3D printing an engine frame?

[ajoeiam]

Thanks, Stan. Hmm ... "not in the public domain, but made freely available" - sounds something like one of the "Creative Commons" licenses, which retains the copyright but makes it freely available with attribution.

What say ye all - shall we tackle #5 as a group FreeCAD project? And how should we go about it? Here's an initial thought - not at all sure this is the best way to do it - just to get the ideas flowing:

1) Agree on the order of developing the parts (e.g., first the cylinder, then the piston, then ...)
2) Agree on a schedule, e.g., one week per part
3) Each person who wants to participate can work on modelling the part for the first half of the week; then in the second half of the week, everyone shares their approach / ideas.

Again, I am not at all sure that the above is a good approach or reasonable time frame or anything else; hopefully, though, it moves us closer to figuring out how to proceed.

This sounds like I might even get to learn FreeCAD.
One big issue is that this is the time of year when I'm totally swamped - - - - its time for construction and gardening.
Its about like a need for a few clones to get everything done before snow flies!!

I even am just setting up a new system with updated gpu so my system should be less of a hindrance.

I might just have to follow along because of these present time demands.
(Maybe stretch the schedule a bit? 2 weeks a part instead of one - - - dunno what would help - - - just have found FreeCAD to be a monster to understand!)

 

[lellasone]

Agreed! About 12 years ago I had a student license for SolidWorks and I was doing real well with it, but that was when I had a Windows computer at work to use. Powerful program, and as a veteran, I am still entitled to student rates with that program. However, I’m a dyed in the wool Mac user (since 1986), retired, and no longer have access to a Windows machine with enough RAM, etc. Therefore, it’s time to re-educate myself and dive headfirst into FreeCAD, which as you’ve said, continues to grow in capability.

We sure do have a great hobby, and I feel very lucky and privileged to be surrounded by such a talented and helpful group of fellow enthusiasts. Thanks for all the guidance folks!

John W

If you have a Solidworks background then Onshape could be worth checking out. It's a free web-based cad solution from the same core team as Solidworks, and with a lot of the same interface and feature set (you'll find yourself missing advanced features occasionally, but on the other hand it has much nicer variable handling). The collaboration features have definitly made it the go-to casual CAD program for ME / CS students right now because you don't have all the version control issues you get sharing solidworks projects with a small group. It doesn't seem to have as much traction here though. I still use Solidworks / Fusion for research, but a lot of my personal projects have migrated to Onshape since it runs under Linux and Mac.

All the best,
Jake

Edit:
Onshape Website: Onshape | Product Development Platform
A #25 in Onshape: Onshape

Edit 2:
The joint free-cad project sounds fun.

 

[radial1951]

Thanks, Stan. Hmm ... "not in the public domain, but made freely available" - sounds something like one of the "Creative Commons" licenses, which retains the copyright but makes it freely available with attribution.

What say ye all - shall we tackle #5 as a group FreeCAD project? And how should we go about it? Here's an initial thought - not at all sure this is the best way to do it - just to get the ideas flowing:

1) Agree on the order of developing the parts (e.g., first the cylinder, then the piston, then ...)
2) Agree on a schedule, e.g., one week per part
3) Each person who wants to participate can work on modelling the part for the first half of the week; then in the second half of the week, everyone shares their approach / ideas.

Again, I am not at all sure that the above is a good approach or reasonable time frame or anything else; hopefully, though, it moves us closer to figuring out how to proceed.

That sounds like a good idea. I will need all the help I can get! FWIW I have just purchased an Ender 3 S1.
Look forward to any progress on the engine here.
Regards Ross G.
radial1951

 

[Richard Hed]

Thanks, Stan. Hmm ... "not in the public domain, but made freely available" - sounds something like one of the "Creative Commons" licenses, which retains the copyright but makes it freely available with attribution.

What say ye all - shall we tackle #5 as a group FreeCAD project? And how should we go about it? Here's an initial thought - not at all sure this is the best way to do it - just to get the ideas flowing:

1) Agree on the order of developing the parts (e.g., first the cylinder, then the piston, then ...)
2) Agree on a schedule, e.g., one week per part
3) Each person who wants to participate can work on modelling the part for the first half of the week; then in the second half of the week, everyone shares their approach / ideas.

Again, I am not at all sure that the above is a good approach or reasonable time frame or anything else; hopefully, though, it moves us closer to figuring out how to proceed.

Often this type of agreement is to insure that someone does not try to sell the plans or make commercial work of something they intend to be free to everyone. That's nice.

 

[besty771]

Hi Folks,

It appears that a legal version of Elmers Engines is available at:

https://www.myheap.com/metalworking/resources-downloads.html
I seem to recall that the family choose to make it available for free, but might be thinking of the Engine Boys books.

In any event, it's good to have these books available, far too many valuable plans or collections of a lifetimes work simply disappear when a magazine or author dies or fails. Think of all the great plans that were in Modeltec and a few other fallen mags.

Please note that this version of Elmers Engines is not placed in the public domain, just made available by the copyright holder for free.

Best to all,
Stan

So copyright on Elmer's Engines is very weird. I got mine from https://www.digitekbooks.com/books/...roduct/25-elmer’s-engines/category_pathway-39

a nice scan...

GB

 

[awake]

Maybe stretch the schedule a bit? 2 weeks a part instead of one

That might be more realistic, allowing for the inevitable variations in schedule that come along.

 

[Curious1]

What say ye all - shall we tackle #5 as a group FreeCAD project? And how should we go about it? Here's an initial thought - not at all sure this is the best way to do it - just to get the ideas flowing:

1) Agree on the order of developing the parts (e.g., first the cylinder, then the piston, then ...)
2) Agree on a schedule, e.g., one week per part
3) Each person who wants to participate can work on modelling the part for the first half of the week; then in the second half of the week, everyone shares their approach / ideas.

Again, I am not at all sure that the above is a good approach or reasonable time frame or anything else; hopefully, though, it moves us closer to figuring out how to proceed.
[/QUOTE]

What a great idea. I do not know enough about FreeCad or any CAD for that matter to contribute anything useful but would definitely learn by repeating any examples that are posted.

 

[a41capt]

I have a partial on the ring gear and spur gear I can share. I haven’t drawn in screw holes on the internal ring gear, and haven’t added the spur gear changes that’ll include the crank throw yet, but it’s a start! When I can get to my computer (I’m on my iPad at my cabin presently), I will attach those two files for folks to play with.

John W

 

[a41capt]

I've been attempting to attach the FreeCAD files to upload, but they appear to be unrecognizable by this site. Anyone have any ideas why a .FCStd file cannot be attached to a message?

 

[krypto]

Yeah, I was wondering if you could attach the Freecad files in the forum...

Did the flywheel. I modeled it in the link branch, but made sure it would load and save correctly on vanilla Freecad 0.20 and it's ready to upload.

Here's what it looks like.

 

[a41capt]

That looks great! Like I said, I can’t load the files, any help would be appreciated. I’m using the Mac version and trying to export it in a different format isn’t working either. Any pointers?

John W

 

[krypto]

Generally, forums like this limit the filetypes you can upload so they don't accidentally start running a warez download site and FCStd files aren't on the approved list.

I added the flywheel file into a zip archive. You should be able to d/l it, unzip it and load it into Freecad.

 

[a41capt]

Great! I’ll zip them so others can use them. I haven’t added the mounting holes to the ring gear, or modified the spur gear to add the crank. Perhaps someone better than I am can do those?

John W

 

[a41capt]

I’ll see if I can start on the base next

 

[krypto]

I finished off the gears you made. It was easier to make a new orbit gear as part objects imported into the Part Design workbench (what I used 99% of the time) are difficult to modify. The gears seem to fit together well enough.

 

[timo_gross]

The thread is called "3d printing engine frame", and now a "team built" of a freecad model is discussed. I do want to be annoying, just thinking it might evolve in a helpful sort of a "beginners" guide to freecad. If so; it would be nice if people would find it more easy later.

Should a new thread be started e.g. in the team build section or in software section?

I finished off the gears you made. It was easier to make a new orbit gear as part objects imported into the Part Design workbench (what I used 99% of the time) are difficult to modify. The gears seem to fit together well enough.

Some questions I already have.

If using the original file could you have modified, before importing? I ask, because that might become important for group workflows or when using download files. e.g. from a vendors Cad files.

If the gears mesh more or less statically in the cad, that does not mean they will work. I learned that the hard way . Spend a lot of time making the gear and then it did not really work properly.
The vido i linked earlier then made the penny drop, I did not consider that the addendum and dedendum of the internal gear must be reversed?
I saw a lot of approaches were the internal gear was obtained by cutting it out of a disc by substraction of a "normal external gear", which ends up in a not working ring gear.

Greetings Timo

 

[krypto]

I'm not a CAD expert by any stretch, but no, you can't import other program's files. The universal object between CAD programs is a STEP file, which will just give you a 3D object without any build history. You can work with that, but with the orbiting gear I mentioned above it was just easier to start from scratch. Five minutes build tops, once you know how to convert DP to module.

https://www.engineersedge.com/gear_pitch_chart.htm
There is no gear mesh (or gear mates) in Freecad so the teeth on the gears are purely cosmetic. I'm not sure how to simulate the motion of the orbiting gear in assembly either as the most I've done is animate simple levers.

Since these are 48 DP gears, I'm not sure how to reliable make them in the shop without involute gear cutters of some fashion. People have been having good luck with printing change gears for the lathe, but they are usually around 18 DP. These gear teeth are much smaller:

The teeth look a little rough under the scope and this is using the newest Cura and printing profile optimized for fine detail. Hitting the limits of FDM and a .4mm nozzle. I have a profile for a .3mm nozzle but only had 1 of that size so today's Adventures in Model Engineering was to drill-out a few nozzles from .2 to .3mm. That's a really small drill!

Nozzle line-up of .2mm, .3mm (shop drilled) and the default nozzle size of .4mm. I'm kind scheduled-up for the next few days so the print will take awhile, but I don't think the .3mm nozzle is getting to make a tremendous difference anyway.

 

[timo_gross]

I'm not a CAD expert by any stretch, but no, you can't import other program's files. The universal object between CAD programs is a STEP file, which will just give you a 3D object without any build history. You can work with that, but with the orbiting gear I mentioned above it was just easier to start from scratch. Five minutes build tops, once you know how to convert DP to module.

https://www.engineersedge.com/gear_pitch_chart.htm
There is no gear mesh (or gear mates) in Freecad so the teeth on the gears are purely cosmetic. I'm not sure how to simulate the motion of the orbiting gear in assembly either as the most I've done is animate simple levers.

Since these are 48 DP gears, I'm not sure how to reliable make them in the shop without involute gear cutters of some fashion. People have been having good luck with printing change gears for the lathe, but they are usually around 18 DP. These gear teeth are much smaller:

View attachment 137684

The teeth look a little rough under the scope and this is using the newest Cura and printing profile optimized for fine detail. Hitting the limits of FDM and a .4mm nozzle. I have a profile for a .3mm nozzle but only had 1 of that size so today's Adventures in Model Engineering was to drill-out a few nozzles from .2 to .3mm. That's a really small drill!

View attachment 137685

Nozzle line-up of .2mm, .3mm (shop drilled) and the default nozzle size of .4mm. I'm kind scheduled-up for the next few days so the print will take awhile, but I don't think the .3mm nozzle is getting to make a tremendous difference anyway.

Now we are diving into rabbit holes, but I hope it does not get too confusing.

In my limited expericence with printing gears, I saw module 1 (approx. 24 dp) work O.K. Those printed gears also worked together with store bought and diy cut gears. Maybe a DP32 can still work, I could try that with some plastic gears.
I think if the teeth become smaller that that I becomes too detailed. My printer has that typical 0.4 mm nozzle using PLA exclusive.
To avoid "Elephantfoot" a raft is suggested by people with gear printing knowledge. (it is definitely better to follow that advise)
The ways to go are a) to cut the gears, if plastic is "good enough" a cutter can be made out of mild steel I guess. b) to just alter the DP of the gears to suit the printing approach. c) use some different sysem to avoid smal involute e.g. lantern Type small gear with the corresponding easier to make internal ring?

As for the gear file, I was assuming I can "import" respective open the original .FCStd file and that should show the elements that are necessary to change details or add others?
I was not able to manage to make an internal ring gear in FreeCad yet. How did you do it?

Greetings Timo

 

[timo_gross]

p.s. I managed to make my Ring gear. I had to create a "new body" first, then start the involute gear operation, then pad it.
Then I made a disc, and substracted the gear from the disc. There is an option external gear true/false. (I hope that makes internal gears).
How to test a ring gear? I think for what we do it is sufficient to just mount two of the small gears in the correct distance on some fixture and rotate the ring gear on them.
I just noticed that I spent hours to design a sprocket in another CAD thing, and that Freecad now has a macro for it.

 

[Bazzer]

I'm not a CAD expert by any stretch, but no, you can't import other program's files.

That statement needs a little bit of padding out, by far the most common form of 3D file transfer is the STP format, however some 3D CAD systems and Solidedge Community Edition (free download) are very smart and have feature recognition, which enables the STP file to be more than the dumb files that it normally is.

If we take a simple example of a square block with a hole through the middle, normally in a STP file transfer that hole has no intelligence, however Solidedge recognises that the design has a hole and enables that hole to be edited by clicking and altering a dimension figure like it was in a history tree of say Solidworks or Fusion.