Sunday 11 November 2018

Conventional or Climb Cut? - episode 223

When I started my CNC adventure about 10 years ago I didn't understand Climb and conventional cuts. To be honest I still don't to a certain extent. I understand how to tell the difference between the two, I understand that the direction of cut can have good and bad effects on the finish of my cuts. I have read up on the subject and tried to learn as much as I can but at the end of the day it is the observations that I have made while playing with my machine that ultimately determines which machining strategy I choose.
In my testing with cut direction I have always found that conventional cuts give me the best results. Now to be clear my observations are related to cutting wood and wood products like plywood. I m not talking about cutting metal which is a whole other subject that is out of my realm of experience. It is also fair to say that most of what I have read is related to metal work. Even the small amount of aluminium and steel cutting I have done on my CNC was done as conventional cuts and I did not do any testing to see if changing machining strategy would help. I was just happy to see it cut.

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The list of climb cut advantages over conventional is long and at first glance it is hard to see why anyone would want to use conventional at all. 
  • Smaller chip load. 
  • Chip thinning reduces heating at the cutter and the load reduces as the cut progresses. 
  • Chip ejection behind the cut prevents recutting of the chips.
  • Longer tool life due to lower stress and less heat.
  • The cutter slices into the the material reducing the likely hood of chipout
  • Better cut quality?
The only thing I have problems with is the last item on the list. When cutting in wood I have not experienced better cut quality. It could be that I run my cutter too quick for climb cuts but why run it slow when conventional cuts do a good job running faster. Maybe the climb cut should be used as a final pass at a slow feedrate. 

I would really like to hear from you and whether you have sucess with climb cutting in wood. It would be good to compare my results with what others have experienced. 

It is always possible that I have been using climb cut wrong all these years and hopefully will learn something new.

Leave a comment below or on the video.
I look forward to reading the comments.


1 comment:

  1. Hi Peter,
    A question on one of your previous issue (Usb/Rs485 to Vfd spindle control).
    Do you advise grounding the laptop to the Vfd?.
    I don't and i believe I'm having a problem.