Hi everyone,
I have posted before and got a lot of help setting up my CNC machine.
Now I am working on a hacked/bolt on component for said machine. I am in desperate need of drilling some very small (.5-.8mm) holes in inconel of high aspect ratio. I was able to do it with PCB drills but I break more drills then I succeed. So I want to use edm. I would really appreciate it if anyone who knows about these things could weigh in on the probability of success.
Here is the plan:
I can buy a edm drill head from aliexpress that handles high pressure. I can use a low pressure pump to pump the dielectric through a water filter. Then I can tap the fluid to an airless paint sprayer to pressurize the dielectric fluid to send to the drilling head (the drilling rods are hollow for flushing debris away). I will also tap off from the pump to return to the fluid container (but first it will be directed at the cut as my work piece will not be submerged). I am ok with replacing filters often.
All of this was taken from Applied Science YouTube channel. Here is a link:
What I am doing different from him and am more worried about:
For starters I am using oil as the dielectric. I am doing this because I already have oil set up for doing traditional machining with.
The biggest thing I am worried about is the power supply. You can buy these cheap EDM machines form aliexpress that are built for broken tap extraction. I have a couple of concerns with this. First, is I am not sure if the power supply output power can be reduced low enough to drill very small holes. I believe it is necessary to lower amperage for smaller holes. Second, I would not have a feedback to know if the arc has shorted. My thought with this is that I could simply run my feedrate low enough that a short is unlikely to occur. Alternatively, I believe the power supply comes with a drill head on it that does not have through coolant so I would not use it. However this drill head does have a servo on it and I think that it has feedback to detect a short and it retracts the drill if this occurs. I could probably workout how to sense when this is ocurring and feed this into my control board. This would require me to modify my LinuxCNC to reverse if a short is detected, but I am sure this could be done?
Alternatively, I could use the Powercore from RackRobotics. This power supply seems more versatile and controllable. But I do not think it is shipping at this moment because they are having some troubles with the board. However, I believe that it does have a logic out for short detection.
I am really hoping I can get something together. I would really love to hear everyones thoughts. I can provide more detail if needed.
Here are some links to some of the parts I am considering:
www.aliexpress.us/item/3256806213357626....yOTE0OTY1MC4xMy4wLjA
.
<!--td {border: 1px solid #cccccc;}br {mso-data-placement:same-cell;}-->
www.aliexpress.us/item/3256803997349850....ller%7Cquery_from%3A
<!--td {border: 1px solid #cccccc;}br {mso-data-placement:same-cell;}-->
www.amazon.com/gp/product/B01CFOFZ08
<!--td {border: 1px solid #cccccc;}br {mso-data-placement:same-cell;}-->
www.amazon.com/gp/product/B004Z2090U?th=1
Best,
-Dylan
