Ron,
Congratulations on embarking on your lean journey, and welcome to the forum.
I have to disagree a little with mattf's description of takt time. One "textbook" definition of takt time is the average rate at which production must operate in order to meet customer demand for a given period of time. As mattf says, the basic formula for takt time is available production time (for a given period of time) divided by customer demand (for the same period of time). To use a simple example, suppose that you are a widget company. To meet customer demand, you must produce and ship 10 widgets per day. Your production operation works 8 hours per day. On these facts, the takt time for your widgets is 48 minutes. In other words, you must produce one widget every 48 minutes in order to meet customer demand. The purpose of calculating takt time is to enable a company to match production with customer demand and avoid both underproduction and overproduction.
Takt time is a common lean tool, but it is not useful for many printing companies. Takt time works well in repetitive manufacturing operations where three conditions exist:
1. The company produces a defined set of products.
2. The demand for each type of product is relatively stable over a reasonable period of time.
3. For each type of product, the process cycle times are approximately the same every time that type of product is produced.
When these conditions don't exist, takt time becomes almost meaningless.
So, if your company is a fairly traditional commercial printing company, you should probably focus on some of the other basic lean tools, especially in the early stages of your lean journey.
I gotta jump in again on David's assessment and disagree with some of his comments.
Your explanation that repetitive manufacturing operations can use takt time is correct. However, I still believe you can take those same tools and put it toward a printing company. As Ron described, this would be within the pre-press setting. Pre-press is the first step in production and one of the most important. Even though you are working in at times a "custom manufacturing" mindset, you can still use the tools of takt time to gather data and see how to improve on the system that is pre-press.
Yes, they are dealing with files that are created differently every time, but what they do with it can be measured. Specific steps such as pre-flighting, proofing, plating, ripping, receiving files, analyzing files manipulating files and so on can all be measured within a timeline.
1) They are creating a defined set of products. Proofs and Plates. Granted, the specific scope of the work needs to be determined, but you can get an idea what type of work a specific printing company can produce.
2) I'll give you number two, as the next job that goes down might be due in 2 seconds! (worked in pre-press before, its a nightmare at times) Granted, if you have a controlled schedule where its all predefined how long certain steps will take, you can analyze the efficiency of that.
3) "For each type of product, the process cycle times are approximately the same every time that type of product is produced." This is true but the model of this can still be used for figuring out an average of how long certain types of jobs can take. So an average business card job could take an average time to get through and an average brochure job can take a certain amount of time to get through. You could even break it down by sheet size if you wanted to instead of mico-managing every specific job that "can" go through.
And yes, the idea is to eliminate overproduction and underproduction. The same idea could be put through with over and under capacity of the production facility of a printing company.