Engines > Your Own Design
Big stroke 55 cc one cylinder ICE
Roger B:
3 D printed herringbone gears is an interesting concept :) :) :ThumbsUp:
This is a gear I photographed many years ago in a Hamburg docks scrapyard.
crueby:
Interesting photo Roger - I never had a close look at a herringbone gear, it does make sense now that the center would not have the teeth meet up, never realized that would be the case.
Roger B:
Apparently my picture is of a double helical gear, a herringbone gear's teeth do meet in the middle. Both have interesting manufacturing problems :headscratch:
AlexS:
Agree just a test print of the gear. Indeed it is rather a double helical gear, no theeth meet in middle section.
Already produced a second one with printing with supports and higher extruder temperature. Without fixing tool, both gears match quit well. Would print the test fix tool later.
Piston
Simulated in Autodesk Nastran. Result quit Okay, only need to add a stiffening around small end boss to bottom side of oil scraper ring (inside of piston) There was a safety factor of 2.5 as lowest of whole piston by 53 bar combustion pressure.
AlexS:
3D printed X Turbolence Piston
Hi there!
After a summer break. Let continue when the rain is falling!
In June tried to make some FEA simulations of version 2 of the piston. Result was that peak maximum von mises stress around 200 MPa and area's around 150.
Currently made a modification. Add some thickness at the piston crown from 3 to 5 mm. I searched and 2.5-3 is good enough for forged piston. This piston would be SLM 3d printed, maybe with a heat threatment. A thicker 5-6 mm piston crown thickness is more recommended for the heat build up (open structure?).
Today made a simular simulation with load 63 bar maximum combustion pressure (according to 1:7,5 compression ratio).
Result showed peak stress around corners of the oil channel 0f 117 MPa. What more leading is the stress area inside connection bottom of piston crown to skird of 92 MPa.
I already adjust internal geometry for more flexibility between piston crown combustion chamber and right small end bush, which already without making hte crown thicker give lower stress around that area.
So far I found that SLM AlSi10Mg have RP0,2 yield strength around 160 MPa as build and 290 MPa heat threaded.
Same as the piston pin recommend safety factor 3 for this medium duty piston.
Result in maximum allowable von Mises stress of 53 as build and 97 MPa heat threaded.
I could adjust geometry. Weight is almost the same as current cast GY6 chinese piston that currently running.
But would contact a supplier that can produce a heat threaded part with increased strength.
3D printed X Connecting Rod
The current connecting rod would not match with higher piston. Connection rod is almost finished. Also 3d printed. Maximum stress is around 300-333 MPa.
Option is to produce it as titanium or Maraging steel (M300). I am leaning to select marging steel, due resistance to fatigue stress and machinable for me. Density is higher ofcourse. But the current aluminium large connecting rod is 44 gram and titanium 30 margensteel should be around 60 grams.
Yes, why difference stress left and right leg? because it include a oil supply channel from small end to big end. Why? because it is easy to add when printed!
FEA safety factor margensteel are around 3-4 without heat treatment!
3D printed camshaft in development, next. to much info for now.
Good night 8)
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