M900 exhaust Flange - Page 5

slob · 23-01-2021, 12:28 PM

just thinking about it , using an OEM part to make a plug is problematic, myfordboy mentions oversizing the model by 4% to allow for shrinkage, easily done with CAD ... select part, then menu > scale

Mr Gazza · 23-01-2021, 01:38 PM

I'd thought about the shrinkage, but I thought he said 2%? Either way it's about a mil all round on a valve cover.
I thought about gluing a 1.5mm ply "gasket" on the gasket face and leaving that about a mil or whatever, oversized on the outline, then either adding filler carefully round the periphery or gluing a strip of thin plastic of some sort round the edge.. Maybe even roll some plasticine out to a thickness and add that? It's only the overall of the gasket face that would matter I think.
The inside could be carved out with a burr if required for clearance or at least to save some weight.

Your models are looking better and hats off to your CAD skills. Hand filing the rounds on the fins would save a lot of both cadding and machining. Agreed there are plenty of UK based CNC outfits.

Equally as easy to add mdf fins to an exhaust ring for a pattern? Shrinkage probably not an issue on those?

Yet another way to do this is to make a physical model with oem parts with bits stuck on, then get it "cloud plotted". Some of the CNC outfits have that capability.

slob · 23-01-2021, 02:03 PM

Yup, you're right, 2%

crust · 23-01-2021, 02:49 PM

You'll be needing one of these then.

https://www.artisanfoundry.co.uk/pro...roducts_id=206

One of my mates has a showmans steam engine, getting parts made usually involves a lot of discussions about shrink rates and how its not always as simple as adding a percentage.

We have the same issues with plastic part design and mould tools.

The material does not shrink universally in the same direction, so in the case of the fins on the exhaust flange it will shrink to the center of the fin causing sinks around the internal face.

slob · 24-01-2021, 08:06 PM

Something like this maybe?

Mr Gazza · 25-01-2021, 12:32 PM

Good innit.

Fins are spot on. There seems to be at least two versions of the finning on the bevels. Some have the centre three fins raised quite tall at the crankcase end, others are just like your model.
I'd so love to get stuck into this project, but business is booming at the moment and spare time has evaporated! I'm not complaining about that as it will suddenly dry up one day, but all work and no play makes Gazza a frustrated boy!

Luddite · 25-01-2021, 02:05 PM

I'm really impressed by your CAD skills, Rob. I used to enjoy technical drawing at school but it would take me about three weeks to draw one bolt!

Seeing your creations, I'm almost tempted to get a computer just to have a play around myself...

pooh · 28-01-2021, 11:44 PM

Slob
Could the valve covers not be plastic printed using high temp material?

Pooh

Mr Gazza · 29-01-2021, 08:50 AM

Pooh. I think you can have just about whatever you want.
When UKMOC had a VIP tour of the BBMF at RAF Coningsby, we also had an extremely privileged tour of the BAE hanger where the Typhoons are serviced and commissioned.
We were told by the head honcho that the canards (fore planes) are 3D printed in Titanium with a honeycomb interior.

slob · 29-01-2021, 03:43 PM

SLS printing in exotic materials is seriously expensive! In theory ABS would be OK, FDM printer head runs at 240-290 deg c for ABS, your outer cylinder head shouldn't get that warm... I wouldn't risk it in practice!!!

Luddite · 29-01-2021, 06:36 PM

Quote:

Originally Posted by slob

SLS printing in exotic materials is seriously expensive! In theory ABS would be OK, FDM printer head runs at 240-290 deg c for ABS, your outer cylinder head shouldn't get that warm... I wouldn't risk it in practice!!!

The valve covers on my Evo are plastic (I replaced one with an MVS aluminium version). I just looked inside the old one hoping to see a resin identification code but, apart from the Ducati logo and the date code, there was no clue as to what they're made from. So I'm none the wiser!

slob · 29-01-2021, 06:56 PM

I'd guess ABS but they'll be injection moulded, the other potential problem with FDM is strength varies depending on the direction they're printed in, this can be compensated for my including a kevlar strand in the material but that involves a much more expensive printer. For production parts from a major manufacturer they do all sorts of FEA which is way beyond my current knowledge and skills.

Albie · 30-01-2021, 10:29 AM

We used to use glass fibre reinforced nylon in some very hard products when I was in plastic moulding 25 years ago. Hard as nails. Delrin also.

Mr Gazza · 30-01-2021, 11:02 AM

Ain't modern technology a wonderful thing?
I think that since I'm not building a Eurofighter, the home casting method appeals to the Neanderthal in me..

crust · 30-01-2021, 01:59 PM

I wouldn't recommend ABS for engine components, it's softening temp can be as low as 85C depending on grade.

For higher temps we use glass filled nylon.

23-01-2021, 01:38 PM	#62
Mr Gazza Lord of the Rings Join Date: May 2013 Location: Norwich Bike: M900sie Posts: 5,980	I'd thought about the shrinkage, but I thought he said 2%? Either way it's about a mil all round on a valve cover. I thought about gluing a 1.5mm ply "gasket" on the gasket face and leaving that about a mil or whatever, oversized on the outline, then either adding filler carefully round the periphery or gluing a strip of thin plastic of some sort round the edge.. Maybe even roll some plasticine out to a thickness and add that? It's only the overall of the gasket face that would matter I think. The inside could be carved out with a burr if required for clearance or at least to save some weight. Your models are looking better and hats off to your CAD skills. Hand filing the rounds on the fins would save a lot of both cadding and machining. Agreed there are plenty of UK based CNC outfits. Equally as easy to add mdf fins to an exhaust ring for a pattern? Shrinkage probably not an issue on those? Yet another way to do this is to make a physical model with oem parts with bits stuck on, then get it "cloud plotted". Some of the CNC outfits have that capability. __________________ Last edited by Mr Gazza; 23-01-2021 at 01:43 PM.. Reason: more ideas coming in..

25-01-2021, 12:32 PM	#66
Mr Gazza Lord of the Rings Join Date: May 2013 Location: Norwich Bike: M900sie Posts: 5,980	Good innit. Fins are spot on. There seems to be at least two versions of the finning on the bevels. Some have the centre three fins raised quite tall at the crankcase end, others are just like your model. I'd so love to get stuck into this project, but business is booming at the moment and spare time has evaporated! I'm not complaining about that as it will suddenly dry up one day, but all work and no play makes Gazza a frustrated boy! __________________

28-01-2021, 11:44 PM	#68
pooh Lincolnshire Area Rep Join Date: Oct 2002 Location: Grimsby Bike: M900ie Posts: 471	Slob Could the valve covers not be plastic printed using high temp material? Pooh __________________ Slighty less brain cells than I was born with

29-01-2021, 08:50 AM	#69
Mr Gazza Lord of the Rings Join Date: May 2013 Location: Norwich Bike: M900sie Posts: 5,980	Pooh. I think you can have just about whatever you want. When UKMOC had a VIP tour of the BBMF at RAF Coningsby, we also had an extremely privileged tour of the BAE hanger where the Typhoons are serviced and commissioned. We were told by the head honcho that the canards (fore planes) are 3D printed in Titanium with a honeycomb interior. __________________

30-01-2021, 10:29 AM	#73
Albie Fanactical volunteer Join Date: Oct 2003 Location: Kent Bike: M900 Posts: 9,034	We used to use glass fibre reinforced nylon in some very hard products when I was in plastic moulding 25 years ago. Hard as nails. Delrin also. __________________ http://albies93m900.blogspot.co.uk/ Last edited by Albie; 30-01-2021 at 10:32 AM..

23-01-2021, 12:28 PM	#61
slob . Join Date: Jul 2003 Location: East London Bike: Multiple Monsters Posts: 9,736	just thinking about it , using an OEM part to make a plug is problematic, myfordboy mentions oversizing the model by 4% to allow for shrinkage, easily done with CAD ... select part, then menu > scale

23-01-2021, 02:03 PM	#63
slob . Join Date: Jul 2003 Location: East London Bike: Multiple Monsters Posts: 9,736	Yup, you're right, 2%

23-01-2021, 02:49 PM	#64
crust rattles when he walks Join Date: Aug 2002 Location: in the comfy chair,moved furniture around Bike: M900 Posts: 1,065	You'll be needing one of these then. https://www.artisanfoundry.co.uk/pro...roducts_id=206 One of my mates has a showmans steam engine, getting parts made usually involves a lot of discussions about shrink rates and how its not always as simple as adding a percentage. We have the same issues with plastic part design and mould tools. The material does not shrink universally in the same direction, so in the case of the fins on the exhaust flange it will shrink to the center of the fin causing sinks around the internal face.

24-01-2021, 08:06 PM	#65
slob . Join Date: Jul 2003 Location: East London Bike: Multiple Monsters Posts: 9,736	Something like this maybe?

25-01-2021, 02:05 PM	#67
Luddite Registered User Join Date: Aug 2011 Location: Southampton Bike: M1100evo Posts: 2,465	I'm really impressed by your CAD skills, Rob. I used to enjoy technical drawing at school but it would take me about three weeks to draw one bolt! Seeing your creations, I'm almost tempted to get a computer just to have a play around myself...

29-01-2021, 03:43 PM	#70
slob . Join Date: Jul 2003 Location: East London Bike: Multiple Monsters Posts: 9,736	SLS printing in exotic materials is seriously expensive! In theory ABS would be OK, FDM printer head runs at 240-290 deg c for ABS, your outer cylinder head shouldn't get that warm... I wouldn't risk it in practice!!!

29-01-2021, 06:56 PM	#72
slob . Join Date: Jul 2003 Location: East London Bike: Multiple Monsters Posts: 9,736	I'd guess ABS but they'll be injection moulded, the other potential problem with FDM is strength varies depending on the direction they're printed in, this can be compensated for my including a kevlar strand in the material but that involves a much more expensive printer. For production parts from a major manufacturer they do all sorts of FEA which is way beyond my current knowledge and skills.

30-01-2021, 11:02 AM	#74
Mr Gazza Lord of the Rings Join Date: May 2013 Location: Norwich Bike: M900sie Posts: 5,980	Ain't modern technology a wonderful thing? I think that since I'm not building a Eurofighter, the home casting method appeals to the Neanderthal in me.. __________________

30-01-2021, 01:59 PM	#75
crust rattles when he walks Join Date: Aug 2002 Location: in the comfy chair,moved furniture around Bike: M900 Posts: 1,065	I wouldn't recommend ABS for engine components, it's softening temp can be as low as 85C depending on grade. For higher temps we use glass filled nylon.