Emerald Group Publishing Limited
Copyright © 2000, MCB UP Limited
Heraeus speeds production with new SMD adhesive
Keywords Heraeus Materials, Adhesives
Heraeus Materials is announcing the introduction of PD955PY, an advanced solvent-free, thermosetting single-component, polymer adhesive. Developed specifically to make the production process faster, by allowing the operator to successfully print variable heights of adhesive dots in just one print cycle, PD955PY is suitable for all SMT applications and for use on bare substrates.
It is obviously quicker to screen print a PCB than it is to dispense dots. In fact, in one print cycle PD955PY can produce 5,000 dots in 30 seconds.
The combination of advanced rheology and adhesive drag on the hole walls allows PD955PY to print dots of various heights (from 0.25mm to 1.3mm) with metal stencils giving diameters up to 2.2mm. With plastic stencils dot heights of 1.98mm and diameters of 3mm have been achieved, thus making it suitable for all SMDs, regardless of component size or shape.
Due to its advanced capabilities, PD955PY always delivers excellent adhesion on both standard and difficult to glue components. It also prevents movement of components during placement due to its very high green strength, and always forms stable glue dots. Cured adhesion strength is typically greater than or equal to 25N per sq. mm. It has been tested to show no dendritic growth and no E-corrosion as it has very high SIR properties. Tests also show that defective SMDs can be removed and repaired without damage.
PD955PY has very low humidity absorption, which allows for steep temperature increases and very short curing times without the risk of air bubbles forming or the loss of adhesion occurring. Heraeus recommends a standard curing time of three minutes at 125°C. Maximum curing temperature is 200°C.
To clean uncured PD955PY, Heraeus recommends Zestron SD300 and Vigon SC - these solvents are specially designed not to attack the stencil frame adhesive.
PD955PY can be stored for up to six months in a refrigerator, at a temperature of 5-12°C.
For further information please contact: Jim Greig, Heraeus Materials Ltd. Tel: +44 (0) 1932 349306; Fax: +44 (0) 1932 347904.