ENG
TECHNICAL MINI GUIDE

How to Select the Right Squeegee

The squeegee controls ink deposit rate and image sharpness. Choosing the correct hardness, edge profile, and composite blade structure is critical for balancing ink coverage and fine-line matrix resolution.

1. Squeegee Selection Workflow

  1. Image & Matrix Analysis: Assess detail density (fine halftones vs heavy solid areas) and mesh screen tension.
  2. Nominal Hardness Selection (Shore A): Select appropriate durometer (Soft 60-65 ShA for irregular substrates; Hard 75-85 ShA for sharp detail).
  3. Blade Profile Geometry: Choose square edge for general printing, bevel edge for curved/rigid surfaces, or V-shape for industrial graphics.
  4. Composite (Triple-Durometer) Selection: Evaluate 75/90/75 ShA triple-layer blades for high-speed automatic presses to prevent blade bending.
  5. Chemical Compatibility Check: Ensure polyurethane compound resists solvent or water-based ink systems being used.

2. Technical Parameters & Profile Selection

Hardness & Profile Selection Matrix
Hardness / Structure Ideal Application Scope Ink Transfer Behavior
60 – 65 ShA (Soft - Red) Textured fabrics, heavy solid backgrounds, high-viscosity inks, manual printing. High ink laydown, heavy blade deflection, lower edge resolution.
70 – 75 ShA (Medium - Green) Universal textile printing, standard line art, Plastisol and Water-based inks. Balanced deposit, excellent edge stability, moderate deflection.
80 – 85 ShA (Hard - Blue) Four-color process (CMYK), high-LPI halftones, flat rigid substrates, high-speed presses. Thin, controlled deposit, maximum dot sharpness, minimal blade flex.
75/90/75 ShA (Triple Layer) High-speed automatic presses and large formats requiring zero blade bending. Rigid 90 ShA core prevents flex; 75 ShA outer lips maintain clean shearing.

3. Troubleshooting: Selection Errors & Remedies

Squeegee Selection Diagnostic Guide
Print Defect Root Selection Error Corrective Action
Insufficient Ink Deposit / Pale Print Squeegee too hard (e.g. 85 ShA) or attack angle too steep. Switch to softer durometer (65-70 ShA) or decrease printing angle.
Blurry Edges / Image Gain Squeegee too soft (e.g. 60 ShA) bending excessively under pressure. Replace with 75 ShA blade or triple-durometer (75/90/75 ShA) squeegee.
Wavy Pattern along Edge Profile Single-layer soft blade used on high-pressure automatic press. Upgrade to triple-layer squeegee to stabilize blade core during stroke.

4. Operational Best Practices

  • Department Color-Coding: Standardize international color conventions (Red=65 ShA, Green=75 ShA, Blue=85 ShA) to prevent press operator mistakes.
  • Instrumental Durometer Checks: Do not rely solely on original color: verify actual hardness with a durometer prior to press setup.
  • Single-Bevel Profile Alignment: Use single-bevel blades only when press head inclination is fixed for unidirectional shearing.

5. Mentor's Insight: Practical Field Experience

Note from Beppe's Shop Floor

Many printers try to solve opacity problems by cranking up squeegee pressure on press. That is a critical mistake: if you apply excessive downward force on a soft 65 Shore single-layer blade, the edge rolls over, the blade drags instead of shearing, and you end up smashing ink into the garment with complete loss of detail.

When you need to push ink through the matrix without losing crispness, don't add pneumatic pressure: switch to a **75/90/75 ShA triple-layer squeegee**. The hard 90 Shore inner core keeps the blade perfectly upright, while the 75 Shore outer lips shear the ink cleanly and evenly.

6. Pre-Selection Verification Checklist

  • Does the selected hardness match substrate porosity and surface smoothness?
  • Is the ink system (water-based, plastisol, UV) chemically compatible with the polyurethane compound?
  • Is blade length at least 20-30 mm wider than the artwork on each side of the matrix?
  • Was a triple-durometer blade selected for high-speed automatic production runs?
  • Has the actual blade durometer been measured prior to holder mounting?

7. Technical Glossary

  • Shore A (ShA): Standard scale measuring elastomer hardness and elasticity.
  • Triple-Durometer Squeegee: Composite blade with a hard inner core (90 ShA) flanked by softer outer edges (65-75 ShA).
  • Blade Deflection: Angular bending of the squeegee under downward pressure, changing the effective attack angle on the matrix.
  • Square Edge Profile: Precision 90-degree cut edge providing maximum dot transfer accuracy.

SHOP NOTES