VIIC 1:45 modell

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bill
Posts: 320
Joined: Fri Jan 09, 2015 9:25 pm

Re: VIIC 1:45 modell

Postby bill » Fri May 11, 2018 2:39 am

I was wondering what modulates ON/OFF the laser in your gcode?

Where did you acquire/purchase the 15W laser module?
hds
Posts: 52
Joined: Tue Feb 14, 2017 8:23 am

Re: VIIC 1:45 modell

Postby hds » Fri May 11, 2018 3:28 pm

finished the frames, "Helling (slade)" and most of the stringers. For the new aft section i have to cut a second set of stringers.

Laser settings:
I do use just plain "grbl". The cutter is from "Eleks maker".
The 15W Laser module is from "Aliexpress" (I'am not affiliated with or get any payment wahtsoever.) Search for "Blue Laser cut module 15W" or similar.
The is PWM modulated by Pin11 of the arduinio board.
On/Off is set by "m3" and "m4" grbl commands in the software. Speed is set with "F number" and the PWM is set with "S number".
I did setup the layers in the DXF drawings in a way that "dxf2gcode" takes it in as steering commands.
In the "gcode sender" you would want to set "$31=1" for the grbl firmware to get into laser mode.

Best
Heiko
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bill
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Re: VIIC 1:45 modell

Postby bill » Fri May 11, 2018 3:41 pm

hds wrote:
Fri May 11, 2018 3:28 pm
...The 15W Laser module
Thanks for info.
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ppemawm
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Re: VIIC 1:45 modell

Postby ppemawm » Wed May 16, 2018 12:41 am

hds wrote:
Fri May 11, 2018 3:28 pm
finished the frames, "Helling (slade)" and most of the stringers.....
How cool IS this?
I am really interested in following your updates. This is a well done presentation.
Thanks for continuing to share your progress.
hds
Posts: 52
Joined: Tue Feb 14, 2017 8:23 am

Re: VIIC 1:45 modell

Postby hds » Tue May 29, 2018 1:52 pm

Finished plastification of frames and stringers. Got acrylic material for WTC and rubber seals.
I like to get some hydrodynamic coefficients for a pitch regulator. Therefore the FreeCAD model has been stripped out of non essential stuff. The mesh in GMSH worked out pretty ok. Now it needs to be plugged into OpenFoam. Not sure if it makes sense at all. But what is life without a challenge ...
VIIC_gmsh_forum.jpg
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thschrader
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Location: Germany

Re: VIIC 1:45 modell

Postby thschrader » Tue May 29, 2018 2:18 pm

hds wrote:
Tue May 29, 2018 1:52 pm
Now it needs to be plugged into OpenFoam.
https://www.youtube.com/watch?v=uV84p_GTUPU
hds: cool project!
freecad-heini-1
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Re: VIIC 1:45 modell

Postby freecad-heini-1 » Wed May 30, 2018 10:55 am

Thank you so much for your great work.
hds
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Joined: Tue Feb 14, 2017 8:23 am

Re: VIIC 1:45 modell

Postby hds » Sat Jun 02, 2018 3:52 pm

Started to put together the DIY "Airfix" Kit. Beginning with the new aft section. Added some more aluminium bars as reinforcements for the motor and rudder forces. Probably over doing but so what.
Checked the WTC and the rubber O-rings. Fits perfectly and checked if the WTC does slide on the bars and not on the frames. One of the reasons i had to redo many of the frames. Maybe these will be carbon bars to avoid scratching the WTC too much while sliding in/out.
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WTCfit2.jpg
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hds
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Re: VIIC 1:45 modell

Postby hds » Sun Jun 03, 2018 2:45 pm

Sunday morning the slade slipped out. These assembled frames have to dry thoroughly before remounting the building slip.
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hds
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Re: VIIC 1:45 modell

Postby hds » Tue Jun 05, 2018 12:51 pm

Meshing howto for CFD.
FlowChannelVIIC.jpg
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"Fish in aspic ..."


In case someone is trying to create a mesh for CFD or such from FC here are some experiences of a hard fight over the last 5 days.

1) Don't use "Ruled Surfaces". Use "Loft" instead. Reason: They are exported differently for example into a ".step" file. The former will not be recognized as a volume by meshing tools. The latter will.<br/>
2) Get your geometry right ! Can't be emphazised enough. I had 4 mistakes where lines did not match the endpoints. Debugging this is not really easy <cough> . So do it right from the beginning. The time spend here will pay off in the end.

In case you need to mass convert over 500 surfaces (as i had to do) these python lines worked for me:

Code: Select all

# get Ruled Surface
obj=FreeCAD.ActiveDocument.Objects
for i in obj:
   if "Ruled_Surface" in i.Name:
      print "#############\n"
      print i.Name + " " + i.Curve1[0].Name + " " + i.Curve2[0].Name + "\n"
      # Get Child Lines/Splines      
      c1=App.getDocument("VIIC_Rumpf_Surf2Loft").getObject(i.Curve1[0].Name)
      c2=App.getDocument("VIIC_Rumpf_Surf2Loft").getObject(i.Curve2[0].Name)
      # Create Loft      
      ttt=App.getDocument('VIIC_Rumpf_Surf2Loft').addObject('Part::Loft','Loft')
      ttt.Sections=[App.getDocument("VIIC_Rumpf_Surf2Loft").getObject(c1.Name) , App.getDocument("VIIC_Rumpf_Surf2Loft").getObject(c2.Name)]
      App.getDocument("VIIC_Rumpf_Surf2Loft").removeObject(i.Name)

App.ActiveDocument.recompute()
And some observations where FC got in the way real hard:
a) Why can i select vertices from the drawing sheet when doing ruled surfaces but doing lofts i have to scroll through an endless list ?
b) Why can i select a "group" within the Draft WB but not in the Part WB for example ?

gmshVolCheck.jpg
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Debugging the "fish" in gmsh i.e. checking if you get a proper volume. The outer box is a flow channel for example and the inner "hole" is the sub. The whole mesh can then go into OpenFoam.