Climb Milling any implications

[JasonBModerator @jasonb]

Posted by Chris TickTock on 24/09/2020 12:25:48:

4. If heavy cuts are taken opposing forces cancel each other out. (why on earth would you take such a big cut, not on my Sherline I think/)

Chris

Forces only cancel out if as shown in your sketch the whole width of the cutter is being used, needed when cutting a slot

[John HaineParticipant @johnhaine32865]

As to where to start, often it depends on where the chips will go! I prefer to mill in a direction where they fly off to the left/back rather than all over me!

[Dave HalfordParticipant @davehalford22513]

Climb milling tends to drag the work in, in other words it can self feed. Standard starts with a slight rub and opposes the feed.

 

Edited By Dave Halford on 24/09/2020 12:35:53

[EmgeeParticipant @emgee]

Posted by JasonB on 24/09/2020 12:25:21:

Emgee the straight arrows are the direction of the work, compare my video on previous page with what's shown in the drawings and it's conventional. See the text that goes with it

Edited By JasonB on 24/09/2020 12:28:39

Reading the text below the picture is clearly something I didn't do, unfortunately the text is not visible in the search page shot.
Clearly changing from tool movement to work movement turns it around.

Emgee

[EmgeeParticipant @emgee]

Posted by John Haine on 24/09/2020 12:31:44:

As to where to start, often it depends on where the chips will go! I prefer to mill in a direction where they fly off to the left/back rather than all over me!

John

Surprised you don't have chip guards fitted, they do save a lot of floor sweeping.

Emgee

[John HaineParticipant @johnhaine32865]

Emgee, so am I!

[Chris TickTockParticipant @christicktock]

Clearly changing from tool movement to work movement turns it around.

Emgee

Would do if they were correct for cutter movement but I don't think they all are…correct me if i am wrong?

If the text that we cannot see states X axis is for cutter movement and the Y axis for work feed then fine, otherwise in error.

Chris

Edited By Chris TickTock on 24/09/2020 13:48:23

Edited By Chris TickTock on 24/09/2020 14:15:14

[EmgeeParticipant @emgee]

Chris

My original comment was that they were both wrong because of the direction of cutter and relationship with the arrows that I mistakenly took as cutter movement, not workpiece movement.

The video link I uploaded starts with climb milling and then moves to back of the work to conventional milling.

Emgee

Edited By Emgee on 24/09/2020 15:09:05

[Chris TickTockParticipant @christicktock]

Posted by Emgee on 24/09/2020 15:05:10:

Chris

My original comment was that they were both wrong because of the direction of cutter and relationship with the arrows that I mistakenly took as cutter movement, not workpiece movement.

The video link I uploaded starts with climb milling and then moves to back of the work to conventional milling.

Emgee

Edited By Emgee on 24/09/2020 15:09:05

Yes having a second look they are both right for work movement

Chris

[Mike PooleParticipant @mikepoole82104]

The sketch showing cutting a slot in a block is a situation where a slot drill cutter is best employed, it is difficult to cut an accurate slot width with a normal end mill in one pass but a slot drill can do this quite well, a slot drill can also plunge as they are ground so they have a centre cutting edge, it used to be that simple but some cutters also have a centre cutting edge with three or more flutes. However more than two flutes will tend to cut oversize. If a very accurate slot width is required it is best to take a finishing cut to open out a smaller slot.

Mike

[Chris TickTockParticipant @christicktock]

My Contribution after taking on board all posts and further research. (Any comments welcome)

Climb Milling:

Downward force is exerted on work so can pull out an end mill out. Backlash is potentially added to depth of cut. This is especially important in lighter machines and those without back lash elimination. In more robust / rigid machines with heavy iron tables and tight gibs may not be an issue.

In lighter machines though the back lash if poor can be dangerous e.g. if milling at an intended .005 inch and the machine is poor with .020 backlash then you may get 0.025 cut which could break the machine. So depth of cut plus back lash is key.

Finally climb milling is reputed to give a better surface finish. However there are opposing arguments as always one being that tool deflection can introduce some surface imperfection.

Final advice from my findings is at least be aware of the dangers of climb milling, something I was totally ignorant of before asking on this forum.

Chris

[EmgeeParticipant @emgee]

Chris

As you state always be aware of the dangers if and when climb milling, if using the side of the cutter for a light finishing pass it is not so much the depth of cut that causes the problems but the amount of backlash that can be taken if the cutter grabs the work, taking very light cuts with all unused axis locks on and some drag applied to the moving axis you should be able to climb mill without problems, try on some scrap so you are familiar with the operation.

Emgee

[Chris TickTockParticipant @christicktock]

Posted by Emgee on 25/09/2020 12:47:07:

Chris

As you state always be aware of the dangers if and when climb milling, if using the side of the cutter for a light finishing pass it is not so much the depth of cut that causes the problems but the amount of backlash that can be taken if the cutter grabs the work, taking very light cuts with all unused axis locks on and some drag applied to the moving axis you should be able to climb mill without problems, try on some scrap so you are familiar with the operation.

Emgee

I note additional point about using unused axis locks

Chris

[Author]

Posts