[heavy metal]

So I'm a mechanical engineering student and I've been messing around in Solidworks lately trying to refine a simple single pivot bike design I would love to build some day (sadly my welding skills are nowhere near that required).

I wanted to know what the engineering monkeys have to say about using Solidworks for this application since its the only modeling program I have any experience with at the moment.

I have been using the weldment feature to create tubing from a 2-D sketch however my student edition of Solidworks seems to have a very limited selection of square and round steel tubing. I was hoping someone could point me in the direction of a data file containing some standard tubing sizes and wall thicknesses to upload into my copy of Solidworks. I know you can create custom tubing profiles and such but if that is what I have to do one by one I'll probably save the task for a rainy day.

I think having a variety of real tubing for me to draw from would be immensely beneficial. That way Solidworks can provide at least a rough idea of frame weight and what not during the design phase!

Also any general wisdom or tips would be greatly appreciated.

 

[gonefirefightin]

doesnt anybody just weld in thier garage anymore? good old fashioned tinkering?


(insert "when I was your age" speech here)

 

[heavy metal]

I mean I've taken a welding class and used stic, mig, tig, and the torch but all that was on like quarter inch steel plate (some thin sheet alu for tig tho, very hard!). I wish I could afford a nice tig setup that would be sweet, I'd probably spend all day in the garage making odd things.

 

[c101aviojet]

On a side note, I think what you ask depends on your design approach.

If you wish to make a fantasy design with exotic shapes (i.e. hydroformed bikes with smooth curves), I'd work with surfaces. It certainly requires some learning, but is a much more powerful tool and will let you draw smooth, complex bikes.

However, if you want to design a bike you could eventually make in your workshop with "simple" tools (such as a MIG welder, lather, mill, pipe bender, etc.) then I'd search for that table (with the shape and physical features of common bike alloys) and go the solids route.
Yet, since "solids" are a particular case of "surfaces", I'd say to go with the surface approach in either case. As I said, it's a lot more complex, but the freedom of design it gives more than pays off. Ever tried to model a typical water bottle with solids?

 

[heavy metal]

I've made models of a water bottle using a solid extrusion that I shelled at school. I can see there being a bunch of lofting and shelling in making hydro-formed tubes. For now I'm just trying to keep it simple with the weldments, building a bike frame in sort of the same way you might draw up a roll cage.

 

[buildyourown]

There is no library.
You can see all the standard available tubing sizes at the manufactures or resellers websites.
Create a sketch of the butt profile and the revolve it around the centerline. Use sketch planes at your miter angles and cut the miters.
You really can't use the weldment feature in SW to create a bike frame.

 

[jdcamb]

Ask Sydasti. He surely knows what you're doing wrong....

 

[heavy metal]

@buildyourown, Damn, that would mean all my miters have to be custom configurations on each individual tube/feature. Thissss is gonna take a while.

edit: found this. was pretty helpful.

edit#2: While were at it, is there any way to use Solidworks to do the job of that suspension design program Linkage? I'd rather not buy it when I have some pretty good software at my disposal fo free! Maybe something in the motion study?!

 

[TheMontashu]

doesnt anybody just weld in thier garage anymore? good old fashioned tinkering?


(insert "when I was your age" speech here)

I play with a welder on the regular, but it's usually helping weld my friends trucks. I've actually got the steel cut out for a bumper right now, I just need to find time to put it together.

 

[JustMtnB44]

I have always created my own weldment profiles. It is not that hard or time consuming, but I have only used round, square, and rectangular tube - no crazy shapes.

Browse to C:\Program Files\SolidWorks Corp\SolidWorks\data\weldment profiles . Here you can either create new tube sizes in the existing folders, or make new folders. I added lots of inch round tube sizes in the ...ansi inch\round tubing folder. Just copy an existing *.sldlfp file then open it in SW and edit the sketch to get the correct diameter and wall thickness you want. It will then show up in the selection list within the SW weldment feature. Obviously this only works for regular straight non butted tubing. But for the purposes of what you are doing, I think that is fine.

If you want to go crazy with butted tubing, then you will have to make revolved parts as buildyourown said. But I would only do that after I had a solid design using non butted tubes.

You can use SW kind of like linkage. Make your frame as an assembly and set a limit distance mate on the shock. Then you can drag and move the suspension throughout it's range of travel. I'm not sure how to create nice plots from that, but it must be possible. Or you can just measure the axle position at different points in the travel and create your own plot in Excel or something.

 

[heavy metal]

Ahh! Thank you! I would like to make most of the frame using weldments because they have a sort of auto miter working for them, with cut patterns too. Yes I am sticking to straight gauge for simplicity's sake. Making the graph might be a pain if I want a lot of data points but I suspected that I might have to do it in excel.

Edit; Ok now any reccomendations for tubing dimensions?

I'm thinking something like 1.25 x 0.049, 1.5 x 0.049 for top and down tubes respectively. I don't want a steel beast but I would rather be conservative with my design so that I know its durable.

 

[c101aviojet]

heavy metal, the bottles you can make with solids have no comparison to the ones you could model with surfaces. Most plastic pieces (like a mouse, or a phone) would be a hell, if not impossible, to model with solids.
But then again, to make a DIY design (where you are using round tubing and some plates), the solid approach is more efficient (=faster & simpler).
My approach would be to draw a simple diamond-like bike with all the relevant geo, and then use such draft as guiding curves to extrude the pipes.

As for the suspension, once you have assembled the frame, as someone already said, you can always insert springs, external forces and certain ligatures, and see how it behaves. I would say you can get some numbers out of that, but honestly, I barely remember how. Must put some hours in the software, now that I have more time.

 

[MMike]

I personally....not that I do much actual modeling anymore, but I'm not a big fan of the weldment function. I prefer doing things as an assembly. But my only real reason for that is because I've typically had to create individual p/n's and manufacturing drawings for each piece. So I find the individual .prt files easier to work with.....but that's just me.

 

[heavy metal]

My final model will be an assembly with configurations on each tube feature but I don't want to put that much time into the model until I have all the geo and suspension sorted out.

I've dropped the weldments and im just sticking with a basic 2-D frame sketch overlying construction lines which define my geometry.

I'll start there and then build each tube individually in an assembly the legit way i spose.

When I find the patience to delve deeper into more complex stuff I'll be sure to check out the surface features.



Thanks for the help.

 

[MMike]

dw is probably one of the more prolific SWx users I've ever known. I think he also might have an interest in bike frame design.

 

[mexMan]

For what I've heard round tubed frames (for anything) design in SW is a pain in the ass, but that's what does the job properly nowadays, dunno, I'd rather make some math to build a proper bike and then start welding. But anyway good luck with the program.

 

[heavy metal]

Yeah it's totally necessary for me to be using solidworks for a personal design that isn't for production. However, as an engineering student I figured having a few proper bike designs with all the details would not only be good practice with the program but might also look good in a design portfolio when it comes time to get an industry job.

If my school will let me do a full suspension bike for my senior design project I would be pretty stoked, so practice makes perfect.

 

[mexMan]

Well, right you are, anyway, my skills in SW are still pretty n00bish.

 

[heavy metal]

I just hate how clunky it feels. Maybe I'm just slow (pretty sure I am) but it takes me endless amounts of time to do anything with the detail that I want.

 

[MMike]

You'll get used to it. All CAD software takes a little time to figure out you own little tricks. And you might want to spend a little time customizing your menus/toolbars. That helps a lot too......

 

[CrabJoe StretchPants]

I just hate how clunky it feels. Maybe I'm just slow (pretty sure I am) but it takes me endless amounts of time to do anything with the detail that I want.

Try using Pro/E. Solidworks is like using a kid's V-Tech computer after that.

 

[Gunner]

Try using Pro/E. Solidworks is like using a kid's V-Tech computer after that.

Agree. And I even work for PTC (makers of Pro/E) teaching the software to fellow enginerds.

 

[MMike]

CATIA

I scoff at Pro E

(How many times are we going to have this argument?)

 

[CrabJoe StretchPants]

CATIA

I scoff at Pro E

(How many times are we going to have this argument?)

Many as long as there are plenty of know-it-all enginerds on here.

 

[heavy metal]

state of california ran out of money so cal poly can only afford a solidworks license we doing it on the cheap! no fancy shmancy catia and proE

 

[JustMtnB44]

I personally....not that I do much actual modeling anymore, but I'm not a big fan of the weldment function. I prefer doing things as an assembly. But my only real reason for that is because I've typically had to create individual p/n's and manufacturing drawings for each piece. So I find the individual .prt files easier to work with.....but that's just me.

The beauty of the weldment feature is that you can then take each individual tube and save it as a separate part, which you can assign a part # and make drawings from. But it will have the properly mitered ends and geometry so you don't have to dick around with trying to create those on your own. It is much easier to draw a frame as a single sketch with weldment profiles then to assemble a bunch of tubes together.

My final model will be an assembly with configurations on each tube feature but I don't want to put that much time into the model until I have all the geo and suspension sorted out.

I've dropped the weldments and im just sticking with a basic 2-D frame sketch overlying construction lines which define my geometry.

I'll start there and then build each tube individually in an assembly the legit way i spose.

I really think that approach is a waste of time at this level. Get some basic designs done with weldments for each, well, weldment, and an assembly to make the whole frame (main triangle, rear swingarm, suspension links, shock, etc). The weldment feature is perfectly legit, I use it all the time.

Try using Pro/E. Solidworks is like using a kid's V-Tech computer after that.

I learned 3D CAD on ProE 2001 and then switched to SolidWorks in 2004ish.

 

[CrabJoe StretchPants]

state of california ran out of money so cal poly can only afford a solidworks license we doing it on the cheap! no fancy shmancy catia and proE

$$$ doesn't really say much. See what percentage of engineering/design places out there use Solidworks. I'm willing to bet over 50% of companies are using Solidworks.