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In short, it's a way to recycle plastics in your garage. Blueprints for the machines are free, so if you are savvy enough, you can just shredd some old plastic you'd put otherwise in the trash and have your own injection-moulding apparature. Or extruder. Or rotation moulding, but I see fairly limitted use for that last one.
Now, the biggest problem is most likely the fabrication of injection moulds you could actually use for something in the hobby. Some serious madskillz are required to make anything more complicated than a spinning top. On the other hand, as far as I know, GW and forge produce their stuff in an injection moulding process too, so there IS potential. And turning your old shampoo bottle that comes virtually for free into let's say a piece of wall or similar scenery, if not a complete new miniature sure as hell is nice.
What do you say, fellow dakkanauts? Anyone with enough madskillz or access to mashinery that can produce moulds?
Small scale tackle and toy accessory makers have been doing it for years. You can even get some of the "commercial" versions for cheap from prototyping shops as they continue to replace those sorts of things with 3D printers:
(a small scale DIY and a somewhat larger single cavity prototype machine)
The issues with recycling are a bit more complicated. Beyond just making sure all your plastics are the same category, there are various additives that go into making molding pellets - even taking "virgin" miscasts and shredding them can cause issues with the process.
The fresh pellets are dirt cheap though - so, I'll let someone else process my garbage and use clean pellets.
I think the hard part is getting a mold, not necessarily a machine... as Sean_OBrien linked to, "manual" injection molding machines have been around for some time. But if you don't have a mold of, say, a stone wall to inject plastic into, it's not much use for terrain making. And making those molds still requires a machinist or at least a separate CNC milling machine, and knowledge of how to use it, etc.
Small scale tackle and toy accessory makers have been doing it for years. You can even get some of the "commercial" versions for cheap from prototyping shops as they continue to replace those sorts of things with 3D printers:
(a small scale DIY and a somewhat larger single cavity prototype machine)
The issues with recycling are a bit more complicated. Beyond just making sure all your plastics are the same category, there are various additives that go into making molding pellets - even taking "virgin" miscasts and shredding them can cause issues with the process.
I know about the problems with polymers. There are tons of additives - hardeners, plasticisers, filler, processing aid - polymer architecture (branching, brushes, copolymers of all kinds) and much more to consider. That's not the point though if you don't have much in the way of requirements other than "should be solid at usual temperatures and fill out the mould nicely".
My concern is a different one:
I think the hard part is getting a mold, not necessarily a machine... as Sean_OBrien linked to, "manual" injection molding machines have been around for some time. But if you don't have a mold of, say, a stone wall to inject plastic into, it's not much use for terrain making. And making those molds still requires a machinist or at least a separate CNC milling machine, and knowledge of how to use it, etc.
As RiTides points out, the moulds are the actual problem. I have no idea about mechanical engineering and CNC drills. I guess there must be some companys though which you can provide with some sort of 3D model and they'll gear up the mould for you. This is the actual challenge for our hobby.
Also:
Sean_OBrien wrote: The fresh pellets are dirt cheap though - so, I'll let someone else process my garbage and use clean pellets.
They very attitude that led to this project in the first place.
This message was edited 2 times. Last update was at 2014/12/02 13:27:56
Recycle GW sprues into the machine.
Recast non-GW models using the plastic.
Non-GW models are now made out of GW materials.
Therefore, I can use them in GW stores.
Problem, Kirby?
Peregrine - If you like the army buy it, and don't worry about what one random person on the internet thinks.
Do you strictly need a metal mould for this kind of thing, especially with the kind of garage-kit hobby-bodge nature? I'm wondering if some other kind of mould material could stand in, if only for a short term. (which, again, would seem to fit with the nature of this thing)
Do you strictly need a metal mould for this kind of thing, especially with the kind of garage-kit hobby-bodge nature? I'm wondering if some other kind of mould material could stand in, if only for a short term. (which, again, would seem to fit with the nature of this thing)
Yes...ish.
I know a guy who does fishing lures with one of the smaller machines. The plastic he uses is rather gummy...a bit more like jello than hard plastic. The molds are in a metal shell - but are actually made out of a resin of some form.
There is a lot of material engineering that would let you get to a harder plastic without using a metal mold - but there is a limit as to how soft your mold material can be without having to go to something like a diecast or other liquid molding process (as opposed to amorphous plastics...).
I know many of the garage kit vinyl guys also do not use regular metal molds. They normally only get a hundred or so shots - and their setup is closer to a diecasting process (more heat - less pressure) but for hobby projects - it is still somewhat feasible.
There are a couple of companies who are playing with 3D printed molds (SLS metal powder). The printed mold is then held in a steel shell. Pretty good results - though there remain issues with surface refinement.
I've been doing a bit of work with a company in Denver who are looking to use 3D printing to create a master and then use that with EDM to create a traditional metal mold. Also, good results - though not quite ready for prime time. A few years back we set them up to allow hand carved masters to create their EDM tools.
That, and of course 6 axis CNC machines have dropped to the price where you can pick one up for about the same as a used car.
Sean_OBrien wrote: The fresh pellets are dirt cheap though - so, I'll let someone else process my garbage and use clean pellets.
They very attitude that led to this project in the first place.
Not against recycled pellets - just don't see the use in taking bottles, bags and what not out of the dumpster to get to that point.
I can buy 100% recycled pellets for cheaper than my time spent dumpster diving...cleaning...shredding...
As to why they aren't used often in new products - it has less to do with anything mentioned in that article and more to do with China not having any interest in using recycled pellets. They make most the plastic stuff...they supply their own plastic - which is very rarely recycled.
If you look at materials that are predominantly still sourced out of Western countries (aluminum, glass, steel, paper) the recycled content is 70% or higher.
But, the original point still exists. I can ring up Entec, tell them exactly what I want, get exactly what I want delivered to me, and not have to worry about dirty diapers.
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Kosake wrote: Or rotation moulding, but I see fairly limitted use for that last one.
Missed this bit.
I actually use my roto-mold quite a bit. Anytime I have something that is relatively large (terrain, ship hulls, the occasional windshield washer fluid tank...) - I will rotocast it. Once I have the hard candy shell - it can stay as is, or I can fill it with expanding foam to give it extra strength.
His design is a bit off though - looks as though it only rotates on one axis - which is rather limiting. Much better to rotate on both the X-Y and the Y-Z axis to get good coverage on the walls of the mold. His would no doubt result in thin or even bare spots on the sides.
This message was edited 2 times. Last update was at 2014/12/02 20:31:25
Do you strictly need a metal mould for this kind of thing, especially with the kind of garage-kit hobby-bodge nature? I'm wondering if some other kind of mould material could stand in, if only for a short term. (which, again, would seem to fit with the nature of this thing)
Sean had some good points there.
Strictly speaking, you don't have to have a metal mould. Anything that does not expand too much and can withstand the heat of your molten polymer can do the trick. There are polymers that are stable at above 600°C. Wood might work. Ceramics, Glas... whatever you can think off. I just don't think that getting a mould from these materials is easier or cheaper.
And yeah, a CNC might be as cheap as an used car but I fear to calculate how many models you'd have to cast to earn your money back....
Laser sintering sounds great. 3D-Printed moulds would be ace, especially since the SLS-types are highly precise and once you have the machine the raw materials should be fairly cheap. Still, that would require some company to make your moulds for you and I don't see that happening cheap either.
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Verviedi wrote: Recycle GW sprues into the machine.
Recast non-GW models using the plastic.
Non-GW models are now made out of GW materials.
Therefore, I can use them in GW stores.
Problem, Kirby?
You earn five internets and a cookie, sir!
This message was edited 1 time. Last update was at 2014/12/02 21:49:32
Heat is easy...pressure is the hard part (and pressure with heat tends to be an even bigger pickle).
Most of the plastics that you would be looking at using for something like this would have a glassy state temperature of much less than 200°C (your PEs, your PSs, your PVCs, your polycarbonates...). More exotic materials which are able to withstand stuff like being put in an oven normally don't hit the recycle bin...at least not with any real frequency.
Most of those are either filled to achieve their heat resistance or are not a thermoplastic (silicone are one of the more popular ones right now). There are some polymides (nylon and aramid fiber for example) and polysulfones (very rarely scene outside of industrial uses) - but those are better suited to making prison shanks...
Verviedi wrote: Recycle GW sprues into the machine.
Recast non-GW models using the plastic.
Non-GW models are now made out of GW materials.
Therefore, I can use them in GW stores.
Problem, Kirby?
Verviedi wrote: Recycle GW sprues into the machine.
Recast non-GW models using the plastic.
Non-GW models are now made out of GW materials.
Therefore, I can use them in GW stores.
Problem, Kirby?
We have a winner!
On to the actual OP, by the time you bought the machine, bought the molds, and got the plastic you needed, would you really save that much money over just, you know, buying the models?
'I've played Guard for years, and the best piece of advice is to always utilize the Guard's best special rule: "we roll more dice than you" ' - stormleader
"Sector Imperialis: 25mm and 40mm Round Bases (40+20) 26€ (Including 32 skulls for basing) " GW design philosophy in a nutshell
Sean_OBrien wrote: Heat is easy...pressure is the hard part (and pressure with heat tends to be an even bigger pickle).
Most of the plastics that you would be looking at using for something like this would have a glassy state temperature of much less than 200°C (your PEs, your PSs, your PVCs, your polycarbonates...). More exotic materials which are able to withstand stuff like being put in an oven normally don't hit the recycle bin...at least not with any real frequency.
Most of those are either filled to achieve their heat resistance or are not a thermoplastic (silicone are one of the more popular ones right now). There are some polymides (nylon and aramid fiber for example) and polysulfones (very rarely scene outside of industrial uses) - but those are better suited to making prison shanks...
PE, PP, PS and the like are only casting material, you can't make a mould out of them. When speaking about highly resistant plastics I thought about aramides too, but those are difficult to process and rare besides. I don't thinkt that making a mould out of that would be any cheaper than metal.
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MrMoustaffa wrote: On to the actual OP, by the time you bought the machine, bought the molds, and got the plastic you needed, would you really save that much money over just, you know, buying the models?
The machine shouldn't be too expensive, the blueprints are free and you can build one yourself. Besides, you can use the same machine for a lot of stuff so it may or may not be a good idea anyways, provided you solve the problem with the moulds. The way I see this, even a quite simple mould will probably cost several hundred bucks, but that's just my guess. This is the actually interesting question here: Is it possible to get moulds cheap? I have actually no idea what a company would charge for a custom SLS-printed mould.
This message was edited 1 time. Last update was at 2014/12/03 08:40:09
Kosake wrote: [qu. This is the actually interesting question here: Is it possible to get moulds cheap? I have actually no idea what a company would charge for a custom SLS-printed mould.
Molds are not cheap. You're either going to pay someone quite a bit to make something for you or spend a good amount of money and ALOT of time making a home setup
As others have said, you've got to either own your own CNC machine or hire it out. If you want hard plastic minis, they've got to be metal to stand up to the heat of the melted plastic. You can save some $ by using aluminum rather than steel but even if you've got some guy in a garage with a CNC machine, the design and milling is time consuming. If hiring it out, you're probably looking at thousands of dollars at the absolute cheapest.
Ken at "Proxie Models" used to have a video detailing his setup, but it's down now which is a real shame. He uses a surplus injection molding machine (that probably cost as much to ship as to buy) with a homemade cooling system and a CNC machine. Unfortunately that video is down, but you can read about his process on his blog. http://proxiemodels.blogspot.com Most of the stuff about the machines, etc is in the first year of the blog 2011, but he's a good dude who could answer the kind of questions being raised here better than most.
PE, PP, PS and the like are only casting material, you can't make a mould out of them.
I know...my point was that those are the casting materials...the heat involved isn't that high - it is the pressure that they need to be able to withstand.
For speed - you also need good heat transfer, not heat resistance. You need to be able to cool the plastic down so that it solidifies before you can open the mold and eject it (benefit of aluminum versus steel...).
Right now...there are prototyping companies who are actually using plastic for their molds. The plastic just has to be able to survive the temperature of the plastic that you want to mold with (so polyurethane can be used with HIPS, ABS can be used with PE...). The plastic mold is held in a steel case to actually withstand the pressure.
They are not meant for large production runs. Something of a few hundred or so shots for R&D type purposes...but even there, for miniature related projects, 300 shots may be enough for actual commercial viability.
Kosake wrote: [qu. This is the actually interesting question here: Is it possible to get moulds cheap? I have actually no idea what a company would charge for a custom SLS-printed mould.
Molds are not cheap. You're either going to pay someone quite a bit to make something for you or spend a good amount of money and ALOT of time making a home setup
As others have said, you've got to either own your own CNC machine or hire it out. If you want hard plastic minis, they've got to be metal to stand up to the heat of the melted plastic. You can save some $ by using aluminum rather than steel but even if you've got some guy in a garage with a CNC machine, the design and milling is time consuming. If hiring it out, you're probably looking at thousands of dollars at the absolute cheapest.
Ken at "Proxie Models" used to have a video detailing his setup, but it's down now which is a real shame. He uses a surplus injection molding machine (that probably cost as much to ship as to buy) with a homemade cooling system and a CNC machine. Unfortunately that video is down, but you can read about his process on his blog. http://proxiemodels.blogspot.com Most of the stuff about the machines, etc is in the first year of the blog 2011, but he's a good dude who could answer the kind of questions being raised here better than most.
Again...not the heat, pressure. Yes, the plastic is hot and will burn you if you touch it...but that really isn't very hot in the grand scheme of things.
Kosake wrote: [qu. This is the actually interesting question here: Is it possible to get moulds cheap? I have actually no idea what a company would charge for a custom SLS-printed mould.
Molds are not cheap. You're either going to pay someone quite a bit to make something for you or spend a good amount of money and ALOT of time making a home setup
As others have said, you've got to either own your own CNC machine or hire it out. If you want hard plastic minis, they've got to be metal to stand up to the heat of the melted plastic. You can save some $ by using aluminum rather than steel but even if you've got some guy in a garage with a CNC machine, the design and milling is time consuming. If hiring it out, you're probably looking at thousands of dollars at the absolute cheapest.
My idea is to design moulds myself - Inventor and other CAD programs have special features that are supposed to help you in that very task. Once you have a CAD file ready, you could send it to a company of your choice who'd only have to feed it into their 3D printer or CNC grinder and voila, "cheap" mould.
You'd only have to pay for materials (block of steel or aluminium, can't be that expensive) and the actual drilling/3D-printing/whatever. With the drill being automated that only keeps the machine busy for so much time. Unless their books are choke-full and everything is running 24-7, I can't imagine them to charge so much for this.
Kosake wrote: [qu. This is the actually interesting question here: Is it possible to get moulds cheap? I have actually no idea what a company would charge for a custom SLS-printed mould.
Molds are not cheap. You're either going to pay someone quite a bit to make something for you or spend a good amount of money and ALOT of time making a home setup
As others have said, you've got to either own your own CNC machine or hire it out. If you want hard plastic minis, they've got to be metal to stand up to the heat of the melted plastic. You can save some $ by using aluminum rather than steel but even if you've got some guy in a garage with a CNC machine, the design and milling is time consuming. If hiring it out, you're probably looking at thousands of dollars at the absolute cheapest.
My idea is to design moulds myself - Inventor and other CAD programs have special features that are supposed to help you in that very task. Once you have a CAD file ready, you could send it to a company of your choice who'd only have to feed it into their 3D printer or CNC grinder and voila, "cheap" mould.
You'd only have to pay for materials (block of steel or aluminium, can't be that expensive) and the actual drilling/3D-printing/whatever. With the drill being automated that only keeps the machine busy for so much time. Unless their books are choke-full and everything is running 24-7, I can't imagine them to charge so much for this.
Mold making is never as cheap, quick or easy as you think it's going to be...
Specialty software can help point you in the right direction but it isn't going to give you a quality end item. Milling a mold is as much an art as it is a science, one that requires experinced engineers and machinests to make.
Heh, a mould that churns out 32mm bases would be neither complicated nor expensive, and you would produce like a zillion bases with it, especially since everyone in your group is likely in need of new bases soon. How about that?
Heh, a mould that churns out 32mm bases would be neither complicated nor expensive, and you would produce like a zillion bases with it, especially since everyone in your group is likely in need of new bases soon. How about that?
It will not be complicated, but it could still be expensive. The cost isn't in the material for the mold, it's for the time and expertise of the person making the mold. Unless you have a very high end CNC machine (in which case it will be alot more expensive to pay for the time) miling a block of metal still takes quite a bit of time.
If you've got the CAD files and some $, it may be workable to hire Proxie models to do the whole process for you. He could even do the CAD work for you. They've done products for several small companies and I doubt their rates are anything like a higher-end company. The Rust Forge Shipping containers for example are a Proxie-produced product.
Going it alone could work, but really only if you get the training or teach yourself to operate a CNC machine. Go read the Proxie posts I linked to before. It is possible to do it yourself, it's just going to take $ and ALOT of trial and error and learning time.
If you're remotely serious about this, I'd take the time to email the guy at Proxie Models and ask some questions (after reading his blog). Perhaps also contact "Champ Industries"
http://www.champindustries.net This is a guy who mostly makes racing bike sliders who also produces a small line of very nice plastic scenic bases. I don't know if he does his work in-house or contracts it out, or if he's even making any new products, but maybe he could give you some idea of what the process and expenses are.
All this to say plastic is possible, but it's alot easier to do a project in metal or resin unless you've got a good bit of time or $.
This message was edited 3 times. Last update was at 2014/12/04 14:44:03
Heh, a mould that churns out 32mm bases would be neither complicated nor expensive, and you would produce like a zillion bases with it, especially since everyone in your group is likely in need of new bases soon. How about that?
With how cheaply plastic bases can be purchased retail you'd have to need a lot of bases to make up for the investment.
There is a reason why there aren't a ton of companies making plastic models...
Waaagh an' a 'alf
1500 Pts WIP 
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