First attempt at CAD and a engine design

[stevehuckss396]

Question for some of you that are using Alibre????

I have been using 2D for some years, but never tried 3D.

That is going to bite you in the a$$. I had a hard time going from 2D to 3D because you need to think completely different. If you stick with it and get used to it, i doubt you will regret it.

I am not the greatest at 3D cad but I am willing to try to answer some questions if you would like some help.

 

[Metal Mickey]

Bob, I downloaded Alibre last night without a hitch this time. One result though is the first attempt seems to have registered my free 30 days so this download has only allowed me the free version. I don't see that as a problem really as I won;t get disappointed with things that will be taken away! I'll only know the free version.

Question for some of you that are using Alibre????


Another question: Are there tutorials in the free version or do you have to master the program in the first 30 days.

Putputman I can set to tutorials through help and they are very good in my opinion. Certainly good enough to get going. Its early days for me (only about an hour playing) but it does seem a lot better than I thought but that may have been coloured with the download problems last time. I think I shall give it go for a while and put the turbocad on hold. So thanks for the nudge Steve. If you designed your engines on the free version then that's as much as I could want so I may have at last found the answer...bit I thought that before.............

Steve, one question....can you animate the free version? Bit much to ask I suppose...and I will be asking questions so you have been warned (although your also to blame so that will teach you!)

 

[stevehuckss396]

I dont believe you can animate.

One other thing to think about. When you start putting things together in an assembly, you can only put 10 pieces together and save the assembly. My heads are one assembly and the block is one assembly ect.

For the head, the 4 rocker arms in that assembly count as one part. the 4 valves count as one part ect. You can assemble 100 parts but you wont be able to save the assembly. Get used to making assemblys and it only takes a few minutes to load all the assemblys and put them together.

 

[steamer]

I have a seat of Alibre and really Love it.

Steve is right though, you have to start thinking 3D and that was really hard for me as I started life out on the boards, then 2D CAD. Even today, if I am concepting something I often use crap o cad to start with just to make sure. Once over the hump, it gets a lot easier. I have found that Windows Vista and Alibre don't always appreciate eachother, but they seem to be Vista problems and minor and I seem to have worked around some of those short commings anyway.

Even full up, the price is very attractive considering the competition pricing.....but lets not go there again OK......

If you have some specific questions, I too would be glad to give some pointers.....

Dave

 

[stevehuckss396]

If you have some specific questions, I too would be glad to give some pointers.....

I would also be willing to give some help. I have done alot of the most basic stuff and some advanced stuff like cutting threads. I went over a friends house to help him along and brought home a few things. It's an oppertunity for everybody to learn something.

 

[Metal Mickey]

Thanks Dave and Steve, much appreciated. Not being an engineer by trade or a draughsman so 2D knowledge is just as poor as 3D. I did get on with BobCad in 3D better than Turbo in 2D for the same time on each, so perhaps I have an advantage in not knowing enough about 2D. Its about time knowing little gives an advantage! :big:

 

[NickG]

Damn it, when will I learn, that is so annoying when you've just spent a while typing a reply and the computer decides to lock up! :'( :'( :'(

Anyway, most of what I said was probably waffle!

My main points were:

- 3D CAD is definitely the way to go.

- Alibre is good, we use Unigraphics, a leader, if not the leader in 3D CAD and Alibre seems to me to have similar functionality and it's more user friendly, easy to pick up.

- Main limitation of free version is number of parts in assembly. As Steve says, once you've mastered assembling stuff, you can build sub assemblies and soon put them all together to give you the picture of the completed model. However, as this can't be saved, you won't be able to produce a general assembly drawing of it, just individual parts or sub-assemblies.

- Another limitation is not being able to produce sectioned views ... this is disabled. As model engineers we can probably work around this in most cases.

- A good reason for assembling the whole thing is, if you assemble with the correct mating conditions, in turn giving components the correct degrees of freedom, you can "move" a part, i.e. you can spin the flywheel around and see all the rest of the engine working. As Steve, said, not sure if you can get it to do this automatically and run in a loop, but you can see what clearances / interference you have etc.

On my Stirling Engine below I inititally had interference between the con rod and cylinder wall, so I lengthened the condrod and other appropriate dimensions until it cleared.

Also attached is a general assembly drawing of my oscillating engine to give an example of a 2D drawing created from the 3D model.

It may sound like a long way around to create everything in 3D first, but trust me, once you get the hang of it (and it's not that hard) it's much better.

Nick

 

[Metal Mickey]

Thanks Nick G. I have just done my first CAD project, a tool setting fixture for an inline boring bar (seperate thread just made) and used Alibre for it. Transfering the 3D model and getting plans out is brilliant (well to a newcomer). I am impressed and only wish I did not have the initial download problems which put me off the program initially. However since this one is free, I am converted!

Still much to learn but it is nice to be able to complete a project even if its a small one. Helps to build confidence.

 

[NickG]

Mike,

No problem, I'm glad you've taken to the idea of 3D CAD. Well done with the setting fixture. Like anything, the more you use it the easier it gets and with this you will soon realise it's much easier and faster to produce and modify complex drawings.

Nick

 

[Metal Mickey]

Alibre lives ......and is good.....

I must admit I have not progressed the engine design as stated in the heading to this post but I have finally settled (for how long I do not know) on Alibre because its cheap (FREE), it had 3D and can transfer a model to drawings very simply indeed.

I know there are limitations with the free version but I doubt I will be pushing at those boundries just yet. To show what I have done in practice here is a outline frame for a ball turning tool exported to a jpeg.....

I'm sold on Alibre and am in danger of becoming a fan! Look out........................

 

[Maryak]

MM,

Your way ahead of me with Alibre. :bow:

I can't seem to find much time and I'm too impatient.

Best Regards
Bob

 

[Brian Rupnow]

Metal Mickey---When you get real good at Alibre, come on over to my house and I'll let you use my Solidworks-- ;D ;D ;D---Brian

 

[Metal Mickey]

Metal Mickey---When you get real good at Alibre, come on over to my house and I'll let you use my Solidworks-- ;D ;D ;D---Brian

Brian I would love to be able to travel to come to your house. I can send the wife though............as long as you don't send her back! I don't think I could ever get to your level of knowledge and from what I hear the price of solid works would require me to own several banks (oh forget that, banks have lost us all our money!)

I would love to see people like yourself at work in real time. It takes me forever to do simple things. How many hours/days or in your case minutes, did it take you to do the image in your post!

I am an admirer of your work (and your speed of making what you design).

Bob, you old smoothy you! Your taking the Mickey (sorry) but thank you. I only posted to show that Alibre £ for £ is value for money really.

 

[Brian Rupnow]

Metal Mickey--I have approximately 180 hours in what you see.--Figure about four and a half weeks of 8 hour days. I just queried my "Assembly statistics" and it informs me that there are 537 parts, which are combined into 44 sub assemblies and 2 master assemblies. And there are approximately 85 engineering shop drawings with complete bills of material. The speed that I work at is absolutely phenomenal.--No, really--it boggles my mind. After working on a drafting board for 33 years, and Autocad 2D for 2 years, and now 3D CAD for 9 years, I simply can not believe how fast this stuff is. Please don't send your wife--she is probably a lovely woman, but I'm not man enough to handle 2.----Brian

 

[kvom]

Somewhat OT, but I am wondering if it would speed the process of learning one of the these programs by creating the parts from an existing 2D plan. Then when you convert back to 2D you could check if you did it correctly.

 

[mu38&Bg#]

That is an easy way to learn a CAD program. If you are trying to learn design and CAD at the same time, that would be tough. Learning a CAD program isn't about making sure you've drawn the parts correctly, however. Learning A cad program is about how to use the user interface, the drawing tools, understanding what input give the appropriate result, organizing your steps to allow easy modification of the parts, etc. Anyone can learn 3D CAD today. Learning to use it effectively and efficiently is the challenge.

In Brian's design above it is possible to design it in Solidworks such that if there were models of the machine that were for instance, wider, entering the width in one place would update all parts that needed it, adjust number of fasteners if needed, update the drawings, etc. A design like that needs to planned in advance and you really need to understand how the program works.

 

[Brian Rupnow]

Kvom--Working in 3D is very similar to working in 2D. In fact, when I design a part, I start with a sketch which is a 2D sketch consisting of standard construction geometry.---Lines, arcs, circles, etc. Once I have tailered that 2D sketch to be dimensionally correct, as I want it, I simply select the "extrude" icon and type in the depth that I want the part extruded to, and Bingo---the program creates a 3D part from my 2D sketch, extruded to the depth in the "Third Dimension" that I have put in a value for. Thats it!!! Likewise, if I want to create a cut away portion of an existing 3D part, all I do is select the face I want to draw on, select an icon that turns that face "square" to the computer screen, and start a sketch on that face. After I have created a 2D sketch on that face and dimensioned it to what I want it to be, I select the "cut" icon, and select whether I want the cut to be completely "through all" or if I only want to run the cut in a specified depth. Then I type in a value for the depth I want the cut to be, and it cuts the solid away, in the shape of the 2D sketch I created, to the depth I have typed in. Deiselpilot is talking about "Design Tables" whereby I can set up a solid part, even an assembly in a manner such that by changing one key figure, everything associated with that figure will change and update automatically.---And if I have previously created drawings of the part or assembly, the drawings will all update and the dimensions will all change automatically.

 

[Metal Mickey]

Whilst I haven't added much to this thread I have been learning Alibre and I must say its a very good program. I am invloved in building my own saw table at the moment and made the images below in about 20 minutes which for me is good. The advantage with Alibre though is I can publish the work as Jpeg,bitmap,PDF and save as dxf files with the ability to produce 2D rawings very easily. I am no where like Brian and never will be but for my small needs this seems to be the answer.....

 

[stevehuckss396]

I am no where like Brian and never will be but for my small needs this seems to be the answer.....

Once you learn to put parts together in an assembly you will be just like him. It's like eating an elephant Mickey, one bite at a time!

 

[Metal Mickey]

Yes Steve, that's the next challenge, fitting the parts together....as you say, one bight at a time....