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Printing issues ...
I had some problems with PLA softening at the top of the JHead which tended to happen when printing the first layer of prints with a relatively large bottom surface area - I think that the problem arose as a result of heat rising by convection and hot air "hanging around" at the top of the JHead as the first - slow print speed - layer was laid down.
What I did seems to have fixed things (famous
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Alzibiff
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Mendel90
Ralph Hilton Wrote:
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> That sounds low to me. The pcb is 0.8 ohms so
> draws 15 amps at 12 volts.
I doubt that ZhangX will be using a single strand to draw current for the bed and without knowing how many strands are involved for the bed current in this set up, we cannot really comment.
The grey ribbon cable used by Nophead in the Di
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Alzibiff
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Mendel90
My £0.02......
I bought a 25mm 12V DC fan from somewhere on a famous internet auction site and made a clip (which I need to redesign as it is too loose really) which attaches it to the X carriage - pointing towards the top of the JHead. The fan is wired to permanent 12V on the extruder PCB. Fingers crossed but this has worked without problems for months. I keep the fan which Chris supplied with
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Alzibiff
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Mendel90
QuackingPlums Wrote:
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Do I need to dismantle the J-Head?
Yup!
What has most likely happened is that the filament has, for some reason gone soft higher up in the JHead and then started to buckle rather than push the filament below it through the hot end. This can happen if you have a large area to fill at a speed which is not providing enoug
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Alzibiff
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Mendel90
For what it is worth, my experience suggests that it is down to getting right, two key parts of the commissioning process: Z height and bed levelling.
I spent MONTHS with my first RepRap machine trying to get PLA to stick to anything other than blue masking tape but once I had sorted out the Z=0 position everything else became easier.
PLA DOES stick to glass and given the consistency of compone
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Alzibiff
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Mendel90
Interesting and very encouraging. Did you print onto cold glass or some other base material? Were you using a standard Dibond kit machine with a 0.4mm nozzle?
Alan
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Alzibiff
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Mendel90
With the Nophead DiBond Mendel90 set up, my starting point for PLA is an indicated 220C. I say indicated because there are many out there who insist that PLA should be printed at 185C and seem to take what is shown up in Pronterface (or other control program) as the whole truth and nothing but the truth. In reality, the real temperature at the melt point inside the nozzle may not be as accurate a
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Alzibiff
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Mendel90
Looking at your photographs, I cannot see anything too amiss given that you are printing a Lithophane - they look very bumpy and irregular anyway, the amount of roughness depending on the photograph used to produce it.
I will leave it to others to comment on your Z leadscrews as I assume you have everything as tight as it is supposed to be. Might be worth posting photographs of a different object
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Alzibiff
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Mendel90
This is just off the cuff an apologies if not fully thought out but ....
It seems to me that the advantage of using a 40W heat cartridge is that it gives a faster warm up time than would be the case with a traditional wire wound resistor. Are there other values available which will reduce the current demand? The resistance of the heat cartidge, 40W at 12V works out a 3R6 - quite a bit lower than
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Alzibiff
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General
Interesting that the advertising talks about "cartridges" when it comes to the print material - which is the route some manufacturers are taking, presumably to maintain sales and profits. However, the Velleman K8200 appears to use standard looking reels of filament which must be a positive.
Alan
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Alzibiff
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General
Adi,
I suspect that the lack of responses to this post is down to the unknown - what IS a "M.O.B 3d printer-Romsrcaj "? Not something I have ever heard of. If this is a ready built 3D printer, or for that matter a kit of parts, your first port of call should be to the manufacturer/supplier.
Where did you find out about this machine? Where did it come from? Did you build it?
Alan
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Alzibiff
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General
Might be worth paying a visit to Nophead's GITHUB repo and taking a look at the configuration.h file in the MARLIN section.
Alan
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Alzibiff
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Mendel90
As Sublime says, you need to amend one of the files in CURA.
To set CURA to produce GCode which is based on relative extruder values I navigated to a file in the CURA directory called settings.py and amended the Relative and Absolute Extrusion values to TRUE and FALSE respectively with a text editor. This followed advice obtained after I raised an 'issue' in Daid's CURA GITHUB repo (issue #385 wh
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Alzibiff
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Mendel90
Take a look at this thread
My answers ...
Q0 Very few folk on a regular basis at least print at a layer height of 0.1mm. Why? Could be that the more regular 0.25mm or so gives acceptable results, that in terms of looks, the layer ridges are of no consequence or more likely that the time taken to generate a print at such a low layer height simply takes too long.
Q1 The thread referred to in my
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Alzibiff
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Mendel90
The common microcontroller in Sanguino boards and their derivatives like the Melzi Ardentissimo is the 1284P which has been the case for the last 12 months or so. Whilst MARLIN will run using the 644P chip, it has to have a number of functions disabled from the code in order that it will have enough RAM to operate. Swapping the chips, (and they are pin for pin compatible), in a bog-standard SANGU
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Alzibiff
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Mendel90
From memory as I am not in front of my machine with Skeinforge on it, the temperature plugin is not enabled in Nophead's Skeinforge profile so that temperatures for extrusion and the bed can be set in the start.gcode file.
Alan
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Alzibiff
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Mendel90
Apart from the hot end temperature and bed temperature (240C and 100C respectively although the hot end varies according to which flavour of ABS I am using), everything else is the same as PLA.
Alan
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Alzibiff
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Mendel90
There was a 20m - maybe longer - length of PLA in the kit, how did printing with that go?
If the supplied PLA did not present any problems it looks as though you may have an answer to your question. I suggest you work with the supplied filament as we know its origin and that it will stick/print.
Alan
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Alzibiff
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Mendel90
@quert75 - The filament on the first layer should be 'squished' on the bed - is yours? It might be worth adjusting things in firmware to bring the nozzle a tiny bit closer to the bed than you have it at the moment. Being more scientific about this - measure the thickness of the outline skirt as this should be equal to, certainly no larger than the layer height which you have set up in the slicing
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Alzibiff
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Mendel90
Amazing coincidence - Tony Lock has just published instructions on what changes need to be made to the Think3DPrint3D MARLIN configuration.h file for the Nophead Mendel90 and RRP firmware:
I think that this makes things a lot easier than I first thought ..... but saying that, I have not tried this out yet!
Ala
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Alzibiff
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Mendel90
The changes needed to MARLIN - on the assumption that you wish to maintain the existing firmware which Nophead has coded to have the bed centre as 0,0 and a Z home command sending the axis to Z-Max - are not trivial. To quote Think3DPrint3D who retail the Panelolou2, they are "... working on a guide for users of non-standard Marlin versions".
No doubt they will announce such a guide when it
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Alzibiff
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Mendel90
Like Traumflug said but....
There is no need to remove the hot end - mark a point on the filament which is say, 110mm from a fixed point on your extruder, command a move of 100mm and then measure the distance between the fixed point on the extruder and the mark which you have just made. If all is fine and dandy, this distance will now be 10mm. If more you need more steps per mm and if less, fewer
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Alzibiff
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General
My £0.02 in the hope that this helps ....
Although I print from SD card most of the time, I use a laptop to switch the fan on/off, adjust speeds (M220 Sxxx) and to monitor progress as and when needed. However, after six trouble free months of running, the "Cannot read/write... " errors started.
The ground connection on the MELZI - tight as it was when first commissioned but decided to rework th
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Alzibiff
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Mendel90
Cylon - Does that mean that you will also be expecting a spool of filament to go with the GCode? Don't forget that the things which go to make the GCode file include parameters taken from the target filament.
Alan
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Alzibiff
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Mendel90
Twisted - Top result in my view - well done.
Having had several goes at this, I am well impressed. One question - where is the brim on your photograph? Variations I have tried: some with no brim, others with 4mm and some with 7mm brim. Some on glass, others on blue tape. I am now playing with retraction settings and lift with a 7mm brim.
Given that "brim" is a Slic3r thing - and a necessary compo
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Alzibiff
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Competitions
I have had more than one or two hotend blockages which I believe are down to the filament at the cool end of the JHead getting too hot and soft which leads to it being pushed out and solidifying in the gap around the top of the hex grub screw. I put this down to one thing - not enough flow (or is it feed?) of the filament through the JHead. That is, the filament moving too slowly and spending too
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Alzibiff
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Mendel90
rhmorrison Wrote:
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> Cool... Never saw that toolbar button before!
>
Me neither - can't wait to get home from work and give it a go! Cheers Nophead.
Alan
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Alzibiff
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3D Design tools
Bob,
Thank you for the reply but the problem I have is that I do not know what values to enter into the rotate boxes. What I need to do is align a face on the STL model, which I can point at, to the XY plane. It is the unknown angle which is the problem.
Alan
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Alzibiff
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3D Design tools
I have downloaded a file from Thingiverse which I would like to print. Unfortunately, the flat face of the "thing" - the face which I want to be my layer 0 is not exactly aligned to the XY plane - it is angled at some unknown value so that the resulting GCode is pretty unworkable.
Is there an easy way of rotating this in something like NETFABB? I am sure there must be but I do not have the knowl
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Alzibiff
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3D Design tools
Definitely a 19V power supply from RRP - they use the sort which I believe are made to power laptop computers and although 19V seems a little high especially when you work out the power it generates via the hot end resistor, 19V does the job and these power supplies are quite neat.
I have heard of this problem before and suggest you take it directly to RRP as I guess that the kit components are s
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Alzibiff
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Huxley