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Building the MK3 kit - my impressions and some comments  

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giles.p
(@giles-p)
Eminent Member
Building the MK3 kit - my impressions and some comments

Congratulations on a really well designed and refined product first of all!

I found a few little things in the build instructions that you might consider as feedback, either just to make it a little more foolproof, or things that I had to do to get it to go together... here they are.

Section 4 Z-axis
Step 7 Assembling X-axis and smooth rods - I had to go back and redo this step. What needs to be made clear is that the rods MUST be pushed all the way into the holes in the bottom (motor) brackets, otherwise the top brackets won't go on straight, and this affects the Z calibration badly later on as they are used to level the X-axis out. I didn't know the significance of this until I looked at what the calibration was doing. I had to ream the holes to 8mm.

Step 8/9 Placing the Z-axis top parts - need to say that the brackets must go on straight and level with no excessive force for reasons above.

Section 5 E-axis
Step 4 idler assembly (part 3) - the pin will not go into the hole. I had to ream the hole to 3mm, but then the pin is too loose. When the idler is assembled into the extruder body, the pin is not trapped and can slip out. Now I know the hole cannot be made any more accurate - but perhaps the body needs to trap the pin so it can't fall out.

Step 21 Mounting the left hotend fan - M3x18 screws are too short. I had to file the plastic ears of the fan down 2mm.

Step 46 Assembling the idler plug - what's this for? It's loose and not secured, and can fall out. I left it out, as it doesn't appear to do anything.

Section 8 Electronics
Step 26 PSU power panic etc. - The photos are a bit dark and unclear; maybe a diagram might be better or a larger photo with all the cables (like the one in step 32 but full page - I downloaded it from the website and enlarged it)

Thanks for listening and hope this helps,
Giles.

Opublikowany : 15/03/2018 8:08 am
JoanTabb
(@joantabb)
Veteran Member Moderator
Re: Building the MK3 kit - my impressions and some comments

Hi Giles,

step 21 fan,

my cap head screws nest inside recesses.... have you got the fan back to front?

Step 46

the plug is to stop ambient light entering the Air Duster, cleaning hole to the filament sensor

it's fiddly, so I made a bigger version, as getting hold of it with long nails, is awkward. i actually inverted a second copy of the plug and moved the top edges together in Slic3r, making a handle exactly the same shape as the plug end, so it will go in, either way round

regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Opublikowany : 15/03/2018 9:41 am
giles.p
(@giles-p)
Eminent Member
Topic starter answered:
Re: Building the MK3 kit - my impressions and some comments

Thanks for prompt reply Joan - no the fan will only go one way (if I turn it over the outlet points off into space)
The other thing if important I'll just stick it in with a drop of glue.

Opublikowany : 15/03/2018 9:51 am
JoanTabb
(@joantabb)
Veteran Member Moderator
Re: Building the MK3 kit - my impressions and some comments

Hi Giles
Dont stick the wedge in place. It will stop you openning the idler flap to remove stuch filament

Was the fan in question the noctua fan?

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Opublikowany : 15/03/2018 12:46 pm
Nikolai
(@nikolai)
Noble Member
Re: Building the MK3 kit - my impressions and some comments

Hi giles,

There is an option to add a comment to each step in the online documentation. This way it will help others to find your suggestions easier.

Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram

Opublikowany : 15/03/2018 9:50 pm
Dewey79
(@dewey79)
Honorable Member
Re: Building the MK3 kit - my impressions and some comments

Giles, thanks for taking the time to provide the notes.
I've just started my build and only have the frame put together up to "Step 18 Mounting the Y-belt-idler" in section 2. I should have gotten a magnetic tray for the small screws and other metal parts. Those M3 screws and nuts bounce alot when one gets loose...

Opublikowany : 16/03/2018 9:58 pm
NiHaoMike
(@nihaomike)
Eminent Member
Re: Building the MK3 kit - my impressions and some comments

Having just built mine, I suggest taking a few minutes to remove the PSU cover and inspect the connections. I found that they were loose and could cause problems later on. I also suggest adding a 47 ohm 1/4W fusible resistor from V- to mains ground to avoid problems caused by the floating ground. When reinstalling the cover, put the bottom plate on last so you can make sure none of the wires are getting pinched inside.

Maybe the EE lead should reevaluate the idea of the floating ground (my guess why it was done in the first place is so a partial short in one of the heaters to chassis doesn't cause a thermal runaway) and perhaps also switch to some better kind of connector like XT60 or Anderson Powerpole?

Inspired to get into 3D printing by Micah Elizabeth Scott, Naomi Wu, and an anonymous Bitcoin girl I met in college.

Opublikowany : 25/03/2018 11:01 pm
Gene
 Gene
(@gene-2)
Active Member
Re: Building the MK3 kit - my impressions and some comments

giles, NiHaoMike

I'm still waiting for my MK3, but thanks for posting your build comments. They are most appreciated. I just realized that while waiting for my delivery (still 2 weeks out), I could be reviewing the docs!

For those that are still waiting for their printers, you can find the docs here: http://manual.prusa3d.com/#_ga=2.65909933.229400436.1523371306-303305379.1485058207

Cheers!
gene

Opublikowany : 11/04/2018 4:26 pm
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