manufacturing cost

[autoguru]

I'm interesting to knowing more about what determines the manufacturing cost of mechanical components.

Common sense tells that a part will get more expensive if:

1. the material is more expensive
2. the parts is larger
3. the tolerance is smaller.

But they don't really tell me how much more expensive the following process will be.

I need to make a component where a shaft goes into a hole and then fix the shaft's position in the whole (with welding). The shaft if round and the whole is round, so the angular position of the two mating parts doesn't matter. You can just randomly insert the shaft into the hole. I would assume this will be easy to manufacture.

But what if I need the shaft to go into the whole at a specific angular position? And the precision has to be within 1.5 degrees. Will this add significantly to the manufacturing cost?

Thanks

 

[ajack1]

How many parts are you making?

Could you just make the hole bigger and locate the shaft and the “collar” at the correct angle in a jig and still weld it?

Depending on numbers, the jig could be very simple and low cost and nothing else changes.

 

[dwt]

What processes are you using to make your parts?
Are you machining, drilling, punching/stamping or torch cutting the hole?
Is the shaft saw cut, sheared, torched, machined?
Eliminating or combining steps, using a different process or combination of process can all reduce the manufacturing cost.
As ajack1 asked, "How many parts are you making?" Can you stack cut or otherwise make more then one at a time?

 

[IFRs]

In my opinioin, assembling in a specific angular position will not make assembly more expensive, it will however increase the cost of the fixture used and the inspection process afterwards.

 

[autoguru]

I'm using punching to make the hole.

The number of parts I'm making is at least 100,000.

The hole is only about 1cm across.

I just want to know about how much the cost might increase (in percentage)if I demand that the shaft be inserted in a specific angular position. For example, 10% increase in price might be okay. But doubling the cost will not be.

But my gut feeling tells me the increase in cost is pretty small, since 1.5 degree is a pretty big tolerance.

 

[MintJulep]

What features on the two parts determine the required angle? Is there an axial alignment requirement? Can you determine correct angular and axial alignment from a single vantage point? Could you design the parts with a "key" so that they maintain themeselves in the correct allignment? Could you add features to the part that could be used by automated equipment to align them correctly? Could you design the part so that the alignment-sensative feature could be added as a third step, after the shaft and the plate are mated?

Do you have to weld? This sounds like a good candidate for vacuum furnace brazing.