Mould die machining

To machine mould tool dies accurately and efficiently it is essential that the programmer is familiar with toolmaking concepts. It is not enough just to know how to cut steel!

Here are some areas that the programmer needs to have a good knowledge of:

• Moulding area - The programmer needs to be aware of the areas of the die that will form the cavity for the material. Different strategies may be required if the cavity form is to be polished to reduce machining marks and save polishing time.  Also material may need to be left in the cavity area if the component finish is sparked.
• Visible and non-visible parts of the moulding - It is useful if the programmer knows which areas of the mould will produce visible areas on the mould. Then the machining parameters can be adjusted to save machining time on non-visible areas and produce a finer finish on visible areas.
• Shut-off faces - Extra care must be taken when machining shut-offs (especially drop shut-offs and slide entries) to select cutters and strategies that ensure correct sizes are maintained. Too much material removed here can be disastrous. 
• Split lines - Edges where the moulding form ends and the split face starts must be absolutely crisp and sharp if split lines and flash are to be kept to a minimum. It is essential not to allow cutters to roll over these edges, so special strategies must be employed to cut these areas.
• Hardening - If the die is to be hardened after roughing, then the programmer needs to judge whether the die will distort in the hardening process and allow for this in the roughing parameters.

Anyone who creates programs for die machining at Alphatech has also worked in a toolmaking environment, this way we can ensure that all die programs take into consideration all of the necessary factors.

Before outputting the die data to our machining software we make sure that moulding area and shut-offs are colour coded to make it easier for the programmer to identify.

Hardened steel dies

Machining dies in their hardened state can save money by cutting down on grinding and sparking operations.
High speed milling machines are not essential for machining hardened steel. Almost any conventional CNC machine with the right tooling and programs can successfully machine hardened die plates.

Although the machining programs have to created very carefully, cost savings from the reduction of the quantity of electrodes needed can be great. Don't forget that for every electrode that is not needed you save four stages of work:
1.    Modelling.
2.    Programming.
3.    Machining
4.    Sparking.
If you are not yet finish machining your hardened die plates then it may be time to think again.