Bow and Twist in the Printed Circuit Manufacturing Industry

‘Bow and Twist’ is a phrase that is commonly used to cover all forms of non‐flat distortion in the PCB industry. The shape that distortions can assume are analysed and quantified; the size and shape of distortion are compared with the physical properties of the material that give rise to them. The special care needed in the manufacture of multilayer circuits is highlighted. The effects of more advanced material and of heatsinks are considered.