134 replies to this topic

[Mini Manannán]

I like the MED bellmouth idea but Professor Pye wanted me to avoid it because of the air vent and mounting bolts on the face "we'll engineer one".  In the meantime I bought the Pipercross bellmouth.  According to Vizard's bible the intake will flow better than the Pipercross by 0.6% if it's a 'flat' bellmouth like the MED version.  

 

  We'd been fiddling around with an airbox design for a while when I remembered an application called Sketchup.  One night before xmas I started drawing a bellmouth [sub stack]:

 

 

It had a fatal flaw with the way I'd drawn it.  It drove me to drink   

I came back to it the next day and drew it again, and again,

 and again,

 and again,

 and again,

 and again...

 

It came back with the same result.    

So I joined a Sketchup forum.  After many naive questions I got a result:

 

 

I took it to Professor Pye, "It's too small, max out the width of the bell".  So I measured up the size of the virtual airbox and went back to drawing it:

 

 

At about this time we thought of 3D printing it.  We were muttering about this 3D printing malarkey when Sid rolled up at the shed and said his brother has a 3D printer!

  Only having the vaguest idea about the technique I went back to the Sketchup forum.  I was told you have to put in support materials on overhangs on desktop printers.  This really threw me, I'd have to put hundreds of supports in and around and under my beautiful bellmouth.   Then I was told that if I went to a commercial powder printer they would just blow the support powder off, job done.  So that was Sid's brother's desktop printer idea blown out of the water!

 

After another 8 hours or so I'd nearly pulled my hair out    trying to make the thing 'solid' for printing (coplanar surfaces, boolean differences, faceless edges etc.   ) trying to design in the mounting holes and vents I thought "balls to it, I'll machine the holes in afterwards" I was encouraged to design the holes in "The beauty of 3D printing is a finished model, straight off the printer."  

 

I went back to it and another 12 hours later (it's been a steep learning curve!) I have it:

 

 

 

 

I think it might be an absolute swine to fit, it all depends on how flexible 4mm thick printed ABS is???  I wonder if I need to do a version 12 with the bellmouth tapering down in thickness?...

 

 

 

[sixtyeight]

looks great, if you are having problems with sketchup, try autocad fusion 360, I'm pretty sure it is still free for hobby users.

[Alex_B]

I would second the need to get it printed in powder, on a desktop printer you wouldnt get the support out. 

incidentally most desktop printers will create their own supports when slicing for print 

[Mini Manannán]

looks great, if you are having problems with sketchup, try autocad fusion 360, I'm pretty sure it is still free for hobby users.

 

Is that simpler?  I'm just starting to get the hang of Sketchup.

[Mini Manannán]

I would second the need to get it printed in powder, on a desktop printer you wouldnt get the support out. 

incidentally most desktop printers will create their own supports when slicing for print 

 

Well I never knew they would create it for you!  Do you know much about it Alex?  Would it build supports in under the inside of bell?

[Alex_B]

 

I would second the need to get it printed in powder, on a desktop printer you wouldnt get the support out. 

incidentally most desktop printers will create their own supports when slicing for print 

 

Well I never knew they would create it for you!  Do you know much about it Alex?  Would it build supports in under the inside of bell?

 

Well I currently run a Davinci 3d printer and it uses its own slicing software (based on Slic3r) and that has the option of working out where you need supports, its not ideal on small parts (like for instance the collet grooves of a valve) but bigger things will work fine, but you have to think about the way the support material will come out after printing and the way yours is it would have to be in two bits, the mounting face and the bell so you could remove the support past the flange. If you want to send me the file (.stl ) I can run it through my machine and see if it will create the correct supports? 

and I dont know that much about 3d printing yet, only bought mine a few months back but I am quite fluent with CAD (only solidworks) 

 

Edited by Alex_B, 03 January 2015 - 11:50 PM.

[Orange-Phantom]

Looking very nice!

 

It always amazes me what you can do with a 3d printer these days, and they just keep getting better!

 

My stub stacks were made out of 4 solid billets of aluminium, a lathe and lot's of patience!

[Alex_B]

Looking very nice!

 

It always amazes me what you can do with a 3d printer these days, and they just keep getting better!

 

My stub stacks were made out of 4 solid billets of aluminium, a lathe and lot's of patience!

You may 3d print a substack like this but it wouldn't be usable on an engine as it is, still only useful for prototyping for this application currently 

[69k1100]

Why wouldn't it be useable? The petrol enters after the bellmouth so no issues with fuel, would need finishing to make the airflow smoother.

Www.shapeways.com

Try these guys. Also while you're at it, think about integrating threaded studs instead of holes. They will print but you will have to use a fairly coarse thread, print a wing nut to suit.

You can invesment cast them afterwards.

[Alex_B]

Why wouldn't it be useable? The petrol enters after the bellmouth so no issues with fuel, would need finishing to make the airflow smoother.

Www.shapeways.com

Try these guys. Also while you're at it, think about integrating threaded studs instead of holes. They will print but you will have to use a fairly coarse thread, print a wing nut to suit.

You can invesment cast them afterwards.

Heat, It doesn't take much to melt the plastic enough for it to deform. 

Abs filament extrudes about 200'c but it will deform below this temp I would imagine. 

I would however be up for trying it. When I don't have a tonne of uni assignments I might print myself one and see if it works

[69k1100]

Abs melts well below 200 degrees. Nylon (sintered) will Melt around 200 degrees so it will be much more stable. If you sinter over extrude the part will be porous too, so you can impregnate it with resin, further developing its strength.

Or if you're really mental then print in out of ceramic :) also on shapeways. Or stainless steel :) shipping is around 20$ To aus, other than that you get charged by the cc.

[Mini Manannán]

$428 in SS from shapeways!  Perhaps not...  The bellmouth would be going inside an airbox so I thought ~180°C would be OK?

[Mini Manannán]

 

 

I would second the need to get it printed in powder, on a desktop printer you wouldnt get the support out. 

incidentally most desktop printers will create their own supports when slicing for print 

 

Well I never knew they would create it for you!  Do you know much about it Alex?  Would it build supports in under the inside of bell?

 

Well I currently run a Davinci 3d printer and it uses its own slicing software (based on Slic3r) and that has the option of working out where you need supports, its not ideal on small parts (like for instance the collet grooves of a valve) but bigger things will work fine, but you have to think about the way the support material will come out after printing and the way yours is it would have to be in two bits, the mounting face and the bell so you could remove the support past the flange. If you want to send me the file (.stl ) I can run it through my machine and see if it will create the correct supports? 

and I dont know that much about 3d printing yet, only bought mine a few months back but I am quite fluent with CAD (only solidworks) 

 

 

 

I'll leave a file on my Google Drive account, if any members want it send me a PM

Edited by Mini Manannán, 21 September 2020 - 02:33 PM.

[69k1100]

Sure it will be expensive if it's 4mm thick.

[Mini Manannán]

Sure it will be expensive if it's 4mm thick.

 

Do you know what a realistic thickness is?  I plucked 4mm out of the air as a guess.