Newman Inst

Newman Roller Frames - Stretching & Retensioning

by Roger L. Jennings

You have made the right decision by buying retensionable frames.

The key to excellence in print quality, ease of printing, eliminating that dirty job of cleaning the bottoms of screens during the printing process is the retensionable frame. Wood, welded and curved screens will not yield equal mesh tension and do not allow retensioning mesh which is required for the best quality printing.

These frames will have the greatest impact on your business, and you will soon realize you were in the dark ages and didn't know it. Well, world, here you come!

EASY MESH INSERTION INSTRUCTIONS
Cap Printing Tips
MESH RECOMMENDATIONS
INK RECOMMENDATIONS
ELIMINATE SCREEN PITCH
REGISTRATION GUIDE (use the same idea for shirts and caps!)
Suggested reading:

EASY MESH INSERTION INSTRUCTIONS with some hot tips!

1. Do not cut mesh. You can snip the edge with scissors to start a tear, but always tear mesh. Mesh tears along a thread line, and a tear will be straight. This will allow insertion of mesh with the threads parallel to the frame, and bringing the mesh to its maximum potential tension. Tear so that the mesh overlaps each side by at least 1".

The Objective will be to get the mesh into the frame so that the fibers of the mesh are parallel to the 4 sides of the frame. The quality of this insertion will determine the maximum tension that can later be applied to the mesh.

2. Remove the locking strips from the Roller Frame (R).

3. Lay the frame on the table with the slot in the bar side facing up, or in the case of cap frames, the thinnest edge of the flat bar facing up. Rotate the 3 Rollers so they have the slots for the locking strips facing up.

4. Overlap the slot in the bar side by no more than 3/8" with the mesh. A short dimension like 3/8" will allow visual inspection to be sure the torn edge, or mill finish edge, of mesh is parallel to the slot before insertion of the mesh. This is the most important step

Click on Photo to Enlarge

5. Insert the clips by squeezing the clip. Press one side of the clip against the Reference Edge of the slot, i.e. the edge of the slot closest to the mesh side of the frame. Then push the other side of the clip in the slot.

6. Push the locking strip in as the mesh is pulled in the opposite direction so that no wrinkles form. Remove the clips when they interfere.

7. If a cap frame, clip with scissors the 2 corners of the mesh so that the nuts on each end of the bar side do not interfere with the mesh.

8. Lay the mesh over the opposite Roller. On cap frames, the mesh is covering the thin edge of the flat side. Pull the mesh tight, and press the clip against the Reference Edge (closest to center of frame) first, and insert the locking strip.

9. Now is the 2nd most important step. View whether the mesh overlaps the 2 remaining rollers so that the mesh edge is parallel to the rollers. If not parallel, pull the mesh in the direction necessary to make the mesh parallel to the remaining 2 rollers.

10. Pull the slack out of the mesh over these remaining 2 rollers, making sure the mesh is being pulled evenly, and insert the clips and locking strips in each roller.

11a. Shirt frames require softening corners so that the mesh will not rip when tensioned. The corner is softened by using needle nose pliers to pull the locking strips out 1" away from the 2 sides that form the corner of the frame. While the locking strips are temporarily out of the slots, depress the mesh in the corner so that some of the mesh will move past the slot and into the corner. Then re-insert the locking strips. All 4 corners must be softened to avoid tears.

11b. Cap frames should not be softened. Rather, be sure the locking strips are inserted as close to the flat bar side as possible when inserting mesh into the 2 short rollers. This will create greater tension in the two corners close to the flat bar so that there is tension in and near the image area. The other corners will become soft.

12. After inserting the locking strips in all 4 sides, trim the excess mesh at the corners. If excess mesh overlaps any of the rollers, snip the mesh with scissors to start a tear about 1/2" away from the locking strips, and tear the remaining mesh. If the torn mesh is parallel to the roller, the mesh has been inserted so that the threads are parallel to the rollers, and significantly high mesh tension and print quality can be achieved.

13. Place the frame on the 4 corners of the frame using 4 squares cut from squeegee blades . Make sure the table is flat, because the frame will mirror the table.

Prepare for tensioning by putting the open ended wrench on the large nut end of the roller to keep the roller from rotating. Then unlock the smaller nuts at either end of the roller while still holding the roller in place. Then the roller can be rotated as instructed below and then tightened in place using the two smaller nuts at the ends of the roller.

Tension the mesh first from the roller opposite the bar side. If you do not have a meter, start with the wrench pointed at 12 o'clock, and pull to 10 after the hour. Lock the roller in place. Then go the the remaining two sides, and again start at 12 o'clock and rotate the rollers so the wrench is at 5 after the hour. You will be close to maximum tension without the advantage of a meter. If you have a meter, tension in both directions should be +/- 1 N/cm2.

Repeat the process in 2 hours, then wait another 4 hours, and then at least another 8 hours, each time moving the first roller 5 minutes on the clock and the two parallel rollers half of the rotation of the roller used for the first roller opposite the square bar or flat bar for caps. If you have a meter, follow the guidelines of a tension chart according to the mesh being used.

Check the frame for flatness by putting it on a glass window or exposure unit. If the frame rocks, remove one of the squeegee blades from a rocking corner, press down on the frame at the corner, and recheck against the glass until there is no rock. Flat screens are necessary for ease and quality of registration, off-contact distance and quality printing.

14. For more information, call R Jennings Manufacturing (518-798-2277) or email roger @ rjennings.com. You can also call Stretch Devices in Philadelphia at 800-523-3694.

Cap Printing Tips:

1. Always use capillary film on cap frames to avoid emulsion breakdown at the bar edge, and to provide a uniform emulsion thickness near the bar edge. This will deposit a uniform ink thickness for color control and for consistent puff height.

2. Use a triple durometer squeegee, e.g. 70-90-70 with a square edge. Squeegee blade tips flare out, yielding less pressure and a different print, when compared to the print from the middle of the squeegee blade. Frequently images are close to the bar side of the frame, as close as 1/16" to the inside of the bar, and printing problems can be avoided by using a laminated squeegee blade with 90 durometer to prevent deflection.

3. Make sure the mesh is on contact with the platen in the entire image area before attempting to register the image to the positive. The graph on the Jennings cap platen will help center the image and insure the image prints parallel to the bill of the cap.

4. Print off-contact 1/32" - 1/16" keeping your hands off of the frame while printing. Keeping your hands off will insure the off-contact is achieved.

5. Print by locking the wrist and elbow with a squeegee angle to the mesh at about 45 degrees. Most people use a higher angle and have to pull the squeegee twice. Rather than moving the arm to print, step back to achieve the print stroke for the first 5-6 caps. This will make the person printing sensitive to keep the squeegee at a uniform angle while printing rather than lifting the elbow which would change the angle and print quality.

6. For more tips, contact R Jennings Manufacturing at Contact Us on this website or roger @ rjennings.com.

MESH RECOMMENDATIONS

             Capillary Film     Screen Tension
              Thickness in      in Newtons/cm2
Mesh        Microns           (Retensioned)    Application

60 50-1000 60 High density ink

86-110 40-50 45 Puff ink; light ink on
dark fabrics

160 30-40 35 Most line art printing

220 20-30 30 Halftones

305 20 30 4-Color Process
manual printing

INK RECOMMENDATIONS

1. Experiment with inks to find out how much they can be thinned with soft hand clear without changing the color. The results will be affected by the color of the substrate under the ink. Nevertheless, the addition of soft hand will improve the printing characteristics of many inks. Experiment to find out.

2. Often modifying ink with 2-4% curable reducer (milky white in appearance), but never more than 10%, by weight will reduce the adhesive quality of ink, allowing it to shear more easily. Less squeegee pressure will be necessary, and the 2nd of the 2 culprits to ink build up under screens can be eliminated. The body of the ink should be fine tuned according to the mesh count, emulsion thickness and substrate.

ELIMINATE SCREEN PITCH

Use a clamping bar on the screen that clamps on the corners of the frame. This is included on all Jennings machines shipped after 12/98, and is available for all machines purchased before 12/98. You could insert a 1/8" x 1" x 12" steel bar between the roller of the frame and the clamping mechanism of your press. Or, your option is:
Use Newman M-1 Clamp Adapters as shown below:

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REGISTRATION GUIDE

for Cap Screens
Shirt Screens, too ! ... but use larger paper !

Directions to Make Your Own

Trace the frame on graph paper.
Draw a line parallel to the bill side of the frame 3/16" away to represent the thickness of the bill. This step is not necessary for shirt screens.
Lay the graph paper over the cap platen with the line for the bill support against the bill support of the cap machine. Trace the platen. For shirt screens, simply lay the shirt platen on the graph paper, and trace the platen in the middle of the drawing of the frame.
Draw horizontal and vertical center lines on the drawing of the platen.
Lay the drawing on a smooth, flat board, and tape a clear piece of plastic over the graph.
Secure wooden strips on two sides of the screen so the screen will always be located over the center of the platen.
Use cellophane tape to place the positive over the platen drawing. Place the second positive over the first in registration.
Put 2-3 pieces of double stick tape on the top of the positive. Lay the coated screen over the positive using the drawing of the screen and wood as a guide.
Pick up the screen with the positive in exactly the right position to expose. Images will not be too high, too low, or crooked. Screens will be exposed correctly every time, and you did not spend money!