Why Is Porting Still Done By Hand?
05-27-2005, 10:03 PM
#51
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Join Date: Sep 2002
Location: Savannah, Ga
Posts: 2,763
[quote name='G_RIDE' date='May 27 2005, 10:53 PM']Hmmmm... As far as I know every port from the factory is done on a machine...but maybe i am wrong and they have little monkeys 
porting the engines
[/quote]
The runners are left as cast. The port shape is CNC milled, but only about 1/4" deep, just enough to go through the casting.
But, something to point out is that is a very simple milling operation, nothing like the complexity to make a smooth finish on the bowl and the short side of the port.
Also look at the quantities they did. CNC port jobs would make a lot more sense if there was that much of a demand.
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The runners are left as cast. The port shape is CNC milled, but only about 1/4" deep, just enough to go through the casting.
But, something to point out is that is a very simple milling operation, nothing like the complexity to make a smooth finish on the bowl and the short side of the port.
Also look at the quantities they did. CNC port jobs would make a lot more sense if there was that much of a demand.
05-30-2005, 11:04 PM
#52
Member
Join Date: Aug 2004
Posts: 62
Talking with Marc from JHB engineering, he told me
"Typically we would use the CNC to cut the ports the same as Mazda does, down
about 1/8" and then blend and polish by hand. We have not set this up for
bridge porting as of yet due to lack of time."
also as for pricing....
"We have set up our porting templates into a CNC Mill but we are still
"perfecting" this process. We would be happy to port your parts for you if
you give us the specs you are looking for. A 12a bridge port would run
about $300-500."
"Typically we would use the CNC to cut the ports the same as Mazda does, down
about 1/8" and then blend and polish by hand. We have not set this up for
bridge porting as of yet due to lack of time."
also as for pricing....
"We have set up our porting templates into a CNC Mill but we are still
"perfecting" this process. We would be happy to port your parts for you if
you give us the specs you are looking for. A 12a bridge port would run
about $300-500."
06-01-2005, 09:45 AM
#53
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Join Date: Nov 2002
Location: Honolulu, Hawaii USA
Posts: 925
[quote name='Maxt' date='May 24 2005, 03:25 PM']Sometime I wonder why I even bother...
Who spends their time doing ports like that, hmm... People that are serious, thats who...
They guy I know, is working from from irons I gave him with with radius corrections plotted in, its not going to be mainstay work for his CNC machines, but shop filler in between large jobs, its better to have a machine making 250.oo then nothing...In between molds sometimes the cnc can sit for a week with nothing going in or out of it..
The problem with this kinda of stuff as someone mentioned you cant go to a machine shop and expect them to know you want or expect, and if its an hourly based shop,you are going to pay primetime money for every minute thats spent on it, be it machining , plotting or talking, but its not like that for places that have CNC machines that are in a niche market, but have down time to fill once the bread and butter is done, and thats the difference, anything they do over above their standard fare is gravy...
I am going there saturday for an update..Maxt
[/quote]
I'd like to know how much this'll cost for the rest of us?
I'd be very interested on getting this done, if the price is reasonable.
I work 80 hour weeks, and I don't have the time to be porting engines at 10 to 14 hours on average for the entire engine.
-Ted
Who spends their time doing ports like that, hmm... People that are serious, thats who...
They guy I know, is working from from irons I gave him with with radius corrections plotted in, its not going to be mainstay work for his CNC machines, but shop filler in between large jobs, its better to have a machine making 250.oo then nothing...In between molds sometimes the cnc can sit for a week with nothing going in or out of it..
The problem with this kinda of stuff as someone mentioned you cant go to a machine shop and expect them to know you want or expect, and if its an hourly based shop,you are going to pay primetime money for every minute thats spent on it, be it machining , plotting or talking, but its not like that for places that have CNC machines that are in a niche market, but have down time to fill once the bread and butter is done, and thats the difference, anything they do over above their standard fare is gravy...
I am going there saturday for an update..Maxt
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I'd like to know how much this'll cost for the rest of us?
I'd be very interested on getting this done, if the price is reasonable.
I work 80 hour weeks, and I don't have the time to be porting engines at 10 to 14 hours on average for the entire engine.
-Ted
06-02-2005, 01:23 AM
#54
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Join Date: Jan 2005
Location: Oxford, New Zealand
Posts: 18
Originally Posted by falcoms' date='May 17 2005, 02:32 PM
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.
Hi good topic :-)
Do you have any suggestions for suppliers of of a CNC kit for vertical or horizontal mills?
Are you able to send me a copy of the CNC files you are generating to cut you profile?
It would be appreciated :-)
What design software are you suggesting for 3d cad?
While I see that it would take a lot to get this set up for small quantitys of work the ability to perform consistantly
even with hand finishing should be an advantage.
Some of the hand porters might like to checkout
http://www.linuxcnc.org/
for BDI EMC Linux (Brain Dead Install Linux).
The Nascar boys use CNC for their headwork a google search
for " cnc porting Nascar" turns up some good results.
Regards
Michael
06-03-2005, 08:59 AM
#56
Senior Member
Join Date: Aug 2004
Posts: 426
actually, i just thought of an ok cnc job..
if you want to use an rew rear iron with the rest being cosmo-style, you can do the rough cut to enlarge the runner on a cnc machine. that'd be an easy program, repeatable, cheap (by comparison), etc...
not for the finish--just the rough cut.
if you want to use an rew rear iron with the rest being cosmo-style, you can do the rough cut to enlarge the runner on a cnc machine. that'd be an easy program, repeatable, cheap (by comparison), etc...
not for the finish--just the rough cut.
06-14-2005, 11:35 PM
#57
Senior Member
Join Date: Dec 2004
Posts: 559
[quote name='RETed' date='Jun 1 2005, 09:45 AM']I'd like to know how much this'll cost for the rest of us?
I'd be very interested on getting this done, if the price is reasonable.
I work 80 hour weeks, and I don't have the time to be porting engines at 10 to 14 hours on average for the entire engine.
-Ted
[/quote]
Ted I have a guy semi local to me, who retired and bought CNC setup to do porting to keep from going crazy in his spare time. I haven't talked to him about what the cost would be for rotary project. But for piston heads, he charges a one time $400 initial setup fee and $100 a cylinder for the porting. I don't have clue what this would equal out to on set of plates, or even if it would be cost effective to even do. But it will be something to look into this summer for me.
I'd be very interested on getting this done, if the price is reasonable.
I work 80 hour weeks, and I don't have the time to be porting engines at 10 to 14 hours on average for the entire engine.
-Ted
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Ted I have a guy semi local to me, who retired and bought CNC setup to do porting to keep from going crazy in his spare time. I haven't talked to him about what the cost would be for rotary project. But for piston heads, he charges a one time $400 initial setup fee and $100 a cylinder for the porting. I don't have clue what this would equal out to on set of plates, or even if it would be cost effective to even do. But it will be something to look into this summer for me.
06-19-2005, 10:57 PM
#58
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Join Date: Aug 2002
Location: Mike is a Liar!
Posts: 4,848
I have no experience with CNC or porting.. i would love to be able to cnc something than have to do it by hand.. because it would save time.. but I really enjoy doin stuff to my car myself.. so i'd rather do it by hand.. or have it done that way some knowledgeable rotary guru.. One because its about the comraderie to me.. and also if i dont feel up to the task.. i'd much rather give the business to someone for their experience.. somethin feels wrong about givin my money (not literally) to a machine...
CNC kicks *** though.. im not knocking it.. I would like the option of being able to have my plates rough cut and sent back.. to save me money and time, and then i could do the finish work.. and feel like i participated.
but with so many variations of ports and styles.. it would be tough to chose.. plus i would hope that the ports would be dyno proven and such before i get em done that way..
CNC kicks *** though.. im not knocking it.. I would like the option of being able to have my plates rough cut and sent back.. to save me money and time, and then i could do the finish work.. and feel like i participated.
but with so many variations of ports and styles.. it would be tough to chose.. plus i would hope that the ports would be dyno proven and such before i get em done that way..
06-23-2005, 08:44 AM
#59
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Join Date: Nov 2002
Posts: 3,108
[quote name='banzaitoyota' date='May 21 2005, 10:57 AM']And what does that shop with the Multi Axis Machining center charge>?
What is their setup rate? What is there hourly rate?
[/quote]
Normal 3 axis CNC is around 150 an hour here. And you supply teh CAD file. god only knows how much it would be if they had to do the tool paths from scratch.
No idea what 5 axis would be. I setup a 3 axis student CNC haas centre with a buffing wheel to polish parts once. What a complete waste of CNC time. Good thing it was done overnight away from the eyes of the mechanical engineering dept.
The thing with CNC is repeatability and balancing flow for both rotors. Which is probably the single most important thing. A couple of thou here, 100th of a degree here or there will affect flow rates. The only way hand porting would be as good as CNC would be if you could flow bench the port after each time the die grinder has touched the port to ensure that flows are equal for all teh irons.
What is their setup rate? What is there hourly rate?
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Normal 3 axis CNC is around 150 an hour here. And you supply teh CAD file. god only knows how much it would be if they had to do the tool paths from scratch.
No idea what 5 axis would be. I setup a 3 axis student CNC haas centre with a buffing wheel to polish parts once. What a complete waste of CNC time. Good thing it was done overnight away from the eyes of the mechanical engineering dept.
The thing with CNC is repeatability and balancing flow for both rotors. Which is probably the single most important thing. A couple of thou here, 100th of a degree here or there will affect flow rates. The only way hand porting would be as good as CNC would be if you could flow bench the port after each time the die grinder has touched the port to ensure that flows are equal for all teh irons.
10-21-2005, 08:34 AM
#60
Member
Join Date: Sep 2005
Posts: 67
Just a tip for the Dremel users. in europe we have the following accessory for the Dremel hand tool
http://www.dremeleurope.com/dremelocs-be/P...225&ccat_id=101
Enableing you to make a perfect shape at the plate face side to prevent sliping and sliding over the plate's face.
Haven't found this item on the US website though
http://www.dremeleurope.com/dremelocs-be/P...225&ccat_id=101
Enableing you to make a perfect shape at the plate face side to prevent sliping and sliding over the plate's face.
Haven't found this item on the US website though