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Critical Success Factors for the Screen Making Department

These five key process areas present opportunities to reduce the price of raw materials and more.

Verne Harnish, known as “the growth guy” and one of the top business consultants in the world, has a great piece of advice in his book Mastering the Rockefeller Habits. In explaining a principle he calls “The Rule of One equals Three,” he contends that you may have to pay 50-100% more to get the right person for a job, but they will produce three times more than an average candidate. The point he’s making is that price does not equal cost. It’s a principle I’ve seen in watching successful companies grow over the years, and I think it can be applied to every function of a printing company’s workflow.

Perhaps no department better exemplifies this principle in our industry than screenmaking. In this article, I’m going to cover what I call critical success factors, or CSFs, for any screenmaking department. It doesn’t matter whether you are printing for graphics, industrial, textile, or even specialty applications: The individual factors will vary from one shop to the next, but the process of identifying and prioritizing CSFs is the same. These are principles that, if ignored, will cost more than what a typical accounting manager thinks.

Throughout this article, I will be pointing to cost. You will see that I don’t define cost as the price you pay for material, equipment, and labor in your screen department. The real cost is how your screenmaking operation affects the productivity of your plant and the quality of the printed parts that drop off the end of the press. I will point to this reality in each of the five key process areas in any screenmaking department, all of which present opportunities to reduce the price of raw materials, but only at the expense of your true operating costs.

Screen frames
No type of screen frame is the “best,” but some will meet your needs better than others. Some applications have critical registration requirements; some don’t. Some jobs require frames over 12 feet in length, but others used in industrial applications may only be a few inches. So, what are your CSFs in frame selection? It’s a simple matter of selecting the right frame for the application (which may not be the type of frame most commonly used by other shops). You may need several different frame types depending on your requirements and the products you produce.

Work backwards in the selection process. Start with the print result you have in mind and think about the characteristics of producing a successful product at the desired production speed. Make checklists like the one in Figure 1 to help you identify the CSFs that apply to the frame you select. Do you typically do very long runs? Are registration tolerances tight? Do you reclaim screens or inventory them for periods of time to handle re-orders? These are just some of the factors that will be affected by your choice of frame.

The mistake I see most often is choosing frames based on price, not on desired results. You may decide that a lower-cost frame is best for you, or you may find that a more expensive frame provides a lower cost by reducing rejects and press downtime. Look at the frames you’re using now and see whether they positively or negatively affect the CSFs you identify.

Mesh
Mesh selection is a CSF in any screen department, one of the most important decisions you can make. Unfortunately, the price of the mesh is mistaken for the cost more often than not. Take textile printing. “How much does it cost?” is the most common question a garment printer will ask their mesh salesperson. Yet if you choose the wrong mesh for the white screen because of price, you may have to do two to three print strokes to get the result you need and the production speed of all your other colors will suffer. In graphics printing, the wrong mesh will cost you color accuracy and repeatability. In industrial printing, it will probably cost you a client. So does a less expensive mesh cost any of these companies less? Not really.

One of the most knowledgeable people I know on the subject of mesh selection is Dan Gilsdorf of Sefar Americas, a member of the Academy of Screen and Digital Print Technology (ASDPT). I asked him what advice he would give someone on choosing the proper mesh, and he said “The first questions would be what product they are printing, what type of inks they are using, and other details like physical size, resolution, stretching equipment, and print quality requirement.” Notice that he didn’t ask me my price range.

He also didn’t ask me what mesh count I wanted. If I ask clients what mesh they want, they often say something like “380,” and I’ll answer “a 380 what?” The mesh count, or number of threads per inch, is only part of the mesh specification. Figure 2 shows three 380 meshes with different thread diameters that give dramatically different results. A 380/34 mesh is one of the worst meshes you can choose if you’re printing process color in medium to high halftone line counts, but for very low line counts, it’s a durable choice that will work fine. Over the past few years, improvements in polyester yarn have become a big deal, enabling manufacturers to offer you thinner and stronger mesh than ever before.

Don’t cut corners on the price of your mesh. Ask yourself the same questions Dan did when choosing your mesh and talk to people you trust. A mesh that meets your CSFs can add many dollars of profit to every job you print.

Stencils
You also have hundreds of choices of stencil systems. Again, do not confuse price and cost. Calculate what you actually spend per screen on film or direct emulsion and you will have a number that is not your cost—it’s your price. Your cost must take into account labor in the screen department, production time saved by choosing a correct stencil system, and more. I talked to Geoff McCue of KIWO, another member of ASDPT, about emulsion choices and he said, “The most important metric to consider is the required image resolution on the print. After that, many other factors weigh in on calculating the most cost-effective product. Do you have a high-quality coating machine? What inks are you running, how are you reclaiming the screens, what inks are you using, etc. All of these factors should be considered.”

Notice that Geoff also started with the end result: “What is the required image resolution?” Any emulsion that doesn’t produce the quality you want or causes you to slow down or stop the press should not be used even if the price is low. The CSF of choosing a stencil system is the result you get on press.

Stencil quality relates directly to the sharpness of the lines and/or dots you can print. Different applications require different levels of quality. If fine detail is a big factor, as it is in industrial printing, you probably need to use a capillary film. It costs more, but it sails through production and the customer is thrilled with the result. In process color, some of worst looking dots I have ever seen wow people in printing competitions. What the viewers don’t realize is that these nasty looking dots may create one great print, but will never be repeatable. They can cause colors to shift during the run, which will kill production and destroy profit margins. The stencil plays a huge role in determining the quality of the lines or dots you can reproduce. Don’t compromise with an inferior stencil system.

Equipment and production
Which is best for your facility: Conventional screenmaking with vacuum frames and film positives, direct to screen, or computer to screen? It depends. Again, it starts with the end result you’re trying to achieve. Determine if your existing equipment is meeting the following needs:
1. What is the definition of good quality internally and to your clients?
2. What equipment issue is stopping or slowing down your production?
3. What level of screen quality do you need to be completely and totally predictable at the press?
4. How many screens are needed to easily keep up with production?
5. What is the image quality that is acceptable at production speed?
6. Is your current equipment meeting these needs?
7. What is the cost to change, refurbish, or buy new equipment?
8. What is the cost if you don’t upgrade?

All of these questions relate to getting the print quality your customers expect at production speed. If you aren’t getting that now, do not hesitate to upgrade your screenmaking equipment or completely change your screen-imaging methodology. You cannot afford for weak technology here to slow down your printing presses or lower the quality of your final output. The cost of bad or slow production is too high.

The labor and production aspects of making press-ready, high-quality screens bring additional CSFs and equipment needs into play. Considerations include the environment, coating procedures, exposure, development, and drying of screens. It’s beyond the scope of this article to cover specific processes such as mesh tensioning and the use of automatic coating machines to get correct and repeatable emulsion thicknesses, but once again, this is not the place to look for money-saving shortcuts. Think about the initial purchase of a coating machine, for example, against the cost of having press downtime and inconsistent print quality that will result from manually coated screens.

Screen inspection, verification, and record keeping
When I do consulting work for screen printers, after assessing and evaluating their screenrooms, I ask them about their screen inspection and verification procedures. Answers range from “We don’t have any” to “Let me show you my records,” and of course the latter is better. An often overlooked but critically important component to a profitable screen-printing operation is not allowing questionable screens to reach the press. Inspecting the screens to verify they are accurate and documenting these steps are CSFs regardless of what type of printing you do.

I asked Bron Wolff, a very experienced production manager who is also an ASDPT member, about the importance of screen inspection, verification, and record keeping in the screen room. He said, “I don't know how you can run or manage a company without them. I read an article years ago by Tamas Frecska (former editor of Screen Printing) and he stated that 75-80% of the problems on press are created before the jobs even get to press. I believe his numbers are low; it's higher. We document damn near everything—the number of turns to a screen, the tension, and the mesh count. We check the mesh count coming in the door to make sure what the manufacturer shipped us is right and within specifications. We check the emulsion thickness and have charts to show spectral output of the direct-to-screen unit to check longevity of the bulbs. We follow preventative maintenance schedules; we face coat screens; we have temperature and humidity gauges in the screenroom.

“I know screenmakers are going to tell me it is a pain and takes too much time to do things this way. But numbers are what it’s about. My overtime in the shop is a third of what it was in 2010 when I took over. Manpower expenditure is down, scrap and rework is down over 80%, press proofs are a half hour compared to half a day or more, and my sales and throughput are up 40%. So you tell me how important processes, procedures, and documentation are.”

You can see by Bron’s statistics that it takes a time to identify and control your CSFs in the screenroom, but the return on investment can be huge. You have to make good decisions about the right frames, mesh, coatings, exposure, and calibration, and then maintain, inspect, measure, and document everything you do. If you are passionate and diligent about quality in your screenroom control, you can have a world-class production facility. It will pay off in more prints hour, week, month, and year.


Mike Ruff has 41 years of experience in the graphic-arts industry and is currently the chief technology officer for Nazdar Consulting Services. He is a former business owner and is certified by G7 as an expert trainer and a process control and conformance expert. He is a regular speaker and has conducted training classes and webinars for prepress, production personnel, management, and sales staffs. He is a member of the Academy of Screen and Digital Print Technology and numerous other graphic-arts and color industry groups. He can be reached at mruff@nazdar.com.



 

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