Battleground Toys 1:18 Puma - Updated 3-23

[grunt1]

The good news is that because this method is digital, scaling up is easy. I can tweak the file and it goes from 1:18 to 1:16 instantly so both scales are done. The bad news is that $200 would be nice, but at this point is pretty unrealistic for either scale whether cast or printed as PH and I have already hopefully pointed out.

Here is an updated turret photo. Note improved muzzle brake, tabs added for easy insertion to body with full 360 rotation, and quite a bit of material removed to cut down on the total amount of cubic cm which greatly reduces the printing cost. For example, this round of tweaking took the turret from $97 to $66 (cost). Trying to bring it down even further at this point without compromising the structure and creating warping.

[aferguson]

why does hollowing the turret reduce cost so much? I assume they are starting with a solid block of material and cutting away the excess. It would seem to me, more cutting, which would be necesary in order to hollow out the turret, would add to the cost.

Are they able to re-use the material that has been cut away or something?

[aferguson]

Jnew: that 1/16 site has some interesting stuff on it. Have you bought anything from them before....if so can you vouch for the quality?

The Su-152 conversion and KV-2 turret both caught my eye.

[Jnewboy]

Jnew: that 1/16 site has some interesting stuff on it. Have you bought anything from them before....if so can you vouch for the quality?

The Su-152 conversion and KV-2 turret both caught my eye.

I have the Su-152 he makes and it is very good quality! I also have the ostwind and wirblewind from him and those are all very good quality. If you get several kits at once it is much cheaper as he uses DHL international flat rate boxes. I want his Maus but it costs alot more to ship due to its size.

[grunt1]

It doesn't work by subtracting or carving from a block like a CNC machine which is a subtractive manufacturing method. 3D printers are additive manufacturing. They work like an inkjet printer. Instead of putting ink on a flat surface(piece of paper) one time like a printer does, a 3d printer lays down .1mm or so layer of material, hardens it with a laser, heat or ultraviolet light, then lays down the next .1mm layer of material. Slowly building up a 3 dimensional object.

Because the machine has to lay down every "pixel" of material most print companies base the cost of the model is on the amount of cubic material it requires. This approach accounts for both material cost and machine time. It takes ~.01 cent of material to do a .1mm by .1mm blob, and it takes 1 second for the machine to harden that blob, then move to the next blob. Multiple that times however many blobs of material you use and you have it.

So by making the turret hollow, then additionally hollowing out the mantlet, gas cans, tires, etc.. etc.. the cost goes way down.

Here is a 3 minute video on the process from start to finish. http://www.youtube.com/watch?v=TQoTro9WfbQ

[aferguson]

very interesting

so was the $1000 cost you mentioned earlier assuming a completely solid model, including the hull, or was it already partially hollow in areas?

i would suggest leaving off any details that the buyer could easily add themselves. Did you say gas cans as in jerry cans? No need to include those at all as they are an accessory everyone has in abundance.

if PH is going to cast it, you may be able to make it thinner than you could if you were going to sell it as a finished product. It shouldn't need to be as durable or strong, if it is going to simply be cast and then stored carefully as opposed to being 'played' with by a buyer. You may be able to cut the material thickness significantly more and reduce the cost of your prototype

[grunt1]

The $1000 was with a hollow shell and hollow turret, but only the basics were done. ie, imagine simply removing a rectangular shape from the body and not really going out to all of the edges and corners. The walls were also really thick. So there is a lot more that can be done which is why I'm hopeful, not certain, but optimistic.

As for PH, good thoughts. However for this particular piece, if I can't get the cost nailed with Shapeways, I'll just send him the one I already have that you saw in the pictures. The only thing missing from that one is the suspension and the tires are wrong. I'll print those as a one-off so he can cast as many as he needs.

My goal is to make enough to share, and the only way to do that is for them to be affordable.

[aferguson]

not trying to burst your bubble but if you already had the hull and turret semi hollowed, via a rectangular shape and the cost was still $1000, i suspect the lowest you'll get the cost of this thing is about $700. The volume of mat'l you will still be able to remove, compared to the volume of the rectangular amounts already removed will be relatively small.

I think your turret work set the tone: you reduced the cost by about 30%....so that's why i say you'll be doing well to get it below $700.

You may want to save yourself a lot of effort and work and just go to plan B, which is have PH cast the prototype you already have. There is no way you'll be able to get a printed version to an affordable level, until the cost of printing more than halves.

in fact you can probably calculate the lowest possible cost. Do you have some computer program that can calculate the surface area of the Puma in 1/18 scale? If so, just multiply that by the minimum thickness of material you can use and still have the strength needed, and then mutliply that by the cost of a cubic mm of material.

The answer will probably come out to be about $700.

[TankAce]

If the thickness has been thinned 3 to 4 times less than the original,i guess the cost will be greatly reduce from the $1,000 originally production cost was going to be.
Thinning will also work good in case things go to plan B(casting in resin)
I remember pikelhaube had to reduce the thickness of the 229 wings to reduce the production cost of the Horten.And it paid off in the end by reducing the amount of resin needed.
Battle ground already produce many other items using the same method.
I remember the MG mount cost was reduce without sacrificing the strength of the parts.
I got the MG mount.The plastic quality is very good.The legs of the mount are very thin,i put a little pressure on the legs and they flex to a certain degree without breaking.
Either way plastic or resin it is OK by me.

[aferguson]

you may be right....i was kind of thinking it backwards last night in my drunken stupor...lol. If there is still a lot of thickness, in the hull in particular, that can be removed, then the cost could be reduced a lot still.

If the surface area calculation can be done fairly easily eg with some type of computer paint program that will tell you the total surface area, then the volume calculation i suggested is still not a bad idea to give you an idea of how low the cost can get. If it's not less than going the resin casting route, then it will save you lots of work, trying to thin it to no avail.

i can see a bright future with 3d printing, as costs inevitably go down and better software makes the designing easier (eg auto thinning programs)

[TankAce]

I was just curious about one thing it pop in to my mind
Is it possible to scan with the 3d printer scanner a 1/35 scale Puma and produce it in 1/18?

I am asking because i imagine that big company's already went trough this sort of proses and those models may already be made as thin possible in order to save plastic.
Some of this 1/35 models have amazing details like hatches that open,separate track links and there is so much to choose from.

[aferguson]

i suggested that on another thread but don't think i ever got a response

i suspect it woudl be a very expensive process and since all you're doing is saving labour, a person might be more willing to put in the time/effort designing, than fork out the money for scanning.

[blitzhazed]

would it not be cheaper to get your own printer with the amount of orders you would get if the prices were low you would recoup the outlay easy or failing that team up with someone else has gburch got one to do a v2 just a idea

[grunt1]

I don't know if this helps but here you go:

The printing material (polymide in this case) is like gas.

The printer is a rental car.

The cubic volume, thus the machine time you use to print your model is mileage.

So pricing wise the material or gas is pretty cheap to drive the car around for a week. Even if you drive a few hundred miles. $40-$80.

Renting the car or occupying the 3d printer, that no one else can use while you have it, costs a lot. $800-$1000.

So hopefully helps?

It of course would be much less expensive if you had your own printer as mentioned, because you only pay for materials/gas and not the rental fees. However, these printers or cars that can print at a high enough detail level for this scale, and avoid most of the sanding and roughness the home built printers have cost $200,000-$350,000 plus software so they are a bit out of reach for a garage operation and would need to be run 24/7 to be profitable.

[grunt1]

Oh and as for the Puma update. The stowage and wheels are done. The turret was too long so it has to be separated into two parts (gun and turret) to avoid the "big item" surcharge at Shapeways. That applies to the body as well.

In all it still comes out around $425, but she's a beauty! I've sent it to another printer to see if somehow a volume print will reduce the cost. Shapeways does not discount for multiple prints. As soon as I get an extra Puma, we'll look into casting to see if that makes the price work better. Stay tuned!