August 1994
Out of the Stone Age
ast session, we observed something that seemed to contradict conventional screen-printing wisdom. You'll recall the one-color "Wyoming," printed manually, first at 25 Newtons through 255 mesh and then, at my suggestion, printed at 85 N/cm through a special 115 mesh designed to handle high-tensions. I reported that printing speed (per hour) more than doubled in the 85-Newton scenario, while (among other benefits) screen wiping and the flood stroke were eliminated. But then I said something contrary to what any experienced printer might reasonably expect when I told you that finer detail was achieved with the coarser 115 mesh than with the 255. More...

June 1994
Controlling the Stone
"... who needs 100 Newtons?" My answer? Everyone. With those words, last month, I left you hanging. We had just concluded a before-and-after examination of our "Simpsons" print with my reporting the 57 percent increase in production realized by boosting mesh tension from 7 to 50 Newtons. Additionally, we observed that, with increased squeegee and flood speeds, along with more uniform interface pressures, came an improvement in print quality, due to the drastic increase in mesh tension. Then I went on to make what seemed a radical claim that such improvements were only the beginning, and a suggestion that every garment printer should consider printing at tensions approaching 100 Newtons. More...

February 1994
The Double Cantilevered Beam
In our last session, I suggested that we think of our ink-transfer machine, the screen, from an unusual but practical perspective, as a cheese-grater-like cutting tool. From that point of view, we considered the concept of interface pressure as the key to keeping our cutting tool sharp, but along the way, we confronted a serious problem unique to screen printing: as ink is transferred from screen to substrate, it is subject to not one but two points of interface pressure. The first, and desirable, point is where the squeegee meets the mesh. The second and, as we discovered, undesirable point, occurs where the mesh/stencil meets the substrate. High tension emerged as the means to apply a nearly equal and opposing upward force to the downward force of the squeegee, successfully preventing the substrate from becoming a significant aspect in the pressure equation. Thus, to recap, the result was more control and an end to ink abuse: ink could be sheared from the mesh cleanly and deposited onto a garment surface rather than mashed into and through the fabric. More...

April 1994
Like a Rolling Stone
Earlier in this series, I made the point that, by comparison to its sister- printing modalities, screen printing lags far behind when it comes to production speed. Why the big difference?

As I pointed out last time, other printing disciplines (litho, flexo and roto) transfer ink from a rigid cylindrical printing plate to a substrate that is either wrapped over another cylinder or sandwiched between the plate and a roller. In either case, the speed at which the ink-bearing plate releases from the substrate is, by design, mechanically dependent on the speed at which the press runs. In other words, the faster the press, the faster the plate and substrate meet and then release from one another. More...

January 1994
The Cheese Grater
Last month, I proposed controlling mesh elongation to achieve tension stability. Below begins an expanded examination of the role high tension plays in making the frame and tensioned screen a suitable ink-transfer machine. I want to re-examine the subject of high-tension printing because, though elevated tension levels are acknowledged now by many as an important part of the printing screen's performance equation, I believe its critical significance is often woefully underestimated. More...

December 1993
Spaghetti with Rubber Bands
Last time I introduced three concepts that affect our ability to get and hold—to stabilize—mesh tension: elongation, retensioning and workhardening. You'll recall we established a mesh-tension goal, to obtain and stabilize high tension, but turned right around and stated flatly that mesh is, by nature, unstable.More...

November 1993
Turning Up Tension
As most people are aware, I am a manufacturer of retensionable screen frames—not a screen printer. Thus, though it would be fair for readers to question the motives behind my writing on the subject of elevated screen tension, let me state at the outset that I'm not here to sell screen frames. At the same time, I make no bones about being here to sell something— that is, the concept of high-tension screen printing.More...