I'd say, make the initial mold on CNC and then Spin the rest on the slow lathe. Jordan drivers are made like this. It's dirt cheap. Not too many people know how to spin aluminum by hand any more but with careful library search the technique could be relearned. If someone could provide the mold, I'd be wheeling to try to spin.
Looki looki I just found a cookie! There are companies that do that.
http://www.franjometal.com/metal-spinning/aluminum.html
http://www.elyriametalspinning.com/spinshop.asp
http://www.ehschwab.com/
http://www.franjometal.com/metal-spinning/aluminum.html
http://www.elyriametalspinning.com/spinshop.asp
http://www.ehschwab.com/
doug20 said:
Several thousand seems like pennies if its for mass production? Or 1 hour on the craps table...take your pick
There has to be CNC shops out there hurting for business in this economy no?
Doug
You don't seem to have a very good handle on the loudspeaker business, if you think that (or you have lots of money!). The volume for hi-end loudspeakers is miniscule and it would take a long time to recoup "several thousand". I need to live off of my business and expenses like these are very hard to justify.
"Hurting for business" just means that they will do it, not that it will be cheap. Years ago you couldn't even get someone to take a job like this because the "money was too small" - at "several thousand".
As Soongsc notes, tooling is cheap in Asia. In Bangkok is was about 1/3 the cost of here and in China about 1/5. But in the US tooling is very expensive - its the labor.
gedlee said:
The term "Several thousand" is relative, from your original post it sounded like the "several thousand" was the R&D cost but it now from your curt reply it reads like its "several thousand" for ever unit?
What about 1000 units, is that $10K, $2K...I have no idea but again $2K for some is just hobby money.
Somehow you jump to a conclusion that I wouldnt have a good handle on the audio business (to me business is business, you build them all and run them all the same way). I was just curious about "several thousand" is just a day of fun for people on my world...and I thought you would have more money
Thanks, I would have thought once the R&D was done and the CNC was programmed then the costs would significantly decrease.
It seems like it cheaper just to spend $$$ on CNC machine and do it ourselves but Im not sure what type/quality CNC is required for this sort of job.
I know people with CNCs, they are very cheap when it comes to making baffles (Ie...$30 or so) but obviously this is more then just cutting some holes.
It seems like it cheaper just to spend $$$ on CNC machine and do it ourselves but Im not sure what type/quality CNC is required for this sort of job.
I know people with CNCs, they are very cheap when it comes to making baffles (Ie...$30 or so) but obviously this is more then just cutting some holes.
My machine is flat bed, 3 axis. You can make these kind of horns by stacking up layers (as in the first post). Yes, there are some things you cannot do (or do as easily) as you could with a 6-axis machine. However, I can cut 3D shapes. See the attached image, for example. This is my machine making a bracket for my motorcycle (which I turned to different sides to get some of the features shown, but you can see it cutting a 3D face. This face could just have easily have had a complex curve.). A lot of this (as I said before) depends on the software you have. That's what makes it (relatively) easy to program the 3D cutting paths from a 3D solid model. 6-axis capable programs are vastly more expensive, although there's one cheap one out there that does 5 axis, I think. From looking at it, there's a lot you have to figure out on your own though and you need a specific 3D modeling package to use it.
Anyway, if you're making your own cnc (as I did), I'd guesstimate that adding 5 axis capability would increase the cost of the machine by another 50%, and if you added a 6th axis as a rotary axis, then that could be done for maybe another 10% if you could directly hold the part. However that's not counting design and construction time. The big thing, as I said, is getting software that will let you make use of the extra capabilities.
To speak to a previous point, I'd guess it would take me ~10 minutes to program a simple baffle. It took me ~10 hours to program the LeCleac'h horn I'm about to make. And that's after I drew the entire thing, did the sheet layout, designed a hold down system, etc. in CAD.
Anyway, if you're making your own cnc (as I did), I'd guesstimate that adding 5 axis capability would increase the cost of the machine by another 50%, and if you added a 6th axis as a rotary axis, then that could be done for maybe another 10% if you could directly hold the part. However that's not counting design and construction time. The big thing, as I said, is getting software that will let you make use of the extra capabilities.
To speak to a previous point, I'd guess it would take me ~10 minutes to program a simple baffle. It took me ~10 hours to program the LeCleac'h horn I'm about to make. And that's after I drew the entire thing, did the sheet layout, designed a hold down system, etc. in CAD.
Attachments
The big issue with waveguides is the height capability not the number of axes. A simple three axis machine would probably work if it had about 8 inches of vertical capability, but this is unusual. Of course you could "stack up" the part in pieces, but my experince with the mating of these pieces has not been good. Its much better to just cut the entire thing in one setup.
Heck for an axi-symmetric device all thats needed is a CNC lathe, or it doesn't even have to be CNC at all. But for the elliptical one its a completely different set of rules - and costs.
Heck for an axi-symmetric device all thats needed is a CNC lathe, or it doesn't even have to be CNC at all. But for the elliptical one its a completely different set of rules - and costs.
I'll make myself an elliptical waveguide at some point. I just haven't made it there yet.
I definitely agree that if the alignment features don't work well or the machine isn't repeatable, then the stacking idea will not work well either. I would think this would be more important for you if you're making a mold, where as for me, I am directly cutting the horn in a material that I can work with by hand - ie, I can sand it a bit if it doesn't fit exactly. Having said that, I haven't had any problems so far. As long as I keep my feedrates reasonable for my machine, I can hold a tolerance of a few thousandths of an inch. Not state of the art for making an aluminum mold, but just fine for making wooden horns (which is what I designed it for).
I definitely agree that if the alignment features don't work well or the machine isn't repeatable, then the stacking idea will not work well either. I would think this would be more important for you if you're making a mold, where as for me, I am directly cutting the horn in a material that I can work with by hand - ie, I can sand it a bit if it doesn't fit exactly. Having said that, I haven't had any problems so far. As long as I keep my feedrates reasonable for my machine, I can hold a tolerance of a few thousandths of an inch. Not state of the art for making an aluminum mold, but just fine for making wooden horns (which is what I designed it for).
8 inches should be quite common. At least it is here. The most difficulty they run into is when the bit has to be long; getting at the throat of an ellipitical wave guide is tricky. Normally, if the sidewalls are +/-30 deg or so, then it should not be a problem; less than that, you run the risk of hitting the walls. That is the part where most shops will stop at about 4 inch depth. For molds, I can see why a 6 axis would be usefull, and expensive. Another alternative that I have not tried is using a 3 blade spiral cutter with a larger diameter and longer length; but this depends on the speed of the spindle to get reasonably smooth surfaces. BTW, round headed cutter helps make a smoother suface as well.gedlee said:
Re: Sure!
Yeah, inhale that and watch the tumors sprout.
Btw, on a commercial run it should probably be vacuum formed plastic. That should cut labor (and material) costs to p!ss little.
optichammer said:Hey Mr. Geddes,
Let's get together and make something cool! Its just me and six figures worth of machinery hangin' out makin (expensive) sawdust! I have a tungsten powder imbedded resin that might change your mind toward glass
Eric
Yeah, inhale that and watch the tumors sprout.
MJL21193 said:
?
I'm coming up a little short...
Btw, on a commercial run it should probably be vacuum formed plastic. That should cut labor (and material) costs to p!ss little.
Re: Sure!
I'm not sure what you mean, but if you are talking about anything that requires a hand layup then forget it. Compared to casting, which only takes minutes, nothing requiring hand labor is going to be worthwhile.
optichammer said:Hey Mr. Geddes,
Let's get together and make something cool! Its just me and six figures worth of machinery hangin' out makin (expensive) sawdust! I have a tungsten powder imbedded resin that might change your mind toward glass
Eric
I'm not sure what you mean, but if you are talking about anything that requires a hand layup then forget it. Compared to casting, which only takes minutes, nothing requiring hand labor is going to be worthwhile.
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