31 Dec The Problem with Technical Data Sheets?
Every new car that you buy comes with an owner’s manual that gives specific information about the car. The exact amount of air to put in the tires in the summer or winter, when and how to change the oil, and what oil should be used. They are very complete, and I have always found any information I needed for my car in the owner’s manual. And, best of all they are included with the price of the car. However, the Technical Data Sheets (TDS) from the ink manufacturers are severely lacking in factual detail.
Bill Hood, ASDPT Fellow
As most screenprinters know, searching for a better way of using ink in the manufacturer’s Product Information Bulletin (PIB) or Technical Data Sheet (TDS) is never really helpful. It should not be this way. The ink manufacturer tested the ink and knows the exact variables used in the testing that achieved the best results. But, this information is never included in the PIB or TDS.
Most manufacturers will specify a range of mesh counts that a particular ink can print thorough, such as 86 to 305-in (34 to 120cm) mesh, but they never specify a thread diameter. The screenmaker searching for an answer only wants to know which mesh will give the best results. Presented with a range of 45 unique mesh counts across 135 thread diameters and 19 Newtons of levels of tension levels is not an answer and does not solve the problem.
The manufacturer in specifying a mesh count, surely understands that the tension level of the mesh changes the size of the mesh opening and the way in which ink will pass through the opening and give the best results. It would be better to actually specify a particular mesh opening size in microns and the volume of the mesh opening, which provides some concrete information as to what works best.
In the PIB or TDS under the stencil, the screenmaker is told that he can use either capillary film or liquid emulsion but is not told a particular emulsion over mesh ratio, which would narrow down the particular thickness of the capillary film or stencil thickness that would provide.
Under squeegee, they may only recommend a “square” blade and sometimes, which is not really helpful. The printer needs to know what Shore A hardness of squeegee, the free length of the squeegee, the angle, pressure, and speed that will give the best results of the ink.
Let’s talk about a specific type of ink – white ink for printing on cotton fabric. Supposedly the manufacturer tested the ink before putting it on the market. And, they most likely tested it on different configurations of mesh counts and colors of fabric. They know that when they tested the white ink on black cotton using a 305-in (120cm) mesh, it printed well, as they state in their literature that it will print through this particular mesh.
Let’s assume for a moment that their testing was done on a 305-in (120cm) mesh, that had a 31-µm thread, was a plain weave, tensioned to 24N/cm2, the mesh opening was 57-µm, the fabric thickness was 48-µm, and they had an emulsion-over-mesh ratio of 8-percent. However, if a printer attempted to print the same white ink through his 305-in (120cm) mesh that had a 40-µm thread, the ink volume would be reduced from 19 to 13 producing far different results than that of the manufacturer.
If the manufacturer provided the actual technical data that was used to achieve the results in the manufacturer’s testing, the screenmaker could come very close, if not exact, in preparing a stencil that would duplicate the test results.
The manufacturer also knows the exact variables of the fill blade, squeegee, and print technique that they used in their testing. The press operator would save hours of testing the parameters on his press. The PIBs and TDSs do not contain enough information to bring you any closer to success.
Until the ink manufacturers decide to begin sharing their actual test results, screenprinters will simply move on to another ink, and the manufacturers will have not only lost a revenue stream from a screenprinter, but their brand recognition is reduced because word-of-mouth has always, and will continue to be, the best advertising.