Feed rates and depth of cut

Mostly Printed CNC - MPCNC Troubleshooting
#1

Is there a list of feedrates and depth of cut that MPCNC users have found to be suitable for our machines?

I found a few online for various CNC machines, but they are all across the board from 200 mm/min to 2000 mm/min and 0.6 mm DOC to half bit diameter DOC for soft wood. I’m new to milling and cutting but long familiar with 3D printing, so I’m struggling at finding reasonable starting points.

My typical materials are soft wood and plywood, but I am interested in doing some simple cuts in aluminum plate and acrylic.

I’m assuming that the spindle will affect it. I’m using a Harbor freight trim router, which I assume to be somewhere between a Dremel and Dewalt Palm router in power.

I’m guessing that there are others wondering the same thing. And I’m sure a few of you who know what you are doing.

#2

Most of the videos out there list what setting they are using, all of mine do. That will give you a ballpark.

Every machine will be different, different size spindle, how the build went how tall it is, how long the bit is, how big the bit is. Start slow, plywood is cheap make some test cuts in high density foam. Ply wood is rough on bits, I think it has something to do with the glue. So when you find a bit you like get a 5 or 10 pack and save a ton of money, I recommend drillman1 on ebay.

My biggest suggestion is get your material as close to the gantry as possible, rigidity will double each time you half the distance to the gantry. Do not cut aluminum until how have lots of wood cuts under your belt. Most machines are either built big for wood or very small for metal.

Most people are making there machines very tall yet cutting flat material all the way at the deck. When I cut aluminum I stack wood under it to get it as high as possible. and I am very happy with the cut

#3

What are the feed rates on the test file on the website? got a bit chatter when i cut that file on mdf, although my cnc in not bolted on very well yet and the table need some work.

#4

first test cut

#5

If you open that file with a text editor I believe all that info is in the first paragraph of the code. I can check after I get back from the post office.

#6

Really stupid question but where do i change the feed rates?

#7

No problem, right here with the arrow.

Christian did a great job on this software. When you hover on the input boxes, there is a ton of information about what it does.

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#8

i tried those but the speed was still the same, does it use the values that are in the red box or do i need to select it somehow?
i dropped the feed rate to 3mm/sec and it still goes the same speed

#9

You need to make sure it is using the tool that you changed to speed on and export it again.

#10

Got it working now, dont know what was wrong but did same thing than yesterday and now it slowed down.
made my first cut out and just a hair of chatter at 17mm/sec 0.5mm deep.
need to adjust the belts and tune the bearings a bit, also made alignment tool for the tubes
camaros z axis rigid add on helped abit

More questions, how can i make it cut the inside first?

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#11

I was wondering how do you get doc @.05? Mine will only go to 0.10

#12

@Josh
He’s using .5, not .05, I think .05mm would be just scraping the tool across the surface, no need to turn it on! 8)

#13

Ok thanks. I am sorry I forgot to mention in my previous post thank you for all the hard work that is involved in the MPCNC.
I have studied this since I first got my 3D printer and decided to make it and I love it so far It is very versatile with the router and laser engraver I done a Batman picture for my nephew for the first test.

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