Thread: Help with drill-Mill conversion
You must be a mind reader I was just going to ask about the tables for speeds and feeds........ Is it not worth me knowing what it should be so I can work back? where can i finf these tables?
I'll have to check the flexing, The quill was hardly down and the bit was 10mm dia, 20mm long in a ER32 collect chuck so I hope it wasnt tool flex. And im not sure how i can slow the spindle down without a major redesign and a shorter belt. I was hoping to check it worked properly before I bought a 3 phase motor.
Certainly shallower cuts and plenty of cutting fluid improved the surface finnish, just how noisy should a rough cut be??? maybe I'm erring on the side of caution.
I'll have to refresh my memory on up hill and down hill milling. I always thought that learning how to use it would be harder than making it :oD
Here are cutting speeds, milling is second table down, calculator below.
It suggests 1600 rpm for 10mm in aluminium. Personally I'd go for about half that. If the suds gets diverted for a moment by a fixing bolt, I prefer it if the tool doesn't go red hot :whistling:
My mill came with a 2hp motor but no way on God's green do I want to put anything like that down a small cutter, it's just too much. I replaced it with a 1hp on a digi phase inverter and I never work it hard.
How noisy should it be? Any loose fittings on a bench mill will rattle. The cutter should make cutting noises, if it becomes noisy that usually means you've lost the tool tip.
Thanks once again for your advice, It definetly looks like I just need to learn how to use it..........The mini mill beginers guide was quite useful too, its suprising how much you read and then forget :heehee:
Ive ordered some 2 flute ali cutters 3,4 and 6mm so i can keep the speed up and find the right feed. Hopefully get there in the end.......
Last edited by Ross77; 31-03-2010 at 05:55 PM. Reason: spelling....
Ok cutters arrived today, tryed the 6mm one and what a difference. 3mm deep cut in one pass with nice clean sides and no burrs on the edge. not sure on the cutting speed but the velocity is set at 400 mm/min. but the feed rate said 18mm/min I think . still need a bit more practice with mach.
You where definetly right Robin, I think I,m getting closer to the machines capabilities, althougth for what it is I'm more than happy with how it performed with the 6mm cutter. I'm sure that I can improve on the 3mm depth with a bit more tuning.
now its cutting clean edges It appears to be 0.3mm out, not sure if this is a step unit error ( had to round up to whole no.) or backlash. When I first tested it under no load I was getting 0.02 accuracy, is it possibly that the machine is still settling down? I dont think it can be machine flex as i was only typing the G-code line by line so it would have plenty of time to straighten up before the change in direction. I wont be to happy if the delrin nuts need constant attention tho...
3mm deep sounds about right for a 6mm tool, so does 1420 rpm suggest you experiment with feed rates.
Measure the backlash, find out how much of the 0.3mm is accounted for. Perhaps a man has to ask himself, is Delrin better suited to free rolling gantry style machines?
I spent a lot of time and money removing the backlash from my machine, if I could have done the same with a plastic nut it would appear somewhat futile :whistling:
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