Assembly Line Balancing Questions!

[JeromeDC]

Hello everyone, I am new to the manufacturing industry and I am having a problem trying to figure out how to balance our assembly line. I have already collected data on the cycle times for the 26 different operations on the line. Once this data was graphed, the Takt time was calculated and shows that all of our processes are below (which is good), however the graph also shows that our line is very very unbalanced. Seeing as this is my first foray into this line balancing issue, I was hoping someone can help me answer a few questions in general for line balancing.

I understand the concept of balancing a line for example, if station 1 takes 20 sec per part, station 2 takes 25 sec per part, station 3 takes 15 sec per part, and station 4 takes 20 sec per part, then you would want to balance stations 2 and 3 so that all have equal cycle times (please correct me if I am wrong).

The first question I have is: am I collecting the data in the correct way? According to the data I have gathered, it looks like there are a whole bunch of operators that are standing around, but this is very minimal throughout the process.

Next is the times I have gathered are operational times, so do I need to collect the downtimes in between each operation? If so, do I collect it from end to beginning for each operation (for the next part), or from how long it takes the part to get to the next operation?

Once I have collected some of this information, my next question is how do I use all this to balance the line?

Finally, I am sure I have left out many details (which I can give), but is there anywhere I can get better examples of line balancing on the net? I have been searching for the past couple of weeks and cannot find anything to help me balance this line. Thanks in advance for any advice/help and I hope to hear from you all soon!!!

Jerome Dela Cruz

 

[BillPSU]

One of the items you need to address is the precedence of the various operations. This will show you operations which can be moved and which cannot be moved. An example is a wheeled vehicle, you cannot mount the tires before the axles are in place. You cannot start the vehicle until the coolant, fuel, oil and other necessary fluids have been put in the vehicle. However, where the fuel is added is determined by being after the fuel tank is installed.
Try to determine the work content of the complete assembly line including subassemblies which occur off the line but is completed by the line assembler. The total work content is then divided by your takt time and you come up with the ideal number of people required to meet production. In the real world more people will be needed to take care of absenteeism, breaks, family leave and vactions.

 

[smitty23]

1 believe it or not sometimes slower is faster\better.
2 what operation is slowest ppm and stick with that#
to much accumlation between operations is ____ __
3 good conponents = zero downtime
4 write down each little problem then slove it (kis_)
keep it simple
5 have a slow machine buy or build another and so on

 

[JeromeDC]

Thanks Bill and smitty for your responses!

Ok now Bill, I have addressed the precedence issue and have found out that the way we are building right now is optimal. I am still looking into maybe re-designing the way the line moves/operator locations etc etc. We mass produce cabinets on these 2 assembly lines and what I am wondering is, from what I've said before, how do I balance this line or any line for that matter?

Smitty, thanks for the comments, they made me look at things a little bit differently. The thing is on this assembly line, the only machines involved are the conveyors as well as the air guns used to put our cabinets together. So what I am wondering is how do I treat this differently since I am dealing with workers and not machines down an assembly line?

Thanks again for your support guys!!!

 

[edspearman]

Ask yourself:

Are you on a paced line - or - non paced line.

Line Balance Technique is different between the two.
"Feed and Speeds" are key, and do you have quality gates
after each operation ?

Ed Spearman

 

[AndrewUK]

If you are working with a labour is the cycle the same for an operation every time? if not why? look at the variation?
I would not try to balance until you undertand and remove the variations. To do this you will standard ops.

Also once you work out the precedence issue you can still tweak things, say station one fits a circuit board (5 secs), station two fits a transformer (20 secs) and station three wires it up (35secs). Takt is is 30 seconds what can you do? Station one could fit the circuit board and place the correct wires in the unit ready for station three, maybe they could even do more. This is a basic example, Remember a precedance is ony the order under currnet conditions, Change the current conditions!

 

[cardelli]

JeromeDC,
How many operators are there on this assembly line? You state there are '26 different operations on the line.' Has the line ever historically been broken into smaller subassemblies? Check into it. It's a lot easier to balance and optimize the halves. Any thoughts?
Cardelli