MK2 Upgrade kit coming Thursday, any advice before I start?  

Re: MK2 Upgrade kit coming Thursday, any advice before I start?

Hi 3Delight. I was going to post some of my issues with a pre-built Prusa i3. Given your Prusa was a kit I don't suspect you will have the same problems. If my hunch and Peter are correct, my problems may be unique and not something the average person would see anyway.

The instructions were really well done. I don't think I really struggled with anything in particular. Having the two bag setup for each stage was really helpful. One bag printed parts the other being screws, zipties, and accessories. Give yourself plenty of time.

Of course read everything carefully. There was a moment were I went looking for 2 or 3 M3x40 screws when it actually called for M3x30 and I was driving myself nuts. I didn’t want to dig into the spare parts bag if I didn’t need to. Then I re-read it and has a ‘doh’ moment.

It took me around 8 hours to complete the tear down and build. One of the other things I found helpful was to read ahead before doing the step you are on. It helped my understand the goal and plan things. There were a couple of times like with the extruder where you need to slide some square nuts in place but you don’t use one of them for a couple of steps. It kept falling out so left it out and read ahead and made a note of when I would need it.

All in all it was well documented and straight forward. Oh, the belts, the dang belts were a bit of pain to get tight. But my wife helped me with them.

Good luck!

Micheal

Re: MK2 Upgrade kit coming Thursday, any advice before I start?

Yeah, the belts. There is a much simpler way to get them tight. Remove all except one of the motor screws, and loosen the remaining one and swivel the motor pulley towards the idler at the other end. Put the belt on (it should be quite loose and then pull back the motor. You will be surprised at the amount of tension you can get... I had to slacken the belt of a couple of notches, so don't cut it until the tension is correct.

Peter

Re: MK2 Upgrade kit coming Thursday, any advice before I start?

Great tip by Peter. Lateral thinking at its best.

Re: MK2 Upgrade kit coming Thursday, any advice before I start?

Don't rush, take your time. Save all the screws and parts from Mk1 you remove, including the filament strengthener. Note new endstops and extruder fan included with Hotend box. Also a bag of bits called spare. I had to fish two screws for mounting Y endstop microswitch from there, not included in Y Axis bags

I have finished the hardware upgrade. Tomorrow firmware upgrade and first print run.

Have fun.

Re: MK2 Upgrade kit coming Thursday, any advice before I start?

Oh man, I was kicking myself today. Over my lunch break I was checking the forum and saw someone else reference your original post. Pure genius. Thanks Peter.

Yeah, the belts. There is a much simpler way to get them tight. Remove all except one of the motor screws, and loosen the remaining one and swivel the motor pulley towards the idler at the other end. Put the belt on (it should be quite loose and then pull back the motor. You will be surprised at the amount of tension you can get... I had to slacken the belt of a couple of notches, so don't cut it until the tension is correct.

Peter

Re: MK2 Upgrade kit coming Thursday, any advice before I start?

One other note I would add is that couple of the printed parts needed a little cleanup for solid fit. For example the four corners on the Y-carriage had plastic globs where the bearings are designed to nestle in along side the rods. Some of the screw holes like the micro switch (end stop) on the X-axis needed to be opened just a tiny bit for the screw to bite. I used a tiny drill bit with just my fingers. Again, nothing truly unexpected.

Re: MK2 Upgrade kit coming Thursday, any advice before I start?

The beauty is , I now have many stepper motors for a Laser cutter/engraver home build 🙂

Re: MK2 Upgrade kit coming Thursday, any advice before I start?

Thanks for all the tips folks! The kit arrived as expected and is all present and correct so we will be starting it tonight. Little bit disappointed that there was not a paper version of the Assembly Manual included as our PC is upstairs and the printer is downstairs so a load of printing to do! Shame there isn't a PDF version of the full paper manual online (I've seen the separate ones) as my printer can print a booklet out fast and backed...

I was amazed at just how much you do get supplied with, I never expected it to include all the tools again, all new motors and spare nuts, bolts, etc. 😮 ! Prusa really are a great company! 😀

I like the way the bags are labelled up as for the full kit with the non-supplied bits crossed out. I think as we disassemble the old printer we will put the need to keep bits in the relevant bags as we go so we keep all the right parts with the right sections.

The beauty is , I now have many stepper motors for a Laser cutter/engraver home build 🙂

That's a thought! I'd like some sort of CNC at home... 💡

Are the new motors different than the old ones in some way? I know that the Z one's are due to the built in lead screws but what about the others?

Thanks again and wish us luck!

Re: MK2 Upgrade kit coming Thursday, any advice before I start?

Yeah, I believe the motors can generally handle more current than those supplied with the Mk1 (they were a little lightweight).

I haven't checked out the specs on the new motors though...

Peter

Re: MK2 Upgrade kit coming Thursday, any advice before I start?

Re: MK2 Upgrade kit coming Thursday, any advice before I start?

Thanks David that's good advice!

Well, we disassembled the Original one last night, all went well and all the needed pieces are now in their proper bags.

One thing I noticed was that the Y-Carriage seems ever so slightly uneven. When my wife assembled it (and since) we've always had problems with getting the bed level so am now wondering if this is the cause and it came like it? If I place it on the flattest surface I've got it rocks a tiny amount from corner to diagonal corner! I placed the edge of a steel rule along that axis and it can be rocked a tiny amount as well... it's less than a mm but then we print at thousandths of a mm so I guess it could make a difference? ❓

Is there a reason you have to glue the new PSU Y brace onto the PSU? Couldn't they have included new whole cover to make it more solid and reliable?

Anyway, we all set for the big rebuild... 😀 😀

Re: MK2 Upgrade kit coming Thursday, any advice before I start?

I have found that with the Mk2 in particular, the Y frame goes out of square, very easily, even if you just move the printer to a workbench to adjust the Y alignment (which needs to be more precise with the Mk2 for lining up the probe).

The problem is with the felt pads and especially with vibration dampers on the feet, you can't always tell that the Y frame is twisted and you go looking for the problem elsewhere...

Peter

Re: MK2 Upgrade kit coming Thursday, any advice before I start?

Thanks Peter, I will pay special attention to that when we do it. I wonder if Prusa needs to change the design in the future to get a more accurate frame? It seems to me that these printers are getting to a 'resolution' that is so sensitive that everything has got to be spot on to the tiniest degree! While I think the whole "Printer capable of printing itself" and Open Source parts is a great idea at first there comes a point where the engineering demands custom made precision parts. I suspect it won't be long until we see the first 1um layer home printer, but I suspect it will not be something the average person could build from a kit as it will require precision engineering and construction! Sad but true... but if anyone can pull it off it will be Josef! 😀

Re: MK2 Upgrade kit coming Thursday, any advice before I start?

Hmm, spoke too soon about the contents all being there! According to the manual I should have 2 pieces of filament a 30cm piece (got) and a 50cm piece (missing) and according to the packing list there are alcohol pads in there, but there isn't! I guess we've got to wait to build it now so Prusa can send out a length of nylon filament! Silly error for them to make! 🙁 It was checked by Tomás or Tomáj (?) so he's the naughty boy responsible and needs a good spanking! 😈 😮 😆

Re: MK2 Upgrade kit coming Thursday, any advice before I start?

No need to wait; just cut 2 or 3 lengths of 1.75mm filament and melt the ends together with a cigarette lighter or hot air gun.

Roll the ends together when still warm between your fingers to get a 3mm end and cut the end off square.

I had to do that on the Mk1 when my original filament gave up.

If you have some isopropyl (70% or above) or a decent window cleaner, no need for the wipes.

Peter

Re: MK2 Upgrade kit coming Thursday, any advice before I start?

Prusa said similar, just use two pieces of 1.75mm filament together to get the desired width and that PLA or ABS is fine... The wipes we've ordered via Amazon(.co.uk) as they are only cheap. We've dug the old bit of 3mm filament from the MK1.75 out of the bin and if it's long enough we'll just reuse that...

Re: MK2 Upgrade kit coming Thursday, any advice before I start?

The old piece of filament was too short, so we decided to buy a bit of sample Nylon 3mm filament from 3D Filaprint as it only cost a couple of pounds for 5 meters.

We started doing our MK2 upgrade tonight and straight away hit a snag... the PSU-reinforcement part does not fit the PSU! The ridge on the PSU does not match up to the groove in the new part! It is not a case of a tiny bit, it is quite a way out! As much as this part is said to be "optional" we want to use it, both to help stability of the frame and we paid for it! What with the missing 3mm filament and alcohol wipes (both of which we've had to buy locally) it's getting more than a bit annoying! 😡

I notice a few people are reporting this in the comments on the Assembly Manual page.

Would it not have been better for them to supply the full PSU housing with the new part built in as in the full kit? Or both so those with the knowledge can swap it, those without can fit the extra part! 🙄

Guess we've got to email Prusa yet again, what a pain!

When they get it right they are terrific, but they let themselves down by not paying attention to the little things, small bits missing from orders, not checking that parts will fit everyone's existing machines, etc. It's these little things that will get them in the end, my Parents always used to say "Look after the pennies and the pounds will look after themselves" and this applies in all things, the devils in the details.

Re: MK2 Upgrade kit coming Thursday, any advice before I start?

While waiting on the PSU part issue we decided to carry on building as it isn't needed until later. We've now finished the Y-Axis. All seems OK, no cracks when tightening the bolts, the Y-Carriage seems to slide as well as it did before, no wobble when finished so fingers crossed. We couldn't get the belt on the last post with enough tension when using the method in the manual, so we used the 'loosen the motor' method that was on here, worked like a charm. So all happy so far! 😀 Tomorrow, the X-Axis...

Re: MK2 Upgrade kit coming Thursday, any advice before I start?

Just make sure you don't get the belts too tight - it is very easy to do that when using the motor swivel.

Make sure the belt tension does not pull the motors off square - the printed motor brackets can't take too much belt tension and will allow the motors to be angled inwards so it is then impossible to get a good belt alignment.

The motor pulleys can work loose; you may need your own allen key to tighten the grub screws.

Peter