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Thread: bearing cap machining
10-17-2009, 04:00 AM #1
bearing cap machining
any body has ever machined a bearing cap .. it requires 5 side machining .. i have machining center 3axis, and cnc lathe.
i guess it's all about fixtures
any help would be appreciated
10-17-2009, 06:14 AM #2
Lets see a drawing or a photo of an example.............
10-18-2009, 02:13 AM #3
sorry..i forgot to attach the image
10-18-2009, 02:22 AM #4
Apart from the bore it's simple enough, though for a one off it's one of those jobs with hours of setting up and minutes of machining.
I'd m/c to thickness, rough the bore, profile to outside, put in the holes and mount it on a block using the main fixing holes to bore to size.
The really tricky part is getting the half hole exactly where you want it.
FWIW bearing caps like that are usually line bored in their housings.
10-18-2009, 03:22 AM #5
thanks Limy ,
i almost think about the same procedures,
what's making me worry .,, that the monthly order is about 3000 pieces.
so, every time reduction is very important.
i hate mass production
10-18-2009, 05:04 AM #6
''what's making me worry .,, that the monthly order is about 3000 pieces.''
Sorry, those #'s are right out of my league ..... by my reckoning - on a 40 hr week that's one every 3.2mins
IMO you need input from one of the auto component guys on this forum
10-18-2009, 05:20 AM #7
At 3000 per month investing in forging dies would make a lot of sense. Better part and a lot less machining.
10-18-2009, 07:55 AM #8
You could probably machine to finish every surface except the bearing bore. That would have to be finish bored when the block is line bored. I think you could do all the other surfaces with your CNC machines.
10-18-2009, 08:24 PM #9
Do you have a cam software? If so, machine a progressive fixture. With those quantities, it would pay for it's self with just the time saved on toolchanges. You would also see one or more finished parts comming off the machine every cycle.
10-18-2009, 08:38 PM #10
OK ICE bearing cap. Too bad we didn't know that sooner. 3000 a month? For how long, a production year?
Work the math to put the job in prospective. At 8/5 that's about 200 parts a day making it a multi-machine operation. You need a finished part coming off a machine every 3 minutes or so. I'm thinking a couple of indexing multi-station machine. A small plain vanilla machine shop has no business tackling a job of this scale. Are there oddballs, like thrust bearing caps?
This is way beyond a 3 axis maching center unless it's a real talented one with a pick and place robot, a large tool carousel for extra tooling, wear monitoring, broken tool detection, tool and part probe, and automated parts handling to and from the machine. The only way you'll compete with the big boys on a job like this is if you are "lights out" capable. A major production machine shop could machine these parts at 3000 a month for about $9 each and make money.
BTW, the half bore needs to have stock left in it for a finish line bore at assembly with the cylinder block.
Better consult an automation guru and be ready to make a major tooling and equipment investment, or take a pass.
10-18-2009, 10:45 PM #11
i would like to add:
i will get the pieces as cast (ductile cast iron). the machining allowance are about 2mm (the orange areas).
the annual contract would be 30k pieces.
i don't have the option to finish the bore with the assembly. i just deliver that part to assembly plant.
i started contacting kitagawa to see if they have a fixture that would help.
'm thinking to reach the final thickness using cnc turnining for turning both sides.
i looked up for some milling fixtures . (sample attached). but my machining centers are vertical.
the good news is that i made 2 sampels ., and they were accepted.
the bad news is that each sample took 15 minutes.
10-19-2009, 12:02 AM #12
It seems to me that you might need to discuss the points raised by at least a few of the posts here, or it will not have been worth your time asking the question, or their time trying to answer it.
10-19-2009, 12:12 AM #13
I appreciate every comment posted here. i didn't ignore any of the above posts.
10-19-2009, 03:28 AM #14
you misunderstand my point, I'm sorry I wasn't clearer.
I wasn't suggesting you were ignoring any posts; I've no way of knowing that.
I don't mean acknowledging or thanking the posters, either (which you did).
I mean: entering into a discussion on key points they raise.
I am suggesting that to get somewhere with solving a hard problem like this, I think you need to respond to more of the points - or at least the "killer" point, which is the cycle time of ~~3 mins
If we were playing tennis, not doing this seems to me like each player is lining up to serve and there's you, at the other end of the court, not returning the ball, just waiting for the next serve, or the next player.
And then occasionally when it comes round to your turn, you serve
What seems to work better is if we get "return of serve" more often, perhaps by you saying things like maybe
"well, I plan to work three eight hour shifts a day for six days" or
"if I have to, I'll get another couple of machines".....
so that then people have some idea of what further angles to consider, suggestions to make, or objections to raise.
.....or if you can't do these things, or other things, to achieve a throughput which looks impossible, at least tell us what you can't do and why, and we might think of some new angles.
So ... I'm sorry if my comment sounded like a criticism, and I can see how it comes out sounding like one.
It was actually intended as a suggestion on how to get the best out of the considerable accumulated experience and mental horsepower available here.
10-19-2009, 03:55 AM #15
i got your point , thanks for the advice,
u r right, i forgot to tell that , we are working 21H/day. 6days/week
but that's what making the jop much easier, concerning cycle time
10-19-2009, 05:13 AM #16
I'm glad to hear you got the contract. Please keep us informed as to how it all worked out.