What is a cast tooling plate?

Unlike rolled plate, it comes from a cast block that is never rolled. It is supplied with a tight thickness tolerance and good flatness, often under a protective film. Common compositions are AlMg-based, similar to 5083, alongside stronger AlZnMg-based grades. It is stock to machine from, not a casting in the shape of the part.

Where does residual stress in plate come from?

In rolled plate, residual stress comes from rolling and levelling and, in heat-treatable alloys, mainly from quenching after solution treatment; stretching, as in T651, reduces it again. Cast plate is neither rolled nor levelled and is stress-relieved: it carries little residual stress and has no rolling direction. A part with heavy one-sided removal, deep pockets or thin walls therefore usually distorts less than the same part cut from rolled plate. How much less depends on the rolled plate you compare with (alloy, temper, stretched or not), the removal ratio, the machining sequence and the workholding. The trade-offs are lower strength and elongation than wrought material of similar composition, possible porosity, and a cast structure that can look blotchy when anodised.

What does the standard say about a cast tooling plate?

EN AW designations apply to wrought material. Cast tooling plate is not covered by the rolled-plate standard EN 485 and is usually sold under the producer's own grade name, even where its composition resembles 5083. Properties, thickness tolerance and flatness come from the supplier's data sheet. If the drawing specifies EN AW-5083, with or without a temper, substituting cast plate needs the customer's approval.

How does a cast tooling plate behave in the shop?

Cast tooling plate is widely used for base plates, fixtures, frames and measuring rigs, where dimensional stability after milling matters more than strength. Its price per kilo is usually higher than that of rolled plate, but the route can be shorter: fewer intermediate steps of unclamping the part, letting it relax and clamping it again, and sometimes the milled faces can be left as supplied. That last option only works if the plate's thickness, flatness and roughness are within the drawing's limits. Whether the premium pays for itself depends on size, removal ratio, flatness requirement, quantity and the route you would otherwise take with rolled plate.

What is a cast tooling plate often confused with?

Cast tooling plate is not a casting: a casting already has roughly the shape of the part, cast plate is stock you machine from. Nor is it the same as rolled plate supplied with milled faces: that has machined faces too, but keeps its rolled structure and residual stress. And less distortion does not mean more strength: cast plate usually distorts less in machining, but is generally weaker than rolled plate.