Poor (spotty) release of ink by pad
Ink
Problem
1. Dried out on pad.
2. Too wet on pad, not tacky.
Solution
1. Use slower thinner.
2. Use faster thinner.
Cliche
Problem
1. Insufficient etching depth.
2. Etched too deeply.
3. Wrong screen ruling.
Solution
1. Produce new cliche with greater etching depth.
2. Produce new cliche with shallower etching depth.
3. Use new cliche with different fineness of halftone screen.
Pad
Problem
1. Wrong shape pad.
2. Surface roughened.
Solution
1. Use more tapered pad shape.
2. Replace pad.
Substrate
Problem
1. Soiled surface (grease, oil, perspiration, mold release agents..).
2. Surface insufficiently pre-treated (polyolefines).
Solution
1. Pre-clean objects.
2. Check pre-treatment, repeat as required.
Other
Problem
1. Print speed setting too slow.
2. High ambient (room) temperature.
Solution
1. Maintain uniform cycle time.
2. Optimal room temperature is
18 °C – 20 °C or
65 °F – 68 °F.
Incomplete or spotty deposit of ink by pad is referred to as “splitting.” It plays a minor role in a continuously
running process. The Problem
only arises when cycle times fluctuate or after short breaks. The pad deposits
the dried ink all at one time, producing an inconsistent image. Using fast thinners will decrease ink build-up
and improve ink deposition.
