Purpose: Purpose of this paper is to investigate the ability of a single roll caster equipped with a scraper. The purpose of the development of the single roll caster equipped with a scraper is casting of the strip without centre line segregation and porosity and with sound free solidified surface. The single roll caster can cast the strip without the centre segregation and porosity. However, the conditions of the free solidified surface and the thickness distribution are not sound. The scraper was adopted in order to improve the free solidified surface. Investigation of the effect of the scraper and the properties of the roll cast strip is the purpose of this paper.Design/methodology/approach: A scraper was developed to improve the free solidified surface condition. The scraper scribed the semisolid metal on the free solidified surface to make the free solidified surface flat. The scraper was made from mild-steel-plate, and it was coated by the insulator sheet of 2 mm-thick. The scraper was pushed to free solidified surface by the constant load.Findings: The scraper was very useful to improve the free solidified surface. AA5182 aluminium alloy strip could be cast at the speed up to 40 m/min. There was no centre segregation and porosity. There was no difference between the roll contact surface and the scribed surface. The mechanical properties of the roll cast strip were as same as those of strip made from D.C. cast slab. Hi-content Al-Mg alloy like Al-10 mass%Mg, which cannot be cast into the strip by the twin roll caster without centre segregation, could be cast into the strip without defect.Research limitations/implications: Metal which was investigated was only aluminium alloy. It is not clear that this process is useful to other alloys like steel, copper et. al.Practical implications: This process may be able to be used instead of the D.C. casting and the twin roll casting. Especially, this caster is useful the strip casting of the Al-Mg alloy.Originality/value: The single roll caster equipped with a scraper is original development. This caster may be useful for aluminium and magnesium sheet making companies.