Confused about feedrates....New tests results...

Mostly Printed CNC - MPCNC Advice
1

Hi everyone, I am sure it has been discussed before, but I am confused about feedrates…
So far, I have been cutting perspex and MDF @8mm/s (XY), and I am quite happy with the result.
When checking feedrates calcultors, I end up with a recommended speedrate of 55mm/s…
This is a big difference, any feedback on best practices for MDF cutting?

2

Can you reduce the number of flutes on the bit or the rpm?

3

I am at the moment cutting with a single flute 1/8 bit, so reducing rhe number is not really an option…and as i dont have a superpid, with the DW660, i am stuck on the rpm side too…

4

You can reduce the speed with a dimmer for a router. Harbor Freight is a typical choice. It’s not going to be as good as a PID, but neither is the router by itself.

https://www.harborfreight.com/router-speed-control-43060.html

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5

 

I use this for mine it was bought for a exhaust fan but repurposed and works great the HF does too but not as flexible Now if anyone could design a Printable box for it i would be grateful no kid or cats here but i would like a cover for it

6

Did some test cuts yesterday to see how I could push my MPCNC to cut faster without quality losts, here are the results, hop it might help others!

Machine: MPCNC/dual endstop/DW660, endbit : 2mm-single flute-1/8" shank

Material: 18mm MDF

Ref. (the one used to compare the cutting time, my initial settings which are the one recommended on V1engineering website).

The picture of the board is just cut, not sending, no finishing pass, test pattern attached was designed in Illustrator, then processed to Estlcam and Repetier Host.

Notes:

  1. The outer shapes have been cut as "holes" when the inner ones have been as "parts".
  2. I noticed when cutting that the lines in the triangles where a bit to close, my board not being perfectly surface, I ended up with the mess on the top left side of triangles...
  3. Measuring the cuts afterwards, they are perfectly accurate according to the initial vector pattern design.
 

 

19092019-scaled.jpg
19092019-scaled.jpg2560×1159 447 KB

test19112019.pdf (28.2 KB)

testpattern.pdf (3.34 KB)

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7

Wow 40mm/s!

So I think my recommendations are pretty good, right? If a normal cut is 3-5mm depth per pass then 8-10 mm/s is probably a similar load.

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