FreeCad Stuff

[Dabbler]

I've been looking into FreeCad lately and trying stuff out, but I'm in no way ready to advise or teach anything at all.
I've been watching a lot of videos on it lately, and if you're interested in seeing how it is supposed to work, this is a good intro:

 

[Brian Ross]

I'd recommend looking at Joko Engineeringhelp (https://www.youtube.com/channel/UC-CubOaooNwC-3RBKUoAOQQ). He has a large selection of videos that cover a lot of the features of FreeCAD and has some videos that compare how to do things FreeCAD vs Solidworks or some other package. I've been using FreeCAD for a few years and I have found that Joko's videos are pretty handy to get tips on how to use the features. There are often several different ways to accomplish the same thing.

 

[BevanTaylor]

I started with FreeCad this year, coming from Solidworks. It's done what I needed it to so far, but I want to try out the FEA capability. They have some really good tutorials on the wiki too.

 

[ShawnR]

I have spent the morning looking at FreeCad. I have tried several CAD programs over the years. I think with the advent of Youtube, I might stand a chance of not giving up this time....
Dr Vax and will go to Joko next. Thanks Brian

Thanks Dabbler for mentioning it.

 

[ShawnR]

I have made some progress with FreeCAD this week. As posted in @David_R8 thread on his CNC Plasma build, I attached the plasma practice diagram so I think that should I get that far in the Plasma build, I will be able to use it.

But I am trying to understand the process to a 3d project. The attached Bearing plate is something I made for someone this week. I built it with napkin sketches but after it was done, I tried to design it in FreeCAD. I see there are several ways to do it so am wondering what the "best" way is...hoping someone reading this thread can give some input.
In the first version of the Bearing plate drawing, I "padded" the post onto the plate, one on top of the other.
Then I saw a video, I think "thehardwareguy" and he used an "additive cylinder" function. That seems to make more sense. That is the one attached.

But when I actually built the part, I cut a 3/16 plate, drilled a half inch hole in it. I then milled the post with a 1/2" ...term=protrusion??? ....piece on the bottom that I used to index the post to the plate, then tig welded it into place. So technically, it is 2 parts. What would be the accepted? best? preferred way to do this in a CAD program? I have seen videos on joining two parts but not gone there yet. I am thinking that since the construction process was in 2 parts, the drawing should reflect that, although the end result for all 3 drawings will be the same, I think.....

Maybe it is a case of "here is what we want...just get there?" versus a build process diagram?

Happy I can make drawing in other than Paint so a good week!

Thanks
Cheers,
Shawno

 

[ShawnR]

As I continue to read/watch, I see a fourth method, the "Revolve" function....now I think there are probably others even....

 

[Johnwa]

I use Fusion. I would build it up 1 cylinder at a time. I’ve used the revolve method a few times, but it’s not as intuitive.

 

[ShawnR]

I started with FreeCad this year, coming from Solidworks. It's done what I needed it to so far, but I want to try out the FEA capability. They have some really good tutorials on the wiki too.

Are you still using FreeCAD?

 

[Brian Ross]

There are often many ways to achieve what you want to do in FreeCAD. I don't think there is any "best" way it's more a matter of personal preference. I prefer using the Part Design workbench because I like the fact that the drawing is built up from fully constrained sketches that are then padded or pocketed as appropriate. I hardly ever use the Part workbench, that uses solid primitives like cubes and cylinders to build up your drawing, because I don't find it as intuitive.

So, for your bearing plate I would use Part Design:
- create a sketch for the largest cylinder and pad that to the thickness
- create a new sketch on the large cylinder for the next smaller cylinder and pad that to thickness
- create a new sketch on the previous cylinder and pad that to thickness

Revolve I find works really well when you are trying to draw a shaft with lots of features. You just have to create a sketch of the profile and revolve it around the axis. In your bearing plate example Revolve would probably be the fastest way to create the drawing. But again it's personal preference.

 

[BevanTaylor]

Are you still using FreeCAD?

Yes, I haven't used it a ton lately since I don't have any projects that need CAD going at the moment, but it's still my go-to.

 

[ShawnR]

There are often many ways to achieve what you want to do in FreeCAD. I don't think there is any "best" way it's more a matter of personal preference. I prefer using the Part Design workbench because I like the fact that the drawing is built up from fully constrained sketches that are then padded or pocketed as appropriate. I hardly ever use the Part workbench, that uses solid primitives like cubes and cylinders to build up your drawing, because I don't find it as intuitive.

So, for your bearing plate I would use Part Design:
- create a sketch for the largest cylinder and pad that to the thickness
- create a new sketch on the large cylinder for the next smaller cylinder and pad that to thickness
- create a new sketch on the previous cylinder and pad that to thickness

Revolve I find works really well when you are trying to draw a shaft with lots of features. You just have to create a sketch of the profile and revolve it around the axis. In your bearing plate example Revolve would probably be the fastest way to create the drawing. But again it's personal preference.

OK, good to know Brian. Thanks. Your method is what I did in one version.

Yes, I haven't used it a ton lately since I don't have any projects that need CAD going at the moment, but it's still my go-to.

Good to know. I now know there are at least two people here than can answer my newbie questions...

I get some stuff, then lose it, then back again...probably a normal learning curve. I was trying to figure out how to print a dimensioned plan today. According to the wiki, it is in versions after .16 I think? iirc, but I could not quite get it. Going back to it later.

Cheers,

 

[BevanTaylor]

Yea, for sure! I'm hardly an expert but I'll do what I can!

If you want technical drawings, you can use the 'techdraw' workbench, it's not totally intuitive but once you get the hang of it I think you can get some nice results, certainly good enough to print off and bring to the shop!

 

[ShawnR]

I found a great video on using the TechDraw workbench to dimension the diagrams.

 

[BevanTaylor]

There are also some helpful tutorials on the wiki with step by step instructions.

https://wiki.freecadweb.org/Basic_TechDraw_Tutorial

 

[Chipper5783]

I use Fusion. I would build it up 1 cylinder at a time. I’ve used the revolve method a few times, but it’s not as intuitive.

I need to get back into some sort of solid modelling activity/ learning. Certainly the documentation and design aspects are very valuable - I want to be able to progress to the CAM side of things. I am enjoying my CNC machine, but I am building my code like I would a manual machining activity. So I set up the coordinates, then enter a tool move, then the next move, . . . . I'll test the cut as I work towards every feature. I end up cutting a lot of air. I have no complaints, it still allows for tasks that would be time consuming to set up on a manual mil (or nearly impossible). It is also good to be G-code literate.

Back to solid modelling - I would like it support tool path generation. Preferably with a DX32 post processor. I played with Fusion (via Titan CNC's tutorials), it can take one all the way: modelling, documentation, design and tool path programming.

Does Freecad? Does it really matter? If something like Freecad gets me literate on the solid modelling, documentation, design - because it has good tutorials and a good support community - then the transition to some other modelling program (a purchased one that supports DX32) is no big deal?

 

[Brian Ross]

FreeCAD does have a Path workbench that has had a lot of development over the past year. It is apparently quite good but I haven't looked at it since I have no CNC machines.

 

[ShawnR]

Attached is the FreeCAD file for the belt sander I am working on. I have not mastered moving objects around based on the plane, ie trying to move the drive motor forward while the frame is back. I have watched some videos on it but lost it again. But since there are a couple of you looking at this thread, I thought I would post what I have so far and ask for critique. The drawing did what I wanted, and that was, to allow me to determine how long to make arms and parts, and if I was getting close to a 72" path, so all good there. Not shown but I used the ruler to measure distances, then old school, marked them down on my printed paper. I will get back to improving the diagram as I progress up the CAD learning curve but now, off to grind and cut metal...

Couple questions though...

Is my general idea/layout correct? Every part has its own, well, part sketch I guess? couple times I drew some sketches but then when I went to pad them, I was told no multiple pads.
Things missing (not required at this time) are wheel brackets, tension arm bracket, etc.
The posts (stand) are not attached to the top bar, but just laid out with a reference to the center using vertical and horizontal distances (as are all parts I guess) That part I get, although I think some need to be coincident somehow? or do they?
When I look at the top view, you will see everything is laying on the y plane. That is the part I am trying to get around. I tried shifting reference points, datum planes, points, ...but not quite got my head there. I watched a vid yesterday morning, thought I had it, but no..... Kind of like a golf coach...has you straight down the range when with you, then back to slicing when he leaves...

Anyways, something to look at if you are interested.

Thanks
Cheers,

 

[Brian Ross]

A couple of comments on your questions. FreeCAD doesn't allow a body to have multiple non-connected parts. That is why you get an error if you try to pad a new sketch that is not connected to the main body. As you have done, you have to create a new body, create a sketch and then pad it. You mention that there are things missing like the brackets etc. I think that you would have a much easier time orienting the parts if you included those missing parts as that is what is holding everything together. I know it seems like a lot of extra work but it really makes things a lot easier in the long run if you include all the major parts and how they are connected.

I would have approached this differently than you have. Rather than creating all of those separate bodies all in one model, I would have created separate FreeCAD files for each of the major parts and then I would have created an assembly of those parts that includes the constraints between them. Doing things this way you don't really have to worry about the orientation and location of the parts until you bring them together in the final assembly. Take a look at the A2+ assembly workbench (you will have to add it from Tools|Adon Manger). I think it is the easiest to use and most complete of the assembly workbenches.

I have attached a copy of an assembly model of a router lift I built recently. All of the individual parts were created as separate models and then assembled with appropriate constraints in the attached file.

 

[ShawnR]

A couple of comments on your questions. FreeCAD doesn't allow a body to have multiple non-connected parts. That is why you get an error if you try to pad a new sketch that is not connected to the main body. As you have done, you have to create a new body, create a sketch and then pad it. You mention that there are things missing like the brackets etc. I think that you would have a much easier time orienting the parts if you included those missing parts as that is what is holding everything together. I know it seems like a lot of extra work but it really makes things a lot easier in the long run if you include all the major parts and how they are connected.

I would have approached this differently than you have. Rather than creating all of those separate bodies all in one model, I would have created separate FreeCAD files for each of the major parts and then I would have created an assembly of those parts that includes the constraints between them. Doing things this way you don't really have to worry about the orientation and location of the parts until you bring them together in the final assembly. Take a look at the A2+ assembly workbench (you will have to add it from Tools|Adon Manger). I think it is the easiest to use and most complete of the assembly workbenches.

I have attached a copy of an assembly model of a router lift I built recently. All of the individual parts were created as separate models and then assembled with appropriate constraints in the attached file.

Thank you Brian! That is exactly the type of input I was hoping for...I will look at the assembly bench. I was suspicious I was not quite right in my process but have no idea how to combine separate parts into an assembly. I will look into it. I am, obviously, still fumbling around but making huge progress over using Paint, which is all I have ever used, or a pencil.

Thanks
Cheers,

 

[ShawnR]

Sooooo....(scratching head....) say I want to draw the platen. Parts are 2 wheels, 1x2x10" rectangle tube (I know, maybe a 1/2" plate would be better but for the sake of FreeCAD, lets go with the tube...) brackets to hold the wheels in place probably 4, 2 per wheel, one per side but they get welded to the tube, and then more brackets to attach the tube/platen and then the bolts to hold the wheels on to the sander via a "platen bar?". Where do you break it down? Each part that could be disassembled? Brackets for wheels get welded to the tube so would 4 brackets and the tube form one part/drawing? or would each bracket be a separate drawing? I looked quickly at the wiki for the assembly bench and see that parts can be duplicated so probably one one "bracket" drawing used 4 times....? And that could be the platen? Main platen? Whatever I decide to call it but without wheels attached ? I will do some up tonight and repost. All of the videos I have watched so far only ever deal with one part. I am still watching the beginner ones. I will go look for some assembly ones.

Thanks

Cheers,