Drill motor conversion kits - guaging interest

Been playing about with a basic design for a drill motor conversion kit that will allow you to essentially take the motor and gearbox out of a cheap cordless drill and quickly and easily mount it. Parts would be 3D printed. Prototypes are in PLA for ease and quickness but final ones would likely be in nylon. Still got a good bit of work to do with tolerances (hence the crack in the picture) but I was looking to see if it's something there would be an interest for before I develop the idea further?

I'd also be looking for an established team to test them in the arena to see if they are suitable for combat (to a point!) before sale.

Attachment 6031

You wouldn't be able to make these fast enough. Sort out some wheels as well and you'd have an inbox full, picking up where gimson and robochallenge left off.

So that's a thumbs up from Dave

How about a double pack to have two motors driving a single wheel?

Adam, these are only meant a a very quick and easy way to use a single drill motor. Machining up casings etc would add to the cost and complexity of the assembly (the casing in the pic comes out the drill gearbox). Generally a single drill motor will be able to spin a wheel on a featherweight so going with twice the power doesn't really gain you all that much. Nice idea though.

looks good. would probably be a lot easier than screwing the drill casings onto the bottom of the bots. Will keep an eye on this one.

Ah I see. Was thinking along the whyachi multi drive principle.

I still use drills in my Feather so i'd be happy to give these a test, Hatchet tends to give it's internals a good shaking around.

I am going to start off with a couple drill motors in my new build and I'd defo pick up a couple of these if they were available

Thanks for the feedback everyone. I'll keep on with the development of these and see if I can't get something in the next couple of weeks that I would be happy to send into an arena.

This sounds fantastic - I think there's some real money to be made from this, especially if you can source some compatible wheels too.

Lol! Unfortunately Rory there's not much beyond pocket money to be made once everything is tallied up however I'm happy to fill the gap that there is for first timers (and those with experience!) looking for an easy bolt in solution for a featherweight drive train.

Is a decent quality nylon 3D print really that expensive? I guess it depends how much people are willing to pay. But yeah, I love that you're willing to help out people who don't want to faff around for ages crafting motor mounts and such.

A 100% infill for strength and rigidity 3D print in high quality nylon isn't expensive materially but there is a fair bit of time involved to print it. The other thing I'm keeping in mind is that I don't want to stray into competing with Ellis and his more high end solutions. This is meant to be a cheap and easy way to get yourself going.

Ohh I see. Yeah that makes a lot of sense.

What is their strength like Gary? I've tried something similar (Replacing GR01 parts) with 3D printed ABS. 4 Walls, 100% fill, 0.3mm layers and they would delaminate when I applied any load to the axles. Could well just be the printer.

Along with the mounting holes for 550 motors, could you add 19mm mounting holes for small brushless motors? With some shortened shafts, this could be a very small and light drive train!

Alex, Nylon is far superior to ABS when it comes to loading however it's an absolute pain to print with. Requires much slower print speeds, higher temperatures and a bunch of other precautions. The inter layer bonding when printed properly is much much better hence why I'll be interested to see how these handle in the arena.

As far as secondary mounting holes, not a problem. Two or four holes at 19mm diameter?

It would be two, countersunk on the gearbox side.

How much do you reckon a pair will go for?

I might be new to robots but not new to using the technology around 3D printing, printing in Nylon would be a much better alternative to using other materials, but i do think that structurally the 3D print will not hold up should the machine take one huge knock, de-lamination regardless of material used is still a critical factor (given some of the FW's sizes, shapes and weights along with the shear damage they can inflict) or awkward landing.

I could suggest 3D printing using one of the metal compounds available should your printer be capable of using these, as their tensile strength is greater than Nylon.

However that said... and not to take anything away from you in terms of ingenuity but...couldn't the mounts be made up using blocks of HDPE and just have then CNC'ed, or for cheaper options since its relatively a simple structure, a block made up of the right size and using a pillar drill, forstner bits and drill bits in various sizes which will in turn provide a much simpler quicker, cheaper and yet stronger mount?

I'll work out pricing once they have had some testing.

Of course it could delaminate. This is why I'm looking to have it tested out before I consider selling them.

Unfortunately my budget doesn't stretch to a metal 3D printer and if it did then the parts would cost more than most bots.

Similar blocks have been made in the past with HDPE or Nylon but I've got a 3D printer sat there so want to give it a go.

Get them CNC router-ed, would be cheaper and tougher! Just make a small jig for the off-axis mounting holes so it's quick and easy to place them with a desktop pillar drill.

Gary, could it be worth experimenting with some of the metal-fill filaments? I don't know if you've heard of them but they are printed on FDM printers (No expensive laser sintering) but are more expensive. I don't know if any of your machines would be able to use them as I think they need quite a high hotend temperature and a full metal hotend as they are quite abrasive, along side a heated bed.
I found some filaments on amazon quick, never used any metal-fil before however so I can't vouch for any of them.
Copper : https://www.amazon.co.uk/colorFabb-C...opper+filament

Aluminium : https://www.amazon.co.uk/FilaMETAL-A...um+filament+3d

Steel : https://www.amazon.co.uk/AlephObject...steel+filament

I would make them in two halves then just use some threaded rod with two nylock nuts on the end to clamp through a base plate or such, I've done this with a CNC mill with some random plastic we had laying around and it worked really well, but it would be interesting to see what you come up with.

Ewan, CNC routing and then manually drilling may be beneficial in some regards but the fact I have the printer sitting there with the material good to go is what is pushing me down this route. The fact that I can also very quickly and easy ramp up and down production is a big bonus too. Changes to the design are also incredibly quick and easy to put in place.

In terms of material properties, the nylon I'm using has the following spec when printed,

Tensile Strength = 8,100PSI
Modulus PSI = 72,932
Max Elongation at break = 31%

Up there with a good few virgin plastics.

Jack, I'm aware of the various metal fill materials. These however tend to be for asthetics more than function. The metal particles are generally suspended in a PLA type material giving no advantage over PLA which would be too brittle in this context. Oh and my hot end with happily go to 300 deg plus. My heated bed happily to 150 deg if need be. The joys of developing your own 3D printer over buying one off the shelf :)

I got a bit more done yesterday / this morning than I thought i would. So here is version 1.0 of the mounts in nylon *fanfare*

Attachment 6032

Few things to note, the bolts need to be a touch longer. I used some that I had hanging around. Squeezing the gearbox casing in can be a bit tricky but there's enough flex in the material to allow it to do so. Had it running for a half hour on a power supply and there were no binding issues.

Onwards to some static loading tests to see when the mount fails and then dynamic tests. Working out how to make the testing applicable to the arena will be interesting.

look good but can you do them in pink?

Being fairly new to this, I assume nylon is pretty similar to HDPE (500) as far as density goes? Is nylon commonly used for feathers for chassis material like the base of a robot for instance?

Graeme the nylon can be dyed in any colour using conventional acid clothing dyes suitable for nylon material so yes, pink is an option

Dan, nylon can be used for chassis material yes. You can find the density with a quick google search.

Quote:

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Originally Posted by typhoon_driver

Graeme the nylon can be dyed in any colour using conventional acid clothing dyes suitable for nylon material so yes, pink is an option

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Now we are talking!

Quote:

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Originally Posted by typhoon_driver

Tensile Strength = 8,100PSI
Modulus PSI = 72,932
Max Elongation at break = 31%

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Taulman 910 alloy?

we have a winner :)

Yes it is.

It's great stuff! Keep it sealed up though, water content in the air wrecks it (found out the hard way).

I recently started using Nylforce from Fiber Force. Its around a 1:5 mix of carbon fibers and nylon. Most other carbon filaments I've tried are terrible gimmicks, but mixed with nylon its actually pretty good. I found T910A to be quite flexible while nylforce seems to be extremely rigid and still exceptionally strong and light.
You should check it out!
http://www.fiberforce.it/nylforce-carbon-fiber/

*edit, 1 part carbon 5 parts nylon, not the reverse!

I store mine in a heated vacuum tank. The vacuum drops the boiling point of the water and the gentle heat then causes it to evaporate and condense on the cool lid. I then wipe off the moisture. Rinse and repeat to remove all moisture from the filament. Storing in the sealed vacuum then stops any more moisture getting in.

Printing also means keeping it dry so I have a sealed set up so the only time the filament sees the atmosphere is when it exits the extruder.

I'll take a look at the other filaments, cheers!

Snazzy setup! And here's me with my tupperware and packs of silica gel!

Haha, it's on the higher end of filament storage for sure :)

Quote:

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Originally Posted by typhoon_driver

Alex, Nylon is far superior to ABS when it comes to loading however it's an absolute pain to print with. Requires much slower print speeds, higher temperatures and a bunch of other precautions. The inter layer bonding when printed properly is much much better hence why I'll be interested to see how these handle in the arena.

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Ah, ok. I've only ever printed in ABS. Tried PLA several times but it always seems to get gunked up in the printer head.

What filament supplier, hot end, temperature and retraction were you using?

The PLA was the stuff that came with the printer some 3 years ago. It was vaccum sealed. As for settings, the makerbot Defaults. The ABS defaults work a treat so I figured they would be fine too. After it kept happening I checked online to see what others used an none seemed to have any problems with the same settings. Its not that important to us right now. The ABS works and its cheap so we will be sticking to that. But if we need it fixing I know who to ask :-)

Fair enough. I've used some filament that is utter junk before. Interestingly price is rarely a differing factor. Some of the best I've used being hatchbox but it's only available periodically on amazon uk. Filaprints own premium stuff is good.

It's funny that your go to is ABS. I hate the stuff but then I'm generally printing very large pieces where warping is a real issue and ABS tends to delaminate after a while although I may have just had a batch of poor ABS! PLA is my standard go to material.

Time for a quick update. I've been quiet on this thread for the past few weeks as I was working away from home. I'm now back and whilst I was away, a batch of bearings, bolts, nuts etc have all arrived so I'm hoping to have a few beta test version kits together for people to test and give me feedback on.

Did some testing this morning and was very happy with the results with some room for improvement (I'll upload pics in a bit).

I bolted the assembly to an piece of 10mm ali. As a very quick and nasty bit of static loading I put PP3Ds 31kg disc on the end of the shaft. After a half hour the mounts were still dimensionally fine and holding onto the weight without issue.

To test dynamic shocking i made a quick and nasty wheel with a nut heated and sunk into a wheel. I then took my sledgehammer and gave it a knock from above my head. The wheel came off instantly leaving the nut which was hardly surprising. The mount however was perfectly in place. Knocks from all directions were absorbed nicely by the material until a sideways knock bend the shaft in the housing. So it looks like I'll need to add a second bearing mount to the front piece similar to what ewan had to do with the gimsons. Not the end of the world.

What i was very encouraged to see was that the nylon really seemed to absorbed the shock. The motor did move during the impact but it returned to it's original position.

I realise this is all less than scientific but it gives me confidence in the material.