[Zathras]

Guys,

I'm considering an extrusion in place of a casting for an application I have in mind.
Being a noob, I have no idea how much an extrusion would cost to commision.
My guess is that it would be b***dy expensive to do and I should just go for sand castings.
Some time ago I requested info from an extrusion supplier here (Australia) and described the cross-section to him but

he said nobody in Aus could do this complex shape.
Ignore the dims, the whole section should fit within a 200mm die with wall around 5-6mm thick if possible.


Thanks!!

[Mcgyver]

it will depend on how many 10's of thousands of feet you're ordering I'd guess you're right about the die and there'd be large minimum quantities involved. Never done it, but been through extrusion plants - doesn't look like a low volume proposition but i may be wrong - find a company that does extrusions and ask them - what are min quantity & set up costs? looks like a tought part to cast - lots of thin walls and special cores required.

[mxtras]

Extrusion is actually not all that expensive. I hope to have many of my production parts extruded instead of laser cut within the next 2 years (need more volume to make it work for me).

You can get as little as 500 pounds extruded and anodized for about $2.65 per pound (***price as of ealier this year***) - not bad at all. Die costs are not all that bad, either. Most places want to extrude a minimum of 1000 pounds, though, so you have to poke around a little to find a smaller place if you can't use 1000 pounds of your profile.

If you are serious about getting a real quote, I may be able to help you - I would have to dig for the info, but I could look up the contact (New Jersey or Delaware) for you. They treated me right - I was VERY pleasantly suprised at the cost and the service. One part I looked at was not as intricate as what you show - it was a lever that was about 5" across, 2" wide with a few holes and the die cost was $1800. My initial investment would have been under $3K for this part to get 500 pounds of this profile.

Example - machining the above mentioned part currently costs $6.58 each. Extrusion - $0.43 each after cutting and tumbling (die cost not included). Awesome. OH - and this is Stateside - not overseas.

For volume, you can not beat extrusion. Not with lasers, CNC, EDM - nothing beats the extrusion costs for appropriately sized, high volume aluminum part production.

Scott

[mxtras]

Oh - the cost of the die and processing is related to what diameter circle the part will fit in. If the part will fit in a circle less than 5", it is easier to find an extrusion house to do it. The 6 and 7 inch or bigger extruders are not nearly as common, so the price would likely reflect that. 4 inch seems to be the wall between the big guys and the small guys.

If the part fits in a 3 or 4 inch circle, these are common and less expensive to access.

Scott

[WayneHill]

We use this company.

http://www.extrude.net/index.html

In house die shop. They can go up to a 7" diameter area.

Don't know if they export to Australia.

[mxtras]

Here's my extrusion guy -

http://www.argylein.com/

Scott

[mechanical]

Does the part have to be made out of Aluminum? If not there are other ways you can go about mfg this part. A couple of ideas injection molding or urethane casting.

[Zathras]

Thank you guys for your input. :cheers:

mxtras:
I have at least a ball park to go on and this info has renewed my interest in extrusions. Something around $1800-$2500(mine?) sounds very reasonable for a die.
The real benefit comes with volume and I agree that nothing can touch high volume extrusions.
I will be using the extrusion perhaps in a wrong engineering context but the cost per unit is extremely impressive! I understand that extrusions do not offer the strength of castings but I want to sell a product at the lower end of the (niche!)market I have an eye on. Hence my decision to look for extrusions.
The dilema is of course that I need to make a prototype to prove it is workable and that hardly lends itself to extrusion. sob sob.
Maybe if I set my sights on 6" or less, as you indicated, I have more likelyhood of finding an extruder.

Anyway, thanks for the links and your consideration.

WayneHill:
Thanks for the link. They look quite impressive.

mechanical:
Aluminium would definiely be my choice. Highest strength to weight. I would prefer something like 7075.
Injection molding sounds expensive to me especially for a large part. I only say this because I have seen figures of AU$60,000 for a (plastic)coffee mug die on a website. Tell me otherwise please!
Urethane casting? Is that equivalent to say investment casting?


Thanks again all.

[Pat2000]

Zathras, you do have a complex part there that you'd like extruded (I'm certainly no expert mind) you have five seperate pockets in there that means five sections in the die that have to be supported in the right place for the ally to flow around, my guess is thats $$$ . can you not simplify the design? thats my guess - and the diemakers/extruders will confirm for you?

[Mcgyver]

well if 2500 for a die doesn't deep six it, I guess its not a one-of for a model maybe lost wax would be a possibility (for a prototype) if each piece didn't have to be too long. a cnc could mill the profile out of wax

[Zathras]

Zathras, you do have a complex part there that you'd like extruded (I'm certainly no expert mind) you have five seperate pockets in there that means five sections in the die that have to be supported in the right place for the ally to flow around, my guess is thats $$$ . can you not simplify the design? thats my guess - and the diemakers/extruders will confirm for you?

OK the pockets are probably an issue. Maybe I should get more basic as bellow. But the walls are too thick (10mm) for a die?? I thought there was a max wall thickness hence the pockets.
In the end I just want to avoid boring a large piece of Alu.

McGyver:

As I said above, I was thinking it would cost big mula, maybe $10k if a coffee mug die costs $60k so comparativley speaking $2500 is pretty reasonable (and that's not knowing how much Alu you can push through it).
Nope, not for a model as such. It's part of a telescope mount that I want to make.

[Geof]

I think you have skipped over the comment in Post #4, 200 mm is 7.8"; that is a big die. I think you should look into getting it machined from solid until you have built up to enough volume to warrant going directly to a big extruder. Both you shapes would be easy to hog out on a decent sized mill.

Incidentally how big is the telescope?

[mxtras]

I would send your drawing to Argyle and see what they come back with for die cost - why not? Then you'd be able to make a decision.

Scott