The Screen Printing Frame

 

Regardless of whether you are using a sophisticated commercial press or one that you made yourself, it consists of three primary components: the work surface, the squeegee and the frame.  The work surface or bed of the press should be perfectly smooth and flat. Imperfections in the work surface show up as imperfections in the print.

The primary function of the frame is to support the screen mesh during the printing process. Today, both wood and metal screens are used by screen printers. Many sign shops select the wood frames because they are lower in cost. The wood frames, however, are prone to swelling and warping.

Some old timers in will staple the fabric to a wooden frame, stretching the fabric by hand.  Although this is a quick, inexpensive method for adhering the fabric to the frame, it is an unreliable method.

For the small shop that is not ready to invest in mechanical or pneumatic stretching equipment, the best advice is to buy prestretched screens from a sign or screen print supply distributor.

Another option is to buy retensionable frames, such as the Newman Roller Frame by Stretch Devices. I prefer the roller frames, because if the screen tension loosens up, you can retension the screen. You can’t do that after you glue or staple fabric to a frame.

The primary objectives in screen making are:

  1. Proper fabric tension over the entire area of the screen;
  2. Parallel thread direction to each other and with the sides of the frame;
  3. Enough fabric tension to produce “screen pop” or release from the printing surface after the squeegee printing stroke; and
  4. Constant screen tension throughout the entire duration of the press run to maintain printing registration.

If the screen is not stretched to the proper tension, the mesh openings of the fabric will be reduced. The smaller openings will restrict the flow of the ink and consequently the thickness of the ink deposit. Improper screen tension can also cause problems with the screen pop or screen snap off.  If the screen doesn’t pop properly, there can be a loss of detail and definition.  Improper tension can also cause distortion of the image and misregistration of multiple color prints.

If the screen is not stretched to the proper tension, the mesh openings of the fabric will be reduced.

 

To compensate for poorly tensioned screens, some printers increase the off-contact distance. (Off-contact distance is the amount of space maintained  between the mesh in the frame and the substrate that you are printing.) Rather than correcting the problem, this can actually exacerbate the elongation of the image and cause misregistration.  As the screen stretches, the stencil in the screen can also prematurely break down.

After a screen is stretched, the tension of the screen should be checked with a tension meter. To ensure accurate measurements and to test for consistent tensioning, measurements should be taken at several places on the screen.

Consistent screen tensioning is important or image distortion and misregistration of multiple colors can occur.

Screen print fabric can be stretched on to the frame using a number of different tensioning devices and techniques.  Traditionally, fabric tensioning was performed using mechanical and pneumantic stretchers. In recent years, retensionable frames have gained popularity.  The advantage of these frames is that the tension can be adjusted as needed. Higher tension can also be attained using these frames. And there is no need for adhesives.

Large screen print operations monitor screen tension using tension meters during the stretching process and after it’s completed.  Poor tensioning can result in the following problems:

  1. Inaccurate registration of multiple colors;
  2. Mesh drag;
  3. Image elongation or distortion;
  4. Inconsistent ink deposit; and
  5. Premature stencil breakdown or fabric wear.

Color Trends

Popularity of colors among designers and consumers can vary from year to year. To keep pace with color trends, vinyl film manufacturers and paint companies try to gauge changes in the marketplace. Colors from the world of fashion and interior décor have impacted color selection in the automotive market and in corporate graphics. Bold and […] Read more »

What You Should Know About Heat Pressing on Dye Sublimated Fabrics

 What is Dye Sublimation? Most polyester fabrics, such as many of the popular “Performance Garments”, are dyed using a sublimation process. The dye sublimation process uses high heat to permanently fuse   the colorant   into a polyester fabric. Heat serves two critical functions in this dying process.  First, the heat causes the pores of the polyester fabric to open up, so the material […] Read more »

Selecting the Best Heat Press Machine for Your Shop

With so many makes and models of heat presses, selecting one is usually confusing.  To make the right purchasing decision for your business, you need to thoroughly investigate your options. Start by asking the right questions. Here’s what you should know before you sign on the dotted line. Read more »

Cutting & Weeding Tips for Heat Transfer Vinyl Films

Not all  polyurethane heat transfer films are the same. That’s because some of these flex films aren’t 100% polyurethane, which are very flexible, and other heat transfer vinyl films are blends of polyurethane and vinyl. These blends are much stiffer that a pure polyurethane film. Read more »

Plotter Cutting Heat Transfer Vinyl Films

If you are a sign maker and have a plotter or printer, garment decorating with heat transfer films is one of those prize opportunities that requires a very short learning curve and an investment in a heat press. The cost for a good clamshell press runs about $1000 to $1200, but  you can buy one for […] Read more »

Supply55, Inc. and NEPATA GmbH announce strategic partnership for NEPATA converting centers

Supply55, Inc. a leading provider of value added products to the sign, screen and graphic arts market is pleased to announce a strategic partnership with NEPATA GmbH for the distribution of NEPATA covering equipment in North America. NEPATA converting centers are the most successful and widely used converting centers world-wide. Engineered and manufactured in Germany […] Read more »

Painting Blake’s Red Dragon

In reverse painting on glass learn which types of paint were used to paint William Blake’s Red Dragon…. About William Blake. Artistic genius is generally not recognized until long after the artist has passed away. Such was the fate of one of Britain’s greatest printmakers, painters and poets, William Blake. During his lifetime (1757 – […] Read more »