Abstract: Alignment plate construction for use in electrostatically aligning particles for particleboard production includes a plate of conductive material to which is secured flexible, controlled resistive material. In a bank of successively positioned plates, particles which are permitted to pass downwardly between the plates are unidirectionally aligned, and the flexible material ensures that the electric field lines between the plates remain substantially horizontal over the entire plate and material height so that field line distortion does not occur adjacent a mat being formed beneath the plates. Because the flexible material is of controlled resistance, voltage grading occurs across its height and arc over between the plates and a conductive caul plate is thereby prevented.