mazdaspeed7

[quote name='laundryhamperman' date='May 17 2005, 04:19 PM']I would agree that machining does not have the human "touch"...and for that reason i give credit to the very skilled people who port these motors and give credit to a hand ported motor over a machine ported one.



Being stubborn and saying that it couldn't be done effectivly is closing doors b4 they can be opened for examination.....saying a rotary won't work b/c piston engines work well is a satire to this point. banzaitoyota...where is your R&D to prove that it won't work? I've backed most of my thoughts where you have simply slammed on the people pro-cnc....or not even pro-cnc, but ppl who simply give the idea credit that it could work under the right conditions.



Again subjectivly...I think that a hand port job would be "better" than a machine port [B]because[B/} a human can better smooth the edges and shape the port to a greater extent allowing greater overall flow and effectiveness of the port job to increase power.



and for your reference...i have well over 100 hours of CAD work (including custom designing for personal interests) and 5 hours or so CNC Mill/Lathe experience as well as a semester working with an automated assembly line. From experence, it doesn't take much to set up this equipment, just the know how to work proficiently. The majority of the time spend is behind the computer and waiting for the machines to complete their job.


[/quote]





The vast majority of porting done is streetporting. There is very little material removal on a a streetport. Its almost all detail work and finishing. CNC maching has no place doing finishing work.



Next you have bridgeporting. It could be used to cut the eyebrow, but theres another problem. A CNC machine couldnt make some of the cuts necessary for proper flow. So you would still be left with a great deal of work that has to be done by hand. doing the rough cutting on a bridgeport eyebrow doesnt take very long to do by hand. Bridgeports are still not very common either, so you have an extremely limited market.



With a peripheral port, a CNC mill would be good for doing the rough cut. But that is a very uncommon port, and its almost pointless to consider it for the sake or argument.



Ill agree it could work under the right conditions. Thats why its common on piston engine heads. But with the prevalence of streetports, and the fact that CNC cant hardly do anything with a streetport, rotary porting does not have the conditions that make CNC porting more efficient than doing it by hand, peripheral ports excluded.

RETed

[quote name='falcoms' date='May 16 2005, 05:32 PM']IDK, My dad is a machinist by trade and programs and builds precision (1/100 of a micron) grinders and has done mills accurite to 1/10,000 of an inch, so I don't get why it's termed so impossible to do it. You don't need any majorly fancy machines to do it, just a CNC kit bolted on to your basic vertical mill, zero it in, and away you go. You guys are talking like we are going to the extreme that we can't do it without multi-million dollar machinery. It's just not the case.


[/quote]

2D ultra smooth surface not a problem.

Have you ever seen an ultra smooth 3D surface from a CNC?

I haven't.

3D CNC still requires "stepped" machining which creates "terraces".

Apologies for the mangling of the nomenclature, since I've only dabbled with this stuff as a casual observer.





-Ted

mazdaspeed7

[quote name='RETed' date='May 18 2005, 09:56 AM']2D ultra smooth surface not a problem.

Have you ever seen an ultra smooth 3D surface from a CNC?

I haven't.

3D CNC still requires "stepped" machining which creates "terraces".

Apologies for the mangling of the nomenclature, since I've only dabbled with this stuff as a casual observer.

-Ted


[/quote]





I alluded to that earlier, those stepped surfaces are why CNC ports still have to be hand finished.

banzaitoyota

"banzaitoyota...where is your R&D to prove that it won't work? I've backed most of my thoughts where you have simply slammed on the people pro-cnc....or not even pro-cnc, but ppl who simply give the idea credit that it could work under the right conditions."



No one said it wont work: IT IS NOT COST EFFECTIVE and it is not as good as Hand porting.



"and for your reference...i have well over 100 hours of CAD work (including custom designing for personal interests) and 5 hours or so CNC Mill/Lathe experience as well as a semester working with an automated assembly line"



Wow! 100 hours of CADD work, that is FREAKING IMPRESSIVE!. Come on down and apply for a job. Whats your specialty?. Yes I am being SARCASTIC, another big-eyed college kid who has been lightly exposed to the wonderful world of design.



Yes I have CADD experience, lots of it (more than 100 hours in a single month); seeing how I make more than the Engineers on the project I am on as THE 3D PDS Operator. Yes I have been trained as a machinist (US NAVY, Shipboard Machinist, It wasnt my primary job, that was a Nuke EWS).



Just because a program or a machine CAN do something doesnt mean that it is the right way to do something. For example: (A very expensive example) I was tired of inner coolant O-Rings that aren't quite the right size and not quite the right composition. So I called on some contacts in the sealing industry that I have worked with before and explained the problem. {side note: MAZDA R&D and talked with them in the early 70's also} We came up with a new seal design, I reached in my pocket and ponied up the R&D funds to produce a test batch. They produced a rather nice seal. Does it work? You bet. Is it cost effective? NO F'ING WAY!!! Design and technology can solve some problems, but the trick is : to solve the problem at a reasonable cost.



CNC Machining irons is not the answer to this dillema, as pointed out by the responders to this thread. CNC MACHINING does have its place in the rotary engine, ie Lightening rotors and production runs of parts. CNC is the wrong application of technology.

laundryhamperman

well im glad that you are soo willing to share your infinite wealth of knoledge with others. If you know something, then explain it reasonably in a WHY statement. don't just rock on other people putting in their best info, that isn't the best way to work in a group enviroment such as engineering/machining or a public forum.



"...IS NOT COST EFFECTIVE" again....please explain why. no amount of credentials is a substitute for relating the reasoning of a point. If you know, be a team player and give numbers and/or references to back up this otherwize unbacked claim. Im not saying your wrong either, if you know i want to hear you answer and be enlightned so this topic can be concluded. I'm looking for an intellegent answer from you so that all may learn from your experence exactly why this path should not be persued.



Speaking of the failure with the O-rings has nothing to do with this topic, but merely shows one ineffective solution (of many solutions) to a different problem. and where does your relative personal income have any relation to this?



JHB performance engineering wrote me a response to an email i sent them.



"We have set up our porting templates into a CNC Mill but we are still

"perfecting" this process."



if it were a total waste i think that they (professional engineers) would have given up on the idea instead of persuing it further. They are working on it and apparently have the basic idea and are refining it down to the final procedures. Hopefully we will be seeing CNC machined ports in rotaries in the near future.

RETed

[quote name='mazdaspeed7' date='May 18 2005, 09:02 AM']I alluded to that earlier, those stepped surfaces are why CNC ports still have to be hand finished.


[/quote]

Yeah, I saw that, but others don't seem to be listening to us.





-Ted

mazdaspeed7

[quote name='RETed' date='May 19 2005, 05:00 AM']Yeah, I saw that, but others don't seem to be listening to us.

-Ted


[/quote]





Its only the ones with no porting experience not listening...

Maxt

[quote name='mazdaspeed7' date='May 19 2005, 08:29 AM']Its only the ones with no porting experience not listening...


[/quote]



Yeah right... Those with no cnc experience are not listening... The hand finishing needed for cnc is not true, all of the cnc work I have had done for me came right off the machine with a near mirror finish, most of my parts came off of 6 axis machines, they leave it with a near mirror finish...While the grain of the metal will sometimes make it look it like there is a terrace, there really is none you cant even detect it with a feeler guage and straight edge, the only time there would be a terrace is if it was deliberate such as the cooling jacket mod on a rotor housing..

The best cylinder heads are not hand finished, they are cnc finished, the repeatability and balancing of the flows is so muc more precise with cnc, you cant even compare the to, even to the best and steadiest hand, all of the top head porters in the world, are now just feeding the know how into the cnc, rather than stabbing away with a die grinder..

And there is not alot of variance in rotor irons or housings, Ive been to shoos where they had one guy loading housings into a cnc machine all day long and pushing the start button , and the finished results are fantastic...

banzaitoyota

And what does that shop with the Multi Axis Machining center charge>?



What is their setup rate? What is there hourly rate?

mazdaspeed7

In an earlier post I stated that a CNC machine *can* take out its own maching marks, but its quicker to just do it by hand.



I never said ports couldnt be CNC cut. I said its not a practical or economic solution to porting on a rotary.