Prepress Takt Time

[mattf]

I don't mean to harp on a point unnecessarily, but I think it's important to clarify the meaning of a few terms. Takt time is a pacing mechanism. It is not intended to be a measure of the time spent performing a particular process or all of the processes required for a particular job. Takt time tells you the pace at which you must produce a particular product in order to meet customer demand. So, for example, if you must produce 16 widgets per day to meet customer demand and you have 8 hours of production time each day assigned to making those widgets, then your takt time for that product is 30 minutes. All this means is that, on average, you must produce one widget every 30 minutes in order to meet customer demand.

The time actually spent performing the activities that are required to produce a product is cycle time. Suppose, for example, that a particular job requires three prepress activities - preflighting, imposition, and plate imaging. If an operator spends 15 minutes preflighting this job, then the preflighting cycle time is 15 minutes. If imposition requires 10 minutes and plate imaging requires 15 minutes, then the total prepress cycle time for this job would be 40 minutes.

Througput time is the total chronological time that it takes to move a product through the production process or through a portion of the process. Suppose, for example, that the job described in the previous paragraph was delivered to prepress at 9 am and that plates for the job were delivered to the pressroom at 12 noon. In that case, the prepress throughput time for the job would be three hours.

The main point I want to make is that takt time is not a measure of the actual time required to produce a product or perform a process. Takt time is the pace at which you must produce in order to meet customer demand.

After careful analysis of David's explanation, I understand what he is trying to get across and I will agree with his analysis.

A potential better way to handle what you are trying to do would be to analyze what is going on in order to create "work cells".

A work cell is "an arrangement of resources in a manufacturing environment to improve the quality, speed and cost of the process."

Creating a system that no matter if a job is hot or not you have a specific infrastructure in place to handle the changing environment that we call printing. The whole idea of a work cell is to have the specific team cross-functional. This might be a bit of a stretch for pre-press because of its need to focus on one project at a time, but creating a system that can improve on the resources used, the quality of the work, the speed and the cost of the process could benefit from this.

It could be your CSR's and pre-press guys are in the same room, right next to each other. Or maybe its rearranging how pre-press are working. Again, there are many ways to handle this, and the more data you have and the more input that is presented the better off you'll be in creating a more efficient process.

[rnavlyt2]

Matt,

We have already established working cells! I have been the Prepress Manager for the past 10 years and have now taken on the new roll of cell leader for our Offset Cell. You knocked the out of the park by saying trust your prepress operators! That statement transcends to each department within your value stream. You must trust their knowledge, experience and input to move forward in a positive direction. The group we have here was a little hesitant at first but we keep trudging forward and the support from within is starting to catch on. The takt times have been the biggest object to tackle, especially within the prepress area. One of my co-workers within our cell has expressed interest in helping with the takt times. She is creating a takt sheet and we will be reviewing processes to track tomorrow.

Thanks again,
Ron

[Mark Flanders]

Greetings,

It's great to see this discussion. Good thoughts. All my smarty-pants ideas have mostly been said already.
I have to agree with David on perhaps shifting focus away from Takt time in prepress. The custom, rush job environment with a fair bit of problem solving isn't well suited to this particular tool. There are other lean ideas to work with mentioned above that would engage your prepress staff toward improvements. Studying and pacing the rhythm of production is best suited to steady production of similar products, aimed at matching supply, demand and production time. Takt time in prepress is a little like takt time at the suicide hotline. One crisis at a time please, and turn your stopwatch off, if you don't mind.

thanks!

mf.

[smmjkg12]

Greeting all,
Great post. I am curious if anyone has created a spreadsheet in Excel to help track the Takt time of prepress, or any other department for that matter. If you have, would you be willing to share?
Best Regards,

[PDeuth]

There are many print markets and print workflows. What I did in commercial printing was very different from what I did printing business forms. What particular market/workflow do you have in your shop?

Commercial printing is very much the pull workflow. Rate of demand is not in the hands of the shop. Rate of production is, however. This becomes a scheduling issue, then, with a trade-off between Work In Progress (WIP) and cycle time: the larger the number of jobs in the system, the longer they will take to produce. Little's Law tells us that Process Lead Time = Work In Progress/Exit Rate. Those are your trade-offs; the question is, What do you want to do with them?

Takt time is useful to know if you want to load-level in pre-press. It's useful if you want to tie Exit Rate to customer demand, so that your pre-press staff might be used to help in hand bindery, or so you can trim your pre-press staff; remember, however, that if you can't definitely determine the rate of customer demand, you're not proceeding wisely with these tactics.

In markets and workflows more repetitive that commercial printing, it can be more informative. My point is that one needs to have a use for a particular method before employing it, one would hope. So, what are your particular needs? What market/workflow do you serve? Can you determine customer demand (takt time)? And if you can, what do you want to do with that information?

[swcook6]

If in a magazine or book manufacturing environment, it may be best to calculate pages as "widgets" because each step in the process (especially imposition and platemaking) will be affected by the number of pages in the publication/book.
Just a suggestion from previous experience.