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Reprappro Tricolour Mangle

Posted by mist42nz 
Reprappro Tricolour Mangle
November 16, 2014 01:53AM
Has anyone managed to print anything worthwhile (not just printer parts, or waste plastic widgets) with one of these things.

I've been trying for months to get the blasted thing to work. Had all the usual teething problems, broken thermistors (they don't sell co-axial thermistors in my country, only disk style), god knows how many hassles with the tiny pins and crimps in the head connector plug and socket, slippage of all types too hot too cold too fast too slow, extrusion too slow too fast, cracked and rotating home sensors (whoever thought that design up and that one bolt was enough is a dreamer), slave and master needing firmware reprogramming, t1 and t2 hotend swapover at the slave board, and the re-level of the heated bed every print....

I brought this thing because it was a reputable company said it was good for basic rapid prototyping.

Still can't get half the printing to stick to the Kafton tape (either the top half, or the bottom half, or the left or the right....) ... and on the rare occasion more than 50% sticks...the second hot end knocks it loose.
And forget the third head... that side of the mount seems to be 2mm lower so jams against the bed (I just hang the second hotend off the side of the printer just so the firmware will let me print with a second head in place.)

So I'd like to know... before I waste more time on this ... piece of... this _toy_... has anyone else who isn't spending every day playing with 3d printers, actually really managed to print anything useful off it?
Re: Reprappro Tricolour Mangle
November 16, 2014 10:02AM
Does the utility (or lack of) experienced by others somehow validate or invalidate what use you may get out of the printer?

Did you buy it as a kit or preassembled?

MakerFarm 8" Prusa i3v
0.4mm E3D v6 for 1.75mm
Re: Reprappro Tricolour Mangle
November 17, 2014 01:23PM
I don't need to re-level the heated bed every print. There are months between adjusting.
Is the heatbed at correct temperature the whole time when printing? I actually have an issue with the printbed - it is sometimes switched off while printing without any reason.
This doesn't happen with the marlin software for mono mendel.
As a mono mendel it works really fine for me. Dual extruder printing is more challenging. I use the second extruder for PVA and never used the third extruder.
The RepRapPro Mendel is sold as a kit.
Re: Reprappro Tricolour Mangle
November 17, 2014 08:36PM
@gurz Then I am tempted to question how well the kit was assembled more than the general quality of the machine.

MakerFarm 8" Prusa i3v
0.4mm E3D v6 for 1.75mm
Re: Reprappro Tricolour Mangle
November 23, 2014 03:38PM
I bought it as a kit. But used to work repair and upgrading machinery like this all the time, from little service station thermal printers, through supermarket tills, PC servers, monitors, up to line printers barreling out thousands of lines a minute and computer hardware with CPU's "chips" over 30kgs. So it's not like the work is unfamiliar or that I'm not up to fine accurate detail.

But that's why I'm asking if _others_ have done constructive stuff - because if no-one else can get one into productive service, then it's not just me. So rather than drop cowardly slights, if you've done some constructive bravely put your hand up and say "I printed a XYZ" using these settings, this software.

I also have purchased a pre-assembled head 0.3mm that managed to do a test print of a cylinder, 16mm dia, 25mm high, then on the next print a 6mm dia 80mm shaft, it started playing up and hasn't managed to get above third layer since.

But there do seem to be some physical issues - the constant need to re-level (yes I have checked and tightened the Z drive) but it's that it goes off level - I'm assuming because it's a thermally flexing plane fixed at three points without compensation. the three point fix is not good, as it creates lines of fulcrum, yet has no stable counter forces. But it could be that - or it could be the method the hot ends are mounted into the PLA carriage. I know I had a big problem with having no dimension (or tolerances) for the extrusion nozzle, so going tri-colour without some sort of lifting technology was always going to be challenging. (personally I'd try some heat expanding meta-material in the form of a spring, so that when the nozzle came off standby temperature the nozzle would extend 0.5-1.0mm which should give a big benefit.) Likewise a sensor that could be used to read the Z differences, for correction (within tolerance) or warning to reset bed level (out of tolerance) that shouldn't be a particularly big challenge.

The support I've had from RepRapPro has been great, but. I can't keep email them every few minutes. But I'm looking through the site and the support materials, and they're fragmented. Like the old HAM days, stealing parts out of TV's and radios. but without the manuals.
Take the sticking issue - it's got to be the most common thing reported - but where is a list of symptom descriptions and solutions. where is the information that tells me what is going to happen if I lift the bed temp or drop it and what to look for? Or what happens with the output by doing certain things to the hotend.

Personally I'd like to see each roll of filament come with a small graph indicating that batches' glass temperatures, and it's adhesion strength and viscosity at those temperature (two plots on graph, w/ abscissas of temperature). this would help enormously rather than having to guess and reset each time.

I have a sneaky suspicion that my problems stem from using 1.75mm PLA in a standard Mendel Bowden (lack of "piston" action in extrusion pool). But as I haven't had much success with anything (a handful of calibration pieces that eventually came out ok, if "hairy") and some gears (which suffer from first layer distortion). So it's hard to diagnose a fault pattern when I can't get a consistent base print.

One print I've trying to do as test run is this one [www.thingiverse.com] but this part " 1 assem_baulk_holed.stl " for example just comes out as faint random segments on the bed...which are then pushed around by the head until they make a spaghetti mess.

I got the tri-material because I hope to be doing two colour (or colour + clear, or colour and black) and also use recycled PLA as infill (as its not so colour sensitive) because I have one of these : [www.kickstarter.com] However getting lumpy objects into a pellet form is proving yet another hurdle - thinking melting to sheets then sticking them in a blender, like the HDPE blender guy did on the Instructables for his plastic lathe stock.

I'm hoping to step up to some ABS once I've got repetition on the PLA prints. But I'm puzzled how a PLA printed mounting bracket will handle the ABS temperatures, so I'm wanting to print a full set of parts before going dowen that roda.

Yet none of that helps me get my actually project that I'm supposed to be working on, off my workbenches
Re: Reprappro Tricolour Mangle
December 08, 2014 01:39PM

Thanks to a PM I've been trying the UHU glue stick (which is not the same as a hot gun glue stick, for any new folk out there). Brilliant, game changer. Everything sticks. OK, after the print I cool the bed, and re-heat to 70deg C, so I can get the print off, but it is now and solved known trustable reproducable solution!

Next step, wipe filament with olive oil, reduce dust, makes filament move more freely. certainly not hurting.

Z axis keeps getting out of plane - the vertical mounted carriage system on the current tricolour Mendel has small nuts on a rotating threaded shaft. The nuts are tensioned by a spring...but not well. there is up to 10mm play in those bugs... so shifts up and down can be at random distances...so when a home signal sets teh Z-axis...it frequently just randomises it!

X axis microswitch is mounted by a single bolt, which loosens enough for gravity to pull it completely flat.

Getting a lot of cracked h-style mounting brackets. The main system of mounting miscellaneous parts to the cylindrical frame is by a PLA print "h" shaped bracket. they need to be tight to stop them moving on smooth shafts, but since there is not support web structure in the "h" they crack. Not affecting print but going to get messy soon.

I customarily use a 100mm usb extension cord with all stationary electronics. This is secured to frame, so if it gets knock or pulled any stress, wear or damage goes to the replaceable cord, not the tiny weak usb socket, or the electronics PCB.

The "baulk plate" I was having problems printing.... with the UHU actually prints a bunch of random pieces...looks like the slicing software can't pick up the top and bottom layers. (too thin in STL file?) Now that the print doesn't move I can trace the fault.
The "head mount" for the filament stand...now that it sits in place...seems to have a problem with the file about 5 mm up - this could be Z-axis nuts, but three tries have all produced identical pieces only the first 5mm high (but printer likes to think its doing the rest). It burns the PLA while faking it.

Having problems with Kisslicer and Cura trying to print off the plate.
Re: Reprappro Tricolour Mangle
December 08, 2014 02:55PM
OK this thing needs fan covers.

Have burnt PLA in hotend. pushing it through and wiping ..... just destroyed my 3rd fan by knocking it with the cleaning blade.

while we're at it, a blasted cover for the back of the electronics boards wouldn't go amiss.

fk! I hate lazy shoddy design
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