Subject: Re: Perhaps I was wrong....40HP? For you Tony! by BeachBum on 2008/12/23 20:15:39
Quote:
jsup wrote:
Sorry, perhaps I wasn't clear. That's why I said that it still has it's place.
I don't really understand how digitizing a port is hard. If you can't probe it, you certainly can't cut it.
If a company that does digitizing does not have the correct probes, they should hire an outside company to do the digitizing or buy the correct probe.
Further, what company is doing 5-axis port machining and does not have the CAD geometry for the casting? If they had the geometry for the casting, they could do the porting in CAD before machining. Am I wrong?
For clarity sake in the old days before CAD availability, the process was to take a head, hand port it, flow the port, see what you get.
The next step was to take the next cyl, port it slightly differently, flow it, see what you get.
Repeat six more times per set of heads. Pick the best one, repeat on a new set of heads.
Sometimes, you hit the mark either by skill or by accident. This was the "old time" process in getting port design. Time consuming and expensive.
Enter CNC, and as you spelled out, you had to re create it in the way you outline.
With current technology that process can be simulated and fed to the CNC machine, hell, I've seen it first hand where a design was fed to a machine that literally spit out a 3 dimensional representation carved from a solid block.
That design will be tested on a wet flow bench to ensure what they got, is what they expected. If it is not, that information fed back into the CAD for modification and further simulation.
As time goes on and more information is gathered, the old grind and guess method will be eliminated completely.
That is the way I understand it. Quote:
Spintron ??? Spintron is most commonly utilized for valvetrain issues.... when did they become involved in "creating" a tool path file for a cylinder head?.... thats new to me. I don't have any clue how that would work, can you elborate on how Spintron (the high speed cameras) would create a tool path ?
Spintron is a separate issue. Remember what I said, outfitted with high speed cameras.
As a wet flow bench is used to verify design scientifically in a static situation, which is the limitation of wet flow, the Spintron allows engineers to see how this stuff works under operational environments. Cameras are actually put inside cylinders to see what happens in those conditions. It is far far more than just a valve train analyzer. It does NOT create a tool path at all. It is a tool to better understand what happens when a design is implemented in the field under the conditions it will be working. Has nothing to do with tooling.
Quote:
btw, with a wetflow tested port, what happens to it after a porter modifies with his own cnc program from a wetflow perspective?
I guess it depends on the change. The wet flow is to find out what happens after a change, hand or CNC port. That's the piont of wet flow and why it is a significant step up from dry flow. But still, because static, is still not as good as Spintron.
With Digitizing, it can actually be complex if you do not have the appropriate equipment. There are machines manufactured by companies like Browne & Sharp dedicated to just Digitizing and/or Tracing which is a similar, but more advanced technology. But, perhaps the toughest is the cost..... if you're going to do integrate the probe system to your VMC, you need to purchase the Probe system, stylists & MI interface system plus purchase the software ability as an option from your CNC manufacturer, provided they can do it, and do it well enough for you to make sense of, or you have to purchase a very expensive software package from Renishaw.....
I've done the above many times without the Renishaw software, luckily because my CNC has some really nice Probing canned cycles & Digitizing canned cycles. But, its all expensive, if you're using a Fanuc CNC, plus with everything above, you can be looking at $ 30,000 or more just on hardware plus the CNC software capability.
But, at the end of the day, if you have everything together and working..... it can be very easy, you are simply entering in the parameters of the area that you digitizing, the speed you are probing, the step down depth, the increment distance back-up and the next stepover.....plus you are labeling a destination file for your coordinate data you gather. Which can then be modified right at the CNC keyboard or downloaded and modified by your favorite cad/cam program. I will say, most companies do not have the ability to Digitize and even fewer have the ability to Trace simply because they do not understand the technology. Nowadays, there is even Laser digitizing that gathers array clouds of data in which you can then manipulate anyway you want..... but its expensive software to do this.
I could ramble on all day about this subject, but I won't.
With head porting without digitizing capability.... I don't know how they can do it without the original port file to begin with. The manufacturers can and do at least to some extent.... but each will have their own methods I am sure.
On Spintron technology, I've never looked closely into it other than I know some engine builders were using it many years ago to monitor what the valve/spring is doing, thus I know it helped some stablize the valve at rpm....or at least help stablize the spring through trial and error based upon what the camera's showed them..... I wasn't aware of any other use for it, but dunno.....
