Expert Guide to Aluminum Cast Tool and Jig Plate
In contrast to rolled aluminum plates, aluminum cast tool and jig plate (CT&J) are brought to format (i.e. to a desired thickness) not by a rolling process, in which force is used to rolling them down, but by sawing and precision machining.
What is an aluminum cast tool and jig plate?
In contrast to rolled aluminum plates, aluminum cast tool and jig plate (CT&J) are brought to format (i.e. to a desired thickness) not by a rolling process, in which force is used to rolling them down, but by sawing and precision machining.
This production process causes very little external forces to be induced into the material and creates little to no internal stress, which ultimately guarantees that the final product machined out of CT&J has a lot higher dimensional stability.
G.AL® C250 is our CT&J in alloy EN AW 5083, and is considered to be the most “relaxed” CT&J in the market. This translates directly into the highest grade of dimensional stability and flatness.
Comparing G.AL® C250 and 6061 T651
When choosing the right aluminum for precision machined parts, both G.AL® C250 (5083 CT&J) and 6061 T651 aluminum are possible choices. Each material has its benefits for specific applications, which is why understanding their differences is important during the selection process.
See our pdf comparison guide comparing the two materials.
1. Material Composition and Properties
G.AL® C250
- is made by sawing and precision machining aluminum slabs, without changing their “as cast” grain structure
- resulting in an isotropic grain structure (same mechanical properties in length, width and thickness).
- an extremely homogeneous grain structure as an result of our special GLEICH Heat Treatment (Temper O3).
- results in stress-relieved plates that show almost no
deformation of the material before or after machining - very high precision parts are possible.
Homogeneous, isotropic G.AL® microstructure
6061 T651 Aluminum
- heat-treated aluminum alloy with high tensile strength,
commonly used in structural applications - “T651” refers to the specific temper, meaning the metal has been solution heat-treated and artificially aged for increased hardness and stability
- due to the rolling process the grain structure is distorted in the direction of rolling
- the mechanical values differs between length and width
Distorted, anisotropic rolled plate microstructure
2. Strength and Hardness
G.AL® C250
- lower tensile strength (around 37 ksi) and hardness
(around 75 Brinell). - while it is not as strong as 6061, its stability makes it ideal for
precision applications where dimensional stability is more critical than load-bearing strength
6061 T651 Aluminum
- stronger than G.AL® C250, with a tensile strength of around 45 ksii and a hardness of 88 Brinell
- more suitable for applications where structural integrity and load-bearing capacity are essential
3. Dimensional Stability and Machinability
G.AL® C250
- Dimensional Stability:
- has excellent dimensional stability, even under
heavy machining. - ideal for applications requiring high flatness and minimal deformation, such as in jigs, fixtures, and mold bases
- has excellent dimensional stability, even under
- Machinability:
- good machinability
- tends to be more forgiving, especially in high-precision machining setups
6061 T651 Aluminum
- Dimensional Stability:
- stronger than G.AL® C250, with a tensile strength of around 45 ksi and a hardness of 88 Brinell
- more suitable for applications where structural
integrity and load-bearing capacity are essential
- Machinability:
- good machinability
- can experience movement during milling and drilling due to residual stress in the material
- the high drop in strength from edge to center of 6061 directly translates into higher tool wear
4. Surface Finish and Tolerance
G.AL® C250
- milled surface finish
- very tight thickness tolerances (within ±0.005 inches or better)
- this finish makes it an ideal choice for applications requiring a precise, ready-to-use flat surface without extensive machining
6061 T651 Aluminum
- generally requires additional surface preparation, especially for tight tolerance applications
G.AL® anodized
G.AL® anodized
5. Typical Applications
G.AL® C250
- best suited for
- precision tooling
- jigs
- fixtures
- bases where flatness and stability are essential
- its stability under machining loads makes it the go-to for
applications like- molds
- inspection fixtures
- base plates
6061 T651 Aluminum
- ideal for structural applications where strength and durability are prioritized, including
- aerospace
- construction parts
Conclusion
G.AL® C250
Choosing between aluminum G.AL® C250 and 6061 T651 depends on the specific needs of the project.
If stability, flatness, and low residual stress are critical, G.AL® C250 is often the best choice. For applications requiring strength and corrosion resistance, 6061 T651 stands out.
other topics ….
Aluminum does not rust
The use of aluminum has many advantages.
However, an advantage mistakenly attributed to aluminum is that it does not rust.
When using our materials, it is therefore useful to take precautions to prevent or minimize corrosion.
Frustration when producing threads
It doesn’t have to be so difficult!
By using a process that is aligned to the specific material, durable external and internal threads can be produced in a flash.