Johnny Shell Vice President, Technical Services SGIA. Option A: Buy a state of the art printing press with every option available.

Transcription

1 High End Screen Printing Johnny Shell Vice President, Technical Services SGIA SGIA.org/Garment 1of 88 Which Will Produce a Better Print? Option A: Buy a state of the art printing press with every option available. OR Option B: Spend time properly making the screen. Then buy a set of hinge clamps. SGIA.org/Garment 2of 88 Screen Printing Process Model SGIA.org/Garment 3of 88 1

2 High End Requirements Better printing screens Frame High screen tension (>20 Newtons) Thinner mesh thread diameter Control of stencil & exposure Adequate film positive or CTS Halftones Pre registration system More complex separations Manual separations Software generated separations Press calibration & squeegee sharpness SGIA.org/Garment 4of 88 Frame Static Inexpensive Simple Solution Low Tension Retensionable More Expensive Advanced Solution High Tension SGIA.org/Garment 5of 88 Tension and Screen Printing SGIA.org/Garment 6of 88 2

3 Tension and Screen Printing SGIA.org/Garment 7of 88 Tension and Screen Printing What we often get: SGIA.org/Garment 8of 88 Tension and Screen Printing SGIA.org/Garment 9of 88 3

4 Tension and Screen Printing SGIA.org/Garment 10 of 88 Typical Tension Loss Tension Loss over Time Due to Fabric Alignment 24 Hours 9 Days Time in Hours SGIA.org/Garment 11 of 88 Retensionable Frames SGIA.org/Garment 12 of 88 4

5 Poor print quality Poor registration Excessive ink use Excessive screen wear Squeegee pressure Off Contact Results of Poor Tension SGIA.org/Garment 13 of 88 Thread Diameter Fabric thickness Open area Tension/durability Mesh Geometry SGIA.org/Garment 14 of 88 Proper coating technique EOM Rz Stencil Chemistry Dual Cure Diazo SBQ SBQ Dual Cure Dryness Stencil SGIA.org/Garment 15 of 88 5

6 Coater edge profile Coating angle Fill volume Coating speed Number of coats on each side Emulsion viscosity Emulsion solids content Coating Variables SGIA.org/Garment 16 of 88 Use a scoop coater at least 3 smaller than ID width of the screen Use a clean, nick free coating trough Use fresh emulsion Be consistent Coating Technique Tips SGIA.org/Garment 17 of 88 Use both hands for best control Coat slowly to ensure even coverage Coat substrate side first, finishing with the squeegee side Coat in a light safe area Coating Technique Tips SGIA.org/Garment 18 of 88 6

7 Round vs. Sharp Edge Profile SGIA.org/Garment 19 of 88 Round Edge Coating Trough SGIA.org/Garment 20 of 88 Sharp Edge Coating Trough SGIA.org/Garment 21 of 88 7

8 Wet on Wet Coating Technique Dry Emulsion Coating Squeegee Side Up / Substrate Side Down SGIA.org/Garment 22 of 88 Automatic Coating SGIA.org/Garment 23 of 88 Automatic Coater Advantages Requires only one person to operate Simultaneous coating of multiple screens Consistent angle, speed and pressure Better emulsion thickness control Direct time and labor savings SGIA.org/Garment 24 of 88 8

9 Stencil Drying Requirements SGIA.org/Garment 25 of 88 Dry in total darkness Do not exceed 100 F Dry squeegee side up on initial coats Coat today use tomorrow Store coated screens in a cool, dark, dry area Tips on Stencil Drying SGIA.org/Garment 26 of 88 EOM Measurement SGIA.org/Garment 27 of 88 9

10 Recommended Stencil Thickness 10% Emulsion to Mesh ratio is a general industry recommendation. Finer detail may require thinner stencils. SGIA.org/Garment 28 of 88 Stencil Too Thin = Poor Bridging SGIA.org/Garment 29 of 88 Stencil Too Thin = Mesh Marks SGIA.org/Garment 30 of 88 10

11 Optimum Stencil Thickness SGIA.org/Garment 31 of 88 Optimum EOM SGIA.org/Garment 32 of 88 Durability Fully harden the stencil Resolution Exactly reproduce the image in the stencil Goals of Proper Exposure SGIA.org/Garment 33 of 88 11

12 Dry Screen During Exposure SGIA.org/Garment 34 of 88 Wet Screen During Exposure SGIA.org/Garment 35 of 88 Acceptable Light Sources Metal Halide Best LED Newest Fluorescent Not so good for High End SGIA.org/Garment 36 of 88 12

13 Spectral Sensitivity Curves - Relative Sensitivity Wavelength SGIA.org/Garment 37 of 88 Choosing a Light Source Relative Energy % 300nm 400nm Fluorescent 500nm 600nm 700nm Wavelength SGIA.org/Garment 38 of 88 Choosing a Light Source Relative Energy % nm nm nm 400nm Metal Halide 500nm 600nm 700nm Wavelength NANOMETERS SGIA.org/Garment 39 of 88 13

14 Choosing a Light Source nm LED Relative Energy % 300nm 400nm 500nm 600nm 700nm Wavelength NANOMETERS SGIA.org/Garment 40 of 88 Choosing a Light Source nm LED Relative Energy % nm 400nm 500nm 600nm 700nm Wavelength NANOMETERS SGIA.org/Garment 41 of 88 Light Source Limitations SGIA.org/Garment 42 of 88 14

15 Exposure Calculators SGIA.org/Garment 43 of 88 Using an Exposure Calculator SGIA.org/Garment 44 of 88 No Color Change = Good Cure SGIA.org/Garment 45 of 88 15

16 Using an Exposure Calculator (Neutral Grey Types) SGIA.org/Garment 46 of 88 Using an Exposure Calculator (Step Wedge Types) SGIA.org/Garment 47 of 88 Using and Exposure Calculator Diazo and Diazo Dual Cure Emulsions Use a Neutral Grey Exposure Calculator Identify where no color change occurs SBQ and SBQ Dual Cure Emulsions Use a Step Wedge Exposure Test because the emulsion doesn t really change color SGIA.org/Garment 48 of 88 16

17 When to do an Exposure Test SGIA.org/Garment 49 of 88 Avoiding Exposure Problems SGIA.org/Garment 50 of 88 Requirements for Fine Detail Minimum Thread Mass Minimum Stencil Thickness Complete Hardening (Exposure) of the Stencil Excellent Edge Definition, Mesh Bridging, and Resolution SGIA.org/Garment 51 of 88 17

18 Pre Registration Systems Used to Align Entire Job Before Going to Press Provides Fast, Efficient Registration Setup Improved Accuracy Improved Consistency Improved Profitability SGIA.org/Garment 52 of 88 Pre Registration Systems Enable Users to Accurately Place Films on Screens Save Press Setup Time All Colors are Aligned More Consistent Registration Takes work out of the hands of the press operator and places it into the art room. SGIA.org/Garment 53 of 88 Pre Registration Systems Not appropriate for poorly constructed screens Get the mechanics of your process under control first SGIA.org/Garment 54 of 88 18

19 What is a Halftone? A reproduction of a photograph or other image in which the various tones of gray or color are produced by various sized dots SGIA.org/Garment 55 of 88 Halftones SGIA.org/Garment 56 of 88 Recommended LPI Most Images lpi Photo Realistic lpi Some shops use >100 lpi (uncommon) SGIA.org/Garment 57 of 88 19

20 150 Line Count SGIA.org/Garment 58 of Line Count SGIA.org/Garment 59 of Line Count SGIA.org/Garment 60 of 88 20

21 Moiré (more ray) A moiré pattern is an artifact that occurs in the print reproduction process when any two, or more, repeating patterns overlap each other. SGIA.org/Garment 61 of 88 Moiré Moiré is an unsightly interference pattern SGIA.org/Garment 62 of 88 Moiré Moiré is an unsightly interference pattern SGIA.org/Garment 63 of 88 21

22 Moiré Moiré is an unsightly interference pattern SGIA.org/Garment 64 of 88 Causes of Moiré Mesh Inadequate Mesh Count to Line Count Ratio Improper Dot Angle to Mesh Inadequate Screen Tension Film Improper Dot Angles Used Substrate Shirt Weave Interfering with Dot Angle SGIA.org/Garment 65 of 88 Avoiding Moiré Consistent Screen Tension Helps determine angle(s) used Consistent Mesh to Frame Alignment Accurate Film Halftone Angles (RIP) Consistent Garment SGIA.org/Garment 66 of 88 22

23 Halftone Screening Techniques AM Screening FM Screening SGIA.org/Garment 67 of 88 Recommended File Resolution dpi At full size Higher resolution Slows RIP Lower resolution Print looks pixelated SGIA.org/Garment 68 of 88 AM vs. FM Halftone Specs AM Line Count (LPI) Angles Dot Shape FM Resolution SGIA.org/Garment 69 of 88 23

24 Types of Print Separations Spot Color Four Color Process* Simulated Process* Indexed* * = High End SGIA.org/Garment 70 of 88 Separations Four Color Process Uses transparent inks Difficult to print and maintain color consistency Good for white & light shirts Very difficult for dark garments Moiré Used when palette of colors is well beyond limits of printing press 45 lpi, 61 degree halftone angle (all colors) SGIA.org/Garment 71 of 88 Separations Four Color Process SGIA.org/Garment 72 of 88 24

25 Four Color Process Screen Parameters Mesh Counts 305 good for high detailed halftones Can use for underbase for CMYK colors Screen tension 305 tension = 25 Newtons Halftones should be 45 lpi, 61 degree angle SGIA.org/Garment 73 of 88 Separations Simulated Process Great for Light or Dark Garments Uses AM Screening Photorealistic Uses Opaque Inks Requires good color identification skills by separator 45 lpi, 61 degree halftone angle (all colors) SGIA.org/Garment 74 of 88 Separations Simulated Process SGIA.org/Garment 75 of 88 25

26 Simulated Process Screen Parameters Mesh Counts 156 underbase 230 all other colors Can use a 305 for softer hand Screen tension 156 & 230 mesh tension = 30+ Newtons Halftones should be 45 lpi, 61 degree angle SGIA.org/Garment 76 of 88 Separations Indexed Uses Opaque Colors Pantone Matching System Good for Light and Dark Garments Likes Lots of Colors (>8) Dither Pattern (FM) Easy to Print vs. Halftone Dots Image resolution should be 200 dpi at full size Requires good color identification skills by separator SGIA.org/Garment 77 of 88 Separations Indexed SGIA.org/Garment 78 of 88 26

27 Mesh Counts 230 for all colors Indexed Screen Parameters Can use for underbase Screen tension 30 Newtons File should be 200 dpi at full size SGIA.org/Garment 79 of 88 Parallelism Platen to Platen Print head carriage to platen Levelness Overall Maintenance Press Calibration SGIA.org/Garment 80 of 88 Press Parallelism Press Calibration SGIA.org/Garment 81 of 88 27

28 Squeegee Durometer (Hardness) 80 Single Durometer Triple Durometer 65/90/65 55/90/55 Sharp Edge Squeegee Sharpener Angle 15 off Verticle SGIA.org/Garment 82 of 88 Who Is? Industry s Non Profit Trade Association Serves its Printer Members Our Product: Unbiased Information Technical Business Management Environmental, Health, & Safety SGIA s mission is to foster growth and advancement to keep the industry viable SGIA.org/Garment SGIA.org/Garment 83 of 88 Events ThreadX Conference Feb ; Palm Springs, CA Designed for and by garment decorators, THREADX is about how you find customers in today's customer centric, smartphonedependent environment. SGIA.org/Garment 84 of 88 28

29 Events Continuous Improvement Conference April 8 11; Chicago, IL Focuses on helping companies achieve operational excellence by using the concepts of lean manufacturing and other management and quality systems SGIA.org/Garment 85 of 88 Screen Making: Basic to Professional Workshop Apr. 30 May 4; Fairfax, VA Totally T Shirts Workshop Apr. 9 13; Fairfax, VA Register Now SGIA.org/garment then select Events>Workshops Events SGIA.org/Garment 86 of 88 Membership I d like to invite you to become a Member of SGIA so visit us at SGIA.org/Garment! If you re already an SGIA Member, I d like to thank you for allowing me the opportunity to service your needs. SGIA.org/Garment 87 of 88 29

30 Johnny Shell SGIA Vice President Technical Services SGIA.org/garment Thank You SGIA.org/Garment 88 of 88 30