Building "The Beast" a large MP3DP2

Hi - am building a large MP3DP. Build volume should be approx. 390 x 390 x around 350 high. I have not got the extruder mounted yet so the numbers might change slightly. I should say I understand I am pushing the boundaries a bit with this build, so we’ll see if it works properly.


Have read the wiring section a few times. The instructions don’t seem to mention the MP3DP. I assume the wiring is the same as the MPCNC and Low rider ? Can someone please confirm ?


The MP3DP has one X, one Y, two Z. The Z can comfortably be wired in parallel. Even with your mega gantry, I doubt it will have much weight. Serial would be slightly better.

The rest is just like any 3D printer. If you have any specific questions, ask.

What controller are you using? What heated bed?

Looks like a fun build.

I am using the SKR Pro 1.2. I have an AC powered silicone mat which I am planning to control via a SSR and are using an aluminium plate as the bed. I am amazed at how well it has gone together so far. …

How did you adjust the flat parts for the larger build? I have lots of random parts laying around lately and I have considered doing a build like this one, will definitely be following your progress here.

I basically stretched each part - keeping the relative position of the holes etc. The DXFs are on Thingyverse, but there are some very minor updates I need to make if you are interested.

I am definitely interested, I have a semi need for a larger format printer and tbh the parts I have laying around would do well with the MP3DP format (at least in my head). I figured you had just re-drawn/enlarged the parts, was curious the difficulty and how it’s been going.

Yes - should say I stretched the flat parts only. The printer parts all are unchanged and it fits together perfectly. Its only the extra cost of the timber for the larger printer, so if you need a larger printer its really good value compared to buying one.
I have not finished yet (obviously) but so far its not any harder than maybe building your own pc. It took a while to work out where everything goes, and a while to work out what to buy. Some soldering is required for cable management, but its all doable.

Could you provide a link? I couldn’t find them.

Here’s the link. This is for the flat parts only. You need to use Ryans 3D printed parts.

The Beast 400 x 400 3d printer frame by CoupePete - Thingiverse

Or search Thingyverse for “The Beast 400” .

I will update the files when I get a chance the holes in the Y plates are in the wrong spot. I needed a sheets of 1200 x 1200mm ply to make all the parts.

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I am having trouble finding the bin files in the firmware zip files.

Assuming this is the correct file :-

There is a bin directory in the zip file but no bin files. Any help appreciated.

Sorry ignore that request - i found it.

For anyone whos interested, there was an issue when flashing the TFT 35 that the programming stopped at 16 or 17%. I found I needed to disconnect the grey cables from the TFT 35 in order to flash it. Once it was flashed i powered off and reconnected and all was working. Maybe that will help someone else in the future.

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Can anyone advise where to connect the z limit switch ? The notes say Z1 is configured for a touch plate ? Do I use Z2 or somewhere else ? I don’t see it mentioned in the notes for the SKR board anywhere.

Zmin. Are you reading notes for the cnc machine?

I am looking here ;- SKR Pro - V1 Engineering Documentation and yes it only mentions MPCNC and Low rider in the text if I remember correctly.

The MP3DP section does not mention it connecting the controller as far as I can see. Main - V1 Engineering Documentation

Of course I could have missed it…

No. That makes sense. The MP3DP is much less common, and more like a project. ATM, I will be more than happy to just answer the questions than write up more detail in the docs.

Ok thanks

I have everything hooked up, except the heated bed. Is there some way I can do a simple test to confirm the connectivity ? The X,Y, Z axis all work and move in the right directions. I think I have found G Code to turn on the fan and test homing so will try that. Looking for some way to test the thermocouple, heater and stepper motor in the extruder ? I assume I can do this without a print ?

You can check the resistance of the bed heater or the hotend heater. They will be tiny, like 10Ohms or less. But find a spec sheet for them to be sure. 12V and 24V versions have different values.

The thermocouples are harder. They are all about the same near room temperature. You can just turn on the printer and see the reported temps. Something that isn’t broken would be in the room temperature range (23Cish). But, for example, if you picked the wrong kind of thermistor in your firmware settings, you wouldn’t be able to tell at room temperature. Even at 100C (which is conveniently where water boils) they aren’t much different. But the good news is, it doesn’t really matter. If you have the wrong config, and you add 5C to the temperature, it will go 5C higher. If that is 195C or 200C… Who cares? The important thing is how the plastic works and you will be tuning temps later for that.

To test the extruder motor, you will need to heat the hot end up to at least 150C.

If you have been a little careful configuring marlin, then you are probably ready for a heat test. Choose a program with a temperature graph, like pronterface or octoprint and set the temp on the bed to 60C. Watch it climb, look out for smoke, keep your hand on the power switch (not literally, but know where it is). Then feel that it is warm. You can measure it with a thermometer. It doesn’t have to be perfect. Turn it off.

Then do the same with the hot end. Start at 150C with no plastic inside. Watch it climb and stop at 150C. Then go to 195C and add some plastic. You can test extrusion. The controllers have an extrude button with some mm. Then turn it off and see that it drops on the graph.

Then onto the tuning. PID tuning, heater tuning, bed leveling, extrusion steps, all that good stuff.

Thanks heaps - will take me a little while to get through this.