Radial forging

[arnaudbb]

Hello,


that may look a strange question, but is any of you ever imagined or consider building a power hammer with four hammers hitting the workpiece on the four sides in the same plan?

The idea is to make radial forging. Very handy to forge hollow parts with thin wall (with the hlep of a mandrel).

Such machine exist for industrial use (AGFM Forging Machines)

[Glenn]

Go to the top of the forum page and click on user cp
click on edit profile
go to the bottom of the page, enter your location, and save.

We would like to know where in the world you are located.

[Feukair]

I'm terrified of getting my single hammer power hammer all tuned and working good when i get it put together. I cant imagine getting 4 hammers all working in tandem.

[HWooldridge]

Rings can be done on a conventional hammer with single mandrel set in V-blocks. The V-blocks are mounted to the lower die; the mandrel must be long enough to rest on both blocks with the piece between. The piece is then rotated while struck but can get no bigger in diameter than the clearance between the mandrel and the bottom block.

Clifton Ralph demonstrates this concept on his power hammer tapes but you would have to create a fairly specialized setup to use it.

[Dodge]

arnaudbb,

That's quite a machine! Thanks for sharing.

-Scott

[arnaudbb]

Thanks for your reply.

Hereunder I share the situation a face:

A try to find a forge to produce my parts made of stainless steel.
The shape is quite simple: A ring with an outside thick crown.
The wall thickness is 1.5 mm. I have several size, ranging from OD 1" to OD 4".
The parts is all machined. So I can do the thin wall, but this is stainless stell and it's incredibly expensive and keep raising every weeks. So each mm count.

I try to find a good way to reduce the machining allowance to it's minimum.

I already asked many chinese traditional forge, but they all told me that they can not produce the wall thin enough to be of interest.

I checked with forge that use ring rolling machine. But they can not produce ring that small (may be for 4" is ok but not under).

I asked to cold extrusion people but my quantity bring limited interest to them (even if I buy 60 000 parts/year!). Moreover it seem's they don't like the shape of the part. They asked me for crazy price.

Today those parts are made by forge. The supplier do not use bar stock but flat plate, cut out disk from that plate, drill a hole in that disk, then hot forge it in one stoke with a big press...

So I start to think that radial forging is a good solution. But the buisness is not good enough to buy that GFM machine...so I had this crazy idea to build a small and simple one by myself...

Here in China, it's easy to find spare part and machine tool. They sell press, lathe, milling machine on the street like you sell cars in Europe!

Any advice is more than welcome.



Sorry for the slope of the pen, english is not my mother tongue.

[HWooldridge]

I think I understand your dilemma - you are making rings from 1.00" to 4.00" with a .059" wall and some thickness of collar or crown.

If I were you, I would try to find tubing in the maximum wall thickness you need and machine the rest. It would be better on a automatic lathe with fixed headstock and bar feeder than trying to do it on an engine lathe (like a Monarch "Predator" or similar sized machine). Here in the US, we also figure the cost recovery on the scrap in the part cost, so that might help if you haven't already thought of it.

The method used by the other supplier is also very fast. It sounds like they could almost dispense with the drill and stamp the entire part then do the final hot forge to size.

The extruder can't provide a net shape if the part has a collar so they are probably going to sub-contract it to someone else - hence the high price.

[John N]

ive done quite a bit of work with GFM's and they are pretty complicated. I wouldnt fancy trying to minaturise one.

[arnaudbb]

Hello,

I have checked to machine the part out of a thick tube.
But even if I get the ideal tube, it's still not cost effective. The problem is raw material price. The machining cost is small (at least here in China) compare to raw material cost.

We deal with 316L stainless steel. It's very expensive (IMO when I buy it, but not when I sell it).

John, I am glad I met someone that worked with GFM machine.... could you please tell me more about those machines?

[John N]

In a nutshell, they are expensive!, and pretty complicated, especially if you need 'control' (automation) on them for large batch, small parts like your doing.

If you post some sketchs of the parts (where is the raised crown , end? middle? ) someone may suggest a good way of making them thats 'scaleable' for production volume.

From your description so far it sounds like a punch operation, and then a dedicated, small custom axial / radial ring roller might be the most economical way forward.

This thread is getting very close to 'work' (day job) for me now, so ill bow out good luck with the project