Re: Machining car end?


destorzek@...
 




---In STMFC@..., <hockenheim68@...> wrote :

Dennis,

With one of these car end moulds, after you were done mopping up in the XY did you polish afterwards using a variant of the original tool paths? I've never seen a mould or pattern polished and I'm curious how it is accomplished when it is needed. Is it a matter of ramping into the work and in effect preloading the headstock a tenth or two  while the machine does its magic or something else altogether?
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I don't, but I'm not sure that directly answers your question, Since I cut very little directly into the cavity. Maybe Brian Leppert will take a stab at this, as I believe he does more 'hard milling'.

We are mostly an EDM shop (Electro Discharge Machining) so what I'm actually cutting are graphite electrodes that will be used to "sink" the cavity through a controlled erosion process. While the process is designed to erode the steel, it also erodes the graphite, albeit much more slowly, so that tends to obscure the tool marks. The process also leaves a consistent matte frosted finish on the steel.

Any surface that needs a higher polish for release purposes is "benched", polished by hand starting with diamond files, on to fine stones, and sometimes continuing with diamond polishing compound.

The same holds true with cavity work that is cut directly, which in our shop is mostly aluminum. This material is sufficiently soft that the diamond files aren't needed, but fine stones make quick work of the tool marks.

Dennis Storzek

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