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RC Keith CNC Hot Wire build log

thenated0g

Drinker of coffee, Maker of things
Mentor
#61
That would probably be workable for a straight wing where the wire is touching the same amount of foam all the time, but on a tapered or swept wing it would be changing constantly.
 
#62
That would probably be workable for a straight wing where the wire is touching the same amount of foam all the time, but on a tapered or swept wing it would be changing constantly.
Hence the option to pre-compute : I supposed the amount of foam at the different points of the cut could be computed, and forwarded as an additional "parameter" in the gcode (like the laser power is piloted in "classic" laser cutters)
 

thenated0g

Drinker of coffee, Maker of things
Mentor
#63
We got evacuated (all of lakeport, ca) for an entire week and than its been a few weeks of getting back to regular life and dealing with tons of smoke. Havent really been motivated to do anything rc. This is some footage from right before the fire. This is my first time using iron on color laminate, like you would use on balsa planes. Usually i would cover with 5mil iron on "new stuff" style laminate for wings. Really like the color. A little harder to use ad the temp range is much more sensitive compared to the clear stuff. But a heat gun tightens it up and it looks amazing. Colors really pop. Other side is going to be a silver color.

 
#65
Parts on order:

www.omc-stepperonline.com
x4 - Nema 23 Bipolar Motors 1.8deg 1.26Nm (178.4oz.in) 2.8A 2.5V 57x57x56mm 4 Wires
x4 - 6.35mm - 8mm Flexible Coupling 18x25mm CNC Stepper Motor Shaft Coupler
x4 - Nema 23 Bracket for Stepper Motor and Geared Stepper Motor Alloy Steel Bracket


Order total w/shipping to US: $115

Banggood.com
2x 8mm 500mm Lead 2mm Stainless Steel Lead Screw + T8 Nut For CNC 3D Printer Reprap
2x 8mm 400mm Lead 2mm Stainless Steel Lead Screw + T8 Nut For CNC 3D Printer Reprap

Are the 500 and 400mm leads enough?
 

thenated0g

Drinker of coffee, Maker of things
Mentor
#66
I cant remember if i updated the post or not but i ended up using 28 inch drawer slides in the horizontal axis so i ordered some longer screws and i ended up using the 500mm screws for the vertical axis.

"Enough" is an individualized problem. My current setup is a 700mmx1000mmx500mm cutting box. That's the area i can move the foam around. So right now its "enough" room to do the types of cuts i want. In the future im sure i will come up with something that wont fit in it and will have to figure that out.
 
#67
I cant remember if i updated the post or not but i ended up using 28 inch drawer slides in the horizontal axis so i ordered some longer screws and i ended up using the 500mm screws for the vertical axis.

"Enough" is an individualized problem. My current setup is a 700mmx1000mmx500mm cutting box. That's the area i can move the foam around. So right now its "enough" room to do the types of cuts i want. In the future im sure i will come up with something that wont fit in it and will have to figure that out.

Fair enough my friend :) I will start with the 1000mm RVS thread for the horizontal Axes and 500mm up.
 

HilldaFlyer

Well-known member
#68
Hey Nate, just saw this - Like Jon, I've had this on my list for a long time, probably 5 years but backed away because I'm not smart enough to figure out the software bits... on my own or so I thought. Thanks to you and everyone else for being a pioneer and blazing the way. I'm now reconsidering building one.
 

thenated0g

Drinker of coffee, Maker of things
Mentor
#69
Hey Nate, just saw this - Like Jon, I've had this on my list for a long time, probably 5 years but backed away because I'm not smart enough to figure out the software bits... on my own or so I thought. Thanks to you and everyone else for being a pioneer and blazing the way. I'm now reconsidering building one.
Keith just came out with his first video on Devfus software. This one of the packages this company sells, has been selling for many years actually. Devfus is for designing fuselages but they have other software that does wings. Pretty exciting the options it gives you. Definitely on my list to start using in the future

 

thenated0g

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Mentor
#70
I meant to be working on and posting more stuff in this thread with stuff im working on, but since the fires here in california and getting evacuated for a week i have had a really hard time getting back into my projects. So just taking some time off. I have been doing a little work here and there on the plank slope soarer. should have it ready for maiden soon.

Gentleman jack is my wingman
IMG_20180826_205422.jpg

AUW is about 930g, but CG is about an inch behind where i want it. But currently sitting at 8oz sqft or 3.99 cubic wing loading.
IMG_20180827_213122.jpg

Made 10x 33g (ish) copper pipe/lead ballast/epoxy and some wooden dowel spacers to put as many as i want in the ballast tube. This will allow me to increase the weight of the plane a little more than 20% on windy days.
IMG_20180901_202708.jpg
 

thenated0g

Drinker of coffee, Maker of things
Mentor
#71
Plank 2.0 is ready for maiden. Honestly the hardest part here at the end was trying to figure out how to program elevons in my x-lite as i hadn't used the version of opentx it has. Final weight and stats are in the second pic below. May be some time before i can get good wind and an opportunity to get maiden done.
 

Attachments

thenated0g

Drinker of coffee, Maker of things
Mentor
#72
I am going to do any new builds based off hot wire cutting in to their own threads. I will just do quick updates here for new stuff im working on related to this machine. Specifically at the moment i am going to get started in vacuum bagging the cores i cut. Ill post a link here after i right up that post.
IMG_20180918_203324.jpg
 

thenated0g

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Mentor
#74
Sharing some pictures of the thinnest cut i have done yet. This was a major reason i wanted to get into CNC hot cutting. Im sure with practice you could do this manually, but i am super happy with these cnc cuts. I could never do this manually and now that i have it dialed in i can repeat this cut anytime i want. This was cut on 28g renee wire using 5w of power.
IMG_20180921_210226.jpg
IMG_20180921_210234.jpg IMG_20180921_211035.jpg IMG_20180921_211917.jpg
 

thenated0g

Drinker of coffee, Maker of things
Mentor
#75

Made a little Instagram story last night as i was doing a test cut on the Jart stabilizers/elevator. I forgot i had the temp on my hotwire turned down for a previous cut job so it got all curvy at the end, but its still usable as the back end is always very thin and unusable anyways. Plus i am cutting multiple copies so i can begin learning how to vacuum bag laminate on to the wings.
 

thenated0g

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Mentor
#76
Heating update.
I have found that i generally have been cutting foam between 9w and 6w. At the moment i have been using a potentiometer that restricts the flow of power. Just a little led light knob. So when i adjust it it turns down the voltage and amps. That's why i have been using Watts. The downside of this is that renee wire really likes the higher voltages to work correctly. At the range of Wattage i have been using it the voltage is usually in the 9-11v range.

Well my little knob unit finally died ($8) so i have ordered a power supply unit from banggood that lets me adjust the voltage and amperage independently. So i can set the voltage at 24v and than control the heat with just the amp settings. This will give me the fine control i need to get cuts perfect.

Also what i have been doing for anything that is not a one off cut, for things i want to repeat, is i have been keeping notes, like a story board, of the position, foam type, thickness, and wattage. I will have to redu and relearn this heat setting but it will be much more exact in the future.

1538759835178.png
 

thenated0g

Drinker of coffee, Maker of things
Mentor
#77
Did some tuning and got a nice flat piece of glass to help with consistency. And some free foam from work to play with.