Newbie- Machining Processes

[nuctail02]

Hello, I was wondering what is the best way to machine the item (depicted in the png graphic) as one continuous piece. The "wire" is 1/16" in OD and the ID of the loop 27/64" of stainless steel.

Yet, I cannot think of a process to accomplish this. Not many places I contacted do sinking electric discharge machining, but those who do said too much money to make the electrodes to machine one item. Wire Electric Discharge Machining cannot make it round.

I been looking at lost-wax/investment casting, but most places do large scale orders for companies. Some places offer casting for artists, but they need the actual piece to mold.

Do you might know of some other process that could accomplish this design?

[mc-motorsports]

casting or wire bending. That's if you can deal with welding to finish the loop. You could have the resistance welded, or even solder/braze them yourself.

[djr76]

Originally Posted by mc-motorsports casting or wire bending. That's if you can deal with welding to finish the loop. You could have the resistance welded, or even solder/braze them yourself.

I concur, check spring manufacturers

http://www.gardnerspring.com/

[warrenb]

Originally Posted by nuctail02 Hello, I was wondering what is the best way to machine the item (depicted in the png graphic) as one continuous piece. The "wire" is 1/16" in OD and the ID of the loop 27/64" of stainless steel. Yet, I cannot think of a process to accomplish this. Not many places I contacted do sinking electric discharge machining, but those who do said too much money to make the electrodes to machine one item. Wire Electric Discharge Machining cannot make it round. I been looking at lost-wax/investment casting, but most places do large scale orders for companies. Some places offer casting for artists, but they need the actual piece to mold. Do you might know of some other process that could accomplish this design?

I concur with wire bending and weld the free loop if required. If you really want to get fancy though you might look at a shop that can do sintered metal 3D printing but you sacrifice surface finish. AND it's expensive.

[nuctail02]

Is there a machine or method that could make a mold for lost-wax casting? I have requested quotes from places on a few places who do rapid prototyping.

[PixMan]

In any bigger quantity, that's a job for a 4-slide machine and a weld. The newer, more advanced machines can weld as they make 'em.

[nuctail02]

I was talking to and showing the plans to some of the more capable jewelers in town. Some said that I don't want something like this casted... I am assuming there is an inherent limitation to this process for an object of that size.

One recommended milling, but from talking to others... this option was never brought up, so I have some doubts.

[Smrtman5]

Sure looks like a job for casting. Depending on the length of the piece, you may run into problems filling the mold before the metal cools. Perhaps this is why the jewelers you contacted were against casting?

Why does it need to be one piece? A nice spot weld could get this job done in a snap.

[nuctail02]

I am wanting something really uniform because the piece is going to be used to make an electric field. Any sharp bends and such will tend to ionize the air.

[harryn]

It might be easier to produce from a pure material rather than from an alloy.

If you could accept it being made from W, Mo, or Ti, you could potentially make it via CVD. (chemical vapor deposition).

In this process, you first machine a mold shape into a pair of carbon blocks. The deposition is done in a vacuum at around 500 - 600 C using WF6 +H2. Basically, you are depositing the metal into the mold, and once it is full, the deposition stops. I have used it in the semiconductor industry and it is sometimes used to make rocket nozzles. For Mo, you use MoCl5 and for Ti you use TiCl4 as your starting materials. Not that many firms can do this, but probably you can find them with some searching. The carbon blocks will likely be single use. I used to do this kind of deposition work for a living, so I know it will work, but the price will be high.

Another non traditional approach would be to first bond a slightly thicker sheet of the metal to a singe use base, such as a plastic. Machine the part out with straight sides, once again, leaving the side wall thickness so that the cross section is a square.

Dissolve away the plastic base layer to free the part(s).

Place the parts in a high rate electropolish system. The cross section will tend to round out as the electropolish action will selectively remove the high spots, forcing it to be more or less rounded everywhere, but at least in general it will be electrical field smooth. This will only work with a relatively pure material, as the etch will also selectively etch some elements faster than others, and occlusions will be a big problem.

It might be possible to instead of machining the part from the "metal bonded to plastic" blank, you could try photo patterning the part onto the metal (like a circuit board is made), then etching it out. I think this would actually be harder to do though than machining it.

These are just ideas that will take some experimenting to develop, but maybe they will be helpful.

Good luck

HarryN

[mcphill]

Do you want it quick, cheap, or good quality? Pick two, and put some more detail around what you want (surface finish, days/weeks/months turnaround, $10 for one or $10,000).

[nuctail02]

I guess for now cheap and good quality.

As for surface area, it should be smooth as possible, but nothing to a mirror finish because it reflects laser light and well sometimes I have to literally look at the particle trapped (electrically) within the ring.

The size is not really specific, but I the item should be in the same plane, round, and with no discontinuities or cusps in the surface.

Nothing special with the material as along as it is conductive, but stainless steel is resistant to corrosion.