15 replies to this topic

[Jyang]

Hey everyone,

 

Hope this is the right place to post, I wasn't sure if this belonged here, or as a concept thread.

 

Basically, I'm hoping to 3D print a nerf flywheel blaster using a PLA printer with a 20x20x20 print capacity, that has yet to be calibrated, but having little experience with flywheels or 3D printing, I'm going to need a little bit of advice.

 

Firstly, because I don't have any better ideas for aesthetics, I'm planning on making a blaster with a similar appearance to the FG42, so the gun is going to be side-fed.

I've seen very little information on this online, and I'm not sure if it's because the only gun that springs to mind with side feeding is the raider (which seems largely unpopular), or if it's because side feeding is a bad design.

 

Secondly, I've found little in the way of people reinforcing their larger 3D prints, like stocks and grips with cheaper, stronger material like wood/metal rods.

Given that I'm planning on 3D printing the case, I'm tossing up between this or trying to find some broken/discarded nerf shells to use as casing, and building upon those instead.

 

Thirdly, I've several DC motors salvaged from printers I'm hoping to use.

The two on the far left are 130s, I believe, but I'm not sure of their specifications, so it's unlikely that I'm going to be using them.

From (fairly unreliable) datasheets I've found online, it appears that the third and fourth motors are capable of producing 12-15k RPM, which is no where near as fast as the desired 20k+ that I've heard reported from Rhino MTBs or the Tamiya Plasma Drives, but I feel as though through a combination of larger flywheels (3D printing custom flywheel cages is an option), and a higher torque, these should suffice.

For reference, I gather that the current "high end" motor is the Rhino MTB, producing 36k RPM, with the 2" radius stock flywheels, this results in tangential velocity of roughly 628fps, achieving the glass ceiling of 120fps

 

Since I'm happy achieving around 100fps, I feel as though this is overkill, especially since I only have NiMh batteries to work with. I'm wondering if anyone has any experience with high-torque, low-RPM motors like the ones I have?

Alternatively, I'm toying around with the possibility of using the third and fourth motors in my image as afterburners, with the small ones as launchers. Also, I should be able to mimic the shape of worker wheels, since I'm 3D printing the cage and wheels, anyway.

 

 

Anyway, I've got a ton of things to figure out, and I really appreciate you guys letting me post here.

[Phillip Roy]

3d printing the whole baster would not be ideal because the flywheels used by common blasters (such as the Stryfe) are made of molded plastic. However, you may pick up a trick or two by just making a custom shell. The printing project itself, being your learning ground, should be of a simple and modular design. Take for instance, the Nerf Stryfe: it all boils down to a mag well, dart pusher, and flywheel cage. For the flywheels, it would be smart to gut a blaster for them or buy aftermarket. 3d printing always gives me the warm fuzzies so I hope you are successful.

[Meaker VI]

Basically, I'm hoping to 3D print a nerf flywheel blaster using a PLA printer with a 20x20x20 print capacity, that has yet to be calibrated, but having little experience with flywheels or 3D printing, I'm going to need a little bit of advice.

Calibration: Do you have a glass build plate and heated bed? What model is it? I have a Duplicator i3 2.x, which has a very similar build area so I'm suspicious you have what I do. It was super easy to physically calibrate (Bed level and tight to build plate? Ok you're done), and if yours is also a D i3 I can give you the settings file I'm using so you don't need spend hours digitally calibrating like I did.
 

For the flywheels, it would be smart to gut a blaster for them or buy aftermarket.

 
Was about to say this. I've heard you can't make worthwhile flywheels on a 3d printer; I'll probably try it anyway at some point but I can see where there'd be problems.
 
I'd stick to the 130's or 180's that are available stock and from 3rd parties for motor size. There is no reason to go bigger, you'll just suck more power and those platforms seem to be working. I'd also skip the afterburner for now - maybe rig it up so you can add it on later, but initially just get something going.
 
I'm ok with side loading, but I think most players like vertical. It is more ambidextrous, but that can't be the only reason to use it. If you make it the right kind of modular, you could be able to rotate the mag well to wherever you want.
 

Secondly, I've found little in the way of people reinforcing their larger 3D prints, like stocks and grips with cheaper, stronger material like wood/metal rods.
Given that I'm planning on 3D printing the case, I'm tossing up between this or trying to find some broken/discarded nerf shells to use as casing, and building upon those instead.

I threatened to make a 3d printable Stryfe on Reddit the other day. I'm not inclined to do it now, but if you are, good on you. My recommendations (and head-notes for the project) are thus:

• Answering your question directly, I don't think you'll need reinforcement for this style blaster. The PSCR parts (with a magwell) are larger than a stryfe needs to be, and they bear way more load. If you do reinforce, use something readily available and cheap - 1-1/4" or 1" PVC, a flat bar of aluminum some dimension that can be replaced with a wooden or plastic one, a steel rod, etc. etc. Despite my recommendation, try to think of the non-US nerfers who don't have our weirdo plumbing conventions as well (And of metric users - if you can, make a part that is close to a real dimension in both Imperial and Metric).
• Make the blaster reciever based (real-steal) rather than split shell (nerf). The PSCR sort-of does this, by having the trigger and catch in a part you can just print and attach. In the case of a 3d printed stryfe, you'd want the trigger, pusher, and magwell to all be one part if possible. If not (sideloader), have the magwell attach to the rest in a way such that it will always allign correctly.
• Use stock flywheels/stock size motors and a stock-based cage design. No need to get crazy; then if someone has leftover stock parts (say, from making a strayven) they can just swap them in.
• Try to make the handle optional. It's tough with the trigger being in it, but I was thinking I could fit the trigger group in a 3/4" slot with some bolt holes through the sides to attach to a grip. Cutting a 3/4" slot is then easy in any material you'd like to use as a grip later. Then you can make a printed grip design (or two), players can make their own solid grip, or they can go the Captain Slug route and use two sheets of something with spacers. There might even be some convention for manufactured grips already like this that you could coopt.
• Try to use NERF-style attachment points. There are loads of attachments out there now, and players love to customize stuff. A barrel adapter, top rail, and stock adapter should be easy and probably exist on thingiverse or shapeways already.

I'll be watching this. Let me know if you want any more help/advice.

[DjOnslaught]

Everything Meaker VI said above is true and alot of good ideas in his post. As for the removable handle, you could only really do it be having swappable lower receivers which is not a bad idea actually. As for the horizontal mag well or rotating mag well, think more deploy and less raider/rampage in that case.

[Jyang]

Wow, so much useful information, thanks so much, guys!

 

3d printing the whole baster would not be ideal because the flywheels used by common blasters (such as the Stryfe) are made of molded plastic. 

 

This seems to be the consensus here, what's the primary issue with the wheels? If it's a matter of surface, I'm planning on doing the plastidip thing, or adding something onto the edges in order to increase friction, and if it's a matter of strength, would it be fixable by using 100% infill?

 

Calibration: Do you have a glass build plate and heated bed? What model is it? I have a Duplicator i3 2.x, which has a very similar build area so I'm suspicious you have what I do. It was super easy to physically calibrate (Bed level and tight to build plate? Ok you're done), and if yours is also a D i3 I can give you the settings file I'm using so you don't need spend hours digitally calibrating like I did.

 

I'm using a RepRap Prusa i3, due to living in Australia, but I feel as though the specifications would be really similar. But yeah, glass build plate, heated bed, that sort of thing.

 

I'd stick to the 130's or 180's that are available stock and from 3rd parties for motor size. There is no reason to go bigger, you'll just suck more power and those platforms seem to be working. I'd also skip the afterburner for now - maybe rig it up so you can add it on later, but initially just get something going.

 

I guess the power consumption thing makes sense, I just read an article on flywheels, and it seems as though I'll need higher than 25k RPM anyway. I'm a little surprised that I haven't stumbled across it before, though.

https://www.dropbox....eel Physics.pdf

 

I'm thinking of getting these (180 sizing it seems) to fulfill the RPM requirement (and price). The power draw is super low though, so I'm suspicious that the torque is super low as well. I'll set it up in a afterburner configuration just to be safe, like you said, I can just take them out, may as well get something going first.

http://www.ebay.com....tm/391265275191

The idea is that if the torque is too low sustain continuous fire, then a set of "afterburners" will help pick up the slack. For the first shot though, before torque drop, the afterburners won't actually do anything.

EDIT:

Whoops, mean to post these instead

http://www.ebay.com/itm/321829215483

 

 

• Answering your question directly, I don't think you'll need reinforcement for this style blaster. The PSCR parts (with a magwell) are larger than a stryfe needs to be, and they bear way more load. If you do reinforce, use something readily available and cheap - 1-1/4" or 1" PVC, a flat bar of aluminum some dimension that can be replaced with a wooden or plastic one, a steel rod, etc. etc. Despite my recommendation, try to think of the non-US nerfers who don't have our weirdo plumbing conventions as well (And of metric users - if you can, make a part that is close to a real dimension in both Imperial and Metric).

 

I was planning on using 6mm dowel rods initially, don't know why using 1" and 1/4" PVC didn't occur to me, that was really silly, given all of the double rainbows and other PVC based pipes out there.

 

What about the infill percentage the PSCR is using, though, it looks to be 100% infill, if I reinforce with PVC, do you think I'll be able to get away with something like 80% infill?

 

Also, yeah, imperial units make me cry . PSI to kPa conversion is part of the reason why this is going to be electronic instead of a pneumatic project.

 

• Make the blaster reciever based (real-steal) rather than split shell (nerf). The PSCR sort-of does this, by having the trigger and catch in a part you can just print and attach. In the case of a 3d printed stryfe, you'd want the trigger, pusher, and magwell to all be one part if possible. If not (sideloader), have the magwell attach to the rest in a way such that it will always allign correctly.

 

I assume that this means to a shell around the components, rather than having all the components mounted on a shell.

 

• Use stock flywheels/stock size motors and a stock-based cage design. No need to get crazy; then if someone has leftover stock parts (say, from making a strayven) they can just swap them in.
• Try to make the handle optional. It's tough with the trigger being in it, but I was thinking I could fit the trigger group in a 3/4" slot with some bolt holes through the sides to attach to a grip. Cutting a 3/4" slot is then easy in any material you'd like to use as a grip later. Then you can make a printed grip design (or two), players can make their own solid grip, or they can go the Captain Slug route and use two sheets of something with spacers. There might even be some convention for manufactured grips already like this that you could coopt.
• Try to use NERF-style attachment points. There are loads of attachments out there now, and players love to customize stuff. A barrel adapter, top rail, and stock adapter should be easy and probably exist on thingiverse or shapeways already.

I'll be watching this. Let me know if you want any more help/advice.

 

Everything Meaker VI said above is true and alot of good ideas in his post. As for the removable handle, you could only really do it be having swappable lower receivers which is not a bad idea actually. As for the horizontal mag well or rotating mag well, think more deploy and less raider/rampage in that case.

 

Modular design, got it!

 

Thanks so much for the help, especially Meaker, your post was great!

Edited by Jyang, 24 June 2016 - 05:56 PM.

[blitz]

 

 

 

This seems to be the consensus here, what's the primary issue with the wheels? If it's a matter of surface, I'm planning on doing the plastidip thing, or adding something onto the edges in order to increase friction, and if it's a matter of strength, would it be fixable by using 100% infill?

 

I'm thinking of getting these (180 sizing it seems) to fulfill the RPM requirement (and price). The power draw is super low though, so I'm suspicious that the torque is super low as well. I'll set it up in a afterburner configuration just to be safe, like you said, I can just take them out, may as well get something going first.

http://www.ebay.com....tm/391265275191

The idea is that if the torque is too low sustain continuous fire, then a set of "afterburners" will help pick up the slack. For the first shot though, before torque drop, the afterburners won't actually do anything.

 

 

 

As for the flywheels, its a matter of balance and consistency at high-ass rpm. 3D printing cannot create the perfectly balanced flywheels that Nerf and others are able to make. I'd recommend cannibalizing flywheels from a blaster or buying third-party products (ex. https://www.amazon.c...dp/B015NAF588).

 

As for your motors, talk to some Australians. The MakeTestBattle guys offer the "Hellcat" 180 motors, among other options. Support your country!

Edited by blitz, 24 June 2016 - 05:09 PM.

[Jyang]

 

 

As for the flywheels, its a matter of balance and consistency at high-ass rpm. 3D printing cannot create the perfectly balanced flywheels that Nerf and others are able to make. I'd recommend cannibalizing flywheels from a blaster or buying third-party products (ex. https://www.amazon.c...dp/B015NAF588).

 

 

That makes a lot of sense, I'll start off with 3D printed wheels, drilling holes to try balance the mass, but I'll probably eventually just grab worker wheels, or modify salvaged stryfe ones, if they don't work. Thanks for the heads up!

 

On a side note, has anyone tried using these? I mean I'm planning on using NiMH AAs, and I don't want to strap 20 batteries to my blaster, but it would be hilarious to see someone utilise the full 50K RPM.

http://www.ebay.com/...Y-/122001853342

[Meaker VI]

This seems to be the consensus here, what's the primary issue with the wheels? If it's a matter of surface, I'm planning on doing the plastidip thing, or adding something onto the edges in order to increase friction, and if it's a matter of strength, would it be fixable by using 100% infill?

Don't do either. You want the surface smooth, plastidip will wear off and cause problems. 100% infil doesn't solve questionable layer adhesion and wrong material choice - Hasbro appears to use something stronger than ABS for flywheels.
 
 

I'm using a RepRap Prusa i3, due to living in Australia, but I feel as though the specifications would be really similar.

Looks identical to my machine, just black plastic instead of black metal. Same architecture; not sure if my settings will work for you though you can try. Cura PLA profile attached:
 NERF Parts General 062416.zip   1.85KB   583 downloads
 

I guess the power consumption thing makes sense, I just read an article on flywheels, and it seems as though I'll need higher than 25k RPM anyway. I'm a little surprised that I haven't stumbled across it before, though.

Look into/ask around on Reddit about flywheel setups. As blitz says, one of your own Australians manufactures *perfect* 130 and 180 (Rhinos and Hellcats IIRC) motors for this application.
 
 

I was planning on using 6mm dowel rods initially, don't know why using 1" and 1/4" PVC didn't occur to me, that was really silly, given all of the double rainbows and other PVC based pipes out there.

Rods would be fine too.
 
 

What about the infill percentage the PSCR is using, though, it looks to be 100% infill, if I reinforce with PVC, do you think I'll be able to get away with something like 80% infill?

Woah! Way too high. Big parts are 1.6-3.0mm shell, 20% infill. Catch and PH are 100%.
 
 

I assume that this means to a shell around the components, rather than having all the components mounted on a shell.

Kind of. It's complex, so I'll explain later.

[Jyang]

Don't do either. You want the surface smooth, plastidip will wear off and cause problems. 100% infil doesn't solve questionable layer adhesion and wrong material choice - Hasbro appears to use something stronger than ABS for flywheels.
 
 
Looks identical to my machine, just black plastic instead of black metal. Same architecture; not sure if my settings will work for you though you can try. Cura PLA profile attached:
NERF Parts General 062416.zip
 

Look into/ask around on Reddit about flywheel setups. As blitz says, one of your own Australians manufactures *perfect* 130 and 180 (Rhinos and Hellcats IIRC) motors for this application.

 

I'm going to experiment with PVC-reinforced PLA flywheels, for SCIENCE. Maybe we'll try resin coating the wheels to assist with layer adhesion. This way I'll be able to mess around with the shape of the flywheels for optimisation, hopefully. The idea here is that by using concentric hollows, there's more surface area, so I can use hot glue/acetone/heat guns for reinforcement.

Here is a vague diagram.

 

Thanks for the settings, I'm looking into Cura as a replacement for Repetier, I hear that they allow more room for controlling various factors.

 

I just ordered some motors that are similar to the 180 Hellcats, they're 30k RPM, 9V, 0.4A instead of the 36k RPM 12V, 0.5A that the Hellcats offer, so tests should return similar results.

 

Woah! Way too high. Big parts are 1.6-3.0mm shell, 20% infill. Catch and PH are 100%.

 

Cool, so shell = 20%, functional parts = 100%.

Edited by Jyang, 25 June 2016 - 01:54 AM.

[Phillip Roy]

 
That makes a lot of sense, I'll start off with 3D printed wheels, drilling holes to try balance the mass, but I'll probably eventually just grab worker wheels, or modify salvaged stryfe ones, if they don't work. Thanks for the heads up!
 
On a side note, has anyone tried using these? I mean I'm planning on using NiMH AAs, and I don't want to strap 20 batteries to my blaster, but it would be hilarious to see someone utilise the full 50K RPM.
http://www.ebay.com/...Y-/122001853342

Use IMRs by lions wholesale. They fit in the stock battery tray, give good voltages, are rechargeable, and come at a good price. Take a look into it.

[Jyang]

Update on the 3D printing:
I'll have more time over the next couple weeks to get on with this project.

I'm still playing with the idea of getting the 3D printed flywheels to work, although some machining/alteration will be required to deal with the inaccuracies of printing.
So far, these are the results, just to put the vibration issues into scale:


Further changes to be made:
1. The shape of the flywheels may have to be changed to just a flat top, having to print supports is just a waste of space
2. I think that I have underextrusion issues, any help with cura in fixing this would be appreciated.
3. After toying with this, I think that I could get away with not having an entirely solid piece, and instead remove some plastic so the wheel looks like it has the spokes of a bicycle wheel. I'm not sure if this will create balancing issues, though, while I'm certain that there is sufficient strength.
4. In this case, the holes in the centre for the motor shaft were drilled out, I'm wondering how much accuracy there is to be had with printing, or if there are any other ways of getting a more perpendicular hole. I hope I won't have to get a drill press to do that. Perhaps sculpting putty, or hot glu might be a possible solution.
5. Consider the possibility of constructing a miniature lathe to smooth/grind the flywheels.

The 180 motors have yet to come at this stage.

[Meaker VI]

Update on the 3D printing:
I'll have more time over the next couple weeks to get on with this project.

I'm still playing with the idea of getting the 3D printed flywheels to work, although some machining/alteration will be required to deal with the inaccuracies of printing.
So far, these are the results, just to put the vibration issues into scale:

Further changes to be made:
1. The shape of the flywheels may have to be changed to just a flat top, having to print supports is just a waste of space

How are you printing it? That looks like it shouldn't need support to print correctly.

2. I think that I have underextrusion issues, any help with cura in fixing this would be appreciated.

 

Make sure you're using full settings under "Expert...", then under filament there should be a flow setting, change that to 105% and see if it helps.

3. After toying with this, I think that I could get away with not having an entirely solid piece, and instead remove some plastic so the wheel looks like it has the spokes of a bicycle wheel. I'm not sure if this will create balancing issues, though, while I'm certain that there is sufficient strength.

 

That'll probably cause balance issues. Circles instead of spokes would be easier for the machine and material, but you're probably not actually saving much doing it that way. FYI, I also wouldn't let the machine print any interior fill on something like this, going all-solid and preferably all-wall. The infill would definitely cause balance issues since it'd be pretty randomly distributed.

4. In this case, the holes in the centre for the motor shaft were drilled out, I'm wondering how much accuracy there is to be had with printing, or if there are any other ways of getting a more perpendicular hole. I hope I won't have to get a drill press to do that. Perhaps sculpting putty, or hot glu might be a possible solution.

 

IIRC, my machine is accurate to something like 0.01 mm in the X/Y directions. Let the machine drill the hole for you.

5. Consider the possibility of constructing a miniature lathe to smooth/grind the flywheels.

 

Not necessary IMO. However, while you're making flywheels, experiment with making them filleted instead of straight sided so they have more surface area in contact with the dart.

[Jyang]

 

Update on the 3D printing:
I'll have more time over the next couple weeks to get on with this project.

I'm still playing with the idea of getting the 3D printed flywheels to work, although some machining/alteration will be required to deal with the inaccuracies of printing.
So far, these are the results, just to put the vibration issues into scale:

Further changes to be made:
1. The shape of the flywheels may have to be changed to just a flat top, having to print supports is just a waste of space

How are you printing it? That looks like it shouldn't need support to print correctly.

2. I think that I have underextrusion issues, any help with cura in fixing this would be appreciated.

 

Make sure you're using full settings under "Expert...", then under filament there should be a flow setting, change that to 105% and see if it helps.

3. After toying with this, I think that I could get away with not having an entirely solid piece, and instead remove some plastic so the wheel looks like it has the spokes of a bicycle wheel. I'm not sure if this will create balancing issues, though, while I'm certain that there is sufficient strength.

 

That'll probably cause balance issues. Circles instead of spokes would be easier for the machine and material, but you're probably not actually saving much doing it that way. FYI, I also wouldn't let the machine print any interior fill on something like this, going all-solid and preferably all-wall. The infill would definitely cause balance issues since it'd be pretty randomly distributed.

4. In this case, the holes in the centre for the motor shaft were drilled out, I'm wondering how much accuracy there is to be had with printing, or if there are any other ways of getting a more perpendicular hole. I hope I won't have to get a drill press to do that. Perhaps sculpting putty, or hot glu might be a possible solution.

 

IIRC, my machine is accurate to something like 0.01 mm in the X/Y directions. Let the machine drill the hole for you.

5. Consider the possibility of constructing a miniature lathe to smooth/grind the flywheels.

 

Not necessary IMO. However, while you're making flywheels, experiment with making them filleted instead of straight sided so they have more surface area in contact with the dart.

 

 

 

Made a new flywheel.

2. Thanks, seemed to have helped, the filament seems more even now.

 

3. I found an alternative to this; I'm now printing with concentric infill.

 

4. Yeah, I found that for other prints, there were misalignments, I was worried that would happen with the holes. Turns out, they were just because they were odd sticking-out bits on the top.

 

5. I made the sides filleted and ridged, but I'm not sure if I went overboard with the ridge depth. I'm curious as to what might happen if I were to actually use these.

 

New considerations:

6. I'm going to be using about 7-8 NiMH in series to power the blaster, I'm wondering if I need to use a high-current switch, or if I can get away with using something like a tactile switch or a toggle switch. I'm wondering what experiences people have had with these previously.

Edited by Jyang, 06 July 2016 - 09:32 AM.

[Meaker VI]

5. I made the sides filleted and ridged, but I'm not sure if I went overboard with the ridge depth. I'm curious as to what might happen if I were to actually use these.

Ridges are probably overboard, just do smooth concave/fillet. There's a company that makes them with ridges, and the flywheelers on reddit seem to be of the opinion that concavity helps, ridges do not.
 

New considerations:
6. I'm going to be using about 7-8 NiMH in series to power the blaster, I'm wondering if I need to use a high-current switch, or if I can get away with using something like a tactile switch or a toggle switch. I'm wondering what experiences people have had with these previously.

This was recommended by a friend; I wouldn't know how to pick them so I don't know if that's like what you're thinking or not. For this stuff, seriously ask around on Reddit - specifically Foam_Data. Lipos with XT60 connectors seem standard. Here is a link to a complete loom prewired; it's got recommendations for extras.

As an aside, Here is a recently released smooth machined flywheel, and here is a machined aluminum flywheel cage. Motors, those parts + batteries would get you most of the way to a blaster.

Edited by Meaker VI, 10 July 2016 - 02:33 PM.

[Draconis]

Ridges are probably overboard, just do smooth concave/fillet. There's a company that makes them with ridges, and the flywheelers on reddit seem to be of the opinion that concavity helps, ridges do not.

Ridges probably do not help with grip, I agree, but they most certainly would increase the radial strength, and that should keep them from bowing out at speed.

[jkovarovics]

You can absolutely print flywheels. I've done it and they shoot Megas up to 120FPS. It's here http://www.fdl1.com. Two things though, I have them mounted on brushless motors so no friction fit here. The other, I do take a lot of care in getting my infill centered and I'm going to try just printing them at 100% in the future.

 

I've gone through more or less what you are suggesting here. If you have the wherewithal to design an entire blaster, do it. Don't let anyone tell you you shouldn't. I did it before I knew anyone to tell me otherwise and it worked out in the end. You probably want to design some sort of frame first then shell it. 3D printing is plenty strong as long as you design proper structure into your design.