The ebike parts designing thread with CAD/CAM

I guess I am too old a dog to learn new tricks. I started using Hogin CAD (not even sure about the spelling at this late date) back in the early 1980s on an HP1000 mini computer. Then I started using one of the earliest versions of AutoCAD on a 8086 MS-DOS computer (with a full 640K of RAM ! --- WOW!). Today I run Linux and have two basic requirements for CAD software:

1. The CAD software must run on Linux
2. The CAD software must be able to read and write standard DXF or DWG 3D file formats

The only two programs that I know of that actually meet that criteria are BricsCAD and ARES Commander (also marketed as CorelCAD and Draftsight).

I did try OpenSCAD and FreedCAD. Both are limited to reading/writing 2D elements for DXF or DWG files. Granted that they can put those elements anywhere in 3D space but all the ACIS solids fail to load.
 
OpenSCAD isn't suitable for CNC, it is more appropriate for 3D printing, which works primarily from STL mesh files which it will produce. It is getting a lot of use in that space.

DXF (and DWG) files are basically 2D files which can have some 3D components, so interoperability can be a problem. It is probably not a good format for 3D.

Both DXF and DWG are Autocad formats, very old, with 3D added later. More modern formats such as STEP might be a better choice for interchange.

FreeCAD will import 2D data from DXF and DWG but doesn't support the 3D parts. FreeCAD supports dozens of other formats. Seems like a reasonable selection.
 
Alan B said:
Both DXF and DWG are Autocad formats, very old, with 3D added later. More modern formats such as STEP might be a better choice for interchange.
You are probably correct about that but I have DWG files going back three decades. I am too lazy to start over. IGES would be a good alternative as well.

OpenSCAD reminds me of the first versions of CADKey we used. The similarities are downright eerie.
 
rberger said:
LewTwo said:
(with a full 640K of RAM ! --- WOW!).

No one will ever need more than 640K RAM
"640K ought to be enough for anybody."

But really:

"There is no such thing as too much Memory, CPU or Bandwidth" - Me

We knew Bill was wrong when he said it. It was a lame excuse for some design decisions they made. Bill was good at business, not Computer Science. He's not too terrible at tennis, I saw him play as Roger Federer's partner. Not that Bill is that good, but he did hit the ball back most of the time.

My mechanical CAD experience doesn't go back very far, but I started in Computer Science long, long ago. Before they had a name for it, as I recall. We let the mechanical engineers do the CAD part of the projects.
 
Alan B said:
My mechanical CAD experience doesn't go back very far, but I started in Computer Science long, long ago. Before they had a name for it, as I recall. We let the mechanical engineers do the CAD part of the projects.
I went the opposite direction Drafting (pushing a pencil across a pieces of vellum) to CAD. Then I had to learn about computers to manage the CAD systems and wound up in IT.

Now I am getting back into CAD ... it is more funner !
 
I started drafting at an early age, but managed to avoid CAD somehow, aside from Schematics and PCB design software, and a few drawing tools for software, project management, etc. Visio was very nice until M$ bought it, it went downhill after that (and the pricing skyrocketed). Ohwell.

I'm getting ready to add CNC to my lathe/mill, so I'll have to choose a 3D CAD Package soon. OpenSCAD doesn't make the right kind of files for CNC machining, so I'll probably go with FreeCAD. I keep looking. Most of my mechanical engineering friends use SolidWorks, but that's not a good choice for home use.

So far FreeCAD and EstlCam seem to be reasonable choices, if CNC machining is the goal.

For 3D printing you can use a full 3D CAD program, but you don't need a lot of the features and the learning curve costs are high. OpenSCAD is quick and easy to learn. Of course it depends on what you want to make. If action figures are the goal, then perhaps something like Blender would be more appropriate. But for brackets, boxes and adapters OpenSCAD is sufficient. I like that you can document your design thoughts, measurements, calculations, etc right in the source file very naturally. You can show the relationships and easily make parameterized designs if one wants to.

I ordered some 6mm screws for the Cycle Analyst design, Amazon makes it easy and has nice assorted screw sets. I'm building up a collection from my other projects, but they are 5mm and smaller at the moment.

I have made quite a few parts for ebikes with my manual Lathe/Mill, a Grizzly G0516. Especially the Borg, which required some special tools to assemble, which I made. 6061 is nice to work with.

Looking forward to learning more CAD and CAM. The 3D printer has been the most productive tool I have ever purchased. I don't necessarily recommend the Lulzbot Mini I have, but it is a good printer albeit a bit pricey for today's models. I got a good discount on it, but even then I'd go for a Prusa i3 mk3 most likely today. I do have an old MendelMax 1.5 kit that never did get finished, I may finish that for the larger printbed it has. Most parts fit fine on the 150mm cubed printbed of the Lulzbot. Lulzbot support has been excellent, the first unit I received developed a problem and Amazon replaced it but Lulzbot was very helpful in getting through the issues prior to that.

If folks are able to design parts they should have a 3D printer, even if the final design will be CNC'd in metal. The test fitting can be done with much cheaper plastic and the resulting CNC will be that much more accurate and more likely to be correct on the first go-round.
 
LewTwo said:
Alan B said:
Both DXF and DWG are Autocad formats, very old, with 3D added later. More modern formats such as STEP might be a better choice for interchange.
You are probably correct about that but I have DWG files going back three decades. I am too lazy to start over. IGES would be a good alternative as well.

OpenSCAD reminds me of the first versions of CADKey we used. The similarities are downright eerie.

Perhaps something like Fusion360 would allow you to convert to a more portable format? Then you could move them into FreeCAD?
 
Alan B said:
Perhaps something like Fusion360 would allow you to convert to a more portable format? Then you could move them into FreeCAD?
After years of dealing with MS operating systems I was able to move to Linux when I retired ... I will never downgrade. Also I am spoiled by a much more capable system (with regards to construction and drawing capability) than FreeCAD. There are some features I would sorely miss :(
 
I'm not too concerned about drawings, I am primarily interested in making parts - so CNC and 3D printing support are the essential goals. Unix, linux and windoze are just tools, and while I prefer Unix/Linux there are too many windoze dependent hardware and software tools that I find useful for me to completely abandon the constantly updated system completely. However I totally appreciate your perspective. All my CNC and hard realtime systems are using Linux or Arduino based systems at the core, if Windoze is involved it is only for the user interface or file preparation, and even there it occasionally manages to foil a 3D print, though I can't tell if the OS or the Slicer software is the real problem (but it probably is rooted in the faulty memory management model of the OS). But it doesn't cause a machine crash, just some wasted time and plastic.

For CNC I'm planning to apply a LinuxCNC system I built to the lathe/mill, though the machine I have is not so popular as to have a bolt-on mechanical kit, so I have a bit more to do to get those parts designed and made. I'm not sure how much CAD I'll actually need, perhaps a good CAM program will be adequate. But thinking in 3D space would seem more natural in CAD, progressing to CAM as a later step. The necessary tool is the specific code to make the part, in some cases I suspect I'll write a gcode generator of my own, a specific wizard so to speak, to make variants of the parts I want, so some features can be adjusted to fit as needed, without going back to the CAD/CAM software. I'll write those in Python, most likely.

If you have any suggestions of tools to consider for any of this, I'd like to see them. I'm thinking FreeCAD and EstlCam, but have not started on either yet and am still looking.
 
One of my main problems with FreeCAD is as far as I can determine the UI is limited to viewing from one side of the virtual box --- no oblique views other than the built in isometric. Adequate for a lot of uses but I am spoiled by having spent so much time on systems that do not have that limitation. Maybe I just need to dig deeper into its UI.

For Lathe work a 2D cad system might suffice. Desault Systems (as in Solid Works) markets Draftsight as a free 2D application with yearly registration. Draftsight is actually a 'lightweight' version of Ares Commander. The difference is that that the menu system does not have the 3D commands and a few modules like 'lisp' are missing. Draftsight produces true accurate DWG/DXF files. I know I have seen free programs in the past (15 years ago) that would convert a 2D DXF profiles to CAM commands for lathes. One thing that you need to know about the Linux Version: their clunky registration system requires that fireless-fox be operational (i.e. login to keyring first) and the 'default' browser.

Milling is a bit more complex issue. I believe that you need a true 3D modeler. By the way Draftsight can do that from the command line but you have to know all the native 3D commands and how to use them. I am old and too lazy to do that anymore so I bought a copy of BricsCAD years ago (version 13). Now that I am getting into 3D printing I will probably upgrade the license for the STL output option. It is overkill for my needs but I already own the PRO license. A perpetual license for either Ares Commander or BricsCAD is in the $750 range.

There a lot of other options out there for the Windows world that are less expensive. Many of those are based on IntelliCAD Technology Consortium which had its origins from Visio's IntelliCAD 98. I have used several incarnations Intelicad and have no big issues with it. Vendors tend to make most of their profits from "enhancements" and custom menu systems.
Reference: http://www.worldcadaccess.com/blog/2015/05/lawyer-tells-story-how-visio-got-intellicad-from-softdesk.html

If money, CPU power and learning curve are not of concern then it is hard to beat SolidWorks.

PS
I did hundreds (if not thousands) of mechanical designs before we had 3D CAD systems and a bunch before we had 2D CAD systems ... some of that when numeric control was in its infancy. I still have a tendency to revert to a carbon pencil for brainstorming an concept :roll: .
 
LewTwo said:
One of my main problems with FreeCAD is as far as I can determine the UI is limited to viewing from one side of the virtual box --- no oblique views other than the built in isometric. Adequate for a lot of uses but I am spoiled by having spent so much time on systems that do not have that limitation. Maybe I just need to dig deeper into its UI

What do you mean exactly?
I use blender mode with scroll wheel to adjust the viewing angle and you can chose between Orthographic and Perspective view for isometric.
Do you have some link to function you miss, where it is explained?
 
parabellum said:
What do you mean exactly?
I use blender mode with scroll wheel to adjust the viewing angle and you can chose between Orthographic and Perspective view for isometric.
Do you have some link to function you miss, where it is explained?
"Blender" mode? Not found that. The only thing the scroll wheel does is zoom in or out.
FYI: I have ...
OS: Linux Mint 18.3 Sylvia
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.15.4671 (Git)
Branch: releases/FreeCAD-0-15
Hash: 244b3aef360841646cbfe80a1b225c8b39c8380c
Python version: 2.7.11
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 6.8.0.oce-0.17
FreeCAD(799).jpg

I am not sure this will be helpful but in BricsCAD it is called "Real-Time Sphere Center".
Actually there is a whole group of 'Real-Time" view controls but "Rtrotctr " is the one I most frequently use.
https://www.bricsys.com/bricscad/help/ru_UA/CurVer/UsrGui/index.html?page=source%2F04_Viewing_your_drawing%2F04_05_View_Rotation.htm#Commands
[strike]
Try looking at this video: [/strike]

Update:
I remade the video .. audio is still pathetic but I am what I am.
https://www.youtube.com/watch?v=ISf9G-VNMRo&feature=youtu.be
 
LewTwo said:
"Blender" mode?
Right mouse click on your work space opens "Navigation style>", choose "Blender".
Now, if you "click and hold scroll wheel" on the mouse, you rotate the workspace around the point you clicked (kind of) with moving a mouse on the pad. Leave the scroll wheel when you found desired view.
Orthographic and Perspective
Is in View menu. Check the mode you like.
Is it what you are looking for?

P.S. This tutorial is nice to start from 0 and it is also good to switch from other 3D software, just switch to 1.5 or 2x speed and rush though to see function sets location.
https://www.youtube.com/watch?v=_HEvhclR4-o&list=PL6fZ68Cq3L8k0JhxnIVjZQN26cn9idJrj
 
parabellum said:
Right mouse click on your work space opens "Navigation style>", choose "Blender".
Now, if you "click and hold scroll wheel" on the mouse, you rotate the workspace around the point you clicked (kind of) with moving a mouse on the pad. Leave the scroll wheel when you found desired view.

Nope all I get from the scroll wheel is zoom in or zoom out :(
However in trying other combinations I found that "Shift plus Right Click" gives me that option :)

I did say that I might need to dig deeper into the UI.
 
Someone told me a few years ago that there's a much better "mouse" for CAD work, some kind of positioning device with more degrees of freedom. Mice are just too limiting. I don't recall what it was called. Sounded like a cross between a joystick and a trackball.

I think it was something like the "Space Navigator" or "Space Mouse".
 
I withdraw that objection to FreeCAD but I still have others ... principally the lack of 3D DWG/DXF support. I not saying it is a bad package but it does not suit my requirements. ... moving on
 
Alan B said:
Someone told me a few years ago that there's a much better "mouse" for CAD work, some kind of positioning device with more degrees of freedom. Mice are just too limiting. I don't recall what it was called. Sounded like a cross between a joystick and a trackball.

I think it was something like the "Space Navigator" or "Space Mouse".
Possibly you are thinking of the Orbit Trackball.
https://www.kensington.com/us/us/4493/k72337us/orbit-trackball-with-scroll-ring

or the 3DX Space mouse (I had to look it up). They were all the rage with SolidWorks operators a few years back
https://www.kensington.com/us/us/4493/k72337us/orbit-trackball-with-scroll-ring
 
Alan B said:
Someone told me a few years ago that there's a much better "mouse" for CAD work, some kind of positioning device with more degrees of freedom. Mice are just too limiting. I don't recall what it was called. Sounded like a cross between a joystick and a trackball.

Well there is this:
Polhemus POWERTRAK 360™
 
Alan B said:
No, these:

https://www.3dconnexion.com/products/spacemouse.html

Looks like they use it in addition to a mouse.
As the IT manager I was somewhat prejudice against those. It was possible that the CAD operators might find them more productive. However any cost savings went into the project manager's budget and the purchase/support cost came out of my budget. I wound eating that cost along with the cost of those infernal presentation pointing devices that seldom worked.
 
The cost of ergonomic issues far exceeds many other costs, as the average was something like 40k$ each, so anything that reduced the ergo load on the operators was a cheap investment. Mice are very bad for ergo, so minimizing dependence on them, and spreading some load to the other hand is quite valuable.
 
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