Thread: BBS FI - Forged
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      05-12-2009, 01:49 AM   #25
Cleveland
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Drives: M3 coupe
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Quote:
Originally Posted by aus View Post
Cleveland,
Why did BBS choose the make the RE-R for the Cayenne? I can't imagine that many Cayenne owners changing wheels out for quality wheels vs. bling wheels that I see all the time on the Cayenne.
Also, could you explain the 5 axis machining and why it costs so much. $10,000/set is WAY up there.
Thanks for the info.
The only reasoning that I could get out of BBS's Technical Director, was this price point would not be too far out of line for this particular fitment. In that respect he is correct, given the median income for the vast majority of Porsche owners.

That retail price would be over the top for Chrysler 300 or Honda Accord owners for example. It wouldn't matter how good the rims were...

Also keep in mind, that many European car owners are more subdued that their American counterparts, and the number of 'bling' wheels abroad is significantly less than it is here in the United States. The bling wheel phenomenon is more pronounced in America, but it also has a presence in many foreign countries as well. (although to a lesser extent thank god!)

Also,

5 axis cnc machines are used for a variety of manufacturing purposes. They are typically very large in scale. The 'standard' machine used in CNC milling operations is a 3-axis unit. (X,Y,Z)

In order to understand a 5-axis unit, I believe it's necessary to breifly explain 3-axis CNC machining first. A standard 3-axis machine operates in 3 linear axes of movement (x, y, z). These axes of movement (along with pre-programmed CAD software algoritim) will tell the tool where to begin and stop each procedure, like on a custom engraving for example. But if you wanted to machine the sides of the project you would be forced to reposition the material. (that costs you time and money)

Trying to produce a 5-axis results with a 3-axis machine is a huge mistake for several reasons:

1) It increases your overall labor costs. (time is money in the world of machining metal parts)

2) It kills your production 'flow' by forcing you to STOP and re-position materials and possibly change tooling bits.

3) It leads to terrible INCONSISTANCY in the quality among the finished parts.

4) It can compromise the intergrity of the finished part, if it has LOAD BEARING duties. It is virtually impossible to re-position each and every part (one-by-one) in exactly the same manner. This could lead to a catastopic failure under severe stress loads.

Now here are the key differences that set the 5-axis machine apart from it's less capable sibling...

5-axis CNC milling machines add two more axes of movement (A & B). Adding two additional axis will reduce or eliminate the amount of material repositioning needed for manufacturing 3-D products. Also, these two axes allow the cutting tool to tilt so that the sides of the material can be machined. The result is machine capable of producing highly accurate 3-D products quickly and efficiently. CNC machinery with five axis are ideal for accurate, high-speed trimming, cutting, and routing of metal parts. They come in many different sizes. Some are larger than your garage at home!

When I worked at Boeing, we used a very expensive 5-axis router that was extremely accurate at cutting and trimming large aircraft parts and other components. They were fully automated, and allowed the operator to input just a few commands into the computer in order to produce many different pieces. Many programs were pre-loaded into the memory, and the freshly milled pieces were done in short order. These machines can also help to trim and finish large metal (surface area) pieces with a quick software upload.

Because so many 5-axis machines typically takes up a great deal of space, it is highly unlikely that you will see these machines in a small local Machine Shop. It's usually only found in the largest shops and full-blown manufacturing plants. These machines are not cheap. The high cost of a 5-axis machine also makes it prohibitive for users on a smaller scale. (it can't pay for itself in a reasonable timeframe)

The typical users are companies that need to produce a large number of pieces, with complex shapes, carvings, or unique finishing details on all sides. Wheel manufacturers, metal fabricators, aerospace factories, automobile manufacturers,etc. are just few of the industries which use 5-axis CNC technology.

Oh damn, I just realized what time it is...

Thanks a lot aus!

I'm pooped...time for sleep. zzzzzzzzzzz