Unusual stepper ratings - vref settings for new Melzi Got my new Melzi board today. I've hooked it up and very briefly tested it. Mostly appears to work except the LED on the board hasn't come on once for some reason. Bit odd but not the end of the world - not thoroughly tested it yet though. Now I want to ensure everything is setup correctly before I try printing anything, but here's the thing. The steppers that came with this machine are rated at 0.4 amps even though I understand a typical Nema17 would be anything from 1-2 amps. So given they have a lower rating, I assume they're a bit weaker than normal ones, but also would need the Melzi's drivers setting to a lower output to avoid overheating them or damaging them? Any idea what the vref should be set to then on account of the 0.4a rating that these steppers have? Appreciate the help Thanks :) Jim https://reprap.org/forum/read.php?13,312562,312562#msg-312562 Wed, 14 Oct 2026 07:13:37 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?13,312562,326915#msg-326915 Re: Unusual stepper ratings - vref settings for new Melzi https://reprap.org/forum/read.php?13,312562,326915#msg-326915 It was stupid because I could feel it was too tight, and I've snapped a lot of bolts over the years so I shouldn't have tried, but anyway.....

New one is en route, so I'm a bit annoyed as I thought it was coming from the UK and would be here in a few days, but it's coming from HK so will take a while I guess. :(
In the meantime I can improve some other bits on it, so that hopefully once the new hot end is installed I should have functional prints quite quickly. Hopefully...]]> Mr Joshua Controllers Tue, 18 Mar 2014 19:54:55 -0400 https://reprap.org/forum/read.php?13,312562,325944#msg-325944 Re: Unusual stepper ratings - vref settings for new Melzi https://reprap.org/forum/read.php?13,312562,325944#msg-325944
Supposedly the nozzle was clogged or the filament was too hard to push and pressure builds inside melting area, that would be the most fragile point hence it fails at that location. I had exact same point of break some time ago, i concluded it was due to two things. One, i was tightening the thread too hard, and it puts pressure unto the upper part, which could of been sort of avoided if the thermal barrier would of started at an angle, a slope instead a 90 degree. To see that imagine that one would force the thread at room temperature, that would still predictably fail at exact same point. Also, the block had no support on itself, so when the filament is pushing hard into the melt zone, it basically tends to push the block away, which would make again a rupture at same spot because well, that is indeed the weakest point of failure.]]> NoobMan Controllers Mon, 17 Mar 2014 03:45:58 -0400 https://reprap.org/forum/read.php?13,312562,325622#msg-325622 Re: Unusual stepper ratings - vref settings for new Melzi https://reprap.org/forum/read.php?13,312562,325622#msg-325622
Here's a pic of the carnage though for now :(


]]> Mr Joshua Controllers Sun, 16 Mar 2014 07:26:55 -0400 https://reprap.org/forum/read.php?13,312562,325561#msg-325561 Re: Unusual stepper ratings - vref settings for new Melzi https://reprap.org/forum/read.php?13,312562,325561#msg-325561
It will run at both ABS and PLA temps, so you simply leave your extruder at the temp you were using, push the Laywoo-D3 through (to remove all your old plastic, then as soon as you get clean wood extrusion, change the temp to what you want to use and repeat the process with the new plastic you want to use.

Note: If you can, when changing you should probably back out most of your filament while slightly colder (eg: PLA reversed/pulled out at say 160 if you use 185, or ABS reversed/pulled out at say 190 if you use 225) to remove most of the existing filament, and hopefully not waste as much. You still run the Laywoo-D3 through at the normal temp.

FWIW: I tend to just remove the idler pressure from my extruder drive (so I can pull/push by hand), turn off the hot end, then watch the temp drop. Once it hits the target withdraw temp for that plastic, I just pull it out by hand. I can them just turn on the extruder again and feed through the Laywoo-D3. Rinse and repeat with the target plastic once you've got the Laywoo-D3 done and you're switched.]]> Cefiar Controllers Sun, 16 Mar 2014 04:09:24 -0400 https://reprap.org/forum/read.php?13,312562,325557#msg-325557 Re: Unusual stepper ratings - vref settings for new Melzi https://reprap.org/forum/read.php?13,312562,325557#msg-325557
I'm very sorry to read about your extruder. This 3D printing business can get very annoying :(

Reading again carefully through all the posts, I believe I might have found some explanation for your misfortune...if that is of any relief...
This is one possible course of events:

1.-What if the wrong reading of the thermistor caused a very high temperature that...
2.- ...caused the PLA to actually overheat, burn and "carbonize", creating a ...
3.- ...jam in the tip of the nozzle?

It seems plausible to me, as it explains the leaking effect...

If that were the case, maybe by cleaning the inside of the nozzle with a little drill (in cold so you can sense the difference in material) you might get somewhere. I ignore where exactly your extruder got broken. I assume it happened in the very joint where the plastic insulator and the metal block meet, which is kind of catastrophic but only to some extent...:)

I would invite you to have a look at this:

http://reprap.org/wiki/DrillandFile_Hot_End

It is a development of a DIY extruder, where they give clear instructions on how to build one with unsophisticated machinery.
The part you might be interested on is the actual insulator...

Of course, it is just a suggestion to bring you "back on the game"! :)

Alternatively, some reprap holidays can also help to "flush the bad energies"...]]> ndujar Controllers Sun, 16 Mar 2014 03:58:39 -0400 https://reprap.org/forum/read.php?13,312562,325517#msg-325517 Re: Unusual stepper ratings - vref settings for new Melzi https://reprap.org/forum/read.php?13,312562,325517#msg-325517
I think I mentioned the leak earlier but possibly I just meant to and didn't actually write it. I haven't read back through it and I'm sligjhtly demoralised right now.

My friend (that I bought the part built printer from) brought his machine round tonight so I could compare settings, try out my PLA in his machine etc etc. The PLA I've got printed fine in his machine so that's not the problem.
Most of my settings are the same as mine too.

I mentioned the leak to him and he said to heat up the extruder then tighten the block with a 14mm spanner so I did that and it was a bit loose. So that was fixed.

Then I had an issue where the extruder was jumping suddenly to 354C reading, and then the steppers would not respond to manual control. I knew of course the reading was nonsense, and it quickly became apparent the insulation on the thermistor was a bit retracted and causing the wires to short. I presume the steppers refusing to work was some sort of safety thing when it thought it was too hot? It hasn't happened before so must be. Anyway I unsoldered it and put new heatshrink on it.

So we printed the same spool holder part on his machine with my filament and it came out perfectly.

i was about to test it with a few tweaked settings (speed set to 100mm/m, 12 extrude, 13 retract, 200 extruder/75 bed, 0.5 nozzle/0.4 layers), then the heater was a bit tight to fit back in the hot end block due to leaked plastic over it and inside the block.

So I cleaned up the heater element, and was about to clean the block when things went bad.
My mate suggested to remove the block (unscrew) it from the rest of the hot end, use the pocket blowtorch to heat the plastic in it and clean it easily. Not such a bad idea until I began undoing the block (unheated, and assured that it wouldn't break as they're really strong etc), then as I'd worried a bit about, the hot end sheared off.

My friend was very apologetic that he'd insisted I undo it without needing to heat it first despite me being a bit reluctant. He wanted to take his extruder off and give it to me but I couldn't accept that so I am out of the game for a week or so now while I find a low cost hot end and wait for it to arrive here.

So after all that, I've still got no idea why it wasn't extruding correctly. But I suppose I will at least have to buy a new hot end and maybe that will help. Who knows.

Bugger. :(]]> Mr Joshua Controllers Sat, 15 Mar 2014 20:55:15 -0400 https://reprap.org/forum/read.php?13,312562,325508#msg-325508 Re: Unusual stepper ratings - vref settings for new Melzi https://reprap.org/forum/read.php?13,312562,325508#msg-325508
Also should find the reason why is hard to push, if the nozzle can be dismantled and left with the block alone, then could try pushing the plastic like that without nozzle but still heated up, and wait for the filament to dilate and see if the filament dilatation is to blame, or else if the nozzle is at fault. If the filament dilatation is to blame, you could check the exact diameter of your hole and say if it is 3.0mm could increase it to 3.2 with a drill, this is an idea. But by now if the inner diameter would of been 3.0 or less and heated up to 230c probably by now the cooled filament would of been already stuck, so probably its not that. Perhaps the nozzle was blocked, which would build pressure and get it leaking if thats the case. If the nozzle was not blocked by something, then perhaps its inner diameter is too small, make sure it is 0.4mm or bigger, and use lower speed settings in slicer program - halve all speeds related to extrusion.

The plastic quality probably does not have any impact, not like that at least. Must be something with extruder hardware issue, or slicing parameters being bit high, but probably both. Dunno what else, as thats all that is involved.]]> NoobMan Controllers Sat, 15 Mar 2014 20:20:06 -0400 https://reprap.org/forum/read.php?13,312562,325395#msg-325395 Re: Unusual stepper ratings - vref settings for new Melzi https://reprap.org/forum/read.php?13,312562,325395#msg-325395


6mm ply then i chamfered the edges to squeeze it in place. As you can see in this pic, it sort of looks like plastic somehow is leaking around the hot end. Not sure where from though.

I also cut slices into the grooved feed bearing although in hindsight Im not sure there was any point since it's not driven!



This is the PLA I bought by the way - the grey stuff:
[cgi.ebay.co.uk]
]]> Mr Joshua Controllers Sat, 15 Mar 2014 14:09:38 -0400 https://reprap.org/forum/read.php?13,312562,325359#msg-325359 Re: Unusual stepper ratings - vref settings for new Melzi https://reprap.org/forum/read.php?13,312562,325359#msg-325359
I've tried what you suggested and the filament is hard to push through. Strangely it seemed good at first, but then got more difficult. I had it up as hot as 230C (and this is PLA not ABS) and it was still needing a lot of pressure by hand to feed through.

I have a suspicion that it's poor quality PLA that could potentially be the issue here since it was very cheap stuff. When I bought it, I didn't realise there was a big variation in quality but have read a lot on this since.


I might ask my mate if he has some I can use so that I can try it with known good quality plastic.

Another thing is that I've swapped from ABS to PLA and I've no idea if there's a particular method you should do in order to do this. Could it be possible for instance that due to the lower print temperature with PLA that there's a bit of ABS still in there that is restricting the flow of the PLA? Basically to change them over I pushed the ABS through as best as I could, then pushed the blank end of a 3mm drill bit in to push it all through, then I inserted the PLA.

On another note, I wonder if there is any design for an extruder that uses double the gripping area of a normal Wades extruder? I have an idea about having one where an opposite main gear meshes with the existing one and of course turns the opposite way, driving a second hobbed bolt against a second bearing, but higher up. I wonder how easy this would be to make, and if it would help reduce slippage and stoppages etc....]]> Mr Joshua Controllers Sat, 15 Mar 2014 13:31:24 -0400 https://reprap.org/forum/read.php?13,312562,325282#msg-325282 Re: Unusual stepper ratings - vref settings for new Melzi https://reprap.org/forum/read.php?13,312562,325282#msg-325282
In all fairness the pictures could also look like that if the slicer settings has some extruder parameter with a wrong setting (e.g. the filament diameter, or flow rate, or things like probably smaller than it should). It could be very well that is the cause and the extruder and hotend work just great. But it doesnt hurt to check extruder and hotend first. Because if it is about a hotend that tends to jam and you upper the extrusion force in this context, things can go band and the extruder can break itself under the pressure, or it may get permanently jammed and you may need to physically dismantle it to clear the jam.]]> NoobMan Controllers Sat, 15 Mar 2014 09:57:39 -0400 https://reprap.org/forum/read.php?13,312562,325170#msg-325170 Re: Unusual stepper ratings - vref settings for new Melzi https://reprap.org/forum/read.php?13,312562,325170#msg-325170 I printed this last night and I'm so pleased to finally get something that worked (I got the blue tape!), but as you can see the infill is really bad.

I wasn't sure why but when it finished I could see it was no longer extruding correctly. I had it at 200 degrees, and at times when I push the filament it came out freely but then seemed to jam. I've got no idea why as the extruder gets a good grip on it. Not sure if I've got dodgy settings that could be causing the hobbed bolt to get clogged up if it's trying to go too quickly. I've got it set at 13mm extrude, at 150mm/min, with 3mm PLA, 0.5mm tip, and 0.4mm layers.




]]> Mr Joshua Controllers Sat, 15 Mar 2014 05:22:11 -0400 https://reprap.org/forum/read.php?13,312562,325017#msg-325017 Re: Unusual stepper ratings - vref settings for new Melzi https://reprap.org/forum/read.php?13,312562,325017#msg-325017
Regarding the hot end, if its teflon with 16mm diameter, you can find a piece of copper pipe with 16mm inner dia usually used for heating radiators, narrow the bottom, and fit the teflon inside that. And then solder with a heat burner some other piece of copper or metal to help attach that to the rest of the extruder. Copper would somewhat help keeping the teflon cool and mechanically rigid, so it wouldnt be bad at all. Anyway its just an idea, and if i understood the situation correctly.]]> NoobMan Controllers Fri, 14 Mar 2014 17:29:25 -0400 https://reprap.org/forum/read.php?13,312562,324985#msg-324985 Re: Unusual stepper ratings - vref settings for new Melzi https://reprap.org/forum/read.php?13,312562,324985#msg-324985 It is definitely much more than a sheet of paper though so once I reassemble it, I will adjust that accordingly thanks. :)

I picked up a roll of Scotch blue painter tape on the way home tonight. It's 3M, and I think has 2090 written on which I'd seen someone else say they have good results with.


Quote
NoobMan
From my experience PLA on glass should be a quite reliable, even more if the bed is heated mildly like 50-60C - if glass on heated bed reaches like full abs temperatures the glass may crack and break.

Perhaps there is something else wrong, with the acetone or temperatures. Imo, try hijacking your girlfriend/wife supplies for some nail polish remover which at content says only acetone and water, and try with that one instead, just to be sure. Or perhaps your extruder pla temperature is too low and plastic gets cooler before reaches the bed, hence wont stick, so try measure heater temperature with a tmermocouple multimeter to check if thats the case.

The glass is fine up to really high temperatures as it's boroscillicate stuff and I've had it up to over 110C so far.
I'll see if I have another empty acetone tub around still to see if there's a label but yeah, the wife will have some. I'd read that NVR acetone generally wasn't good stuff to use though due to other ingredients they mix in. Won't hurt to try I suppose.

PLA temp I've tried between 185 and 200 (possibly higher, I forget). It extrudes easily.

Anyway, I'm just rebuilding this new extruder assembly. I've got the stepper to fit correctly now, but just found there's no means of attaching the damn hot end to the housing!! The old PLA one had two bolts the went through the side of the plastic on the hot end to secure it, but the new housing has no holes and, as they hung lower than the rest of it, I can't just drill a couple since they need to be positioned where there's actually no plastic on the new ABS piece. If that makes any sense!
So the slot around the upmost part of the hot end, sits pround of the new housing. I think I will have to make a piece of ally that sits across the whole foot of it and goes through the groove in question to secure the hot end in place.
Not feeling too motivated though as my garage is freezing and I've just been drained by the kids throwing a tantrum when I was settling them to bed!

Maybe time to just have a beer and ponder it until later this evening. :)]]> Mr Joshua Controllers Fri, 14 Mar 2014 16:30:03 -0400 https://reprap.org/forum/read.php?13,312562,324808#msg-324808 Re: Unusual stepper ratings - vref settings for new Melzi https://reprap.org/forum/read.php?13,312562,324808#msg-324808 Actually, the "correct" distance for the nozzle is such, that when it is not printing you can pass a piece of paper and feel the friction, but without blocking.

This is an excellent tutorial:

http://reprap.org/wiki/Leveling_the_Print_Bed

Regarding the blue painter's tape, it is something like this:


https://www.google.com/search?q=blue+painter+tape&client=ubuntu&hs=kkU&channel=fs&tbm=isch&tbo=u&source=univ&sa=X&ei=uxEjU6SvAuTa4ASUs4HAAQ&ved=0CDUQsAQ&biw=1024&bih=510

It has some paper-ish texture, but overall has a rough surface here PLA can attach. It doesn't work with ABS at all, by the way..:-/
However, I am inclined to believe that the problem is that of the separation...]]> ndujar Controllers Fri, 14 Mar 2014 10:40:45 -0400 https://reprap.org/forum/read.php?13,312562,324749#msg-324749 Re: Unusual stepper ratings - vref settings for new Melzi https://reprap.org/forum/read.php?13,312562,324749#msg-324749
Perhaps there is something else wrong, with the acetone or temperatures. Imo, try hijacking your girlfriend/wife supplies for some nail polish remover which at content says only acetone and water, and try with that one instead, just to be sure. Or perhaps your extruder pla temperature is too low and plastic gets cooler before reaches the bed, hence wont stick, so try measure heater temperature with a tmermocouple multimeter to check if thats the case.]]> NoobMan Controllers Fri, 14 Mar 2014 08:45:48 -0400 https://reprap.org/forum/read.php?13,312562,324734#msg-324734 Re: Unusual stepper ratings - vref settings for new Melzi https://reprap.org/forum/read.php?13,312562,324734#msg-324734
Sorry, when I mentioned acetone I meant just using that to wipe the bed clean, not using ABS juice. I should have been more clear.
Not sure re the label, it was a gallon I bought when rebuilding my boat but there's no label on it now.

I've tried direct on heated glass but that won't stick either. Going to get some hairspray at lunchtine!

I nearly got the new extruder assembly working last night but the mounting of the stepper motor does not seem to allow the pinion to mesh with the main gear, so I need to get the dremel on it to modify the fit. It's a bit of a mess though. I'm not certain if it will work correctly but I'll try again tonight.

I'll try to buy some blue tape. Does it go by another name at all that specifies more what it is?]]> Mr Joshua Controllers Fri, 14 Mar 2014 08:04:32 -0400 https://reprap.org/forum/read.php?13,312562,324682#msg-324682 Re: Unusual stepper ratings - vref settings for new Melzi https://reprap.org/forum/read.php?13,312562,324682#msg-324682
And perhaps double check the acetone label, if its that type of acetone for removing paint from finger nails, it may have other components like aloe vera stuff or paraffin which is a wax and wont help with adhesion. Sort of speaking label should say that content is only acetone and water, and nothing else.]]> NoobMan Controllers Fri, 14 Mar 2014 06:34:18 -0400 https://reprap.org/forum/read.php?13,312562,324640#msg-324640 Re: Unusual stepper ratings - vref settings for new Melzi https://reprap.org/forum/read.php?13,312562,324640#msg-324640
Regarding PLA, acetone (with dissolved ABS) does not work with it. ABS juice is only for ABS.

A good solution mentioned here (http://reprap.org/wiki/Print_Troubleshooting_Pictorial_Guide#Bed_Adherence_insufficient) is blue painter's tape. It works...

Happy printing!]]> ndujar Controllers Fri, 14 Mar 2014 05:02:05 -0400 https://reprap.org/forum/read.php?13,312562,324497#msg-324497 Re: Unusual stepper ratings - vref settings for new Melzi https://reprap.org/forum/read.php?13,312562,324497#msg-324497
I managed to damage the extruder assembly by getting it too hot, and it had been printed in PLA instead of ABS so it wasn't too pleased and mutated itself as a result.
Oops.
I managed to get it working again and swapped to PLA, plus fitted the proper tensioners to the belts etc.
The PLA prints to begin with were WAY more neat than the ABS ones, except for one problem I just cannot resolve so far.
I can't get the damn things to stick to the bed at all. :(

I might get 3/4 of the way through the 20mm box test with it looking great, then it suddenly comes free from the bed. It's not curling at all - it just suddenly comes loose.
I'm printing to kapton covered glass, and have wiped it with acetone. I've tried tons of variation in both extruder and bed temperatures, but all to no avail. I just can't get the sodding stuff to stick at all.
I've even removed the kapton from one half of the bed as I'd read it can work better that way with PLA but it's no different. The gap between the bed & extruder is maybe 1mm or so. It's pretty close.

Any good ideas?

I can't do much right now anyway as i need to build up the new extruder assembly my mate has made for me in ABS. It's very different to my current one, so I need to find suitably long M3 bolts etc to fit the filament clamp.]]> Mr Joshua Controllers Thu, 13 Mar 2014 19:48:21 -0400 https://reprap.org/forum/read.php?13,312562,320961#msg-320961 Re: Unusual stepper ratings - vref settings for new Melzi https://reprap.org/forum/read.php?13,312562,320961#msg-320961
Layer height is controlled in the Slicer.

If you have Repetier it is the second menu, under the button of "configure". Then Slicer pops up and you can see it in the first menu where it says "Print settings".

If you have Pronterface or any other you will have to find the Slicer, open it and change the configuration...

Happy printing!]]> ndujar Controllers Thu, 06 Mar 2014 19:20:42 -0500 https://reprap.org/forum/read.php?13,312562,320960#msg-320960 Re: Unusual stepper ratings - vref settings for new Melzi https://reprap.org/forum/read.php?13,312562,320960#msg-320960
Shame about the fosfet :( Hopefully it won't happen again.

Do you happen to know where the layer height is stored at all?
*ignore actually - I found it in slic3r* thanks]]> Mr Joshua Controllers Thu, 06 Mar 2014 19:10:42 -0500 https://reprap.org/forum/read.php?13,312562,320958#msg-320958 Re: Unusual stepper ratings - vref settings for new Melzi https://reprap.org/forum/read.php?13,312562,320958#msg-320958 Fortunately, now I finally have my Melzi running, so as soon as I have the time I will get back to it..:)

Regarding your temperature control, I am not quite sure the rational is correct. The curve of the thermistors in not linear but more like this:
[attachment 28121 Untitled1_html_25f2da62.jpg]

So it could be that at 110C you are having a completely different reading...

Again, it is just a matter of finding the upper bound at which both extruder and hotbed work fine so I think your approach of leaving it as it is is also correct...:)

EDIT:

There is quite a lot of science behind all this temperature control that IMHO is getting very complicated: [reprap.org]]]> ndujar Controllers Thu, 06 Mar 2014 19:07:58 -0500 https://reprap.org/forum/read.php?13,312562,320953#msg-320953 Re: Unusual stepper ratings - vref settings for new Melzi https://reprap.org/forum/read.php?13,312562,320953#msg-320953
The thermistor for my bed gives the wrong temp readout for some reason, so when the ambient temp is 11 degrees say, the extruder temp will say 11C, but the bed will say 26C.
So because the default bed temp was 110, I changed it to 125C so it would really be giving 110 if you follow my rationale?
I think it's too hot though and is warping the prints from seeing a pic on the link you provided.]]> Mr Joshua Controllers Thu, 06 Mar 2014 18:48:58 -0500 https://reprap.org/forum/read.php?13,312562,320952#msg-320952 Re: Unusual stepper ratings - vref settings for new Melzi https://reprap.org/forum/read.php?13,312562,320952#msg-320952
I mostly have trouble with the hotbed. In the beginning my board was a RAMPS1.4 that got the hotbed controller MOSFET fried and now I am trying with this Melzi.
The theory (and the hard experience) is that if the bed is not warm enough, then the adherence is crap. I have tried many things (ABS juice made out of ABS and acetone, sugar in water,...) but still because of not getting good temperature in the bed the pieces shrink in the corners and after a while they begin to loosen, so eventually the extruder just pushes the piece off...normally close to the end of the printing!! :?

So, that being said, congratulations again...:)...I think tomorrow I will try a bit more...]]> ndujar Controllers Thu, 06 Mar 2014 18:44:59 -0500 https://reprap.org/forum/read.php?13,312562,320946#msg-320946 Re: Unusual stepper ratings - vref settings for new Melzi https://reprap.org/forum/read.php?13,312562,320946#msg-320946
It's ABS that I've used. I was going to buy some PLA but my friend gave me a reel of ABS that he had spare so I thought I'd use that even though it's meant to be more difficult to get good results with ABS.

Thanks for the link - I'll have a look, and I need to look for the layer height setting and adjust that too potentially.
It could be the extruder steps actually. I measured all the Axes movement was correct before, but didn't test the calibration of the extruder I must confess!

What trouble are you having yourself? I hope you get it sorted out ok.(tu)]]> Mr Joshua Controllers Thu, 06 Mar 2014 18:30:40 -0500 https://reprap.org/forum/read.php?13,312562,320938#msg-320938 Re: Unusual stepper ratings - vref settings for new Melzi https://reprap.org/forum/read.php?13,312562,320938#msg-320938 Congratulations...is actually very good...:D...is it PLA or ABS? I am having a terrible time with ABS...X(

Maybe you want to have a look at this: http://reprap.org/wiki/Print_Troubleshooting_Pictorial_Guide
Your "wobbliness" problem is, unfortunately, not listed 8-) but it might be caused by excessive pressure in the exit of the nozzle. I would try to calibrate the extruder motor to make sure it is not pressing too much...

Happy printing! :D]]> ndujar Controllers Thu, 06 Mar 2014 18:07:06 -0500 https://reprap.org/forum/read.php?13,312562,320932#msg-320932 Re: Unusual stepper ratings - vref settings for new Melzi https://reprap.org/forum/read.php?13,312562,320932#msg-320932
Here are some photos of my printer's first successful (but rather inconsistent quality) printed object. It's meant to be a 20mm block.

Here it is on the bed with the squiggly surround bit:


Position of the print job on the bed (no idea if this is right?)


And close ups of the printed item. The underneath/first layer (it missed the first corner of fill in for some reason):




And from the top. You can see it has sunken a bit in the middle, and along each edge, leaving the corners raised:



I'd be really interested in feedback on the visual appearance in terms of obvious things I might have less than optimal settings on, leading to the print being a bit 'wonky'!

So so happy to have actually produced a print though at last. :)
]]> Mr Joshua Controllers Thu, 06 Mar 2014 17:54:13 -0500 https://reprap.org/forum/read.php?13,312562,320907#msg-320907 Re: Unusual stepper ratings - vref settings for new Melzi https://reprap.org/forum/read.php?13,312562,320907#msg-320907
The perimeter line around is called skirt. You can configure it in Slicer and yes, I also think it serves the purposes of pre-testing adherence and other stuff.

Regarding the wiggliness, it might be (but i'm not sure) that the layer is too high. It should be a number slightly smaller than the nozzle size (mine is 0.3 and my layers are 0.25).

Happy printing!]]> ndujar Controllers Thu, 06 Mar 2014 17:15:37 -0500 https://reprap.org/forum/read.php?13,312562,320904#msg-320904 Re: Unusual stepper ratings - vref settings for new Melzi https://reprap.org/forum/read.php?13,312562,320904#msg-320904
So I changed that and so far so good - it is currently printing a 20mm box in ABS. I can see it's not quite right as it prints but it's doing it anyway so I will let it finish then inspect/analyse.

One thing I have noted is that it first prints like a perimeter layer or two that is not the main print, before it starts the model it is printing. I'm guessing this is:
1) To ensure the filament is fed through and ready to begin, and
2) Gives you a chance to see if it's sticking to the bed or behaving right before it starts the model.

Is that the case?

When it begins both the perimiter print and the model itself I notice the plastic extruded is done in a very wiggly line. Does this indicate a fault?]]> Mr Joshua Controllers Thu, 06 Mar 2014 17:08:33 -0500 https://reprap.org/forum/read.php?13,312562,320852#msg-320852 Re: Unusual stepper ratings - vref settings for new Melzi https://reprap.org/forum/read.php?13,312562,320852#msg-320852
Yes it's been frustrating getting to this point with all the problems but only from the perspective that it was meant to be something that would have worked more or less straight away.
I do enjoy the learning, and getting a better idea of what's what by virtue of it not working until now. I would be very lazy about taking the time to learn though had this thing worked from day 1, so all this is to my advantage really.

Re' my two remaining issues I'm not at this point hugely concerned over the bed temperature reading.
As I say it's reading 15C above real temperature, but I'm wondering if I can cater (temporarily at least) for this by setting the working temp 15C higher than it currently is?


More importantly, the one issue I really have to address before I can do prints properly is the rate that the Z axis moves.

I realised that with all the corrections and faults I've had to look at and resolve I've actually overlooked the part of the commissioning/calibration process whereby I should measure how far each control moves, relative to the manual commands issued for a given distance.

I think most movements are close to being correct, but know for sure that when I tell the Z axis to move 10mm, it actually moves closer to 2mm!! So I assume from this that the step size setup for Z at the very least is incorrect. I've never looked at those settings so I will investigate tonight and look on the wiki for how I calculate all that stuff.

I will also look for the setting you described (DEFAULT_AXIS_STEPS_PER_UNIT) to see how mine is currently set!

Hopefully once that's done I'll be able to actually print something properly, but I'm still really pleased that I got it do 'something' anyway.

I get the point of the suggestion re' changing the firmware, but I think with getting this one so close I'm going to persist with it for now as it's so close to working correctly now. I don't want to potentially go back to square one again with different firmware if I can avoid it easily.

Cheers]]> Mr Joshua Controllers Thu, 06 Mar 2014 15:34:31 -0500