In this paper we investigate the causes of poor alignment in antiferroelectric liquid crystal devices making use of spin coated and rubbed polyimide. We found that poor alignment is due to the deviation of the layer normal from the rubbing direction. By optimising the skew between the rubbing direction on opposite substrates we found that a high quality and stable alignment can be obtained. Quantitative experimental results showing a static extinction ratio higher than 3000:1 and dynamic contrast ratio higher than 2000:1 are presented.