Correlation Production Time Study on a Process on an Assembly Line

[mechboy]

Hi I am a recent graduate Industrial Engineering doing a production time studies on a process on an assembly line, my data does not make sense i have 3 variables perimeter,square footage and sewing times. Which is a better property to use square footage or perimeter vs sewing times?.The problem is when i run queries for sewing times vs square footage and perimeter there is no noticable variances, i.e 1 larger pieces has same/similar times as small pieces, is there no correlation that a small square footage should take less time or does the perimeter play a more critical role in detemining sewing times

 

[Stijloor]

Re: Correlation Production Time Study

Can someone help?

Thank you!

Stijloor.

 

[Miner]

This is part of exploratory data analysis. You graph both perimeter and area against time to see whether either or both seem to form a relationship.

Recognize that you may have a more complex relationship. For example, there may be a fixed component of time required to handle one piece regardless of size. The length of the sewing path should add to this, but what drives this length, perimeter or area? Complexity of the sewing path might be another driver. Is this driven by shape or something else?

 

[tomvehoski]

I'm not sure I understand your process, but I don't see value in looking at square footage. The linear amount of sewing seems to be the important thing, which is probably closer to perimeter.

Say you sew a 1 X 1 square. That is 1 ft^2 and 4 linear feet of sewing.

Now say you sew a .1 X 10 foot rectangle. That is still 1 ft^2, but 20.2 perimeter feet.

Now say you sew an X in the rectangle. That adds another 20 feet of sewing, but no additional perimeter or square footage.

To do a time study you really need to look at a single "part". Mixing a 1X2" square and a 1 foot diameter circle will introduce other variables like handling, set up, allowable speed, number of corners, ........ It is kind of like trying to compare a drive on a treacherous winding road through the mountains vs. an interstate in Montana. One requires you slow down and be careful, the other is a straight shot with no speed limit.