Dear Garypl,
Did you get 2rms finish in 35 mn per 1¨ Area by starting from a D3 machining or by starting from Zero milling.
(We started with a milled surface usaully for every surface - pocket and some times we used cutters as small as .015" Diameter down achiving at least 32 or better finish. I always used 2 electrodes for all burns and added one for "HQSF"polish.
The first was stopped at a 10 Umrmax. this was a standard for large surface area large metal removal. Exception (1), for small areas like those < 1" square trode we stopped at 14 Umramx. This was always followed by a second trode reguardless of finish requirements and stopped at 10 Umrmax. Exception (2), depending on the amount of hand electrode polish and the amount graphite removed by polish we might use this second trode for a couple of minutes of High Quality Surface Finish ("HQSF" polish). For high quality surface finish we would add one more trode (Note *Identical and perfect polish is required for this exceptional finish) and burn from 10Um to 4Um plus into HQSF for the required time per surface area of graphite and add .001 to the finish depth. This depth change allowed the absolute contact of the trode during polishing.
Ok, we always checked our first burn and if necessary change of process and possibly but very rarely added one more trode. I believe that the few times I did add the Fourth trode it was because of problems of consistancy in electrode size because of polish or coolant heat problems. When achieving such high finish any small area really shows up..)
1- How many electrodes you may need to get so exlcelent finish. Whats the price of those AF electrode. Do you know how long it takes to polish the electrodes.
(Read above, one more, almost always.)
2- I heard that AGIE has one as well.. But I also heard that the price is more around $240k, I may be wrong..
(our machine was exactly that much 5 years ago, don't forget to expect a very costly additive to your coolant)
Many thanks for replying, it is really interesting.
If some of the terms used are not making sense just ask, tell me what machine type you are using or what details you would like I will get much more detailed. Once again, I feel that this technology is best used for lesser surface finish. It was easier to achieve an "A" type finish , add only a few minutes to each burn and still hand polish. Every burn that makes up a cavity has multiple burns and just a .00005 differance in trodes or depth makes steps and most all efforts usless for a smooth finish.  |