WIP - Graber I3 updated to A3

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nemesis
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WIP - Graber I3 updated to A3

Postby nemesis » Mon Mar 07, 2016 12:58 pm

Hello all,
a snapshot of an actual Work In Progress

I'm currently reverse-engineering the Graber i3 from S Graber based on its DXF files.
the target is to be sure nothing is missing for the day I will start the real printer.

I Used the "group" function from the Draft Workbench to use the DXF, then convert the wire to Sketches.
each single part as a "MainP" worksheet with parameter.
then a made some sub assembly with assembly 2, and a larger one with all the parts.

the target is to have all the part fully tunable according the technology use to cut them. normally it's a laser cut process, but as I have no access to laser cut, I may use a "classical" CNC so I need to adapt design to the CNC.
for the moment nothing is changed from the GraberI3 version.
I need to finalize all the detail.
then I will start to constraint correctly all the sketches and make the appropriate changes.

by the way constraints in the assembly are not all perfect, but it does the job.
other point, the "edit" function works quite well, but it looks better to change parts from the sub assembly outside the big one.

Git Repo if someone wants the files https://github.com/Nemesis81/GraberI3_Freecad.git
edit : in the git repo link or broken to edit part, as the location looks to be absolute. by the way anyone knows how to update it?

OS: Mac OS X
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.16.6510 (Git)
Build type: Release
Branch: (detached from 556ff4a)
Hash: 556ff4a4ac4f1dbfbdd9c6cc0e669a96f739465a
Python version: 2.7.11
Qt version: 4.8.7
Coin version: 3.1.3
OCC version: 6.8.0.oce-0.17
Attachments
GraberI3.png
GraberI3.png (364.79 KiB) Viewed 3724 times
Last edited by nemesis on Tue Sep 11, 2018 7:45 pm, edited 1 time in total.
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nemesis
Posts: 344
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Location: France, Lyon

Re: WIP - Graber I3

Postby nemesis » Mon Mar 14, 2016 9:58 pm

Little Update with a full re-assembly.
Only 3 DOF lefts, the 3 for each axis.
added motors and some fasteners.

I'm wondering if there is a way to pilot them with a python script? I guess this is possible as the function to see DOF is available.
Need to go deeper into this.
Attachments
graber_2.png
graber_2.png (395.18 KiB) Viewed 3487 times
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NormandC
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Re: WIP - Graber I3

Postby NormandC » Tue Mar 15, 2016 2:18 am

Nice work nemesis! :)

I don't know if you're familiar with the Arch Panel object... I'm not sure it could have been useful to you (I'm thinking about the lasercut frame parts), but you may be interested in knowing what was the planning for this tool. I don't think it's been worked on much since its introduction. See Yorik's blog about it: http://yorik.uncreated.net/guestblog.php?2014=156
nemesis wrote:I'm wondering if there is a way to pilot them with a python script?
Definitely! But I am not a coder myself so I wouldn't know where to start.
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nemesis
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Re: WIP - Graber I3

Postby nemesis » Tue Mar 15, 2016 7:17 am

In fact :
The dxf files made available on the wikihouse site seem to have a weird formatting that FreeCAD doesn't read well, so I opened and resaved it in LibreCAD, then FreeCAD opened it correctly. Then, it's just a matter of selecting all the profiles and pressing the Panel button. The profiles that have holes can be done in two different ways: either making a panel, extruding the hole, then subtracting, or, better, first turning both the profile and the hole into a single sketch with the Draft2Sketch tool, then creating the panel.
indeed that's exactly what I did, except I split the parts from the DXF downloaded from github inside librecad.
when I opened the full dxf in freaked it was lagging too much for me.

so
-1 I split the parts in different dxf files
-2 create a sketch from wires, then validate the sketch automatically to close it. I also change circle that where not circle in the Dxf.
-3 create a profusion with the thickness linked to a spreadsheet with all the parameters I want to manage (thanks to expression support on 0.16!!)
-4 assembled the printer, working with the strategy of 4 main Sub assembly (the from, the Y carriage, Z Carriage, and X carriage).

now I'm looking at the problems.
for example there are some clash between lateral big parts and the central ones when I make the assembly (when it's too short, it's too short..)
so now I'm re-designing each sketch to got it well constrained and put inside it my parameters from my process (As I said, I may not have access to a laser cut so I need to but some minimum process radius.
triplus
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Re: WIP - Graber I3

Postby triplus » Tue Mar 15, 2016 9:48 am

Looking good.
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nemesis
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Re: WIP - Graber I3

Postby nemesis » Tue Mar 15, 2016 8:43 pm

So, I try the animation Workbench but I have an issue to use the assembly constraint as controller.
so
it's working with the move controller, the parts are moving.... the good point is the animation in the assembly2 WB, where I can see that my constraint are consistent. and that's the important at the end :D
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nemesis
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Re: WIP - Graber I3 updated to A3

Postby nemesis » Tue Sep 11, 2018 7:44 pm

So,
after 2 years, I came back to this project and updated it with Assembly3, mainly for A3 testing purpose.
all aprts are also updated to 0.17/0.18
design of parts is not perfect... clearly
Graber ASM3.png
Graber ASM3.png (260.8 KiB) Viewed 1436 times
triplus
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Re: WIP - Graber I3 updated to A3

Postby triplus » Tue Sep 18, 2018 10:21 am

Hi @nemesis.

It would be great if you could share your opinion on how Assembly 2 / Assembly 3 experience ended up being. That is doing the same project in both of them.
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nemesis
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Re: WIP - Graber I3 updated to A3

Postby nemesis » Tue Sep 18, 2018 8:24 pm

triplus wrote:
Tue Sep 18, 2018 10:21 am
Hi @nemesis.

It would be great if you could share your opinion on how Assembly 2 / Assembly 3 experience ended up being. That is doing the same project in both of them.
Well, not a bad Idea ;)

let's tlk first about assembly2.

pros of assembly2 :
  • quick to understand
  • quick to use and to get an assembly done when you have already all the parts designed, or if you work with imported files found on the web
cons of assembly 2
  • designing inside the assembly is impossible, you need to modify the file outside of it and then update it
  • complex modification ends to a nightmare if you don't have a methodology define before each modification. I mean if you just modify the size of an extrusion, there is no issue, if you start to re-define completely a part, you need to first delete the constraint inside the assembly and then the rebuilt them. but it may ends to a headache when you have a constraints between various parts.
  • you cannot use other things than the one available in your final solid


pros of Assembly 3
  • designing a small assembly within one file or a big one with multiple file is possible and it can be mixed ... I don't see the use case of a mixed assembly in an industrial environment, but for a personal project it can be cool. You can have your small library of component that you want to put inside little assembly without the need of many file (for example a bearing)
  • you can design inside the assembly, even if the file outside of it
  • you can make big modification in your design, it is quite easy to update the constraint (indeed you need to update the element). For example you can build part with only volume to simulate there position, and size, and then go deeper in the design of each part quite easily.
  • link for multiple instance of one part are just a must have
  • an assembly file is very lightweight when just pointing to external file as it is just a bunch of links
  • Links to All type of feature/element (by element I mean sketch, point, edge, face or whatever) allow total freedom
cons of assembly 3
  • not easy to learn without reading the manual (yes I'm the kind of guy who doesn't read IKEA manual) so you must have a look at the wiki in github or to this site to get the philosophy of the beast ;)
  • there is so much possibility inside it that you need a clear plan to build something complicated. My case was easy as this is an already define assembly, but starting from scratch needs a good preparation..... but this would be the case with all assembly WB and all software.
  • interface is not easy to handle, I guess some ergonomic improvement are possible, or some right click possibility could be interesting.
  • when you load a big assembly, like the printer, you have something like 20 files open, so it can be tricky to navigate in the tree view. Even with Freezed subassembly it can be huge.
From my point of view I will not go back to assembly2.
Assembly3 looks complicated at the beginning, but once you get the philosophy of it it is very easy to handle it. indeed the the WB has the defects of its qualities. as you can do a lot of things, you will make a lot of mistake. But I think it's always like this when you learn a new stuff. At least for me.
Also as I already said, the possibilities open with links are easy to imagine to be implemented in other WB.
for example this assembly solution :
Screenshot_20180918_221415.png
Screenshot_20180918_221415.png (6.92 KiB) Viewed 1177 times
It is always the same on each part of the printer.
so if you define a file with each element of this assembly, you can easily imagine to "plug" it directly in all the files needed. so when you want to modify something, you just modify the source/body file.
I'm actually trying to do it, and find the best way to achieve this result. this is exactly what lattice2 is doing today, and I guess if link was merged into master, it may simplify it. Bu I know, there are huuuge discussion about it, as I'm unable to give a devloper POV, I will stay in my User POV, and I will vote for it ;)

ps: I may update the list if I see big pros or cons
triplus
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Re: WIP - Graber I3 updated to A3

Postby triplus » Wed Sep 19, 2018 10:50 pm

Thanks for the feedback. Always nice to read such opinions from end users.

P.S. Although not advised AFAIK you can assemble in single document with Assembly 2.