aluminum forming...press mold?

[mc-motorsports]

I need to make a part VERY similar to the one below. It's what I need is actually the air intake for my car, pretty much just like the K&N cold air kits, only a totally custom app. The one pictured below was for a motorcycle and I actually cut it out of aluminum and welded it together. Turned out good, but I want to try something diffrent this time.

I'm concidering cutting 2 molds out of wood, one for each side, and using a plastic body hammer to shape the alumium to the mold, after clamping or screwing the aluminum to the outside of the mold. I'm just worried about getting a nice finish as the part goes on my car for the world to see... I guess a planishing hammer, a sander, 5 diffrent grits of sandpaper and a buffer would get the tooling marks out, and I could powder coat it if I couldn't get it to polished quality in a reasonable amount of time.

The other thing I was concidering, and am more interested in is making a press mold. But for a manual hydraulic press. A set of molds for each side of the finished part and weld the two parts together.

What are the do's and do not's? Bad idea? Won't work?

Looking for some input here before I go re-inventing the wheel. Never worked in a press or stamping shop. I've made molds, but to prints, and they were all plastic injection.

Any input appreciated.

Thanks in advance!

[mc-motorsports]

No replies???

I'm suprised CAM1 isn't posting? Usually he has good idea's about oddball projects?

Am I barking up the wrong tree? If I owned a bearing press or a manual hydraulic press, I would just try it. Let me know if I'm pissing in the wind.

[Geof]

Originally Posted by mc-motorsports ....The other thing I was concidering, and am more interested in is making a press mold. But for a manual hydraulic press. A set of molds for each side of the finished part and weld the two parts together.....

This would be a challenge but not impossible, however you would need a big manual press. I think the total force needed would be in the many tens of tons and maybe into the hundreds.

Making matching forming molds may not be necessary if you used urethane for one side; Google 'urethane die' or have a look at this;

http://www.urethanetooling.com/uteccati.pdf

Another possibility if you are ambitious is use high pressure water to form the material inside a die; Google 'hydroformimg' or have a look at this;

http://www.cnczone.com/forums/showthread.php?t=19583

You will need to also look up different aluminum alloys to find one that is suitable for forming; 6061 will be far too strong.

[ckm]

What you describe is a VERY common technique known as flow forming. As long as the mold is smooth and made of a relatively hard wood, you will get a good finish. You can use a pneumatic air hammer with a hard plastic head to save time. You can get one from here: http://tinmantech.chainreactionweb.c...ming_tools.php

BTW, the guy who runs that website is one of the top sheetmetal guys in the world. I've taken one of the workshops and it's amazing.

You can also hydroform it as Geof mentioned. A couple of companies use this technique to make intakes. This page has some instructions:

http://www.eurospares.com/frame8.htm

Here are some photos:

http://www.two-stroke-addicts.freese.../hydropipe.htm

HTH,

Chris.

[mc-motorsports]

Thanks Chris! I'm leaning more towards "flow forming". An educated guess from many years of mistakes tells me that it would take me atleast 3 tries to get a press mold right. And I REALLY like the idea of using an air hammer, save the elbows.

Next question... I would rather just make my own hammer attachments. Seems how I know little about plastics, what should I use for the hammer ends? I'll guess some form of nylon?

[ckm]

Originally Posted by mc-motorsports Thanks Chris! I'm leaning more towards "flow forming". An educated guess from many years of mistakes tells me that it would take me atleast 3 tries to get a press mold right. And I REALLY like the idea of using an air hammer, save the elbows. Next question... I would rather just make my own hammer attachments. Seems how I know little about plastics, what should I use for the hammer ends? I'll guess some form of nylon?

It depends on what you are forming. Soft aluminum would require a softer, but stiff plastic, while steel would be more like delrin or at the extreme end something like a lexan. It's probably a lot of trial and error.

Chris.

[mc-motorsports]

Originally Posted by ckm It's probably a lot of trial and error. Chris.

That's what I'm trying to avoid... I've paid for a lot of lessons in the past. .090 aluminum, 5052 or 3003? I don't even know if you can get 3003 in sheet, but that is what they use to make bicycle frames because it's easily formable and weldable. And I'm thinkning .090 aluminum because the flow forming process will thin it out a bit, but I still need to weld it.

MC

[ckm]

I don't think it matters what the type is as long as it's T0. Last time I did this, we used 5052, 6061, 7075 and something else (I think a 1xxx), and all were T0. 7075, not surprisingly, was the hardest to do, but an air hammer made short work of it. Part of the material choice will depended on how much you plan on stretching the part and what the final use case is and if it will be hot or cold formed.

I understand your desire to make your own tools, but avoiding trial and error is why I pointed you at a place that sells the correct tooling.... You'll have enough other trial and error to deal with.

Chris.

[mc-motorsports]

Last question before I start. What kind of material do you use for your molds? My mold has to be roughly 2" deep and 4" wide, 16" long cavity.

I was thinking wood just because I will probably only ever make 1 of these. Glue together a bunch of plywood? Solid 6 X 6"? I'm guessing MDF would just fall apart.

BTW, I'm going to machine the two mold halfs on a CNC mill. Plus if it was wood, it would be easy to just screw the aluminum to the mold to hold it in place.

Thanks for the replies!

[ckm]

Originally Posted by mc-motorsports Last question before I start. What kind of material do you use for your molds? My mold has to be roughly 2" deep and 4" wide, 16" long cavity. I was thinking wood just because I will probably only ever make 1 of these. Glue together a bunch of plywood? Solid 6 X 6"? I'm guessing MDF would just fall apart.

Wood is good. Almost anything that won't break up. MDF might work, depends on the shape.

Originally Posted by mc-motorsports BTW, I'm going to machine the two mold halfs on a CNC mill. Plus if it was wood, it would be easy to just screw the aluminum to the mold to hold it in place.

Don't screw it down. The metal needs to flow into the mold, so you don't really want to do that. The tool pressure should be enough to hold it in place, at least it was on the ones I have done.

Chris.