hello, i finished building my mpcnc a few days ago and i started testing on medium but i have two problems
-The first is that my dimensions are not good at all for example the outer contour of this piece should be
150 x 50mm while it is 146 x 47.5 so smaller while the inner contour that should be 35 x25 mm is 36 x27 so bigger ...
I do not understand anything
-The second problem is that I already broke 2 end mill and my cups are not very clean I use these endmill:
https://fr.aliexpress.com/item/5Pcs-Extra-Long-3mm-2-Flute-HSS-Aluminium-Extended-End-Mill-Cutter-CNC-Bit-Kit-P0/32795794539.html?spm=a2g0s.9042311.0.0.27426c37S3YgdL
and I try these 3 parameters only the first to work but the endmill blackened while my cutout lasted only 5 minutes
So if someone could explain to me a little bit I look in all google but I did not find anything
I just see 50mm/s is to fast for mpcnc
I also have these end miill but I do not know if it’s better
Okay so I keep looking for my answers and I have advanced a bit
For the problem of ugly cut I try with a straight cutter 2 teeth
a depth of 1mm and a feed speed of 10mm / sec for started and I get perfect results :)
I believe that the endmill that I had sullied were of bad quality (HSSAL) or not adapted
On the other hand I still have my problem with the dimensions
I redid two trial one with elstcam and one with cambam to see if the problem
came from the software or possibly my mpcnc etc I put you picture that's even worse with cambam ...
Frankly if someone has an idea ...
Check your gcode to make sure it is moving the length of your dimension plus the bit’s diameter, if not you are not cutting on the correct side of the path.
Mio, what size end mill are you using? 3mm, 6mm? Have you tried drawing with a pen instead of cutting? When it draws a square, is it square? Is it the right size? Before diagnosing cuts that have a width it’s easier to diagnose pen drawings because the width is minimal. You could be seeing issues with your build or issues with your CAM.
By the way when you think about it if the exteriors are too small and the interiors
are too big maybe the endmill is on the line instead of being in front or behind
I think that’s what ryan meant (I did not understand) but how did that change?
Your gcode is not correctly formatted you need to look over my instructions again. For one of the cuts I am getting 32mm x 22mm, which doesn’t match anything you have show me yet.
I'm really sorry to bother you ryan
I spent several hours searching on google before bothering you but I did not find anything
So today I was going to do several new pen tests, with a 6mm endmill and a larger piece to see
if the problem is linear
By cons for dimensions 32x 22 that you found it could correspond to 35 x25
of the original drawing of the interior square if we add the 2 x 1.5mm of the endmill
And now that I think about it, it could be the endmill that is not perfectly centered
and that eats a bit more than it should
This is the first section it cuts. It moves from your beginning to X41,Y65, drops the Z to 0.5mm off the surface, then again slower to 0.5mm deep. Then it cuts along the X axis to X9, turns and cuts along Y to Y87, turns and cuts back along X to X41 and finally turns and cuts along Y to Y65. Remember those numbers match the center of the bit. That forms a box that’s 29mm inside on the X and 35mm outside on the X. The Y size is 19mm inside and 25mm outside. So, if you were starting a hole it will be cutting a hole 35mmx25mm. If you are cutting a part it will be 29mmx19mm. Which are you attempting, hole or part? From your image it looks like you are trying for a hole that’s 35x25. Since the actual hole is 36x26 your bit either is actually 4mm instead of 3mm or it’s wandering in a circle instead of spinning in place. Can you take a caliper and measure to verify the bit is 3mm?
Thanks Bill and Ryan too for taking the time to help me
You’re right bill this afternoon I made a hole in the mdf just to see
and instead of 3mm it was 4 mm so it was not my gcode but my endmill that made a wrong round
Yes it is a beautiful project that reduces much of the parts to be printed which is very rigid,
square in addition
it's been a long time since I wanted to do it
And a very important point is that it is customizable (scad file) I modified mine to make a 30 x 30
And since it seems to please you I put you a picture of the second and last board I cut today :)
I built an iTopie early last year to replace the MP3DP v1 because I was looking for something a little bit stiffer. Due to workmanship issues, my MP3DP wasn’t as reliable as I wanted and I ended up having to do lots of repairs to it. The repairs were generally effective, but the sheer number of them plus a fair amount of brute strength and ignorance led to some cracks in the corner pieces. I could have reprinted them, but I decided instead to just go with the iTopie instead. Haven’t had any issues with the frame since
I used a leadscrew similar to what Ryan sells in his shop here. I am not using the threaded rod. I did end up installing a BL touch for the z-axis end stop and for bed leveling. It helped with getting the first layer down and making my printing more successful.
-The second problem is that I already broke 2 end mill and my cups are not very clean I use these endmill:
https://fr.aliexpress.com/item/5Pcs-Extra-Long-3mm-2-Flute-HSS-Aluminium-Extended-End-Mill-Cutter-CNC-Bit-Kit-P0/32795794539.html?spm=a2g0s.9042311.0.0.27426c37S3YgdL
