Engines > Your Own Design
Big stroke 55 cc one cylinder ICE
MJM460:
Hi Alex, thank you for taking the time to post this. Great to see FEA being used to develop a model design. And most interesting results.
(Now to apply it to my boiler design!)
How do you intend to make the piston to your final design?
MJM460
AlexS:
Hi MJM460,
If you need a design FEA of your boiler, let me know. I can try it with Autodesk Nastran. I use it only for design and not validation.
The idea is to produce this piston is to outsource 3d print it with SLM as homogeneous structure. As a tip form an other member of this forum, Craftcloud give you an overview of wide range of materials and suppliers.
Yesterday I saw that the site ask 40 euro for printing an piston including shipping. Search to the supplier it self and upload there the model. And it ask 16 euro I think there should also need shipping which is half of price for a single part. I have idea's to create more 3d printed AISI316 parts for additional upgrades (I have for years idea of dry sump oil system, which could 3d print tubing and spray nozzles). But maybe to much for one upgrade. Oil lines could be printed as Nylon PA12 (maybe with a vacuum chemical coat, but could be over engineered for an model engine running in mineral oil!) it is quit common material MJF or hard lines AISI316 or even aluminum. All collecting and printed at one supplier to reduce shipping price.
Printing the model with oversize and extra material top and bottom side to possible to fix in chuck and center. Creating a 3d model where I can reuse 100% final model with additional material.
After 3d printing I was thinking to mill the piston skirt in an 4 axis setup where one side is oval. And after that make skirt to correct size in a lathe.
AlexS:
Well I just use this project for testing and enjoy of making something!
3D printed X Connecting Rod
In more detail about version 3 connecting rod. Current aluminium rod has 75 mm distance between centers. New one 72mm.
Weight as material titanium 30 grams without bearings. 53 grams with bronze bearings. They might be adjusted to smaller ones, but see if there are good reamers for smaller size. I think it is good to ream the holes before press fit the bearings.
Maragingsteel M300 without modification model 52 grams without and 75 grams with bearings.
Current rod is 44 gram.
I have to re calculate needed counter weight of crankshaft en balance shaft to fully apply weight oscillating and rotating weight. Or just to deal with a bit of % of not taken in counter weight which I read in SAE ICE book without balance shafts is 100% rotating and 50-60% oscillating mass.
Currently mass large aluminium connecting rod + piston only rotating is taken account in counter weight no oscillating (0%) add extra mass without balance shaft would already improve if I understand it correct!
Contacted supplier 3d printing:
"Firstly, all 3d printed aluminium pieces are heat treated. Generally, Maraging Steel is strengthened via ageing at approximately 500 °C (900 °F), “heat treatment is divided into many types. For instance, “surface heat treatment”, “induction heating treatment”, “vacuum heat treatment”, “isothermal quenching”, “martensitic isothermal treatment”, etc. The heat treatment carried out for the (Maraging Steel) in daily practice is just the basic one. "
Stay tuned. work in progress!
MJM460:
Hi Alex, that is indeed a generous offer, and much appreciated.
I would be most interested to see the FEA for the boiler. It is not needed of course, the model boiler codes don’t give much credit for advanced design and analysis methods, but it would be interesting to see how the standard details stack up.
I assume by design, not verification, you mean that you use the analysis to identify the high stress areas then modify the design to get stresses closer to the average. Like wise you could refine the low stress areas to more efficiently use the material. But verification would mean proving the design overall met the code requirements for the specified load/ pressure. I am happy to avoid the issues involved in verification, as it is all designed to the code requirements, and more than adequate for my modest pressures, and a very simple standard arrangement. More interesting is just where are the higher stress areas in those standard design details.
If you still feel you would be willing to give it a try, I will put together a data sheet with all the necessary information and send it in a pm. I could then start a separate thread when there are some results or conclusions available.
Of course, it’s a very theoretical exercise, that will not change boiler design in the model world, but understanding such things, and improving them while staying in code requirements can only make our boilers safer in general.
Thank you
MJM460
AlexS:
Okay. If there are drawings available is great to add. PM me with the your email. There we can share data and communication if needed. Good to have a separate topic to share results.
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