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Old Jan 12, 2014, 11:42 AM
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Airman87's Avatar
Sweden, Dalarna County, Sälen
Joined Apr 2007
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Build Log
1.6m F3F racer From CAD to Mold to Plane

New year new projects!
I thought it was time to test my new invested cnc machine and what better to do when draw up 1,6meter slope racer and mill some molds?
Im a completly newbie to everything from cad drawing to cnc milling but not composite construction. So i hope in some help from all of you out there to push me forward in this project.

The plane is going to be a v-tail around 1,6m wingspan 2piece wing. Home brewed airfoils from 10% at the rot to 7,8% from the middle of the wing to wing rot. 10% You say? Yepp thats right. The reason for this is that im going to mount the wing servos in the wing rot to get an easy acces and have a completley built in linkage without using rds. Im throwing up the airfoils on here so that you can judge them yourself. But i think succeded pretty well. As my maximum x tevel on my cnc machine is 830mm the fuse is also going to be a 2piece construction. Splitted just aft of the wing with the tail servos mounted in the aft part to get easy acces to the servos even here and to be able to actually have it as a 2piece constrution. Ballast tube will be moulded in the aft part.

I upload some pictures on my drawing so far and hopefully im going to mill the v tail molds on thursday or friday if everything goes as planned.
Please feel free fill in with questions, suggestions, comments and kind words to push me forward with this project
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Old Jan 12, 2014, 02:14 PM
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Tehachapi Jim's Avatar
United States, CA, Tehachapi
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I want to see this as.of progresses. Please keep posting as it goes.

Jim
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Old Jan 12, 2014, 03:14 PM
13149876
Airman87's Avatar
Sweden, Dalarna County, Sälen
Joined Apr 2007
159 Posts
I will try to keep up the posting here. And if i dont. Please remind me to do so!

Here comes a litle picture of a quick sketchup of the fuse that i made tonight. Having a hard time to get it to look god then the part under the wing need to be straight because of the 2piece fuse.

//Kalle
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Old Jan 13, 2014, 03:28 AM
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Airman,
I'm watching with interest. What CAD and CAM software are you using?
Martin.
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Old Jan 13, 2014, 10:13 AM
13149876
Airman87's Avatar
Sweden, Dalarna County, Sälen
Joined Apr 2007
159 Posts
Martin
Using Solidworks and Vectric cut 2D/3D
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Old Jan 13, 2014, 02:29 PM
13149876
Airman87's Avatar
Sweden, Dalarna County, Sälen
Joined Apr 2007
159 Posts
Smal uppdate on the the fuse outline. Thinned out the rear end and the nose cone. Started to draw the shape of some frames and there they should be. Still having problems to decide how the two fuse parts should be shaped there they join together. I want there to be space enoght for some serius ballast. But in the mean time i want to be able to mount the servos right into the aft fuse part without getting them to far back because of weight distrubution in case of making a light setup as well.

My plan is to mill thing wing and stabilizer in negative molds out of plexiglass. And the fuse will be a positive mold because of some problematic shapes aroaund the wing. Havent decided what material yet but maybe mdf.

Two questions to you solidworks and vectric users out there.
When im trying to make the wing mould. In the last step when making the parting surface. The program says somthing like "cannot knit surfaces together" and refuses to do it. What could be wrong? A gladly share the wing file if someone would take a look at it.
Vectric users. Then im trying to make the cutting paths for my stab mold. IS there any way to make the program to not to cut the outline of the parts in the roughing and finishing toolpath? And just do it the cut out toolpath? Would save a lot of time.

//Kalle
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Last edited by Airman87; Jan 13, 2014 at 03:35 PM.
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Old Jan 13, 2014, 04:28 PM
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Joined Oct 2010
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Airman,
Welcome to the world of Cad, G-code, CNC and hours of fustration!

Remember it's a building process but it will all come together.

1- Making molds out of plexiglass is a mistake. Hard to get a smooth surface. You are better off getting corian or Hi-Mac countertop material. Machines like butter. Will polish out to a glass like surface. Make all test cuts in cheap foam until you become better in learning your CNC skills. You WILL make mistakes! Making molds out of MDF also sucks as you have to seal it and it's just too time consuming.

2- Not sure what you are asking on your rough and finish cut-out question. Remember you can use "LAYERS" in your solidworks to aid you for different cut files. Veritec is limited to what you can pick to cut or not cut. I dumped it and went to RinoCad which can do anything. Still Veritec will do a lot and you should cut your teeth on it.

3- Jump over to Cad/Cam thread for help on your mesh issue. Sounds like you have a OPEN area and it will not Mesh if you have a open area.

Good luck and never give up.

Steve in Maine
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Old Jan 13, 2014, 04:56 PM
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Airman87's Avatar
Sweden, Dalarna County, Sälen
Joined Apr 2007
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Sunnybreeze:
First of all. Big thanks for your input!
Hours of frustration and head pain!? Tell me about it! But i guess thats what i like with this as well... Sometimes at least....
I have heard some complaints about milling molds of plexi but not really listned to it. I dont know, maybe its the clear shiny surface that speaks to me. So im probably going to try it anyway. At least on some smal parts. My old bad habbit of reinventing the wheel
But, by a happening a friend of mine who i buillt the mill together with just got some corain. But only in sheets of 12mm thicknes. Do you know any good way to glue them together to get greater thicknes?
What speeds and feedrates are you using?

Yes, i bought vectric for its simple layout and thought that it was just what i needed. But im allredy starting to realize that it has its limitations. But on the other hand, i alredy think i need a bigger machine as well.....

I will change forum with the wing problem. But right now its bed time.
//Kalle
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Old Jan 14, 2014, 03:11 AM
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Kalle,
Make sure that you export the Solidworks file at the highest resolution possible ( I assume you will export as .STL). Otherwise you may get polygons appearing on the cut surface.
Test all your cut files on a cheap material like, MDF, before committing to expensive corian or plexiglass.
Have a look through my Teaser F5B thread on the CAD/CAM forum.
Martin
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Old Jan 14, 2014, 12:39 PM
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Vectric issues

Kalle,

The issue with vectric cutting out the part at the same time as shaping it is possibly down to the way the file was imported into Cut3D.

How did you export from Solidworks?

I'm no expert but I do own Cut3D as well as Aspire. I also have access to Solidworks. If I can help, please let me know.

Martin.
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Old Jan 17, 2014, 04:36 AM
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Airman87's Avatar
Sweden, Dalarna County, Sälen
Joined Apr 2007
159 Posts
Sorry for not replying faster. Crashed with my snowmodbile and have been in hospital for a few days.
So my planed cnc milling theese days went to hell. And no uppdates in drawing yet.
I do export to .stl file and then pick it up thought cut3 "load 3d file". Still having the same problem that it wants to cut it out in both roughing and finishing stage.
And it wont cut the holes in the LE either?
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Old Jan 17, 2014, 04:53 AM
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Kalle,
I am of the opinion that the cutting out in roughing and finishing is down to the file being exported from Solidworks as an STL file. It converts it to a single entity/part which is what Cut3D sees.
You could try exporting just the plan view and holes in the LE as dxf 2D files to overlay the part in Cut3D. They could be used as selectable vectors then.
Failing that, if you wish to share the files, I could have a go using Aspire. I can give you access to my Skydrive if you don't want to put the files on this forum.
Martin.
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Old Jan 17, 2014, 03:51 PM
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Airman87's Avatar
Sweden, Dalarna County, Sälen
Joined Apr 2007
159 Posts
Didnt know it was possible to import a dxf file over an stl in cut 3d. Will try that one.
My goal is to share the complete mold files to everyone that wants them. As long as no one is making money on my work and maybe share a picture of the work they done with my files. So i have no problem at all to share.
I will complete the the stab molds and try again with the new tip. Otherwise id like you to give it a try!
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Old Jan 23, 2014, 05:31 PM
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Airman87's Avatar
Sweden, Dalarna County, Sälen
Joined Apr 2007
159 Posts
Finaly finished all the paperwork for my little snowmobile incident and got some hours left over for drawing and thinking.
I have found out that if i make the mold edge square, insted of following the the wings siluette. Cut 3d dose not "cut out" the part in roughing and finishing stages.
And the only reason for using the siluette shape was to save machine time.
So i did remake the stabilizer mold tonight and here are some pictures of the progress.
Still havent tested out the hole cutting thing but im now confident that i will solve it one way or another.
//Kalle
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Old Jan 24, 2014, 05:42 AM
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Kale,
Looking good. I am glad you have solved one problem. If you overlay a dxf of the hole positions onto the tail plane mould, you will be able to select the hole vectors and cut them out using the inside of the line or drill them using cut3d.
Martin.
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