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  1. antknee

    Drill from both sides?

    Hi Jay, Yes I'll be using a Nd.YAG and would prefer the taper minimised. What is the principal behind reducing the taper? For example does the focal length change? I don't understand the difference between gaussian and flat distribution. Thanks, Ant.
  2. antknee

    Drill from both sides?

    So how exactly will the fiber laser drill the underside. Will the laser move, the part move, or something else? Thanks, Ant.
  3. antknee

    Drill from both sides?

    Is it possible to accurately laser drill both sides of a plate? For example I have some 200 micron thick steel, I drill from the top side right through the steel, the entry hole is 40 microns diameter and the exit hole is 20 microns diameter. I then drill from the bottom side to create a hole...
  4. antknee

    Boring dream?

    It is nice to get a quality job done although it doesn't happen to me often, to be fair I never know exactly what I want from a subcontractor so they don't have much chance of sending it. R&D is just one long series of mistakes :) I found the company that I could only vaguely recall, they are...
  5. antknee

    Boring dream?

    The last order for laser drilled parts I had in the 200 micron material had an entry of 30 microns and exit of 10 microns, I took advice from another company and they couldn't do any better taper in the stainless. They used an ND Yag as far as I know, but could be wrong. The taper is important...
  6. antknee

    Boring dream?

    It is interesting to read your post, i too have to make nozzles. I was thinking it would be better to laser drill these first because i couldn't see how i could drill through stainless without the drill bits breaking or it taking hours, my stainless is 0.008" thick. I presume from your post your...
  7. antknee

    Boring dream?

    Well I was thinking of a technique to machine stainless that involved laser drilling the holes then boring them to remove the taper. The catch is that the laser drilled holes have an entry diameter of 60 microns and exit diameter 30 microns, so the drill bits for bore need to be around 60...
  8. antknee

    Electropolishing is warping my thin stainless parts

    It is in the CH900 condition. The stainless was bought in the C conditon, laser processed and then aged. It hasn't had any re-aging, I didn't know that was possible? How would it help? I will use a disc instead of a rectangular sheet and ensure that the connection is much bigger, I think just...
  9. antknee

    Electropolishing is warping my thin stainless parts

    I'm electropolishing just one face and the other face is to be left unpolished. I'm not agitating at all, i don't have any means of doing that, the cathode is a rectangular stainless sheet. I've uploaded a picture of the test rig I'm using, it works, just not so well - they're warping. The...
  10. antknee

    Electropolishing is warping my thin stainless parts

    Your explanation makes sense although I did find that the quicker I polished the more warping I got, not sure why. I haven't annealed and don't think I could, what is stress-relieving? I'm using very hard 17-7Ph that came in condiditon C and has been preciptation hardened. Thanks, Ant.
  11. antknee

    Bright anneal stainless in a Carbon steel annealing oven

    I don't think some high T cycles would make much difference. You could wrap them in some spare foil.
  12. antknee

    Electropolishing is warping my thin stainless parts

    I have some stainless parts that I am electropolishing, the parts are discs that are 0.2mm thick and 15mm in diameter. What I'm finding is that they are warping and I can't figure out what will stop them warping. I can't change the thickness which is very thin and I've reduced the current so...
  13. antknee

    Probably stupid electropolishing question

    Thanks for answering all. Ant.
  14. antknee

    Probably stupid electropolishing question

    The cathode is 5mm from the sheet to be polished and the bath/rig does hinder a line of sight to the other side of the sheet. So its going to mostly polish just one side...?
  15. antknee

    Probably stupid electropolishing question

    Hmmm. I was figuring one side would get most/all of the polishing. With one side not much affected.
  16. antknee

    Probably stupid electropolishing question

    If I have a sheet of stainless steel and put it into an electropolish bath with just one cathode will just one side of the sheet get polished?
  17. antknee

    Stains on electropolished stainless

    I'm electropolishing some stainless steel in the lab and as a novice a few things went wrong. In particular the stainless has ended up stained. There are marks were the electrodes were touching the part and there appears to be some kind of 'wash' on the rest of it, like tide marks. It doesn't...
  18. antknee

    Electro-polishing stainless steel

    Well i've been working with a setup that I thought would work, it used duct tape, aluminium tape and a plastic holder. I thought that will work no problem. And then it didn't. I realised that the bubbles were collecting under the part and stopping the polishing altogether. It'll need some strong...
  19. antknee

    Electro-polishing stainless steel

    Hi Ed, I tried the sulphuric acid but it is weak, I was too cautious when I bought it, so it works but not aswell as the salt and hot water. The salt and hot water also ate away at the cathode leaving not much cathode but plenty of green sludge in the bath. I moved on to caustic soda, it works...
  20. antknee

    Electro-polishing stainless steel

    I had a go using salt, hot tap water and a 12VDC 1amp power adapter. There were lots of bubbles so it worked. The part is small (a 15mm diameter disc) so not much fumes, but a little, is that much to worry about?
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