need advice (sourcing manufacturer US/EU) & casting method!

firstly - before i begin - i should make clear i have no experience in metal casting. i used to be a welder about 20 years ago - but that's about it. no foundry experience.

so - i have a design that needs casting. i have been told that my design cannot be sand casted and that it was recommended that i consider lost-wax casting instead.

there are a couple issues with this. i live in iceland - there are only 2 foundries - and both only offer sand-casting. so i am having to now out-source elsewhere. i am looking at either a US manufacturer or the EU.

i am needing to know & understand what casting options work best for me and my design. the design will eventually be sold in the icelandic marketplace - a country of about 360 thousand.

for the year 2021 - i am hoping for 1st round to produce somewhere between 1000 to maybe 3500, 5000. and it 2021 proves to be successful - i will amp up much higher numbers for 2022.

i was told even with lost wax casting - machining will be needed. please review the attached images regarding part of the design - small radius(s).

sooooo
- i need to source a manufacture first .
- then i need an approximate quote (including machining, if needed) for either 1000, 3500 or 5000.

can you help me?
jón

 

Those small-dimension callouts look like deburring. A radius there might well be best, and is best done with a special cutter, i.e. machined countersink.

What kind of material is wished, and how critical is the end part, i.e. will people get hurt or killed if it fails? (No, not (legal) liability. Conscience.)

One might sand-cast this in (fine-gradation) Petrobond, but then the machining... that might be an issue in those numbers. One, ten maybe - do that at home. (I've done this). Thousands would, at a minimum, need some jigs and fixtures to obviate the need for exceeding vigilance sustained for hours at a time.

I used to be able to do that. Now - not often.

 

You're going to have a hard time( =$$$$$) keeping those radiuses as drawn even if they were machined. You're talking a radius that's 1/5 the diameter of a human hair (hair 0.06-0.04mm in diameter). I don't know of a casting process that can do that. You're talking High end 5 axis machining center to hold tolerance. You'd be farther ahead to make them out of solid stock at that point.

I think this is a case of where we can help you reevaluate your design for production.
For a part the size your talking I'd bore the trough hole and the counter bore. Then have the part tumbled to break the edges and remove the bur. The tumble should radius the corners. This sounds like a part that might be better suited to Die casting. But I'm not experienced in that.

These parts are fairly small. The machining is going to cost as much as the part. My guess if you can find someone to make them it's going to be $15-$25 ea US plus shipping, Plus setup and Tooling fees for 1000. With adjusted tolerances. If you keep the .01mm radius you're looking at maybe $150-$1500 ea (you're in aerospace tolerance land).

Keep in mind that I'm a backyard hobby caster..... I don't know the business side of things, and I design my own parts so if I screw up it's just me. So a large grain of salt must be consumed with the above information.

But I did stay at a Holiday-Inn express once.

 

What were you planning on paying for these? Just thinking about it think, you will have a hard time finding someone to make them for under $50 each. What are they for by the way?
Patrick

 

@DavidF i am assuming a standard steel (stainless/carbon). not interested in plastic for this part.

 

@dennis fortunately, this will in no way potentially harm/kill the user. maybe i just need the skip the machining altogether!

 

@crazybillybob indeed - the more i review these posts - the more i realize how unnecessary the machining is actually needed.

 

@crazybillybob so this process of tumbling the part - i think that would be the most viable and rational solution for this. if i were to reach out to a manufacture for casting - is this process generally an option they offer? or will i have to take the finished parts from them and tumble elsewhere?

 

so thanks everybody for their posts on this.

it seems the best route for this design is to skip machining altogether - as those radius accents are truly unnecessary for the design.

i thought i'd share a photo of just how small this fastener is that will fit into the design. given this perspective - it now makes even more sense to skip the machining process!

the option to tumble the piece in softening the edges (rather than paying for the process of deburring) how common is this? it seems the more logical choice.

i guess my last questions is this - in order for the manufacture to create the mold for casting - the edges would need to be softened beforehand, correct? i can't give them a design with the sharp edges intact?

so in that case - any suggestions as to the minimum radius i could apply to the outer edge?

 

In smaller numbers (per batch) I would tumble them myself. I made a cartridge case tumbler many years ago. I'd use ceramic beads, and tumble "moist". Figure an hour or two per batch, and adjust so you get the finish you are after.

Nice thing about tumbling is putting the tumbler on a timer, then returning when you are ready to unload it.

 

It looks like the holes should be 2mm and not the size called out in the drawing.

 

I'm not 100% sure but I think he was referring to steel for the tooling necessary to injection mold or die cast the part, not for the actual part itself.

 

Ahem, let’s not forget cast iron as a possibility! And just guessing about it’s function, aluminum may also be a consideration.

Denis

 

Do you think you could get us some full pictures, and maybe a few more? And what is it for exactly?

Something that small doesn't seem worth casting to me. I think a decent quality cnc milling machine could probably do the entire part in a couple of hours. Just some of my skewed thoughts.
Patrick