Line Balancing

[PennStateIE]

Hi. I have a pretty basic question about line balancing. After time studies have been done at each station of current assembly line, you can calculate the allowable minutes and delay time for each station. When trying to balance the line, how do you take into account that you can add accumulation space between stations (in essence reducing or eliminating the delay time)? How do you show that? In other words, if the allowable minutes for the line is 1 and the normal time for a station is 0.5 minutes, then the delay time would show up as 0.5 minutes for that station. I can add accumulation in front of the line which I believe will allow the worker to continue working and not have delay time due to the worker in front of them. Do I just show the line as balanced at that point?

 

[PSE]

Adding accumulation space will not help the line to be balanced and ends up costing more in terms of floor space and having inventory sitting within a que. It is OK to have some binning but don't depend on it for balancing. If the upstream station is faster, it will just fill up the que regardless of size and still ends up waiting.

Regards,

 

[PSE]

PennStateIE,

Might I enquire as to the background behind your query? Generic questions tend to yield generic answers.

Regards,

 

[PennStateIE]

I'm looking at a small repackaging area. Each function only takes a few seconds. Basically, associates are picking up 1 of 4 items and packing them into a bag.

 

[Barry1961]

I think you should explain the problem to the labor union. They should be able to find a way to balance the line.

Barry1961

 

[macvicar]

Is your goal to show a high linebalance percentage or to maximize the utilization & efficiency of the operators ?

 

[Drazen]

As I see, part of your line is manual assembly point. As PSE clearly stated, you cannot use accumulation space for solving faster upstream equipment; accumulation space will just delay overfilling, but you can use it in two other ways:
1. If you cannot have more people in manual working station you can separate this point from the rest of the line by making temporary warehouse on that position. This is the same as very big accumulation space, but this way you can optimize separated half-lines by different working schedules (fast line can work, say 1 shift, while part of line which includes manual point can work 2 shifts and similar: that can help overall production effectivenes: line usage and schedule efficiency very much)

2. Accumulation space will generally help to overcome short stoppages upstream. That is the best use of it.

When we are talking about balancing, we have to go back in design and concept phase of the line setup, that is the moment when you do it! I know in practice for two balancing concepts:

1. Starting from the equipment with most expensive machine time (normally it is the most expensive and complicated equipment). From this point you gradually add capacity upstream and downstream. The point is to have uninterrupted work of your main equpment which overwhelmes cost of added capacity of other equipment.

2. Backwards balancing. The last equipment in line has the largest capacity and then it is gradually lowered upstream.

I saw in literature forward balancing (opposite to backward) but never saw it in practice.