Line Balance Study and maybe Takt Time and Cycle Time

jkittle

Involved - Posts
#1
I have a question about line balancing and maybe Takt time and Cycle time play into this as well.

The main question I have if you’re trying to conduct a line balancing study, do include queue times.

For example if I have a primer that has to set for 10 minutes before adding adhesive do I include this in the cycle time/line balance study. I also have a time of 2 hours that parts must remain in a clamped position before going to a test stand.

Are these times included in the cycle time as well as part of the line balance study?

Thank you for your help.
Jerry
 

onestout

Inactive Registered Visitor
#2
I'm sure someone with more experience will chime in with a better answer but what I have done is to set up the curing (in your example) as a seperate process. This way you can see that the machine isn't actually tied up. If you have the space you could run several different parts through the one machine and have them curing in different areas. If you combine the curing with the machine then it looks like the machine is only capable of 1 piece per hour vs. 5 min. to apply and 55 min. to cure. There are many other factors that could change this such as it needs to stay in a fixture for 10 min. But this is how I have done it.
 
A

Adam.m

#3
First of all you need to determine what you are actually measuring.

Is it and their calculations:

a. Machine time - Uptime (production) vs. Downtime
b. Process time - Lead time of product per step and total
c. Man (person) time - Productive time and non productive

Each has it's separate calculation and opportunities. If you indicate which one you are after I can provide more information.
 

Bev D

Heretical Statistician
Staff member
Super Moderator
#4
"Queue" time is when the product is just sitting with nothing happening to it. It isn't inlcuded in lien balance calculations. (It IS included in total cycle time calculations)

What you describe is process time. When I have these kinds of processes I do seperate them out as different processes.

The idea of line baalnce of course is that all processes take the same amount of time and that time is equal to takt time. (Make sure you have the right definition/formula fo rtakt time - there are a lot of misconceptions about this critical calculation) If process time is = takt time (and you have no defects and you are pulling into the process not pushing) you won't have any queue time.

Sometimes a process can't be broken down to smaller increments to achieve line balance. This is when you use the concept of 'toll booths'. Parallel processing of units through longer process times are staggered into the shorter process. The stagger is equal to takt time...
 

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