after some time of building, improving and testing my own MPCNC build I decided to join this forum for the following reason: I definitely want to thank you Ryan @vicious1 for all your work on this machine! I really appreciate your efforts for giving every interested hobbyist the possibility to build a versatile and cheap CNC router. Certainly, I also thank everyone of the community who tried to improve or extend the functions or helped others building their own MPCNC.
After this acknowledgement I will also present my own build, of course.
My Background
PhD student in Physics
Some experience in milling aluminum and wood on another CNC router (self-built but not by me… )
Some more experience with electronics and microcontrollers. Atmega, Arduino, ESP,…
I started with 3D printing roughly a year ago and felt quite confident to print all needed parts (with an Anycubic i3 Mega).
What I wanted to do with the MPCNC
Main Idea was to build furniture and other things out of wood. First project was a nappy changing unit with some engraved animals.
Additionally, I was triggered by Leon aka @BraunsCNC and wanted to see if I can actually work with aluminum on this “plastic mill”.
My specifications and used parts
Work area: 920 x 470 mm (36” x 18.5”), longer axis with support, Z travel ~70mm
25x2 mm stainless steel tubes (1250 and 750 mm)
All parts printed in PETG 50-60% infill.
Controlled by Arduino Nano CNC shield (v4) with TMC2209 drivers and 24V power supply, both motors of X/Y axes wired in series. Nano CNC shield is compact but one has to do some soldering before it works with estlcam…
Software: EstlCAM & Fusion360
Spindle: Makita RT0700 router, 710W (clone available from Katsu or Anesty)
Deviations from the original design:
– Corners from “doubleBelt” setup. Looked to me more rigid but don’t know if it makes a difference.
– 15mm GT2 belt, but as single belt and I designed some belt clamps: MPCNC Belt Tensioner (15mm GT2 Belt) by sfarm - Thingiverse
– No tool mount plate for the spindle, instead I made parts out of aluminum that hold directly the Makita as close as possible to the z-axis (see pictures) and keep the z-axis extremely rigid. Basically this part here out of 25mm Al: MPCNC Makita (Katsu) mount by Klalle - Thingiverse
Pictures:
The control electronics is of course now inside a box below the table.
Examples of what I did so far:
I was very happy when I finished the first project just three weeks after I started to build the MPCNC. The animals were done with the carving mode of estlcam.
After I finished the aluminum Makita holder with another CNC machine I wanted to try aluminum also on my MPCNC and I’m quite happy with the results. I used 600mm/min, 30000rpm, 0.6mm WOC, 12.5mm DOC, 6mm single flute end mill. There was some chatter and I could feel the vibrations in the z axis but not so much in the cross of the axes. Maybe 12.5mm DOC was too much, with 8 mm DOC it was better. After a finish pass the surface looked quite reasonable.
On another CNC machine I tried some pyrography with a glow plug (Beru CGP003) because I’m little afraid of using a laser without a complete housing. This also works great on the MPCNC. If someone is interested I can provide some more details on that.
Examples of cutting speeds
Birch wood: 8mm two flute from ENT, 20000 rpm, full slotting, 2.5mm DOC, 2600-3200mm/min
Aluminum: 6mm single flute, 30000rpm, 0.6mm WOC, 12.5mm DOC, 600mm/min
What I still need to do:
Wire the end stops and the emergency off button.
Some acrylic wall below the outer tubes to keep the chips inside.
A dust shoe that is fixed on the burly, not on the z axis.
Something on the rollers that cleans the tubes. But this might get better with a dust shoe.
Okay so If you see me say anything that is incorrect regarding this stuff you have to ignore it and act like I am right! (kidding, glad to have some assumption checking).
Well that is one heck of a first post! Welcome to the crew!
I am absolutely floored with your projects and that Aluminum is insanely thick. WOW
My BS is in Physics. I find it very useful in this hobby. Both because of the intense problem solving, and the gross estimation :). Phd though, that is Piled Higher and Deeper. It shows in your results. Great work!
There was (a long time ago) a hobby wood engraver. They used it to make signs for veggies in the garden, IIRC.
@jamiek These pulleys were actually hard to find. Finally, I found some on the chinese bay: https://de.aliexpress.com/item/32695175292.html
Four pulleys including shipping were around 4,50€ and 10m of 15mm gt2 belt another 15€. But of course it takes a few weeks until everything arrives.
@vicious1 The glow plug is nice for safety reasons but it has also some cons of course. If your wood is glued together and very inhomogeneous like bamboo you’ll probably see it also in the lines. I don’t know if it’s the same with a laser? And the part where the plug is slipping up and down cannot be 3D printed because the glow plug gets too hot.
But on the pro side it’s also rather cheap. The glow plug is around 5-10€ and despite you just need a fan and something that limits your current to 4-5 A (voltage will be 5-6V). For the latter part (if you don’t have a lab supply) these cheap dc-dc step down regulators (google DPS3005 or DPS5005) are suitable and around 30€.
If I find some more time I’ll write a post about it in the hardware development category.
Or in the use/tools section of the docs, either way. It seems like a good solution that could be very robust for the people that just want to mark / brand their wood products.
I wish I’d have the same attention span for my thesis… No I’m kidding, I’ll hopefully finish it within the next few months.
But actually the idea has grown during the working time. I had a discussion with our engineers how much this machine can do. Most had the feeling it might cut wood but were worried about the dimension accuracy. And none believed it can really cut aluminum within reasonable time and will rather “file” the metal. At this point I was triggered and had the feeling that the MPCNC is somehow a nice optimization problem (that physicists love to solve).
@peter: Due to a lack of time I didn’t start with the unmodified MPCNC, unfortunately. The corners looked to me more stable but it might not be a difference to the original ones if you have this small z travel. Maybe with this corners it’s easier to get some tension on the 15mm GT2 belt which I just bought because it’s not so expensive (from china) and I could not see any disadvantages except that you need more filament for the belt clamps.
What I can not recommend is the use of a spindle holder with this two small rings like (https://www.thingiverse.com/thing:2114351) because it does not keep the z-axis as rigid as the tool mount plate does. Better use a tool mount with the full length of the motor body or something out of wood or metal. For me the solution with aluminium was cool because this Makita motor is quite thick and this way I could keep it really close to the z-axis.
I have milled the tool mount on another CNC but with the experience now I would say it can be milled on the mpcnc. With the parameters I used so far for 25mm thick aluminum Fusion estimates ~35min for the center and another 45-60min to cut the outside. The holes were done later on a drill press (first end mill for a flat surface, then spot drill and normal drill), then cut with a saw in the front. To have the right orientation for the holes I made lines on the surface:
A draft of your thesis under those cuffs? Good idea to make the tensioning gaps with a sawcut. I would add some small threaded holes to mount any accessories like a laser pointing array (two lines) etc.
@chattermark Wish I had the Idea with the threaded holes before… Sometimes this would be very helpful.
@ben78 Dann am besten direkt loslegen! The holders are fixed to the z-axis with m4 countersunk screws. The counterbore was the most difficult part in terms of available tools. I used a long 10mm spot drill. Inside the tubes there is the usual setup with the nut trap and M4 nuts.
Funktioniert leider nicht mit dem Aufbau der MPCNC, da ich keinen Händler mit Paypal finde, der die Pullsey (15mm // 5mm Bohrung // 2mm Pitch) noch den Riemen (zu einem akzeptablen Preis) hat -.-
Und Kreditkarte fĂĽr AliExpress besitzen wir nicht
die 15mm sind nicht unbedingt notwendig! Ich kann wie gesagt leider keine Aussage darĂĽber machen, ob die 15mm Riemen besser als 9mm oder 6mm sind. Ich habe sie nur verwendet, weil ich gĂĽnstig daran gekommen bin. Du kannst auch das ganz normale Design verwenden. Falls dir 6mm Breite zu wenig sind, kannst du auch nach 9 oder 12mm GT2 Riemen mit Pulleys gucken, meine Riemenspanner gehen auch mit schmaleren Riemen und falls du unter 9mm bleibst, kannst du auch das Design von @braunscnc nutzen: MPCNC Belt Tensioner by BraunsCNC - Thingiverse
Short translation: Just to make it clear, I have no idea if 15mm belt is better than the original 6mm! If 6mm is too small for your feeling but you can’t get the 15mm pulleys/belt somewhere you can of course look for 9/10/12mm belt and use the same holder or the design from @braunscnc: MPCNC Belt Tensioner by BraunsCNC - Thingiverse
)
No I’m kidding, I’ll hopefully finish it within the next few months.
Sometimes this would be very helpful.
Short translation: Just to make it clear, I have no idea if 15mm belt is better than the original 6mm! If 6mm is too small for your feeling but you can’t get the 15mm pulleys/belt somewhere you can of course look for 9/10/12mm belt and use the same holder or the design from