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Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
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Parts with ball missing in it
I produce a part which has a 5mm "ball" press fitting operation. The
ball is pressed in the hole at a depth of 20mm from the face, this I do on a power press. Lot sizes are about 100000nos Operations are sequenced below: 10. A ball is dropped into the hole of the part by hand. 20. Place the part on the press. 30. Push the press lever by his leg. 40. The punch 26mm long then rams & press fits the ball. 50. Lift the part and put it in processed bin. I have not been able to think of a way to get 100% process capability. I have to do 100% visual segregation, even then there is no 100% percent guaranted result. Regards Kamal |
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Bar_turned_Components_mfg wrote: I produce a part which has a 5mm "ball" press fitting operation. The ball is pressed in the hole at a depth of 20mm from the face, this I do on a power press. Lot sizes are about 100000nos Operations are sequenced below: 10. A ball is dropped into the hole of the part by hand. 20. Place the part on the press. 30. Push the press lever by his leg. 40. The punch 26mm long then rams & press fits the ball. 50. Lift the part and put it in processed bin. I have not been able to think of a way to get 100% process capability. I have to do 100% visual segregation, even then there is no 100% percent guaranted result. From the Subject, "Parts with ball missing", are you asking how to inspect the parts, to be sure the ball is where it should be? Ball is in part pressed to correct depth. Ball is in part & not pressed. Ball is not in part. All of the above. Go-NoGo guage pin? -- Gary A. Gorgen | "From ideas to PRODUCTS" | Tunxis Design Inc. | Cupertino, Ca. 95014 |
#3
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Ball is not in part. - is my problem...
Go-NoGo guage pin - I have already implemented, but checking 100000 parts is cumbersome. 100% inspection is never reliable. This is a critical characteristic. I want to do something when the ball is being inserted... or can this process be automated. can a single ball be pushed in during pressing... cfan the manual part in the ball insertion be changed to fixture or something like that??? I get totally engrossed with ideas to settel this simle issue - I would like a totally foolproof process capability |
#4
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Bar_turned_Components_mfg wrote: Ball is not in part. - is my problem... Go-NoGo guage pin - I have already implemented, but checking 100000 parts is cumbersome. 100% inspection is never reliable. This is a critical characteristic. I want to do something when the ball is being inserted... or can this process be automated. can a single ball be pushed in during pressing... cfan the manual part in the ball insertion be changed to fixture or something like that??? I get totally engrossed with ideas to settel this simle issue - I would like a totally foolproof process capability Well ..., if I had 100000 parts to do, I would seriously consider designing and building a machine to do the job. If this is 100000 parts/yr., delete the word "consider". :-) I could probably think of many ways to solve the problem, and I'm sure there's 30-50 other people in this group that could the same. But, without knowing a *LOT* other information, it's hard to know where to start. Shape of part, material, ball material, tolerance, pressing force. Is the press-fit, a few mm. or the whole 20mm? Maybe some drawings & specs, would help. Photos of the current setup. How much $$$ do you want to spend. BB guns, do a good job of putting small balls in a little hole. Come to think of it, most automatic firearms deal with this problem. Where are you located? -- Gary A. Gorgen | "From ideas to PRODUCTS" | Tunxis Design Inc. | Cupertino, Ca. 95014 |
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On 24 Apr 2005 11:12:54 -0700, "Bar_turned_Components_mfg"
wrote: Ball is not in part. - is my problem... Go-NoGo guage pin - I have already implemented, but checking 100000 parts is cumbersome. 100% inspection is never reliable. This is a critical characteristic. I want to do something when the ball is being inserted... or can this process be automated. can a single ball be pushed in during pressing... cfan the manual part in the ball insertion be changed to fixture or something like that??? I get totally engrossed with ideas to settel this simle issue - I would like a totally foolproof process capability Could you do something simple like a sense pin tip for the press tooling? Make the ball press setting anvil hollow, put a "Firing Pin" probe down the middle and bury a microswitch in the base of the tool. If the machine cycles and the tip sense switch isn't triggered by seeing the ball by the time you reach the 'high pressure' stage of the press cycle (or a 'cycle distance' switch you set up on the side of the press yourself), set off an alarm and/or stop the cycle... Make the machine operator set the part aside in the "Inspect" bin. (And to catch sense switch failure 'false positives' quickly if the pin jams or the return spring breaks, you also need an alarm if the switch does NOT go open again when the cycle finishes.) I'd have to see the machine to tell if this would work, but there's usually a simple answer if you get an inventive person on the problem. -- Bruce -- -- Bruce L. Bergman, Woodland Hills (Los Angeles) CA - Desktop Electrician for Westend Electric - CA726700 5737 Kanan Rd. #359, Agoura CA 91301 (818) 889-9545 Spamtrapped address: Remove the python and the invalid, and use a net. |
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Gary A. Gorgen wrote:
Where are you located? India |
#7
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"Bar_turned_Components_mfg" wrote in message
ups.com... | Ball is not in part. - is my problem... | | Go-NoGo guage pin - I have already implemented, but checking 100000 | parts is cumbersome. 100% inspection is never reliable. This is a | critical characteristic. | | I want to do something when the ball is being inserted... or can this | process be automated. can a single ball be pushed in during pressing... | cfan the manual part in the ball insertion be changed to fixture or | something like that??? Since we don't have more detail of your machine and process most of us are tossing out ideas to see if one will stick, but something that came to mind, depending on your process, would be a load sensing device with interlock or other control to either reject the part or recycle the process that loads the ball. Yeah, that's rather broad solution, but the exact solution depends heavily on your machinery. Now, I'm going from your description that the ball is placed in the part by hand, the part placed in the press by hand, the press is operated by foot, and part then removed by hand. With that in mind, a tubular magazine (like the ones you saw in the carnivals for the BB guns where you punched out the star,) could hold lots of balls that the operator could insert with the part already in the machine, directly from the magazine. It might be able to offer some degree of confidence on the part of the operator that the ball was indeed placed where it should be. If the pressing mandrel face has an extra sensing pad or mechanism that, if the ball were sensed to be not in place, would stop the press to prevent the pressing operation or otherwise flag the operator. It could even eject the part either before or after the pressing operation. For this kind of part count, I have a hard time imagining that a human operator is the active part of this process, or else you need to upgrade your process. The inherent unreliability of a human is not well suited to this process by any means. |
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ff wrote: Where are you located? India I guess I have to start reading email address again. :-) -- Gary A. Gorgen | "From ideas to PRODUCTS" | Tunxis Design Inc. | Cupertino, Ca. 95014 |
#9
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Is the problem that the press is sometimes actuated with no ball in
place? Even an automatic ball feeder could misfeed at times. Perhaps you could instrument the press wtih a load cell to measure force when it is actuated. If force is too low on the downstroke, there was no ball present on that stroke. Take whatever action you think is appropriate when that condition is sensed. On 24 Apr 2005 11:12:54 -0700, "Bar_turned_Components_mfg" wrote: Ball is not in part. - is my problem... Go-NoGo guage pin - I have already implemented, but checking 100000 parts is cumbersome. 100% inspection is never reliable. This is a critical characteristic. I want to do something when the ball is being inserted... or can this process be automated. can a single ball be pushed in during pressing... cfan the manual part in the ball insertion be changed to fixture or something like that??? I get totally engrossed with ideas to settel this simle issue - I would like a totally foolproof process capability |
#10
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Place the component on a check weighing conveyor when it comes out of the
press. If the ball is more than .1 % of the part you can automatically reject it. "Bar_turned_Components_mfg" wrote in message oups.com... I produce a part which has a 5mm "ball" press fitting operation. The ball is pressed in the hole at a depth of 20mm from the face, this I do on a power press. Lot sizes are about 100000nos Operations are sequenced below: 10. A ball is dropped into the hole of the part by hand. 20. Place the part on the press. 30. Push the press lever by his leg. 40. The punch 26mm long then rams & press fits the ball. 50. Lift the part and put it in processed bin. I have not been able to think of a way to get 100% process capability. I have to do 100% visual segregation, even then there is no 100% percent guaranted result. Regards Kamal |
#11
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"Bar_turned_Components_mfg" wrote in message oups.com... I produce a part which has a 5mm "ball" press fitting operation. The ball is pressed in the hole at a depth of 20mm from the face, this I do on a power press. Lot sizes are about 100000nos Operations are sequenced below: 10. A ball is dropped into the hole of the part by hand. 20. Place the part on the press. 30. Push the press lever by his leg. 40. The punch 26mm long then rams & press fits the ball. 50. Lift the part and put it in processed bin. I have not been able to think of a way to get 100% process capability. I have to do 100% visual segregation, even then there is no 100% percent guaranted result. Regards Kamal What is the cycle time? How long does it take in man-hours to make a run? What is the cost of 100% inspection? How much $$$ is it worth to automate to what % of good parts? How long (years) will you have this job? Review your procedures to see why you can't get 100% on a manual operation...I don't buy that you can't...I do it all the time. Often it's cheaper to kludge your way through a PIA job than over-automate. Think out of the box!!! Engineering expertise is cheaper and better in India than anywhere but creative thinking is less prolific. |
#12
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"Bar_turned_Components_mfg" wrote in
oups.com: I produce a part which has a 5mm "ball" press fitting operation. The ball is pressed in the hole at a depth of 20mm from the face, this I do on a power press. Lot sizes are about 100000nos Operations are sequenced below: 10. A ball is dropped into the hole of the part by hand. 20. Place the part on the press. 30. Push the press lever by his leg. 40. The punch 26mm long then rams & press fits the ball. 50. Lift the part and put it in processed bin. I have not been able to think of a way to get 100% process capability. I have to do 100% visual segregation, even then there is no 100% percent guaranted result. Kamal, A simple method would be to make the insertion punch in the following way: Spring load the insertion punch by mounting it in a cylindrical holder that has a spring inside of it and slot milled through one side. The insertion punch will need a cross drilled and reamed hole in it that will accept a pin that will be inserted into the punch through the side of cylindrical holder. Use a pin that is long enough so that it can be used to actuate a micro switch if the ball is not in place. When the ball is in place the pin should not be able to reach the micro switch. As far as what the micro switch does, well that depends on your set up. You could use it to actuate a blow off that would eject the part away from the good ones. You could also use it to actuate a buzzer or a red light. You could even use it to actuate a counter so that at the end of the shift you can compare the number of parts rejected to the counter, thereby giving you 100% confidence that all of the parts in the finished product container have a ball in them. If it were me I would use the blow off in combination with the counter, and make an accounting at the end of each shift. -- Dan |
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