Monday, 27 March 2017

Core XY - failure

When I built my core XY one of the changes I had to make was to make it 2.85mm filament compatible. Since this is the size most of my filament is in.

The clone hot end "0.4mm E3D-V6 Metal 3D Printer Extrusion Head Exturder Nozzle With Fan" 
Has a 3mm option.

BUT...

When it arrived I was quite concerned that the PTFE tube was ID=3mm, but OD=4mm  Ie very thin walls.  But I decided to give it a go.

Sure enough half way threw a print the PTFE tube tore off at the entrance to the extrude push to fit connector. Removal of the PTFE tube from the connector was also impossible.

I have now replaced the PTFE with some nice thick OD=6mm tube.


The tube on the right is the original complete with torn off end

 Hot end with new 6mm PTFE tube

This wasn't as simple as you would hope. The 4mm tube extends down into the hotend some what, So I kept a small bit for that and drilled out some of the 6mm to ID=4mm. This happens inside the PTF connector so the 4mm tube isn't being stressed at all.

Only time will tell if this will last





Sunday, 19 March 2017

Original Prusa i3 MK2 upgrade kit to full printer - progress thus far

The Y axis is assembled

And the X and Z
No X belt yet as I ran out of time.

A note on the provided belts: They are really nice and solid. Comparing it with stuff Ive had from china, their stuff is soft and lacking material (its almost like they use a filler vs what ever the belt is meant to made from) "Prusa" belts also have steel (at a guess) cores    

The extruder im still missing a few parts, the idler bearing and springs are the main hold up at the moment.

Also it would seem that m3x18 is a non standard size. Not available from my local supplier. Looks like another order from china is needed. Either that or ill have to make 17 odd of them from m3x20's


My Z axis was quite problematic. The lower plastics the holes in my alu frame are sloppy and I have lock nuts on the back side. The issue is you need to make sure the stepper rods are straight up and down, but the bolts are behind the steppers... So you cant loosen and adjust them when the stepper are in place and you need the steppers in pace to align the position of the lower plastics. Got there in the end. Wouldn't be an issue if I had a higher quality plate


Wednesday, 15 March 2017

Original Prusa i3 MK2 upgrade kit to full printer - checking Y plate

I checked that the old Y plate I have will fit on a new mk42 heated bed



Yes it will, once in the correct orientation all 6 holes line up nicely. (4 corners + 2 on Belt clamp)




Sunday, 12 March 2017

Original Prusa i3 MK2 upgrade kit to full printer - planning

I'm going to build a printer based on the MK2 upgrade kit

It will be as close as I can make it to the "Original Prusa I3 MK2"

I’m not going to worry about the colour of parts, ie threaded rods nuts and washers will not be black. Mostly because I can't find any source for such things at a reasonable cost or locally. Even M8 half height nuts seem to be rare here. So ill be using standard size M8 and M10 nuts


So far its all theoretical, but this is BOM so far.  docs.google.com

Everything with a red background in the spreadsheet needs to be acquired.

This will be updated as I complete each section.

The provided spares bag with the upgrade kits has been a lucky inclusion,containing just enough of a lot of the required hardware.

If anyone wants to send me 10 of these "spares" bags, ill convert the nuts and washers to black. :)














Saturday, 4 March 2017

Core XY update 2.8, first print

I've leveled the bed close enough, and enabled mesh leveling to compensate for the remainder (its as close as I could get it without using a dial gauge)


I’ve also set the nozzle distance from the probe so Z0 is correct for the hot end.

 
First print!

Just a few seconds of a test cube (still on slow ADSL here, so uploads are painful!)

The bed is still cold aluminium, here I am attempting to print on glue stick with PLA. Seems to work for this small object


Finished first print looks great.


Now I have it working I have a few comments about the hypercube.

It is very much a build in place design. If you expect to change things later there may be lots of dissembling involved.

Not all tslot is equal, the tslot nuts in my extrusion are tight, as is will not turn freely to get into correct position. I find I need to force the nuts into the correct orientation with some long nose pliers then screw them down. Another person I know whom is building a hypercube his tslot is so loose in comparison that they work as designed, ie they self orientate on tightening.

The Z build height is only about 145 with current parts. (Z tslot 350mm)
This could be increased 15mm ish by dropping the bed onto the alu extrusion and letting auto be leveling take care of any offsets. (ie remove the springs), Make sure your bed is still electrically insulated from the alu if you try this)
Secondly the Y lm8uu holders could be modified so the bed is at the bottom of the part, this would also add about 20mm to Z (others have done this on thingiverse)

The current Y smooth rod mounts, the mounting screws end up behind the smooth rod (slightly offset) these are not fun to tighten.

Lots of parts stick out the sides...  making it very hard to stick any sides on the machine.

I’m now going to diverge from the standard machine.
Make some of the changes mentioned above and put the re-arm on this machine.