so the model broke away as you can see.

 

so what do you do then?  tilt the model like this:

 

 

why? well tilting it reduces the maximum area printed at any one time.  So with the model flat, you can see here (circled in red) the slice 'wot dune for it' on my failed print:-

 

 

all that area being laid down in one hit creates a lot of suction

 

so by tilting, the area printed in a single layer can be greatly reduced, this is about the most  material laid done in one layer in the tilted version:-

 

 

so why not do this all the time? the 'cost'of resin printing is mostly time and with resin printing height = time, the taller something is, the longer it takes to print, unlike extrusion printing complexity and layer area doesn't matter.

 

so laying something flat produces the least height, therefore shortest print time, but it's always a trade against suction.

 

Tilting makes it higher (and therefore slower) but more reliable. 

 

 

Sorry every one else, hopefully some use to the resin newbies

 

 

Nick

 

 

 

[nick]

So just to back up the theory of my earlier post, here is the successful slanty print;-

 

 

regards

 

Nick

[Pouln]

This mishap was a pity, however, good that you were able to find the reason and correct it

[Microbike]

On 7/19/2020 at 7:32 PM, nick said:

Here is the link for the free hobbyist version as I mentioned in my earlier post:

 

https://www.autodesk.co.uk/campaigns/fusion-360-for-hobbyists

Awesome thank you Nick

[nick]

Put all the test pieces together for the first time

 

 

for the first time, I’m starting to think I may actually pull this off.

 

Nick

[Pascal]

Looking really good Nick, just a little tweak or 2 to make it excellent.

 

Sincerely

 

Pascal

[nick]

15 minutes ago, Pascal said:

Looking really good Nick, just a little tweak or 2 to make it excellent.

 

Sincerely

 

Pascal

it’s only a lash-up made out of my reject test pieces the real thing is in paint at the moment

 

Nick

[Pascal]

Those are reject pieces ?!? Wow, if you want to sell those, please let me know.

[nick]

Real heads in place now

 

 

Still haven’t cured my warping issues, I may need to play with exposure times a bit.

 

still working on the full version of the block

 

Regards

 

Nick

 

 

[Pouln]

Wow, this is looking like the real thing. Fantastic work, Nick.

[larchiefeng]

Just looking at it I can see that the fit between the block and heads is more precise and clean mating of the two surfaces compared to the Pocher parts. I can also see that the front and back engine plates have a lot more detail. I know that when installed into the frame and covered with all the external bits it’s probably going to disappear however, when you start with well fitting parts and build up from there, the overall end product is going to be much better no matter how much is seen. I just wish that I had the block and the front and rear covers so, could build my engine knowing that the basic foundation is well mated. Great work Nick!
 

[Sabrejet]

That alternator alone is a work of art. Is there a cottage industry waiting to burst out here? I for one would buy a 3D-printed 250 GT/GTO engine, even if I didn't have a kit for it to go into. Hint, hint.....

[Schwarz-Brot]

Well, be careful what you wish for. If you consider the hours spend on designing the parts a complete engine would cost you a fortune if anyone would make this a business.

 

Nick, your parts look really good for a newcomer to CAD design. I am really impressed. It shows what powerful tools the average guy has right now to work with. Obviously the time invest is high and leads to a shift in modelling from the real world into the digital domain, but the results are stunning.

[nick]

9 minutes ago, Schwarz-Brot said:

Well, be careful what you wish for. If you consider the hours spend on designing the parts a complete engine would cost you a fortune if anyone would make this a business.

The last two replies are very interesting, I am toying with the idea of producing something here I must admit. 
 

I am currently testing out my workflow to see how much I can bring the drawing time and effort down to make this viable. Shapr 3D is the key, it’s a lot quicker than PC based equivalents for the basics.  
 

im also still learning how to do this, and my technique is improving all the time. I spent days staring at a load of stills to start with not knowing where to start, now I can jump straight into most shapes fairly easily, and getting better all the time. 
 

im working on the induction system now, which paradoxically looked almost impossible to my untrained eye when I embarked on this, but turns out to be very easy now I have all the datum points from the rest of the engine. 
 

As you say, it won’t be cheap, but equally when you look at the rarity, cost and quality of Pocher and associated transmits, a small number of people are willing to pay these prices. 
 

the other appealing element is the print on demand nature of this, so no wasted stock, tooling costs etc. 
 

im also toying with the idea of downloadable commercial versions, but even the concept of DRM is not existent for 3D objects, it will come now doubt, when people see the potential and printers are good and widespread enough to need it. 
 

so watch this space. 
 

Nick

[Schwarz-Brot]

I did a printrun of very simple parts that needed to be done in multiples. https://www.britmodeller.com/forums/index.php?/topic/235077497-wire-locking-bolts-for-large-scale-vehicles/ 

 

Thus I could not simply print a lot and then ship them out - I had to ensure a consistent print quality and this was the main time consuming part - redesign, testprint, redesign, testprint. In the end it worked out fine and I did not intend to make real money from it, but it is really time consuming to get a design to the point of consistent and repeatable print quality. I now have the design at a point were I could simply print away and be sure it would come out fine, so further prints won't be a hazzle.

 

Next thing I always have in mind is the bad reputation any kit with poor fit receives. With large scale kits, especially Pocher, it is a real love-hate relationship. I wouldn't risk my reputation shipping out poor fitting or damaged parts.

 

3d Platforms usually give you the possibility to set a licensing option. Of course this won't prevent copying the files, but our community is quite small, so the risk is at a minimum imho.

 

You might want to check out our new 3d printing area - your topic would fit in there perfectly.

 

 

[Pouln]

13 hours ago, nick said:

im also toying with the idea of downloadable commercial versions, but even the concept of DRM is not existent for 3D objects, it will come now doubt, when people see the potential and printers are good and widespread enough to need it. 

Hmm, are saying that you cannot copyright the design one makes (the CAD work)? 
Not that it would be of help, because if someone breaks the copyright, you need lawyers to go after them and cost would be prohibitive.

[nick]

34 minutes ago, Pouln said:

Hmm, are saying that you cannot copyright the design one makes (the CAD work)? 
Not that it would be of help, because if someone breaks the copyright, you need lawyers to go after them and cost would be prohibitive.

No not copyright, the ability to prevent digitally redistribution, the way it works with kindle books, online movies etc, ie you Buy and download something for your own use and you can’t share it further with others. 

[Pouln]

Ah ok, I get it.

[nick]

The Devil, they say, is in the detail.

 

Whilst these may look the same as a week ago, there has been innumerable small tweaks to get them warp-free, correctly proportioned, generally looking right, and reliably printable.

 

I have also done more work on the finish and have finally arrived at something close to the crackle finish on the originals at this scale I think..

 

 

A normal, sane person probably can't see any difference to where I was a week ago, but I can

 

I will continue with the medication.

 

Regards,

 

Nick

[Matt Crane]

They look absolutely spot on!

[Pouln]

1 hour ago, nick said:

A normal, sane person probably can't see any difference to where I was a week ago, but I can

Well, I see that you have thinned the extruded circles around the plug seats (don’t know if I use anything like correct terminology😏) and the number seems to be a bit smaller.

Could you explain what you did to arrive at the surface finish that you have. It looks really good.

[nick]

2 hours ago, Pouln said:

Well, I see that you have thinned the extruded circles around the plug seats (don’t know if I use anything like correct terminology😏) and the number seems to be a bit smaller.

Could you explain what you did to arrive at the surface finish that you have. It looks really good.

After much experimenting I found lowering my airbrush pressure and misting MrSurfacer at arms length, allows droplets to form which builds up a slightly rough (but even) finish. I applied zero red colour in the same way with lots of light coats. 
 

Nick