I get when you are designing for a million cars, that the engineering of the production, the associated high speed equipment.... That you get huge economies of scale but at a very high price point to enter the market.
This is also a highly optimized production scenario.
Exclude the drafting aspect.
Think low volume, one unit or five hundred a year. What is the fundamental difference in production costs?
Tim
From having built a dozen here and a dozen there prototypes for early trials and testing, I can tell you that you can plan for less parts. Yep, sand cast all of the aluminum cases, weld up the intake and exhaust manifolds from tube and flat stock, go for low volume ways of making the internals, machine some parts from solid, etc. One path to low costing this product is to use existing pistons and rods, valves and guides and valve trains. And hope the parts keep being made for other purposes so they stay cheap.
Those $1000 transmissions in volumes of 25 to 50 cost on the order of $50k to $100k. Prototype engines are similar. There is no way around it, low volume is really expensive per unit.
Let's just stick with castings. Left and right crankcase halves, sump, accessory case, oil pump housing, intake manifold. North of a million dollars for dies to die-cast them, probably closer to 2 million. Options? Sand cast. Cheapest tool sets to make sand castings only last 50-100 castings, make the walls thicker and the parts heavier. While you are at it, there will be a lot more lost due to voids than with pressure die casting, more rebuilds in-house and warranty to replace cases that crack, and your $25-50k bill for patterns has to be spent again every 50-100 parts. That is $250 to $1000 for each one you cast, not each one you finish. Now if you only make them one at a time, you casting shop is gonna charge you for set up every one you want. First time you have to make and set up the tools, work out your process to get a couple good ones, and then put everything away. A month later you want two more. Well, let's see where we can fit you into production. Next Tuesday, and it will be $1000 to pull the tools, spin up the guys on how to do it, run a couple three to get a good one, and you only want two? OK, $1000 bucks plus the two parts. Nope, run a hundred at a time, and we can waive that $1000 set up charge.
Now let's ship two sets of castings to your machining center, they have to pull the fixtures from storage, idle the work center and install the fixture and cutters set up right for the part, run them. The set up and tear down will take a bunch of time with the cutters not turning that all costs money too. You want to do that in bigger batches than one or two. Somewhere there is a batch size that suits the whole outfit best, between setup costs and costs for parts sitting around waiting to be used.
Then there are gaskets and seals. They almost all have to be custom. Some O-rings and shaft seals might be COTS, but the rest have to be for your stuff. I had prototype O-rings that cost $2500 for a short run tool, $250 for set up and $2.50 a piece for a 1000 piece run. The small ones were well short of a dollar for one of each size in production. Gaskets are fussy thing to get right on production, you want to make a bunch at a time.
Gears with splines and snap ring grooves and mistake proofing features. don't even think about building them one at a time, the set up can be big to get them machined and heat treated right.
You do not want to even talk about building whole engines one at a time. Build all of the pieces in batches of 25 or 50, and you are still in expensive land, but perhaps in a viable zone.
Billski