Using a CNC Router to Machine Aerospace Grade Mold Patterns (part 2)

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Part 1: • Using a CNC Router to ...
DarkAero 1 - www.darkaero.com/aircraft
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In this video we go over how we machined the mold patterns (also referred to as master molds or plugs) for the DarkAero 1 aircraft. We also talk about strategies for machining accurate multi-section plugs on your router.
Some of the key strategies for making a high quality, aerospace grade plug include selecting the right plug materials (tooling board), having a good method for securing them to your router table, and being strategic about how you program your tool paths.
If you enjoyed this video and would like to see more of this type of content, follow along as we work to create the fastest, longest range aircraft you can build in your garage.
More information on DarkAero can be found on our website and other social media accounts:
www.darkaero.com
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[@SuperYellowsubmarin]

You've got this 100% right. Very impressed by your talent guys. Wish you a lot of success.

[@DarkAeroInc]

Thank you so much!

[@SuperYellowsubmarin]

@@DarkAeroInc Have you guys worked as manufacturing engineers ? Either that or you are very good at learning.

[@hcr-motorworks]

Finally part 2! Thanks fellas

[@edthompson9569]

I really enjoy this. Thank you very much.

[@DavidSL64]

Very informative. Lots of thinking goes into those parts.

[@user-tv5dt3nm9y]

So well explained. Thanks.

[@varokke137]

You are now my most favourite youtube channel. Thank you Sir.

[@garyplewa9277]

Wow, very impressive. I am looking forward to your subsequent videos and the finished airplane.

[@RifullOfTheWest]

There is a bike I've wanted to design for so long and this helps my knowledge grow how to make molds and plugs. ty

[@xnavyro]

The array of talent is very impressive, i wish you all the best & can’t wait to see the final product? Good luck!

[@keithskillz90210]

Wow, I built my own router and what I learned with months of experience, you taught in a 12 minute video. Lots of good info

[@DarkAeroInc]

Thank you for the kind words! Building your own router actually sounds a lot more challenging to me. 👍🤓

[@ddegn]

Great video! I learned a lot. I have a CNC router I'm still working on. It's great to see how tooling board can be cut and layered to save on costs.

[@mh369]

Thanks for sharing your valuable info!!

[@DarkAeroInc]

You’re welcome! 👍

[@RenegadeADV]

Really enjoyed this video, learned a lot from it. Giving me damn ideas now, and that always gets expensive! But glad I watched!

[@TitusLivy777]

If you ever find yourself wondering what topic you should cover in your next video, I'd like to suggest that you take us much deeper into the details of your manufacturing process. I'm particularly interested in the processes through which you proceed from CAD drawing -> plug -> mold -> part. I should confess that my interest is purely driven by idle curiosity, so I can't reasonably ask you to devote much time to a task that will not move your project forward. But hey, keeping us viewers entertained/educated is perhaps not a total waste of time. Of course, I understand that you may not want to reveal proprietary manufacturing processes, but I probably wouldn't understand those anyway. So the "kindergarten" version of carbon fiber manufacturing will be more than enough to keep me awed and confused (a chronic condition I'm afraid). In any case, I enjoy your videos, and I'm grateful that you take the time to make them!

[@ryanmcgowan3061]

@11:30 Tidbits like this are what make KZbin great for this sort of platform. You learn these sort of things by very costly experience otherwise.

[@BenTheMagnifice]

You got a great logo man.

[@DarkAeroInc]

Thank you!

[@illla]

When you do multisection plug make two holes on the datum bottom face of the plug at the ends of the plug. Place all those holes in one line on all sections of the plug and when you will assemble the plug use those holes and dowel pins inserted in those holes to align the sections. It is the proper way to alight the sections of the plug rather than using the sections split faces. You also can use those holes to control the length of the plug, not only straightness, just maintain a little gap between the plug sections to be able to adjust the plugs positions.

[@jhouser972]

Awesome video. Could you post a link where I can purchase this tooling board?

[@stevemelton966]

I am going to start wearing my hat like that. Turned up and just a little to the side. Not perfectly straight. That's because they are crazy. Crazy good!

[@DarkAeroInc]

Thanks Steve! I've said this to Ryley and River, but I'm not sure why I can't figure out how to keep my hat on straight. Oh well! :)

[@Anton-zb9dc]

Does alabaster (gypsum) have significantly higher thermal expansion coefficient?

[@Ciprian-Amarandei]

Is higher density foam like extruded polystyrene a good alternative?

[@hokiebama1187]

what densities of tooling board are used, when vendor? what resin is used for infusion? vendor?

[@ibrahimfirat990]

Hi guys! Which material do you use on foam which is gray?

[@ZOD268]

For tooling material - Necuron :)

[@RexusKing]

Nice analogy on Gordon Ramsey! Have you guys looked at those Kuka robot arm types of machines? I know they are much higher priced than the router, but you could probably machine a whole plug without needing to separate it into parts?

[@DarkAeroInc]

We actually have researched those. The idea of that is really compelling. I think the big challenge there is achieving the right dimensional accuracy but also don’t know if it could handle machining the higher density tooling board and still get accurate results.

[@Thomas..Anderson]

900th like was from me. Just that you know.

[@addicted2climbing]

I just watched both parts. Wow so informative. Good timing too as I am about to order a similar router. Was considering the 5'x10' Avid Pro but space is tight so maybe I can get by with 4'x8'. However will mostly cut thin sheet aluminum for an airplane that was plans built but i own the rights and will be kitting it. When you ordered your machine, did you have them add the extra crossbars or did you just order from 8020 yourself. Also it looks like you have more welded cross braces on the leg kit. Can you confirm? I already have my electronics (clearpath Servos) and an ATC S30 spindle since I will need the auto tool changing. Also have same Series 3 Tormach as you. Very inspiring to see you pull this all off with the same tools I have. I shoudl be able to make a low Tech Ultralight if your able to make this high tech aircraft. So inspired by your work and been following. Only disagreement is I am a Solidworks guy from so long ago I can't make the switch to Onshape. :) Oh one last question I am also getting the 8" risers, but was going to get the 12" Z axis as I may need the extra height for a rotary axis I will make to cut the fishmouth in 4130 and 6061 tubing. Did you ever consider the 12" Z axis to be able to go below the table, or off the side if needed? My rotary may end up beside the machine installed always with the longer boom option.

[@addicted2climbing]

Aircraft plans are here: www.cloudbaseaviation.com

[@DarkAeroInc]

Marc, thank you for watching and for the questions. We ordered additional crossbars and cross braces after we already received the machine. I'm not sure why Avid doesn't just do 8020 angled braces, but I would do those instead. We will likely drop our welded braces for those down the road. If you are planning on using the machine to primarily cut thin sheet aluminum I wouldn't opt for the 12" Z axis. I would look into incorporating a mist cooler as well for cutting aluminum on the router. If you want to cut tubing, it may be more efficient to outsource that portion to a place like Precision Tube Laser in Nevada. We don't have a lot of experience cutting aluminum with our router so I'm hesitant to speak to it too much. The "Breaking Taps" kzbin.info/door/06HVrkOL33D5lLnCPjr6NQ KZbin channel seems to have a lot more time on his router cutting aluminum and can probably speak to it better than us. Good luck with your aircraft! Excited for you!

[@Sean-Aviation]

beautifully explained. how do you overcome the Z axis limitations (8"-tool)? do you split the plug drawing into sections and fix them together later on?

[@DarkAeroInc]

Thank you! Yes, for taller plugs we split them up into sections, machine them out and then combined them back together for making the mold.

[@Sean-Aviation]

@@DarkAeroInc cool. one thing i didn't understand is that your plug at the beginning of the video seemed very tall and unfinished. how did you machine the whole piece with the Z axis? very nice work on your plane! well done.

[@georgespapillon364]

Hello ! Very informative video. Thank you. What is the cost of tooling board ? And with one have you here in this video ? Thank you, George

[@DarkAeroInc]

George, thanks for watching and the kind words! Not sure what your tooling board projects look like so we don't necessarily want to recommend exactly what we've used. A good place to look for tooling board companies is the exhibitor list for CAMX (composites and advanced materials expo). We went to this a few years back to get a good grasp on which tooling board made most sense for our application. You don't have to physically go to learn more though, you can check out their list of exhibitors online to get a really good overview of what's out there.

[@MJOLNIR49]

Are there any other KZbin channels like this documenting the development process for their product on the CNC floor?

[@BearcatB]

Yes. Check our Raptor Aircraft. Large CNC machine used to make the plugs.

[@nevillecreativitymentor]

Do you have a vlog on how you made one actual PLUG!?

[@DarkAeroInc]

We don’t at this time but that could make for a good, informative video. 🤔

[@snowgoer540]

Just saw watched the Garmin Osh Kosh video with the Patey brothers, one thing they mentioned that suck out to me and reminded me of your build is how carbon fiber breaks down under the UV from the sunlight. How do you plan to prevent that? Further they said that the heat from the sun causes the carbon fiber to get “soft” and lose its rigidity, going on to say that some manufactures limit dark colors on their carbon products. How do you plan to handle that as well? Especially because I don’t think your design has a metal frame to pull strength from.

[@DarkAeroInc]

Thanks for the question. The resin matrix that holds a carbon fiber composite together is what will determine these properties and not the fiber itself. Some carbon fiber composites use resins like vinyl ester that actually cure under UV. In the case of the resin used in our parts, the parts are cured in an oven to give them higher temperature capability so they maintain their desired mechanical properties even under higher temperature conditions. UV radiation does have an effect on our resin and requires that our plane be coated in a UV blocking paint.

[@timkremer]

​@@DarkAeroInc curious. Since you're baking in an oven anyway, I'm wondering why you're going with resin infusion instead of prepreg carbon fibre?

[@DanFrederiksen]

You could 3D print a flimsy shape that would't be smooth anyway, then add a CF layer and weld in a tube skeleton, then finish it as a plug. Say you were to make a plug of the entire fuselage, that would be very heavy to deal with. Hint hint single piece fuselage is a good thing.

[@DarkAeroInc]

Dan, you could definitely take different approaches to this. In general, from our experience, its best to avoid trying to combine different materials and different processes to avoid tolerance stack-ups.

[@DanFrederiksen]

@@DarkAeroInc sure, making one massive solid plug will tend to be quite stable. To a point. As a free body, say the entire fuselage, a solid piece might be problematic.

[@mrschultze1]

Is there a video explaining the process of pulling a mold from the plug? How is this done?

[@DarkAeroInc]

Not yet. That’s more of a “not public info” type of content at this time but we may do a video on that down the road.

[@mrschultze1]

Sounds good. I thought I missed a video. Looking forward to the finished product.

[@bradley3549]

There are some great videos out there on KZbin I've seen if you search for something like multi part fiberglass molds or similar terms.

[@jacksonsmith4648]

Lights-out machining with a budget machine. Brave...

[@DarkAeroInc]

no guts, no glory ;)

[@bradley3549]

budget machine = budget repairs. YOLO.

[@boriskolnestrov9957]

Goodbye clay mold new technologies are faster accurate and reliable, good job guys nice 👍

[@johniii1220]

Where do you get your tooling board from?

[@yagwaw]

And what does it approximately cost?

[@SuperYellowsubmarin]

FYI polyurethane tooling board typically costs $3 per liter and epoxy $7 per liter.

[@johniii1220]

AeroGarage where is the best place to buy tooling board?

[@SuperYellowsubmarin]

@@johniii1220 if you're in the US I guess General Plastics is a good place to go

[@Jobbawabbahahahaha]

John III freeman’s manufacturing makes some great stuff.

[@RCjunkie]

were is the link for part 1

[@DarkAeroInc]

Kevin, the link to part 1 is in the description of the video. :)

[@felixsu375]

I take it aluminum is too expensive for what you need to do? I can see small parts using aluminum but those plugs look really big.

[@armenakhakobyan6456]

pls whats the name of that tooling board???

[@DarkAeroInc]

Armenak, thank you for checking out the video. The tooling board is a mix of two different densities of polyurethane tooling board. If you do a quick Google search for "polyurethane tooling board" you should get a list of both manufactures and distributors for your area.

[@armenakhakobyan6456]

@@DarkAeroInc Thank you brother am beginer and your response was very usefull !!!

[@kurtlindner]

-and now I want to build a plane.

[@marcusrickeard1983]

Climb milling vs conventional milling, has to be programmed

[@jamesso6811]

yall hiring?

[@user-ol1qm9ey7g]

การบินที่ง่ายก็คือทำให้ข้อมูลการบินเหมือนรถยนต์ที่วิ่งบนถนนเราไปสถานที่ต่างๆถูกต้องเพราะเราอ่านป้ายจราจร

[@13anomalous16]

Walgreens sells frozen pizzas?

[@ScottLindelof]

A frozen pizza from Walgreens... 🤔

[@DarkAeroInc]

You ever eaten one of them?

[@ScottLindelof]

@@DarkAeroInc nah but I hear they're pretty Nice

[@slevinshafel9395]

7:58 to much work and waste time. Just use 4-5 axis CNC machine to make the entire positive for mold.

[@DarkAeroInc]

Thanks for watching and the feedback! We actually mention in part 1 that the ideal setup would be to pair a really nice 5 axis machine with tooling board. Because we were budget constrained, we went with high grade tooling board with a more economical router instead.

[@Dug6666666]

@@DarkAeroInc I use a 5 axis router I use at work with a 2.4x5.4m x 1.5m H machining envelope. It feels the norm to me, but I guess I'm kinda spoilt really :) Great talk on plug making, all good advice. Can't remember if you covered join placement to minimize feather edges but that's all I would add. We get a mixture of customers for plugs. Some want tooling board and a good finish, some want a slightly undersized one in polystyrene and they have a labor force that puts a hard glass shell over that then bring to a finish. Typically the boat hull people go down that road and the motor racing and defence types go the tooling board. Haven't had any aero plug work, more aluminum spare parts.