Overview

General Description

The TF-100CE is a versatile screen printer that is used for patterning of conductive, dielectric, and other (e.g. graphics) pastes and inks for printed electronics applications.  Both rigid and flexible substrates may be used.  The TF-100CE provides the high degree of precision required for screen printing circuits in both low volume prototype (R&D) and medium volume production uses.

Specifications

Substrate Size: 6"x6" (152 mm x 152 mm) maximum

Screen Size: 5"x5" up to 12"x12" inside dimension (127 mm x 127 mm, up to 304 mm x 304 mm); 12" x 12" is most common

Printable Area: 4.5" x 4.5" (115 mm x 115 mm) maximum

Feature Resolution: approximately 80 micrometer, screen and ink dependent

Technology Overview

Unlike inkjet printing, which can immediately convert a digital image into a printed pattern, screen printing first requires the fabrication of a screen from the digital image.  However, once the screen is available, it can be repeatedly used to print multiple impressions of the same pattern in rapid succession.  A typical screen print cycle takes only a few seconds, while inkjet printing can take 10s of minutes for a single print.  The screen can also be reused in subsequent print sessions.

In addition, for circuitry where low resistance is required, screen printing is a generally preferred technique over inkjet printing due to the thickness of the deposited material.  For screen printing, typical print thickness is on the order of 10 micrometers, while for inkjet printing, the typical print thickness is several hundred nanometers.  Additionally, the print thickness of screen printing is highly tunable depending on the choice of screen parameters and may range from 5 micrometer or less up to 100 micrometers (wet).

Sample Requirements and Preparation

Substrates

Substrates should be of uniform thickness and at least 0.5" (12 mm) larger than the print pattern on all sides.  (For example, if the print pattern is 100 mm x 50 mm, the substrate should be at least 125 mm x 75 mm.)  For best print results, the substrate should have low roughness. 

Inks/Pastes

Inks or pastes obtained from commercial suppliers should be designed for screen printing; about 50 mL is needed to print on the TF-100CE.  Please see the list of potential ink suppliers further down on this page.  For user made inks, the viscosity needs to be high enough so that it will not bleed through the screen between prints, but low enough so that it can be flooded and pushed through the screen by the squeegee.  (Typical is 1-100 Pa*s)  Also, particles in the ink need to be well dispersed and small enough to easily go through the pores of the screen (pore size > ~5X or more the size of largest particles).

Screens

To prepare the screen, the pattern needs to be drawn to scale in 2D CAD or line art program and then converted to AutoCad format (.dwg).  Please draw the outline of the screen edge (typically 12" x 12" square).  This drawing is sent to the screen fabricator along with details about the screen choice, which depend on the desired print thickness, ink, and resolution of features.   Please contact Nick Glassmaker, who can facilitate choosing screen parameters and placing an order with the screen fabricator.

Standard Operating Procedure

Questions & Troubleshooting

Process & Material Library

Commercial Ink Suppliers

Celanese (formerly DuPont), Distributed by Insulectro

Creative Materials

Henkel

Marabu Inks (graphics inks)

Nagase ChemteX

Novacentrix

Please note that this is simply a list of known commercial screen printable ink suppliers and does not constitute a recommendation or endorsement.

References