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Well I've scored a great deal: for a school project I need to create a business plan for creating a miniatures game company. now I need to look into the manufacturing side of producing the minis. I've decided that resin will be the best material for what I need, so the question is: what manufacturing process should I use: spin casting or vacuum casting? I don't know much about manufacturing other than plastic extrusion, but I'm good with machines so i think that the real question is which process produces better quality minis faster? does anyone with experience in these processes know which would be better?

Well very few companies have got spin casing to work for resin: GW with finecast, Ed at Trollforged Miniatures with his stuff, and I think maybe a caster who's going to be working with Raging Heroes on their KS stuff

basically the resin has a several issues that make it tricky to spin cast,

1st is that it is far less dense than metal so it's harder to get it to fill the whole mould during a spin

2nd is Resin likes to retail bubbles that can get stuck in the mould obscuring details and weakening the figure (think of the first year of finecast for what this looks like)

3rd you can't open the mould till the resin is set, so if you use a slow setting mix it's easy to de-gas in a vacuum
, and you have plenty of time to spin BUT your productivity is very low, a fast setting mix is much harder to work with, but if you can manage you can increase productivity

4th unlike metal you can't reuse bad casts, they just need to be thrown out (so if you're not doing well you'll be tempted to sell stuff that's not good enough, thus trashing you're reputation... again see GW finecast when it first came out)

Casting in gravity moulds (with Vacuum or similar) is a lot more labour intensive and slower, but is probably easier to get working (and it's what all the real high end mini makers use)

You could consider 3d printing?

OrlandotheTechnicoloured wrote:Well very few companies have got spin casing to work for resin: GW with finecast, Ed at Trollforged Miniatures with his stuff, and I think maybe a caster who's going to be working with Raging Heroes on their KS stuff

basically the resin has a several issues that make it tricky to spin cast,

1st is that it is far less dense than metal so it's harder to get it to fill the whole mould during a spin

2nd is Resin likes to retail bubbles that can get stuck in the mould obscuring details and weakening the figure (think of the first year of finecast for what this looks like)

3rd you can't open the mould till the resin is set, so if you use a slow setting mix it's easy to de-gas in a vacuum
, and you have plenty of time to spin BUT your productivity is very low, a fast setting mix is much harder to work with, but if you can manage you can increase productivity

4th unlike metal you can't reuse bad casts, they just need to be thrown out (so if you're not doing well you'll be tempted to sell stuff that's not good enough, thus trashing you're reputation... again see GW finecast when it first came out)

Casting in gravity moulds (with Vacuum or similar) is a lot more labour intensive and slower, but is probably easier to get working (and it's what all the real high end mini makers use)

ah I see, so gravity molds are the way to go. I was unaware what the big guys were using, but that makes it a lot easier to work this out.

Eldercaveman wrote:You could consider 3d printing?

of course I'll be using 3d printing. but the 3d printer is for the master prototype, it's not at the point where it's economical to 3d print the production model, they're just not fast enough.

I think a really important question is whether you would cast in house or use a casting service.

of course in house, I currently have available facilities for production, I just need the machines and people to run them. the model for this is the same as those that have worked for my family's companies for over 65 years: more control over production means more quality, and quality is our best quality. that's why you find our brands in almost every major hardware store.

Spincasting resin is probably the most common way of handling production resin casting (read not a guy in his garage doing a few hundred casts per year...but a shop producing hundreds per day). The process isnt that difficult to get good results out of, but whenna company like GW wanted to get the same production numbers out of resin as they did white metal...they had problems. You need enough time for the resin to fully fill the voids in the mold before it sets up, so it ends up needing much longer per spin then a similiar cast in white metal. However it is still many times faster than pressure or gravity casting.

Provided your molds are properly vented, you select the correct viscosity of resin and you have a long enough pot life, you should have almost no rejects. Even my chunky hands will usually only have a handful of miscasts over the life of a mold. Air gets forced out quite readily during the spinning process, so you get to avoid the degassing and centripetal force provides pressure far exceeding gravity, and you are able to achieve higher pressures faster than you can using pressure vessels.

If you look at most resin dealers, they will even have guidelines to help select the proper resin for your casting job. I have used resin to spin cast from both alumilite and Smooth On.

Check out http://www.resinaddict.com/forum/ for some good insights into the casting industry. There are a number professionals that post there. Also, a lot of casting companies use pressure casting. I know Spartan Games pressure casts their resin figures.

What is the stuff your family has in hardware stores?

um we own the Evermark brand, so door, hinges and jams.
EDIT: but you probably never noticed the brand of your doors, so if you're in the central Ohio area you may have heard of another one of our companies, Able Roofing. honestly we're trying to diversify and this minis thing is one of the sectors we're looking at.

@yeri

You might want to PM a Dakka member, mechanicalhorizon.

I used to work with him at GW and PP, he's one of the most knowledgeable people I've ever met when it comes to moldmaking and casting for metal, resin and plastic.

He was the moldmaking/casting manager at GW in Baltimore and Memphis and he did the initial set-up and testing of PP resin casting.

He loves talking shop about this subject and has a wealth of experience you can draw on.

thanks,
also I have one question: I've decided that to simulate the accurate scales of the weapons that will be used for this game I've decided to make the minis in 15mm. what I was thinking was to have the units come in packs of three units to a blister pack, each on their own sprue and each in a different set of poses: one running, one firing, and one on guard. each set will have between 5 and 3 figures, so that's about 15 poses for each type of unit. then each type of unit has ten different variations (like for example one variant has rifles, the other has an HMG) so my question is: would I need to pay full price for each individual sculpt, or will artists accept being paid the base rate for a sculpt for the overall basic unit and then additional smaller amounts for each additional pose?
so let me explain: I've heard that the general rule for minis sculpting is $10 per mm of the figure. so say I would pay a base fee of $150 for the basic unit (unarmed and with basic kit) then say $50 for each weapon type rendered (so $50 for a basic rifle 15mm render) and then like $20 for each pose made from those two. so if an artist sculpts an entire variant of 15 poses the fee would be $500. I've already approached a friend of mine who does CGI animation, and he says that after basic body and weapon are made with a skeleton it should be easy to make a bunch of variants using CGI animation software.

Look to the past. I'd recommend vacuum casting as it is typically cheaper to create the environment, I'm assuming you are working on limited funds because of the school project nature of it. I'd love to share my 10+ years of experience. I think you should also understand the differences in venture costs for replication with the advent of 3d printing. Gun control doesn't make sense because of this technology, the same could be argued for ridiculous GW price rate increasese.

actually I'm playing the "what if" game, so like the goal of the project is to explore possibilities of how much funding I would need and how I would get it. funny part is that I was going to be doing this anyways because I'm actually planning on following though with this plan and making this happen once I get out of college. so I'm really killing two birds with one stone.

Wouldn't you be elongating your supply chain if your current business is currently working with a metals supplier who presumably stocks bismuth, antimony,chromium, and tin?
It sounds to me like in your position that white metal casting is logistically more feasible.
Also spin casts.

Well those aren't our only businesses, if you can think of a matterial used in construction chances are we have worked with it, but the whole thing actually started with a plastic extruder in great grandpa's garage, so resin is not too foreign to us.

How you manufacture depends heavily on economies of scale.

Injection molding is very fast, uses cheap materials and since polystyrene is a thermoplastic excess sprue can be ground up and reused. The expense is in the tooling since the mold needs to be machined out of steel (tooling marks are still visible from the CNC machine on the new Leman Russ kits) or possibly cast.


As a result metal molds are pretty expensive, but all is not lost, with Metal 3D printers or even Just Powdered metal mixed with plastic You can have your cake and eat it too.


The biggest problem with cold resin is that it doesn't scale up very well, and for anything other than small orders you wind up not being able to keep up with demand.

 yeri wrote:
thanks,
so let me explain: I've heard that the general rule for minis sculpting is $10 per mm of the figure. so say I would pay a base fee of $150 for the basic unit (unarmed and with basic kit) then say $50 for each weapon type rendered (so $50 for a basic rifle 15mm render) and then like $20 for each pose made from those two. so if an artist sculpts an entire variant of 15 poses the fee would be $500. I've already approached a friend of mine who does CGI animation, and he says that after basic body and weapon are made with a skeleton it should be easy to make a bunch of variants using CGI animation software.

Those costs are possibly on the low end. Will you be doing the concept art for the figures or will you just be telling the sculptor to do X? Art is an additional cost and doesn't factor into that rule of thumb cost.

well I' m planning on using the local art college to recruit my sculptors, and yes I've done some concept art for all the parts I need sculpted as well as the poses for each sculpt. basically it seems low because the way it's going to be done is that there will be only one basic sculpt that is then animated to create the poses. it's very similar to how the Massive CGI engine makes the battle scenes in the LotR movies. that's why I've been reaching out to my friend in their animation department.