tumbling vs shot-blasting aluminum slugs

Finishing include of three types: Mill finish, Tumbled, Shot Blasting.

What’s the difference between tumbled and shot blasting?

The surface of the slugs is treated in order to obtain a rough texture. This is done by one of two methods: tumbling or shot-blasting. Tumbling, the first of the two methods, is done by placing the slugs inside of a mechanically operated gyratory drums. Slugs hit each other hence roughening the surface. Final customer needs this roughness in order to apply a lubricant necessary for cold extrusion. If slug has an inner hole, surface finish is done by a shot-blasting machine that uses aluminum shots to shoot the slug while they are rotating on a belt. The surface finish stage last between 12 and 15 minutes depending on slug size. This stage also makes sure no scrap is attached to the border of the slug. Once surface treatment stage is completed, slugs are transported on a conveyor belt to a hopper which will feed the next stage.

Tumbled

Shot Blasting